West Metro Fire Rescue - Ning

West Metro Fire Rescue Nozzle Study 2005

Introduction

Fire streams and nozzle selection have become an increasingly popular topic of discussion and research in the American fire service. It is this renewed interest in one of the most basic and traditional elements of fire suppression that has prompted a review of West Metro’s equipment and procedures. There are two main reasons leading to the review of fire streams and nozzles. The first is recent studies and research by individuals and the second is from incident case studies and investigations.

The fire service has been greatly influenced by a small group of instructors and educators who have dedicated careers to helping firefighters across the country become better at what they do. One such individual is the late Andrew Fredericks of the Fire Department of New York. Andy is best known for his work in engine company operations for Fire Engineering and his involvement with F.D.I.C. Next, Captain David Fornell of Danbury Connecticut Fire Department has become known as an engine company “guru” with his publication of “The Fire Stream Management Handbook”. His book is regarded as the foremost text on the subject of nozzles and fireground hydraulics. Lastly, Paul Grimwood of the London Fire Brigade and his extensive research and testing of nozzle reaction and its effects has been a catalyst for change in equipment for fire attack on an international level.

Department initiated studies and equipment reviews have also prompted changes. Following nozzle and hose studies Bo ise Idaho, St. Petersburg Florida and Oakland California recently changed their preconnect equipment and operations to increase fireground flows for modern fuels and decrease the nozzle reaction encountered by firefighters. The studies and changes that resulted in Boise and St. Petersburg were acts of forward thinking and efforts to be progressive in firefighter safety and equipment. Oakland Fire Department unfortunately made their changes based on the recommendations of a board of inquiry that investigated a firefighter fatality in which inadequate fire flows were cited as a key contributing factor in the death of one of their own. In September 2004 a nozzle study was initiated at West Metro to see how our 1 ¾”equipment and operations compared to these cur rent national trends.

We quickly came to realize that our current nozzle of choice (Elkhart SM-20FG Automatic Fog) was capable of meeting the current 1 ¾” flow rate trend of 150 GPM but did so with a high nozzle reaction force. We also found that most of our pump operators had developed the habit of “under pumping” the initial deployment of our handlines and gradually increased pressure for greater flow as the interior crews indicated. Their reasoning was to provide a more manageable line however in doing so they are only supplying our firefighters on average 128 GPM. By planning to increase pressures with demand we are playing catch up with our fire and compromising firefighter safety by putting them behind the ball and conversely increasing their work load in terms of nozzle reaction with the increase of pump discharge pressure. With these initial findings we decided to outline specific objectives for our study to move forward. The first was to meet the NFPA 1710 by setting a fireground standard flow of 150 GPM from our 1 ¾” handlines. The second was to improve the effectiveness of fire stream application and hoseline management by decreasing nozzle reaction. And the third was to simplify fireground hydraulics to ensure we were getting the consistent fire flows with every handline deployment.

Why 150 GPM? Nationally, 150 GPM has become the target flow for 1 ¾” handlines. This number comes from NFPA 1710 (Organization and Deployment of Fire Suppression Operations by Career Fire Departments). The standard outlines that the first two handlines in operation at any initial alarm structure fire flow a minimum of 300 GPM combined. Consultation with members of the Oakland and Boise fire departments as well as review of other publications and articles 150 GPM per 1 ¾” handline was the most common way to meet the 300 GPM minimum. The WMFR operations division also felt that 150 GPM minimum from all 1 ¾” handlines would be the most appropriate operation. As we mentioned before our current nozzle choice was capable of supporting this flow rate. Due to the associated nozzle reaction we also wanted to evaluate other nozzles that could meet 150 GPM or greater at lower operating pressures in order to decrease our associated nozzle reaction forces. Smooth bore nozzles provide a high GPM flow with a nozzle pressure of 50 PSI. We chose to test two smooth bore tips, the 7/8” tip with a flow of 161 GPM at 50 PSI and the 15/16” tip with a flow of 185 GPM at 50 PSI. Another low-pressure option was 50 and 75 PSI low pressure fixed gallonage fog nozzles that provide us with low-pressure qualities and an adjustable stream. We chose to add the 150 GPM at 50 PSI Elkhart Chief low pressure fixed gallonage fog tip to the study in order to meet the 150 GPM minimum and simplify hydraulics by having a target nozzle pressure that was the same as the smooth bore tips.

Why is nozzle reaction now an issue? To start lets review exactly what nozzle reaction is. Nozzle reaction forces are based on Newton’s first law of motion, that for every action the re is an equal and opposite reaction. In fire streams this equal and opposite reaction is dictated by the volume of water leaving the nozzle and the pressure at which that water leaves the nozzle. In order to change the reaction force we must either change our Gallons Per Minute out put, the nozzle pressure or both. The reason this has recently become such a popular consideration in nozzle selection is because the work by Capt. Dave Fornell of Danbury, Connecticut Fire Department and FF Paul Grimmwood of the London Fire Brigade. The two through extensive research have outlined working limits for firefighters in respect to safely managing nozzle reaction. This is a simple theory; firefighters are not safely fighting fire when their efforts are focused on fighting nozzle reaction. Some of the most common “side effects” of high nozzle reaction are improper stream selection (the change from a straight stream to a fog pattern), gating down the bale to lessen nozzle reaction forces, and excess water damage due to difficulties in stream direction. Paul Grimwood’s study outlines the number of firefighters required to safely counter nozzle reaction. 1 ff 60pounds/force, 2 ff 75pounds/force and 3 ff 95 pounds/force. Keep in mind these working limits are strictly for safely managing nozzle reaction. This is not how many firefighters should be on the handline for hose advancement or management this is how many firefighters should be directly behind the nozzle to support the reaction. During our initial flow testing we found the Elkhart SM-20 automatic nozzle (our current choice) had 75 lbs/force of nozzle reaction at 150 GPM the upper limit of 2 ff this is our typical staffing for handlines. This presented us with a safety issue because as we mentioned before it does not free up one of those firefighters to properly advance and manage the hoseline because that firefighter would be committed to supporting the nozzle firefighter while flowing water. The flow testing found that at the same 150 GPM flow rate the low pressure fixed gallonage fog had a nozzle reaction force of 54 lbs/force. This is 21 lbs/force less than the SM-20 at the

same flow. The smooth bores provided even higher flow rates with reaction forces that were also well below that of the SM-20. The 7/8” tip with a flow of 161 GPM and a nozzle reaction 57 lbs/force and the 15/16” tip with 185 GPM and 66 lbs/force.

How are we simplifying hydraulics? It is a rule of thumb to provide a fog nozzle 100 PSI nozzle pressure. With automatic nozzles because of the compensatory spring and working parts your target nozzle pressure varies with what your target GPM flow is. By providing 100 PSI nozzle pressure you may be supplying anywhere from 100 to 200 GPM. The GPM output of automatic nozzles is actually determined by pump discharge pressure not nozzle pressure. The fact that it is so versatile in its flow range is an attractive option for departments seeking nozzle with a wide operating range. This same characteristic is also viewed as a hazard due to the fact that the stream does not change with the flow rate. This can lead to poor GPM output without recognition by firefighters at the nozzle. Also as was mentioned before the knowledge of the wide operating ranges can lead to misconceptions of hydraulics and “under pumping”. By changing to a nozzle with a single target nozzle pressure for a single target GPM output we can make our pump discharge pressure a single setting dictated by our hose length. This would eliminate the need for slide rules to assist with varying flow calculations. By choosing a fog nozzle with a 50 PSI operating pressure the target nozzle pressure now becomes standard for both smooth bores and fogs 2 ½” and 1 ¾” simplifying training and department pump charts. Additionally, we all know exactly what our flow rate is from the firefighter to the incident commander, making operational decisions as to adding lines or changing to bigger lines easy to calculate.

Our department, like many, has readily accepted the use of low pressure fixed gallonage nozzles for standpipe operations. Unfortunately low pressure fogs and smooth bore nozzles operationally have remained a component of high rise packs and not revisited for our more common preconnect operations. The main reason is that pressure is not viewed as an issue for us in our day-to-day fireground operations due to the quality of our apparatus and hydrant system. Additionally, the wide operating range of our current nozzle of choice (Elkhart SM-20FG Automatic Fog) is considered to be a valuable quality and one West Metro wanted for operations.

The operational phase of this study is to evaluate the performance of these low-pressure fixed gallonage nozzles as potential compliments to our current nozzle selection. The profession of fire suppression is ever changing and the thought of a single piece of equipment for situations is impractical. The goal of this is study to provide crews with a variety of choices in equipment and, the information to make educated decisions to ensure successful initial attack operations.

West Metro Fire Rescue Nozzle Study

2005

What : This is a study of two types of nozzles. Our current automatic fog nozzle and low pressure fixed gallonage nozzles. This study will take place over a period of six months at four stations evaluating the effectiveness and operations of each nozzle. Why : Recent tragic events, case studies and research by our peers in the American fire service has made fire streams and nozzle selection a front line issue. Lower operating pressures and consistent GPM delivery lead to more effective operations and safer firefighting. In addition, the selection of a single nozzle pressure for all handlines simplifies fire ground hydraulics and affords crews more options in their nozzle selection. Who : Flow testing of has been conducted by Company 1 B-Shift and the study will now begin it’s operational phase. This phase will involve the training division and four test stations. When : The operational phase will begin on or around May 1st and will conclude around December 1st 2005.

Frequently Asked Questions Wasn’t a nozzle study just done? Yes, in 1998 Lt. Kevin Schmidt led a nozzle study regarding the use of automatic nozzles on our high-rise packs. It was determined that the use of automatic nozzles in high-rise incidents was not only ineffective but dangerous and we changed to our current set up. (Elkhart Chief 185 GPM @ 75 PSI fog and 15/16” 185 GPM @ 50 PSI Smooth Bore). At that time we did not test these nozzles or review the automatic nozzle on our preconnects. What is wrong with our current nozzles? The Elkhart SM-20 is an excellent automatic nozzle. The theory of an automatic nozzle is attractive in that once the 100 PSI nozzle pressure is achieved every 1 PSI increase will produce an additional 1 GPM of output. Unfortunately for every 2 PSI increase there is 1 Lb. of additional reaction force put on the firefighter. In order to meet the NFPA recommended 150 GPM fire flow on our 1 ¾” handlines we face a reaction force of 75 lbs. versus a reaction force of around 55 lbs. with low pressure, fixed gallonage nozzles.

Is this a smooth bore study? Smooth bore nozzles will be included in this study because of their lower operating pressure and high GPM flows. The study however is not a smooth bore study, rather, it will be focused on the use of low pressure fixed gallonage nozzles both fog and smooth bore to meet NFPA recommended fire flows and decrease the nozzle reaction forces experienced by firefighters. Why 150 GPM? Nationally, 150 GPM has become the target flow for 1 ¾” handlines. This number comes from NFPA 1710 (Organization and Deployment of Fire Suppression Operations by Career Fire Departments). The standard outlines that the first two handlines in operation at any residential structure fire flow a minimum of 300 GPM combined. Why 50 PSI? The benefit of a 50 PSI nozzle pressure is two fold. First, it decreases nozzle reaction and provides a more manageable hose line and fire stream. Second, by lowering operating nozzle pressures to 50 PSI we simplify our fire-ground hydraulics. All nozzles, fog, and smooth bore, both 1 ¾” and 2 ½” will be 50 PSI. Why is nozzle reaction now an issue? There have been several studies done over the last decade into nozzle reaction and how it effects hose line operations. The goal of these studies has been to identify how much nozzle reaction firefighters can comfortably handle while still being able to effectively advance and manage a hose-line. The studies have outlined three working limits; 1 firefighter (60 force/lbs), 2 firefighters (75 force/lbs), and 3 firefighters (95 force/lbs). Which nozzle is better? Smooth bore or fog? This question will most likely be forever debated. Over our careers our experiences will shape our preferences and no one nozzle will be the end all solution to all situations. The benefit to lowering our operating pressures is that both our fog and our smooth bore nozzles will be working at the same nozzle pressure. This allows crews to have a choice between the two high gallonage nozzles without complicating fire-ground hydraulics. What about the Saber Jet combination nozzle? The Akron Saber Jet nozzle is designed to function as both a fog nozzle and solid bore nozzle in one. Although a good concept, the change from one nozzle setting to another requires close communication between the pump operator and the nozzle firefighter as operating pressure is either cut in half or doubled. These nozzles are still in a continuous state of development and at this time have not become widely accepted. Would future recruit classes be trained in the use of the different nozzles? Absolutely, our CMCB job sheets outline the education of both smooth bore and fog nozzle operations with all handline operations for apprentice firefighters. Would the methods we currently use to put out fires change with new nozzles? No, currently our two accepted guidelines for interior fire attack (IFSTA and CMCB) state that a straight or solid stream be used.

Calculations Used

Friction Loss

FL=CQ2L FL (Friction Loss)

C = Coefficient (1 ¾”= 15.5)( 2 ½” = 2) Q2 = GPM / 100 2

L= Hose Length / 100

Fog Nozzle Reaction

NR = .0505 Q NP NR (Nozzle Reaction) Q= Gallons Per Minute NP = Nozzle Pressure

Solid Bore Nozzle Reaction

NR = 1.57 D 2 NP NR (Nozzle Reaction)

D = Diameter of tip NP = Nozzle Pressure

Discharge Formula for Solid Bore Tips

GPM = 29.71 D 2 NP

GPM =Gallons Per Minute D = Diameter of tip

NP = Nozzle Pressure

NOZZLE STUDY PUMP CHART

PUMP DISCHARGE PRESSURES

Chief (150

GPM)

SM 20 (150

GPM)

7/8” (161

GPM)

SM 20 (185

GPM)

15/16” (185GPM)

200’ 100 PSI

150 PSI

110 PSI

185 PSI

140 PSI

250’ 113 PSI 163 PSI

125 PSI

208 PSI

163 PSI

FRICTION LOSS PER 100 FEET

Chief (150

GPM) SM 20 (150 GPM)

7/8” (161 GPM)

SM 20 (185 GPM)

15/16” (185 GPM)

Friction Loss Per

100 Feet

25 25 30 45 45

These figures are results of actual flow testing and measurements from West Metro 1 ¾” hose and in conjunction with nozzle manufacturer’s recommendations.

April 3, 2005

Flow Testing and Nozzle Evaluation

Akron 7/8” tip model 1410 Elkhart 15/16” wip with rubber bumper model 185- A Elkhart 15/16” Slug Tip model 186- A Elkhart ST-185A 15/16” Plain Tip with B-275-A Elkhart shutoff Elkhart Chief Model 4000- 24 constant gallonage fog nozzle on an Elkhart B-275-GA shutoff Elkhart SM-20FG automatic fog nozzle E1-#1 Elkhart SM-20FG automatic fog nozzle E1-#2 Elkhart SM-20FG automatic fog nozzle E1-#3 Elkhart SM-20FG automatic fog nozzle E1-#4

Date: 11-17-04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with a 1½” inline pressure gauge at the nozzle and a pump panel flow minder.

Tip/Nozzle: Akron 7/8” tip model 1410. Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 102 PSI Nozzle Pressure (NP): 50 PSI Expected Nozzle Reaction(Force/Pounds): 57 Lbs. Actual Nozzle Reaction(Force/Pounds): 57 Lbs. Expected GPM : 161 GPM Actual GPM : 132 + 30 for calibration = 162 GPM Expected Friction Loss: 80 PSI Actual Friction Loss: 52 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: This nozzle performed consistently with expectations with 162 GPM at 50 PSI nozzle pressure. Pictures:

The 7/8” tip and ball valve shut off.

Above: Flow testing the nozzle.

Right: Flow minder reading of 132 GPM (plus 30 for calibration consistency) and Pump Discharge Pressure of 102 PSI.

Below: The nozzle with the inline pressure gauge reading 50 PSI.

Date: 11-17-04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with a 1½” inline pressure gauge at the nozzle and a pump panel flow minder with a typical West Metro Fire Rescue preconnect length of 200’.

Tip/Nozzle: Elkhart 15/16” wip with rubber bumper model 185-A Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 130 PSI Nozzle Pressure (NP): 50 PSI Expected Nozzle Reaction(Force/Pounds): 66 Lbs. Actual Nozzle Reaction(Force/Pounds): 66 Lbs. Expected GPM : 185 GPM Actual GPM : 153 + 30 for calibration = 183 GPM Expected Friction Loss: 106 PSI Actual Friction Loss: 80 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: This nozzle performed consistently with the expectation of 185 GPM at 50 PSI nozzle pressure. Pictures: The 15/16” solid bore with rubber bumper tip and ball valve shut off.

Above : Flow testing the nozzle. Right : Flow minder reading of 153 GPM (plus 30 GPM for calibration consistency) and Pump Discharge Pressure of 130 PSI. Below: The nozzle with inline pressure gauge reading 50 PSI.

Date: 11-17-04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with a 1½” inline pressure gauge at the nozzle and a pump panel flow minder.

Tip/Nozzle: Elkhart 15/16” Slug Tip model 186-A Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 128 PSI Nozzle Pressure (NP): 50 PSI Expected Nozzle Reaction(Force/Pounds): 66 Lbs. Actual Nozzle Reaction(Force/Pounds): 66 Lbs. Expected GPM : 185 GPM Actual GPM : 152 + 30 for calibration = 182 GPM Expected Friction Loss: 106 PSI Actual Friction Loss: 78 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: This nozzle performed consistently with expectations at 182 GPM at 50 PSI nozzle pressure. Pictures: The 15/16” slug tip and ball valve shut off with inline pressure guage.

Above: Flow testing the nozzle. Right: Flow minder reading of 152 GPM (plus 30 for calibration consistency) and Pump Discharge Pressure of 128 PSI. Below: The nozzle with the inline pressure gauge reading 50 PSI.

Date: 11-17-04 Location: 16th& Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with a 1½” inline pressure gauge at the nozzle and a pump panel flow minder.

Tip/Nozzle: Elkhart ST-185A 15/16” Plain Tip with B-275-A Elkhart shutoff. Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 125 PSI Nozzle Pressure (NP): 50 PSI Expected Nozzle Reaction(Force/Pounds): 66 Lbs. Actual Nozzle Reaction(Force/Pounds): 66 Lbs. Expected GPM : 185 GPM Actual GPM : 153 + 30 for calibration = 183 GPM Expected Friction Loss: 106 PSI Actual Friction Loss: 75 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: This nozzle performed consistently with the expectation of 185 GPM at 50 PSI nozzle pressure. Pictures:

The 15/16” tip and ball valve shut off.

Date: 11/17/04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with a 1½” inline pressure gauge at the nozzle and pump panel flow minder.

Tip/Nozzle: Elkhart Chief Model 4000- 24 constant gallonage fog nozzle on an Elkhart B-275-GA shutoff Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP):160 PSI Nozzle Pressure: 75 PSI Expected Nozzle Reaction(Force/Pounds): 80 Lbs. Actual Nozzle Reaction(Force/Pounds): 86 Lbs. Expected GPM : 185 GPM Actual GPM : 166 + 30 for calibration = 196 Expected Friction Loss: 106 PSI Actual Friction Loss: 85 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: The nozzle performed very close to its designed operation. We actually were flowing 11 GPM over the expectation for the 75 PSI nozzle pressure. Once again we saw a friction loss that was significantly lower then what was expected.

Pictures: The Elkhart Chief constant gallonage, low pressure fog nozzle with the 185 GPM at 75 PSI stem and ball valve shutoff.

Date: 11/17/04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with a 1½” inline pressure gauge at the nozzle and a pump panel flow minder. The goal is to test the Elkhart pump chart for the SM-20FG nozzle to achieve 150 GPM through a 200’ typical West Metro preconnect length. The recommended PDP is 147 PSI for 150 GPM through 200’ of 1 ¾” hose per Elkhart.

Tip/Nozzle: Elkhart SM-20FG automatic fog nozzle E1-#1 Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 147 PSI Nozzle Pressure: 98 PSI Expected Nozzle Reaction(Pounds/Force): 75Lbs. Actual Nozzle Reaction(Pounds/Force): 73Lbs. Expected GPM : 150 GPM Actual GPM : 117 GPM + 30 for calibration = 147 Expected Friction Loss: 47 PSI Actual Friction Loss: 49 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: The SM-20FG tested is #1 of 4 on Engine One. The nozzle was supplied with the appropriate 147 PSI PDP to achieve the 150 GPM flow at 200’ per Elkhart. The Elkhart pump chart is accurate with a flow of 147 GPM. However, what is confusing is that the nozzle states a flow of 212 GPM should be delivered when the nozzle pressure is 100 PSI. Our results showed a nozzle pressure of 98 PSI and a flow of 147 GPM. Pictures:

The SM-20 FG Automatic Nozzle E1-#1

Above: Flow testing the nozzle. Right: Flow minder reading of 117 GPM (plus 30 GPM for calibration and consistency = 147 GPM) and Pump Discharge Pressure of 147 PSI. Below: The nozzle with the inline pressure gauge reading 100 PSI.

Date: 11/17/04 Location: 16th & Pierce Alarm# : . Operation: Nozzle flow testing using front bumper discharge of Engine One with an 1½” inline pressure gauge at the nozzle and a pump panel flow minder. The goal is to test the Elkhart pump chart for the SM-20FG nozzle to achieve 150 GPM through a 200’ typical West Metro preconnect length. The recommended PDP is 147 PSI for 150 GPM through 200’ of 1 ¾” hose per Elkhart.

Tip/Nozzle: Elkhart SM-20FG automatic fog nozzle E1-#2 Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 147 PSI Nozzle Pressure: 100 PSI Expected Nozzle Reaction(Pounds/Force): 75Lbs. Actual Nozzle Reaction(Pounds/Force): 75Lbs. Expected GPM : 150 GPM Actual GPM : 118 GPM + 30 for calibration = 148 Expected Friction Loss: 47 PSI Actual Friction Loss: 47 PSI

Variables: No kinks, elevation or additional appliances to consider. Comments: The SM-20FG tested is #2 of 4 on Engine One. The nozzle was supplied with the appropriate 147 PSI PDP to achieve the 150 GPM flow at 200’ per Elkhart. The Elkhart pump chart is accurate with a flow of 148 GPM. However, what is confusing is that the nozzle states that a flow of 212 GPM should be delivered when the nozzle pressure is 100 PSI. Our test showed a nozzle pressure of 100 PSI and a flow of 148 GPM. Pictures: The SM-20 FG Automatic Nozzle E1-#2

Above: Flow testing the nozzle. Right: Flow minder reading of 118 GPM (plus 30 GPM for calibration and consistency = 148 GPM) and Pump Discharge Pressure of 147 PSI. Below: The nozzle with the inline pressure gauge reading 100 PSI

Date: 11/17/04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with an 1½” inline pressure gauge at the nozzle and a pump panel flow minder. The goal is to test the Elkhart pump chart for the SM-20FG nozzle to achieve 150 GPM through a 200’ typical West Metro preconnect length. The recommended PDP is 147 PSI for 150 GPM through 200’ of 1 ¾” hose per Elkhart.

Tip/Nozzle: Elkhart SM-20FG automatic fog nozzle E1-#3 Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 147 PSI Nozzle Pressure: 98 PSI Expected Nozzle Reaction(Pounds/Force): 75Lbs. Actual Nozzle Reaction(Pounds/ Force): 77Lbs. Expected GPM : 150 GPM Actual GPM : 124 + 30 for calibration = 154 Expected Friction Loss: 47 PSI Actual Friction Loss: 49 PSI


The SM-20 FG Automatic Nozzle E1- #3.

Date: 11/17/04 Location: 16th & Pierce Alarm# : Operation: Nozzle flow testing using front bumper discharge of Engine One with an 1 ½” inline pressure gauge at the nozzle and a pump panel flow minder. The goal is to test the Elkhart pump chart for the SM-20FG nozzle to achieve 150 GPM through a 200’ typical West Metro preconnect length. The recommended PDP is 147 PSI for 150 GPM through 200’ of 1 ¾” hose per Elkhart.

Tip/Nozzle: Elkhart SM-20FG automatic fog nozzle E1-#4 Hose Size : 1 ¾” Hose Length: 200’ Pump Discharge Pressure (PDP): 147 PSI Nozzle Pressure: 100 PSI Expected Nozzle Reaction(Pounds/Force): 75Lbs. Actual Nozzle Reaction(Pounds/Force): 79Lbs. Expected GPM : 150 Actual GPM : 126 + 30 for calibration = 156 Expected Friction Loss: 47 PSI Actual Friction Loss: 47 PSI


The SM-20 FG Automatic Nozzle E1-#4

Articles and Resources

Little Drops of Water: 50 Years Later, Part 1 By Andrew A. Fredericks Little Drops of Water: 50 Years Later, Part 2 By Andrew A. Fredericks Planning a Hose and Nozzle System for Effective Operations By Jay Comella Engine Company Operations: Back to the Basics By Matt Rush Advancing the First Handline By Andrew A. Fredericks Fire Streams and the Aggressive Interior Attack By A rmand F. Guzzi Jr. Firefighting Nozzle Reaction By Paul Grimwood Low Pressure Fog Nozzles By David Polikoff Nozzles and Handlines for Interior Operations By David Wood Preselecting Pump Discharge Pressures for Preconnected Handlines By Douglas Leihbacher Smoothbore Nozzle Basics By Tim Adams Stream Selection By Andrew A. Fredericks Structural Fire Attack: Misinterpretations and Misapplications By Troy Cool The Evolution of the Combination Nozzle By Tim Adams The Retooling of the 1" Smooth-bore Tip By Capt. Joe Bruni &Lt.Rob Edwards Why Fires Are More Dangerous Today By Andrew A. Fredericks

Little Drops of Water: 50 Years Later, Part 1

As we approach the new millennium (re-member, the new millennium begins January 1, 2001), a debate still rages over the use of water fog in interior fire attack. This debate has become more lively in recent years because of the proliferation of on-line computer users in the fire service and the ever-expanding role of the internet as a forum in which to present new ideas or support old ones. This article begins with a brief history of the use of fog streams in structure fire attack. I obtained much of this information by studying the original articles, books, and papers written by three men generally considered to be the fathers of fog firefighting in America-Lloyd Layman, Keith Royer, and Floyd W. "Bill" Nelson.

Fog Nozzle History

Fog nozzles and spray streams have been around for almost 150 years. The first United States patent for a fog nozzle was granted to Dr. John Oyston in 1863. During the late 1800s and continuing through the turn of the century, various articles appeared in fire service literature extolling the merits of spray streams. One of the earliest such articles, entitled "Extinguishing Fires," was written by Oyston himself. It was originally published in Oyston's local newspaper but was reprinted in the March 16, 1878, edition of the National Fireman's Journal (known today as Fire Engineering).1 Significant research in fire behavior and the use of spray streams for interior fire attack began in the United Kingdom and several western European countries during the 1920s-research that continues to this day. In the mid-1930s, Elkhart Brass introduced the first production periphery jet fog nozzle to the American fire service. Known as the "Mystery" nozzle, it was based on a nozzle designed by the Mystery Nozzle Company in Hamburg, Germany, some years before. The United States Navy and Coast Guard used a combination fog/solid-stream nozzle during World War II, although its exact date of issue may predate the war by several years. Manufactured by the Rockwood Sprinkler Company, and known as an "all-purpose" nozzle, it was available for both 11/2-inch and 21/2-inch hose and had a three-position shutoff that could produce both an impinging jet fog stream and a solid fire stream. It could also be fitted with a variety of extension applicators. It is still in limited use today by the Navy as well as several fire departments. Despite their long history, fog nozzles were virtually unknown through the first half of the 20th century. The solid fire stream stood for decades as the unchallenged weapon of choice for structure fire attack by America's fire departments. Then, in 1950, it all changed.

Little Drops of Water

In the February 1945 issue of Fire Engineering, an article described the results of experimental shipboard fires conducted at the U.S. Coast Guard Firefighting School at Fort McHenry in Baltimore, Maryland. Entitled "Coast Guard Conducts Tests on Ship Engine Room Fires," it explained both the testing process and various techniques developed for combating fuel oil fires in the confined machinery spaces of large ships using water fog (a decommissioned Liberty ship was used as the test vessel). While the article is interesting, its impact on structure firefighting tactics is not considered significant. It wasn't until five years later that the importance of the Coast Guard tests would begin to be understood.

What happened in 1950 that so radically changed fire suppression tactics? The late Chief Lloyd Layman of Parkersburg, West Virginia, presented a paper entitled "Little Drops of Water" at the Fire Department Instructors Conference (FDIC) in Memphis, Tennessee, and in the process stood the fire service on its collective head. In his paper, Layman introduced what he termed the indirect method of attack to suppress interior building fires using the tremendous heat-absorbing properties of expanding and condensing steam, produced in great quantities by fog (spray) streams. Most of the theory and methodology of indirect fire attack was based on the Coast Guard experiments (Layman was in charge of the Coast Guard's wartime firefighting school at Fort McHenry), as well as additional testing conducted jointly by the U.S. Navy and other agencies in San Francisco under the project name "Operation Phobos." Layman

continued his experiments after he returned to his position as fire chief in Parkersburg, where he began in earnest applying the indirect method of attack to building fires.

Layman explained his theories and methodologies in great detail in two books published by the National Fire Protection Association (NFPA): Attacking and Extinguishing Interior Fires (1952) and Fire Fighting Tactics (1953). To objectively evaluate Layman's approach, we must be familiar with both the underlying theories and the specific techniques advanced in his books and other writings. First and foremost, the "indirect method of attack" is not an interior fire attack operation. Rather, Layman's methodology emphasizes that the fog stream should be remotely injected into the fire compartment at the highest possible level with the nozzle held in a fixed position. The following quote from Attacking and Extinguishing Interior Fires could not be any more explicit in warning of the dangers personnel face from the large quantities of steam created during an indirect attack: "An indirect attack should always be made from positions that will enable personnel to avoid injuries from super-heated smoke and live steam."2 Layman continued by stating that "if possible and practical, an indirect attack should be made from positions outside the involved building." 3 In other words, he advocated that fog streams be directed through window openings because of the voluminous quantities of steam created within the fire building. Layman went so far as to discourage the use of doorways for fog application, as the outflow of scalding steam would be extremely debilitating to the nozzleman.

In addition to remote injection of the water fog, there are two other requirements for success when using the indirect method. First, the ceiling temperature within the fire compartment must be at least 1,000°F to ensure ready and efficient conversion of the fog spray to steam. When a fire is in the first or early second phase of development, the direct method of attack with timely and adequate ventilation is preferred.4 Second, the fire compartment (building) must be well sealed to prevent premature leakage of valuable steam to the outside. A well-ventilated fire building on the fire department's arrival warrants a direct attack, since the indirect method is only effective if the fire building remains sealed with doors and windows intact. Layman also stated that "where the major area of involvement is on upper floors, it may be possible and practical to attack from an interior stairway below the involved floor."5 He continued by warning that "the nozzleman may have to discontinue the attack temporarily to avoid the downward movement of heated smoke and steam."6

The National Exploratory Committee

Shortly after "Little Drops of Water" was published, the Exploratory Committee on the Application of Water was formed to evaluate fire extinguishment techniques using fog and spray streams. Perhaps better known as the National Exploratory Committee or, more simply, the National Committee, it was comprised of fire chiefs, training officers, and members of fire insurance rating organizations and was created "to bring some badly needed light to a very foggy subject."7 Beginning in 1951, the National Committee began conducting instrumented live fire tests to collect hard data on the growth and behavior of interior fires and the most effective me thods of attacking these fires using water or, more specifically, water fog. Throughout the 1950s, tests were conducted under the auspices of the National Committee and independently by various fire departments, as well as the National Board of Fire Underwriters (NBFU), Underwriters Laboratories, and other research institutions. It was the research work of two individuals, however, that has had the most long-standing impact on the fire service.

Beginning in 1951 and continuing for more than three decades, Keith Royer and the late Floyd W. "Bill" Nelson headed the firemanship training program at Iowa State University's Engineering Extension. With the resources available to them at Iowa State, as well as through their membership on the National Committee, they helped collect and analyze data from literally hundreds of experimental fires. Their efforts provided the nation's fire service with a much better understanding of interior fire behavior and the mechanisms of fire extinguishment using water. Among their many contributions, Royer and Nelson developed a formula for

estimating, with a high degree of accuracy, the amount of water required to control an interior fire based on the following: a) the amount of heat liberated by common fuel materials burning in ordinary air within a compartment, b) the extinguishing (heat-absorbing) capacity of water, and c) the cubic foot volume of the fire compartment. In the "critical rate of flow" formula, as it came to be known, Royer and Nelson determined that the amount of water (expressed in gallons per minute) needed to control (not completely extinguish) a fire in the largest open space within a structure can be determined by dividing the cubic foot volume of the space by 100. Royer and Nelson explained the formula and its scientific basis in Engineering Extension Service Pamphlet #18 "Water for Fire Fighting-Rate-of-Flow Formula" (1959, Iowa State University). They also introduced the fire service to a fire extinguishment technique they called the "combination method of attack."

The Combination Attack

Several factors must be considered to execute a successful combination attack. Chief among them is that, like the indirect method of attack, the combination attack was designed primarily for exterior application of the water. Remember, turnout clothing in use during the 1950s and 1960s lacked the thermal protective qualities of modern fabrics. In addition, many fire departments had few, if any, self-contained breathing masks available. These facts, coupled with the large amounts of steam produced during a combination attack, necessitated an exterior application of water fog whenever possible. If a fire had to be attacked from an adjoining room or hallway, or if multiple rooms were involved in fire and exterior application of the stream were impractical, Royer and Nelson cautioned that a very narrow fog stream should be used to begin the attack. The narrowest fog stream is, of course, a straight stream, which would cause the least disruption to the thermal balance.

In addition to Engineering Extension Service Pamphlet #18, Royer and Nelson's discoveries were published in two Fire Engineering articles. "Water for Fog Fire Fighting-How Much and How to Apply It!" (August 1959) described the combination attack but did not specifically identify it. "Using Water as an Extinguishing Agent: Part 2-Utilizing Heat" (November 1962) contrasted and explained in some detail the various methods of structure fire attack-direct, indirect, and combination. But three films produced by Iowa State University-The Nozzleman (1959); Coordinated Fire Attack (1960); and, to a lesser extent, Where's the Water? (1971) introduced the vast majority of firefighters to the combination method of attack.

To initiate a combination attack, first select an opening(s) for stream application. Adjust the size of the fog pattern (discharge cone) based on the approximate dimensions of the fire compartment. Next, thrust the nozzle about an arm's length through the opening into the fire compartment and rotate it as violently as possible with a clockwise motion. Speaking to the lack of personal protective equipment during the 1950s and 1960s, Royer and Nelson noted that "to do this the nozzleman must have glove, helmet and protective coat."8 During their many experimental fires, Royer and Nelson discovered that a clockwise rotation of the fog nozzle was required to drive heat, smoke, and flame away from the nozzleman. The objective of the combination attack is to "roll" the stream around the perimeter of the room, cooling the walls, ceiling, and floor with the outer edge of the stream while the inner portion of the stream cools hot gases being produced by the fire. Striking the heated ceiling, walls, and fuel materials produces the maximum amount of steam within the shortest period of time. If the rate of flow is sufficient and the water distribution is efficient, the main body of fire should be "blacked out" after no more than 15 to 30 seconds of stream application. By shutting the nozzle down promptly after the fire darkens, enough heat will remain within the fire area to permit the smoke to lift and afford the overhaul crews improved visibility and lower humidity. Royer and Nelson were very emphatic in their writings when discussing the importance of avoiding "overcooling" and managing the thermal balance to aid in ventilation and overhaul.

Misapplication and Confusion

Misapplication of Royer and Nelson's methods began almost immediately. For example, the concept of managing heat-using the thermal balance within the fire area to advantage-was quickly lost on many practitioners of the combination attack. In a telephone conversation I had with Royer a few years ago, he said he was very surprised when he first learned how commonly firefighters attempting a combination attack were beset with poor visibility and often suffered steam burns. I believe the misapplication and confusion is attributable to several causes. One involves improvements in firefighter protective clothing and SCBA during the 1960s and 1970s, prompting more and more fire departments to attempt interior fire attack operations. David Fornell, author of Fire Stream Management Handbook,9 believes that since the tactics depicted in the The Nozzleman and Coordinated Fire Attack utilized fog streams exclusively, many in the fire service became convinced this was now the only type of stream suitable for structure fire attack.

Fornell described what he terms the "interior, indirect attack." Like the misunderstanding surrounding the combination attack, Layman's indirect attack was also widely misunderstood and improperly applied. Layman, himself, contributed to the confusion by including a single paragraph in Attacking and Extinguishing Interior Fires that stated a "direct" attack with fog nozzles may sometimes be indicated and that a 30-degree fog pattern directed at an upward angle is the preferred method. Unfortunately, he made no mention of the role of ventilation when employing this technique; and warnings about the dangers of steam burns to the nozzle crew, prominent earlier in his book, are conspicuously absent here.10 Fornell sums it up best in Fire Stream Management Handbook: "The interior indirect, or combination, attack as practiced by a large percentage of the fire service today was invented by the fire service itself to compensate for problems encountered employing techniques based on earlier self-invented principles. Nowhere in his writing did Chief Layman present scientific arguments that advocated spraying water over firefighters' heads in a fire situation in order to create steambath conditions. On the contrary, he said firefighters would be enveloped in a hurricane of water converting to steam."11

Water Fog and Life Safety

While many an interior fire attack has failed when the nozzle team had to quickly retreat because of steam burns, the full impact of live steam on civilians trapped within the fire building remains uncertain. Studies indicate that when heated air becomes saturated with moisture, the opportunity for and severity of burn injuries rise dramatically. The Fire Protection Handbook (17th Edition), in discussing the impact of heat on life safety, states that "the effects of exposure to heated air are greatly augmented by the presence of moisture in the fire atmosphere."12 Studies by the National Research Council of Canada indicate that 3007F is the maximum survivable breathing air temperature and that "a temperature this high can be endured for only a short period and not at all in the presence of moisture." 13

Insofar as Royer and Nelson's writings are concerned, there is no mention of the impact of steam on trapped occupants. In Fire Stream Management Handbook, Fornell writes in reference to the articles and films of Royer and Nelson: "In viewing the films and reading the results of their research, it must be noted that their tactics advocated application of water from outside the fire building. Though they did discuss interior application, the first priority in the Iowa method was to knock down visible fire before making entry. Mr. Royer says their testing did not address the problem of fire spread caused by applying streams from the outside of the building. The subject of life safety or the effects of steam on trapped victims was never addressed in the three films (italics added)."14

In Attacking and Extinguishing Interior Fires, Layman states: "In answer to the question regarding the effect on occupants of steam from fog application, we can only state that we have not heard of any adverse effects (italics added)." Layman continues: "Contrariwise, the much more rapid flame suppression with indirect application makes it possible to reach

endangered persons more quickly so as to be able to remove them to safety and render aid as necessary."15 This statement, which appears in the third paragraph on the third to last page of a 148-page book, does not specifically address the impact of steam exposure on trapped occupants. It simply implies that indirect attack may knock down the fire faster than other methods and allow quicker removal of any victims.

Layman Before Fog

Few members of the fire service know that long before "fog mania" swept the nation and confused a generation of firefighters as to proper structure fire attack methods, Layman wrote a book emphasizing the importance of the direct method of fire attack. Published in 1940, Fundamentals of Fire Fighting Tactics examines eight basic fireground functions that together comprise a tactical plan for the successful attack, control, and extinguishment of fires in buildings. I will limit this discussion to Chapter VI, simply called, "Extinguish Fire."

Layman stated that "the most important factors in extinguishing a fire within a building are first-to locate the main body of fire, second-to apply [the] necessary amount of water or other extinguishing agent on the BASE OF THE FIRE."16 (The capitalization is Layman's emphasis.) Layman continued by providing a list of nine "principles and suggestions" for extinguishing interior fires.17 In examining this list, numbers three through seven are particularly interesting, especially in light of Layman's later writings. They are reprinted below:

• If possible, attack the main body of fire so as not to drive heat and flames into uninvolved sections of the building. • Use streams of sufficient size to provide necessary volume of water, but avoid using a one-inch stream where a quarter-inch stream would be sufficient. • Direct the stream to the base of the fire. • As soon as all visible flames have been killed, close nozzle; if the fire flares up, open nozzle again, but close it when visible flames have been killed. • Don't direct streams into smoke-filled rooms. Wait until the fire has been located and the stream can be directed into the burning material."

These five principles are so sound and basic; they are as true today as they were when they were written 60 years ago.

The Debate Continues

In the past 15 years or so, we have witnessed a resurgence in the use of solid streams, or at least straight streams, as many firefighters and fire officers have realized that using fog streams inside the fire building is rarely a wise and productive action. The fire service has taken many years and detoured down many dead-end paths (remember high-pressure fog?) in reaching this conclusion. Many within our ranks still lack a complete understanding of the tactics and techniques developed by Layman and the Iowa State researchers. Others are just plain stubborn and refuse to face the truth. Sadly, unnecessary firefighter burn injuries and excessive property damage will continue as net results of this situation. Recently, researchers in the United Kingdom and Sweden introduced the American fire service to the idea of "offensive" water fog application. This has generated still more confusion, and the debate over "fog" vs. "solid" shows no signs of abating.

Part 2 of this article will analyze offensive fog te chniques as well as Class A foams and other "advancements" in our ability to control and extinguish interior fires.

Special thanks to the following for their assistance in researching this article: Richard Arwood, executive officer, Fire Service Institute , Iowa State University Extension to Communities; Glenn P. Corbett, P.E., technical editor, Fire Engineering; Vernon B. Morris, Jr.; Diana

Robinson, senior librarian, New York State Academy of Fire Science; Mark Saner, Akron Brass Company; and Bruce Guard and Gordon W. Harris, Jr., Elkhart Brass Manufacturing Company.

Success depends on several factors. Three of the most important are sufficiently high tempera tures in the overhead of the fire area to permit efficient conversion of the water fog to steam; a well-sealed fire building to retain the steam blanket; and patience on the part of the nozzle crew and fire chief as the steam accomplishes its mission of cooling and smothering within the fire building. After the fire is controlled, extensive overhaul may be required to extinguish spot fires. (Photos by author.)

Introduced in the mid-1930s, it is a rotary controlled nozzle of the periphery jet design and was America's first production fog

nozzle. (Photo courtesy of Elkhart Brass Manufacturing Company.)

The U.S. Navy and Coast Guard used an "all-purpose" nozzle capable of producing an impinging jet fog stream and a solid fire stream. This was the type of nozzle Layman used in his Coast Guard firefighting tests that led to the development of the indirect method of attack. This nozzle also saw extensive service in many municipal fire departments. (Photos by Ronald Richards.) This was followed by the first constant-gallonage fog nozzle, which Akron called the "Imperial." According to Keith

Royer, the Imperial was developed in response to widespread adoption of the "rate of flow" formula by fire departments across the nation.

Endnotes

1. "Fire Engineering 120-Year Retrospective," Fire Engineering, Jan. 1997, 90. 2. Layman, Lloyd. Attacking and Extinguishing Interior Fires. (Boston: National Fire Protection Association, 1952), 45. 3. Ibid, 45. 4. Chief Layman was one of the first fire service authors to identify the three stages or phases of growth of interior fires-incipient, flame producing (combustion), and smoldering.

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5. Layman, Lloyd. Attacking and Extinguishing Interior Fires, 46. 6. Ibid. 7. Nelson, Floyd W. Qualitative Fire Behavior, (Ashland, Mass.: International Society of Fire Service Instructors, 1991), 100. 8. Royer, Keith and Floyd W. Nelson, "Water for Fog Fire Fighting-How Much and How to Apply It!" Fire Engineering, Aug., 1959, 810.

9. Fornell, David P. Fire Stream Management Hand-book. (Fire Engineering Books & Videos, 1991). 10. Layman, Attacking and Extinguishing Interior Fires, 50. 11. Fornell, Fire Stream Management Handook, 84. 12. Hartzell, Gordon E., "Combustion Products and Their Effects on Life Safety," Fire Protection Handbook, 17th Edition. (Quincy, Mass.: National Fire Protection Association, 1991), 3-9.

13. Ibid. 14. Fornell, Fire Stream Management Handook, 88. 15. Layman, Attacking and Extinguishing Interior Fires, 148. 16. Layman, Lloyd. Fundamentals of Fire Fighting Tactics. (Parkersburg, W. Va.: Lloyd Layman, 1940), 30. 17. Ibid.

References

"All-Purpose Nozzle," U. S. Coast Guard Instruction Bulletin #11, revised Apr. 6, 1945.

Clark, William E., Firefighting Principles and Practices, 2nd Edition. (Saddle Brook, N.J.: Fire Engineering, 1991).

Clark, William E, "Using Water Wisely," Fire Engineering, Sept. 1995.

"Coast Guard Conducts Tests on Ship Engine Room Fires," Fire Engineering, Feb. 1945.

Fornell, David P., Fire Stream Management Handook (Saddle Brook, N.J.: Fire Engineering, 1991).

Hartzell, Gordon E., "Combustion Products and Their Effects on Life Safety," Fire Protection Handbook, 17th Edition. (Quincy, Mass.: National Fire Protection Association, 1991).

Layman, Lloyd. Attacking and Extinguishing Interior Fires. (Boston: National Fire Protection Association, 1952).

Layman, Lloyd. Fire Fighting Tactics. (Boston: National Fire Protection Association, 1953).

Layman, Lloyd. Fundamentals of Fire Fighting Tactics, (Parkersburg, W. Va.: Lloyd Layman, 1940).

Lindsley, Lawrence W., "All-Purpose Nozzles," WNYF, Oct., 1953.

Nelson, Floyd W. Qualitative Fire Behavior. (Ashland, Mass.: International Society of Fire Service Instructors, 1991).

Royer, Keith and Floyd W. Nelson, "Water for Fog Fire Fighting-How Much and How to Apply It!" Fire Engineering, Aug., 1959.

Royer, Keith and Floyd W. Nelson, "Using Water as an Extinguishing Agent-Part 2 -Utilizing Heat," Fire Engineering, Nov., 1962.

Royer, Keith, "Iowa Rate of Flow Formula for Fire Control," Fire Engineering, Sept., 1995.

"Water for Fire Fighting-Rate-of-Flow Formula," Iowa State University Bulletin #18, 1959.

ANDREW A. FREDERICKS, a 20-year veteran of the fire service, is a firefighter with Squad 18 in the Fire Department of New York (FDNY). He is a New York State -certified fire instructor at the Rockland County Fire Training Center in Pomona, New York, and an adjunct instructor at the New York State Academy of Fire Science. He has two bachelor's degrees, one in political science and one in public safety, with a specialization in fire science, and a master's degree in fire protection management from John Jay College of Criminal Justice. He developed the Fire Engineering "Bread and Butter" Operations videos Advancing the Initial Attack Handline (1997), Stretching the Initial Attack Handline (1998), and Methods of Structure Fire Attack (1999).

Little Drops of Water: 50 Years Later, Part 2

By Andrew A. Fredericks

As we learned in Part 1 (February 2000 Issue), the “indirect” and “combination” methods have been largely misunderstood and widely misapplied. By the 1980s, many fire departments, disillusioned by years filled with failed fire control efforts and painful burn injuries, abandoned the use of fog streams for interior firefighting. Some returned to solid stream nozzles that for years had been relegated to dusty shelves in fire station closets. Many others, heavily invested in fog nozzle hardware, instructed their firefighters to employ only straight streams during interior fire attack. THE MODERN ENVIRONMENT Today’s fireground environment is far more hostile and unpredictable than it was in the 1950s. One reason is the endlessly expanding role of plastics. Plastics, being derived from petrochemicals (hydrocarbons), burn vigorously given the opportunity and produce large quantities of dark, acrid smoke. Plastics may be found partially or wholly in furniture, window treatments, clothing, toys, sporting goods, floor coverings, wall coverings, countertops, electronics, major appliances, housewares, and hundreds of other consumer products. Significant amounts of plastic are used in building construction. Plastics are often expanded for use in seat cushions, pillows, mattresses, insulation, and packaging materials. Expanded plastics (also known as cellular or foamed plastics) may pose a significant fire hazard. “Some reports tell of fast-spreading, high-intensity fires and voluminous smoke production.”i Many plastics used in interior furnishings and finishes are “thermoplastics.” Thermoplastics, unlike thermosetting plastics (or more simply thermosets), produce flaming drips when they burn, which may flow and extend fire to uninvolved fuels. Pools of burning liquid plastic generate additional quantities of smoke and flammable gases and make firefighting more hazardous. One firefighter from a busy engine company in the South Bronx inadvertently knelt on a molten plastic TV cabinet and was severely burned. He had to undergo multiple skin grafts and extensive rehabilitation. Buildings today further contribute to the hazard because they are often well sealed and limit the opportunity for heat loss. A fire growing within a compartment (room) that loses little heat to the outside will become hotter faster and build up large quantities of toxic gases more quickly than a fire in a less insulated room of similar size. The widespread installation of wall and attic insulation, draft barriers, membrane roofing systems, and energy-efficient windows in new construction and renovations plays a significant role in the subtle (and not so subtle) changes in interior fire behavior that have been observed during the past two decades. Probably the most significant factor is the energy-efficient window (EEW). These windows, often called thermal pane windows, do not fail as readily as older, single-glazed windows. As a result, the highly heated, sooty smoke characteristic of today’s plastic filled fire environment, since it cannot escape, will quickly fill the fire occupancy.

Firefighters today routinely encounter brutal head conditions and, more and more frequently, a complete absence of visible fire. This phenomenon has been termed “black fire.” BLACK FIRE A firefighter from a busy Bronx, New York, engine company related to me the following story. He was assigned as the nozzleman for the tour. His company arrived first due at a fire in a renovated multiple dwelling. On entering the fire apartment with a charged handline, he noted that heat conditions were severe and the apartment was filled with dense smoke. Unable to quickly locate the seat of the fire and anticipating that flashover was imminent, his officer ordered him to open the nozzle. As he directed the stream into the blackness, conditions improved somewhat, and the line was advanced through the apartment. The officer then ordered the nozzle shut down. As the smoke began to lift, he realized he was kneeling in the middle of the fire room! He stated that throughout the fire attack, he never saw so much as a lick of flame despite a well-advanced fire. A friend of mine, a very experienced firefighter, described to me the next incident: At a recent training exercise in an acquired structure, student firefighters were preparing to advance a charged handline through the kitchen and extinguish a fire at the far end of the adjoining living room. He was assigned as the engine company officer to coach the students through the exercise and ensure their safety. The fuel materials consisted of an upholstered sofa on end, one or two swat cushions, and cardboard as kindling. After the fire was lit, he entered the house to check on fire conditions and verify that the ignition officer was safely removed to the outside. From the doorway between the kitchen and living room, he noted that flames were starting to roll across the living ceiling, but visibility was still good, and nothing seemed out of the ordinary. He then duck walked the 15 feet back to the entrance door and instructed the student firefighters to bring the line inside. In less than a minute, conditions in the kitchen and living room had changed drastically. Almost all visibility was lost, and dark smoke was banked down to within two feet of the floor in the kitchen and to within an inch or two in the living room. As the advanced the line into the living room, he was unable to see even a hint of fire at ceiling level. With a high heat condition and the very real threat of flashover, he told the nozzleman to open the line. This action more than likely saved them from severe burn injuries. I had an experience at a private dwelling fire several years ago that is eerily similar to the incidents described above. The occupants of an older, 2 ½ -story, two-family home reported a smoke condition in the attic. We brought a charged handline up the stairs to the attic and were met with heavy, dark smoke. With no visible fire and a moderate heat condition, I thought the fire might be behind a knee wall or above a finished ceiling, but there were no void spaces present. Heat levels continued to increase. Crouching down, I could feel a significant amount of heat on my thighs and groin area (I was wearing a protective hood but only ¾-length boots). After inching ahead slowly, I caught a glimpse of what looked like glowing coals at floor level. I opened the nozzle, sweeping the ceiling and floor. We then advanced the line toward the front of the house (the attic stairs were closer to the rear), and I was able to vent the attic through a small window that had remained intact during the fire. The fire itself involved a foam mattress and some clothing, which explains the dense smoke and intense heat. Because of the confinement of the fire in the attic with its limited ventilation opportunities, we most likely encountered a fire in the third (smoldering) stage of development. Because we entered the attic from below, the pressure of the heated gasses

initially prevented intrusion of any significant additional oxygen. But had I not opened the line when I did, I believe it would have been just a matter of time before the attic would have “lit up” in flames. COMPARTMENT FIRES One recent Fire Engineering article cited a scientific principle known as “Thornton’s Rule” as the basis for concluding that fires today are no more challenging and dangerous than in the past.ii I disagree with this conclusion and believe that the widespread use of plastics has significantly increased the hazards posed by interior fires. Let’s examine Thornton’s Rule, not from a theoretical, laboratory perspective but from one grounded in the reality of the fire floor. We’ll begin by comparing the hear energy potential of various plastics vs. more traditional fuel materials. The heat of combustion (heat energy potential) of plastics is tremendous and ranges from approximately 16 kJ/g for polyvinyl chloride (PVC) to approximately 41-46 kJ/g for polystyrene and high-density polyethylene. Both polystyrene (rigid and expanded) and polyethylene are widely used in consumer goods and building materials. By contrast, paper, wood, cotton, jute, and other natural (cellulosic) materials have much lower heat energy potentials, in the range of 12-15 kJ/g.iii What Thornton discovered before World War I was that in any oxygen-regulated fire (compartment fires are generally oxygen- or ventilation-regulated, whereas outside are fuel-regulated), heat of combustion will not vary significantly for a variety of organic liquids and gases.iv In the 1970s, further research by Hugget indicated that the heat of combustion for many organic solids is also relatively constant and is a factor of the oxygen available for consumption within the fire compartment. [4] Although these laboratory findings viewed independently may indicate that plastics pose no more of a hazard to firefighters than the cellulosic materials of fires past, at “real world” fires, other factors (variables) add elements of dynamic complexity to the behavior of interior fires and suggest that the dangers faced by firefighters have increased dramatically in the past 50 years. These factors may be related to the fuel materials themselves (amount, flame spread rating, surface-to-mass ratio, arrangement, and heat release rate), the compartment (insulation, ventilation), and firefighting actions. FUEL MATERIALS Fire load (sometimes called fuel load) refers to the total heat energy potential of the combustible materials contained in a building (or compartment). Expressed in SI units as kJm2, under most definitions, the term fire load includes both the contents and any combustible structural components. As society has grown more affluent, families have introduced increasing amounts of combustible material into their homes and apartments. By some estimates, the average residential fire load is at least two times greater today than it was 50 years ago. Even if heat production doesn’t vary significantly between plastics and cellulosics burning within a compartment, if the amount of combustible material increases, so, too, must the heat energy potential. This might be called the “more stuff, more heat” principle. Another important factor is flame spread. High rates of flame spread across exposed fuel surfaces decrease the safe operating time for firefighters before flashover occurs. The use of plastic materials as wall and ceiling coverings, as well as in furniture and furniture veneers, greatly increases the risk of rapid fire development and firefighter injury. “Very

high surface flame spread rates have been reported – up to approximately 2 ft. per sec. (0.6m/s), or 10 times the rate of flame spread across most wood surfaces.” But let’s not forget that wood and other cellulosic was and ceiling finishes also produce dangerously high rates of flame spread. Exposed wood surfaces, such as paneled walls, can contribute to rapid fire development, particularly when flammable gules or adhesives are used in the installation and the paneling itself is subject to delamination when exposed to excessive heat. In Building Construction for the Fire Service, Third Edition, Frank Brannigan details the extreme flame spread hazard posed by combustible acoustical ceiling tiles made of low-density fiberboard.v Paints, coatings, and other surface finishes also play a role in flame spread, but to what extent is not well defined. The surface-to-mass ratio of the fuel is another factor. Obviously, expanded plastics pose a significant hazard in this regard, but consider a rigid plastic form that is in common use as a storage place for everything from toys to videotapes to vintage record albums-the milk crate. Now commercially manufactured specifically for home and office storage applications, milk crates have a very high surface to mass ratio. Recently retired Fire Department of New York (FDNY) Deputy Chief Vincent Dunn believes that a variety of rigid and expanded plastic items, including several milk crates filled with toys, contributed to a flashover that fatally injured FDNY Captain James F. McDonnell in 1985.vi Another possible contributing factor in McDonnell’s death was the arrangement of the combustible material (also known as fuel “geometry”). Consider the impact on fire growth and spread of perhaps two dozen plastic milk crates stacked five and six high or even nailed to the walls of a typically sized bedroom or living room during a fire. Filled with plastic toys or other items, they might be likened, in the words of one fire officer, to “bombs” of solid gasoline. According to Vytenis Babrauskas, Ph.D., a leading researcher in the field of compartment fire growth dynamics, the most important factor in the speed with which a fire reaches flashover is the heat release rate (HRR). Put very simply: “If the HRR is high enough, flashover will occur. If it’s not, the fire won’t reach flashover...”vii Fuel materials that have high rates of heat release, including many plastics, generate significant heat early in the development of an interior fire before fire growth becomes strictly ventilation-regulated and heat production levels off, “The heat release rate is important during the growth phase of the fire when air for combustion is abundant and the characteristics of the fuel control the burning rate.”viii Cellular plastic items, such as foam-filled mattresses and furniture, are extremely hazardous in this regard. This is because of the characteristics of cellular plastics: They have a low density; they have very high heat release potentials; and they tend to liquefy and gasify (not char) when they burn.ix The Fire Protection Handbook, in discussing the heat release rate of upholstered furniture (encountered at virtually every residential fire and a major culprit in the “black fire” examples described earlier), states the following: “The HRR of upholstered furniture can, in the worst circumstances reach values of around 2,000 to 3,000 kW (2 to 3 MW) in a very short time, only 3 to 5 minutes after ignition.”x The Handbook continues by noting that the hazard is extreme “since it only takes about 1 MW to flash over a room with a normal-sized door opening.” [10] While one can never predict with absolute certainty the outcome of any compartment (room) fire based strictly on the composition of the fuels involved, the higher energy potentials and high heat release rates of modern plastic furnishings and finishes make early flashover and severe firefighter injury more distinct possibilities. In tragic testimony to the dangers posed by interior fires today, between 1985 and 1994 alone, approximately 47 firefighters suffered

fatal injuries as a result of being caught or trapped by flashover and other “rapid fire progress” events.xi ENERGY-EFFICIENT WINDOWS Consider the following quote from an article written by Deputy Chief James Murtagh of FDNY more than 10 years ago: “Fires in buildings with energy-efficient, double-paned windows will contain smoke and fire for extended periods. This leads to delayed alarms and the development of large volumes of extremely dense, pressurized smoke which will bank down farther than normally expected. If the smoke is hotter than its ignition temperature, but too rich to burn, it may ignite suddenly when sufficient oxygen is mixed with it; if the gas-air mixture is within its explosive range bur below its ignition temperature, it may ignite suddenly when heat is added.xii The widespread installation of double-glazed, energy-efficient windows has added so many complicating factors to firefighting efforts in New York City that procedural bulletins have been changed specifically as a result.xiii Fifteen years of field experience with these windows at literally thousands of fires indicates that (a) they do not fail as readily as older, single-glazed windows; (b) in multiple dwelling and commercial installations, the resistance to failure is increased because of the use of heavier-gauge aluminum or vinyl frames); (c) because they resist heat-induced failure, they often hide the location of the fire from firefighters assigned to perform ventilation and search operations from ladders and fire escapes; (d) EEWs are extremely difficult to break with firefighting hand tools; and (e) once the windows do fail or are vented, fire conditions often change dramatically. For a more complete discussion of the hazards and problems posed by EEWs see “Energy-Efficient Windows” on page 134. FIREFIGHTING ACTIONS Because of the behavior of EEWs, many times the first (and only) ventilation of the fire area is the door opening through which first-arriving firefighters begin their primary search and advance the attack handline. Once this door is opened, anticipate a dramatic change in fire conditions. Consider the following example. An engine company prepares to advance a charged 1¾-inch hand-line through the front door of an apartment. A long hallway connects the entrance door with the fire room deep the “flat.” Volumes of dark smoke under considerable pressure are “pushing” out the open apartment door and rising up the stairway. As the nozzle team disappears into the murk, flame begins issuing intermittently from the top of the door opening. The nozzle team, unaware of these conditions, continues to advance down the hallway toward the seat of the fire. Suddenly, heavy fire is “blowing” out the top half of the door opening, and the hallway has turned into a mass of orange flames. The nozzleman finally opens up, but not before he and the backup firefighter have sustained second- and third-degree burns. What happened? The fire burning within the unventilated (or poorly ventilated) apartment described above is akin to a flammable gas factory. Large amounts of heated, unignited combustion gases (carbon monoxide mostly) outflow from the main fire area (maybe a rear bedroom) and accumulate in the adjoining rooms and spaces. When the door to the apartment is opened (a ventilation opening), these fire gases travel along the ceiling toward this outlet. As the gases reach the entrance door, they begin missing with ever-increasing amounts of oxygen, causing the vapor-rich mixture to enter its flammable range. With the door kept

open to permit advance of the handline, the intermittent flaming at the top of the door opening is soon replaced with solid fire. As increasing amounts of oxygen flow into the apartment through the open door, the flames travel back toward the main fire area, feeding on the ceiling gases, giving the appearance of a lit fuse. Sometimes termed “vent point ignition,” the entire hallway is soon filled with fire, and the nozzle team is literally fighting for its life. One question that may be asked is why the nozzleman didn’t open up sooner. While rollover (flames appearing in the overhead smoke layers) is a reliable warning sign of impending flashover, it cannot provide warning if it goes unnoticed. Flames in the overhead may not be visible because of smoke once entry is made into the fire occupancy. The full encapsulation and exceptionally thermal protection provided by the latest bunker gear and protective hoods may prevent firefighters crouching below from feeling heat radiating downward from above. In this case, the nozzle man never opened up because he didn’t realize the severity of the situation. Another question concerns the position of the entrance door. Should the entrance door have been partially closed behind the advancing firefighters to limit air movement and delay or prevent flashover? In my opinion, once a handline passes through a door opening, the door must remain fully open to prevent any interference with the movement of the line and to allow an influx of fresh air to aid in ventilation as the fire is knocked down. During the primary search, however, the question is more difficult to answer and is the subject of much debate within the ranks of FDNY. A veteran lieutenant assigned to a busy ladder company in the Bronx believes that at apartment fires, the door should be kept closed during the primary search (not locked or latched, just shut to limit air movement). The calming effect on a growing fire that results from the simple act of closing the door behind you can be quite astonishing. At a fire in a multiple-dwelling in the Bronx, the first-due ladder company initiated a primary search with the apartment door closed. To complete the search, the firefighters had to pass the fire room. A 2½ -gallon water extinguisher (commonly called the “can,” carried by all FDNY ladder companies during primary search operations) was discharged on the fire, but the “can” firefighter was unable to pull the fire room door shut. When the engine company officer opened the apartment door to check on conditions, the fire roared out of the fire room and filled the hallway, trapping the search team at the rear of the apartment. As soon as the apartment door was closed, the fire retreated back into the room. This condition was observed again after the primary search had been completed and the handline was brought inside to extinguish the fire. The effect of open doors and windows is enhanced greatly during windy conditions. Depending on wind direction and velocity, extremely rapid fire progress may result. The fire service has an insufficient understanding of how wind and other weather-related factors affect fire behavior; much research remains to be done.xiv Another question concerns the issue of applying water on smoke. For years, it was considered taboo, but the volatile nature of the smoke produced by the contemporary fire environment requires that we rethink this approach. “Although this [applying water on smoke] flies in the face of traditional training, we must recognize that the fire environment has changed with the addition of plastics that generate high heat and dense smoke when they burn. This, combined with energy-efficient windows, may justify putting water ‘on smoke’ to prevent flashover in certain situations.”xv While this tactic should remain the exception and not the rule, if you find yourself lying in a hot, smoke filled hallway and that dread

feeling in the pit of your stomach tells you that something very bad is about to happen, opening the nozzle may very well save your life. FOG, FANS AND FOAM Part 1 of this article described our 50-year experiment with fog streams and the mixed success they’ve achieved on the fireground. Although fog streams did not turn out to be the “magic pill” some had hoped, the jury is still out on other, more recent “advancements” in the art and science of interior fire control. Specifically, I’m referring to positive-pressure ventilation (PPV), Class A foam, and “offensive” water fog techniques.

• PPV. Does PPV have a place? I believe it does, particularly during overhaul, to reduce heat and humidity levels and clear the fire area of smoke. It has also shown much promise when used to pressurize stairways during high-rise fire evacuation. During the initial stages of a fire attack, however, it poses several problems. First among these is the danger of pushing fire into uninvolved areas of the building. Another is the potential for violent acceleration of fire growth. At one training burn in an acquired structure, the local fire department wanted to experiment with PPV. The action of the fan on the fire suggested that someone had injected atomized gasoline into the fire area. Setting up a PPV fan also requires that a firefighter or firefighters be taken away from other important tasks and, considering the staffing levels of most engine and ladder companies, this becomes an important issue. If vent-enter-search (VES) operations are employed. PPV will drive heat and flame toward the searching firefighters and cause severe burns and other injuries as they scramble to dive out windows and escape serious burns. One investigator suggested installing small nozzles on the perimeter of the fan to blow a water mist into the fire area (similar to the cooling fans seen on the sidelines during football games in warm weather). This introduces the very real danger of steam burns and is similar in effect to having a misplaced fog stream directed through a window opening while you are inside the fire building. As a result of these issues, many fire departments that practice PPV do so on a much more limited basis today than previously.

• Class A foam. The current buss in “progressive” fire suppression circles is Class A foam. Class A foams are not new – they’ve been around for almost a century. Used in wildland firefighting for many years, they have only recently been introduced into the arena of structure firefighting, A am not disputing some of the advantages offered by wetting agents in general and Class A foams in particular (better fuel penetration and the ability to cling to vertical surfaces), but they are not quite the panacea some salespeople would have us believe. In a fairly extensive study conducted by the National Institute of Standards and Technology (NIST) on the performance of Class A foam, testing showed that its most clear advantage over plain water was in the extinguishment of tire fires.xvi In other tests, the advantages offered by Class A foam were less well defined. The NIST report also indicates that there are little quantitative data on the effectiveness of Class A foam vs. plain water in the extinguishment of interior structure fires and that more testing is required. In addition to incomplete information on the effectiveness of Class A

foam, there are other issues to consider. I hate to be a pessimist, but my experience with Class B foam systems installed on municipal fire apparatus hasn’t been good. They often don’t work properly when you need them, especially when they’ve been dormant for months at a time. And having been a firefighter in two paid municipal departments, a combination department, and a small volunteer department, I also understand the issue of budgets. Many fire departments lack funds to maintain basic necessities like turnout gear and SCBA, let alone to invest in Class A foam systems. Other questions must be answered as well. If a foam system is purchased, will it be adequately maintained? Will firefighters be permitted to use foam during routine training sessions to ensure proficiency in proportioning and application techniques, or will this prove too costly? Have your firefighters been properly trained to extinguish fires using water plain first so that when the foam system fails, fire suppression efforts can continue uncompromised? While there is no doubt that the use of Class A foam will continue to expand, there exists to date insufficient scientific data and actual field experience to provide a true cost-benefit picture of the effectiveness of these agents in interior structure fire attack.

LITTLE DROPS AGAIN As a result of two Swedish firefighters being killed in a flashover in the early 1980s, fog nozzle techniques were devised to counter the effects of fire gas ignition and prevent injuries from flashover and backdraft. Termed “offensive” or “three-dimensional” water fog application, these techniques have been explained in great detail in the writings of Paul Grimwood, a retired 26-year veteran firefighter from the London Fire Brigade. Grimwood was kind enough to address my questions and concerns about “3-D” fog techniques. Although I agree with his assessment of the modern fire environment and its attendant hazards-particularly the volatile nature of fire gases and the increasing hazards of flashover and backdraft-I disagree with several of the specific tactics he advocates. The brief examination of 3-D water for techniques contained here is taken from a pamphlet entitled “Flashover & Nozzle Techniques” prepared by Grimwood.xvii Offensive fog application requires that small (around 400 micron) droplets produced by special fog nozzles be directed into the overhead gas layers in short bursts or “pulses.” The objective is to suspend the droplets in the gases to cool them and retard their ignition (in other words, putting water on smoke as a preventive measure). While ideally 3-D fog application will prevent ignition of the fire gases, Grimwood states that the technique is suitable for both pre- and post-flashover fires. As the water fog turns to steam and expands in volume, it is accompanied by a corresponding decrease or contraction in volume of the fire gases, reportedly avoiding the debilitating effects associated with steam production caused by fog streams during interior firefighting efforts. In addition, by avoiding contact between the water and the heated walls and ceiling (opposite of what the combination method of attack requires), unwanted steam production is further reduced, thereby maintaining tenable conditions for the nozzle team. Offensive fog techniques require rather precise execution for success. Grimwood states that firefighters employing 3-D fog techniques should be “extremely well practiced in nozzle handling and ‘pulsing’ actions.”xviii Given the wide spectrum of distractions faced by the modern fire service (EMS, haz-mat, technical rescue, and so on) and the youthful look of many fire departments, handline and nozzle techniques must be kept as simple and

straightforward as possible. Regardless of its reported effectiveness, offensive fog application does not fit this description. I believe a more traditional approach is in order. INTERIOR DIRECT ATTACK Fifty years after Layman’s “Little Drops of Water,” it’s time to admit that fog streams are not the answer. I strongly advocate a return to the time-tested direct method of attack. Its simplicity and effectiveness, coupled with the level of safety it affords the nozzle team, is a good fit with the unpredictable fire grounds of the new millennium. While solid streams are preferable, straight streams may be substituted, provided that fire flows are not compromised. The following tactics and techniques will ensure success when employing an interior direct attack: Due to the volatility of today’s fires, a minimum fire flow of 150 gpm is recommended for residential fires. This flow is easily achieved using 1¾-inch hose, provided friction losses are accurately determined and correct pump discharge pressures are used. One firefighter told me that when his department flow tested its 1¾-inch preconnected handlines using its standard pump discharge pressures, the average flow was only 84 gallons per minute (gpm). While in theory 84 gpm, properly applied, will extinguish a significant amount of fire, a flow this low allows no room for error and does not provide any reserve to handle unforeseen contingencies. Commercial building fires demand a minimum fire flow of 250 gpm, and this is best delivered through 2½-inch hose using solid bore nozzles. Other parameters that deserve consideration include the minimum effective reach of stream (50 feet for streams used in residential firefighting) and the nozzle reaction burden. Nozzle reaction forces should be no greater than 60 to 70 pounds. Field tests have indicated tha t a reaction force exceeding 70 pounds is very difficult for a single firefighter to handle. Realizing that a backup firefighter is most often a luxury and that even when present he will often be positioned well behind the nozzleman to pull hose around corners and feed it forward to the nozzleman as he advances, the reaction burden that can be safely handled by a single firefighter becomes a very important safety issue. Since nozzle reaction is a factor of the weight (volume) of water being discharged and the nozzle pressure, nozzle reaction can be made more manageable by reducing flow volume (an unwise decision) or decreasing nozzle pressure. The only effective means of reducing nozzle pressure without adversely impacting firefighting effectiveness is to employ solid stream tips or low-pressure fog nozzles. Unlike each of the fog firefighting methods that involves the application of water into the heated overhead to cool the gases, direct attack goes to the root cause of the problem-the source of gas production. David Fornell, in Fire Stream Management Handbook, uses the analogy of a propane cylinder leaking a jet of burning gas. The heated solid furnishings and finishings within a burning room are likened to the leaking cylinder; flammable carbon monoxide is substituted for the propane gas. In controlling a leaking and burning LPG cylinder, the goal is to control the fuel supply-the cause of the problem, as opposed to first extinguishing the burning gas-merely a symptom. The goal of the interior direct attack is to apply water directly on the heated solid materials within the fire area, reducing their temperature and halting the production of flammable carbon monoxide gas. “In any space containing heated gases which are likely to flash over or in any area already flashed over, cooling the heated solid material providing the fire’s fuel must take place to successfully stop the fire.xix Getting water onto the heated materials, however, is often easier said than done.

In addition to using the reach afforded by solid and straight streams, the ceiling and upper walls may be used to redirect the stream when heat conditions or obstructions (partitions, piles of stock, partially closed doors) make application immediately to the base of the fire impossible. Sweeping the ceiling with the stream in a side-to-side or clockwise motion also helps eliminate the threat posed by the heated gases without excessive unwanted steam production and violent disruption of the thermal balance characteristic of the indirect and combination methods. Unlike 3-D fog application, which involves cooling the gases with very small water droplets, sweeping the ceiling with a straight or solid stream causes an action that the late Floyd Nelson termed “rattling the fire’s chain.” “Inside the area of the flame, the chemical reactions that take place are often referred to as chain reactions. These chain reactions depend on a smooth flow of oxygen and a smooth flow of fuel vapors to continue their act of combustion.”xx Nelson calls it the “straight stream off ceiling” attack, and he states that it is highly effective in disrupting the flow of oxygen and fuel, thereby reducing the threats of rollover and flashover. In addition to agitating the gas layers, using the ceiling to break up the stream creates coarse droplets that will rain down on the burning solid materials and start the cooling process. Unlike the fine droplets that compose spray streams, the droplets created by splattering stream on the ceiling will be larger and heavier and less likely to vaporize prematurely or be swept away by convection currents. There is another reason for initially directing the stream at an upward angle anytime a fire has progressed to the point where flames are traveling across the ceiling. If a solid or straight stream were to be directed immediately into the lower portion of a well-involved room, the expansion of the water to steam could cause a violent displacement of burning fire gases, which might result in burn injuries to the nozzle team. The stream itself might cause burning debris to scatter, and unwanted steam creation would be increased. (This should not be confused with the action of sweeping the floor with the stream periodically during the advance to push aside glass and debris and cool heated objects and scalding water runoff.) Lastly, the importance of patience on the part of the nozzle team must be stressed, before entering the fire occupancy with a charged handline, pause momentarily, and observe the smoke venting through the door opening. Try to get a read on the its pressure and temperature, and pay attention to its color.xxi Veteran firefighters know the importance of “lying low and letting it blow.” By waiting briefly at the door, the severity of fire conditions can be gauged, and burn injuries caused by the sudden ignition of fire gases can be prevented. Sometimes, by looking back and studying the proven tactics and techniques employed by firefighters of generations past, we can best learn methods for staying alive at the fires we confront today. Special thanks to the following individuals who helped in the preparation of this article: Deputy Chief (ret.) Vincent Dunn, FDNY; Glenn P. Corbett, P.E., John Jay College of Criminal Justice and Fire Engineering technical editor; Firefighter John P. Grasso, FDNY Squad Company 61; Jerry Knapp, Haverstraw (NY) Fire Department and Rockland County Fire Training Center; Lieutenant Daniel Maye, FDNY Mand Library; Daniel Madrzykowski, P.E., national Institute of Standards and Technology; Lieutenant William McGinn, Squad Company 18; Captain David M. McGrail, Denver (CO) Fire Department Rescue Company 1; Lieutenant (ret.) Bob Pressler, FDNY and Fire Engineering technical editor; Diana Robinson, senior librarian, New York State Academy of Fire Science; and Firefighter Mark Wesseldine, FDNY Ladder Co. 58. Thanks also to Paul Grimwood; our tactics differ, but our goal is the same-to keep firefighters alive.

ENDNOTES 1 Cohn, Bert M., “Plastics and Rubber,” Fire Protection Handbook , 18th Edition [Quincy, Mass.: National Fire Protection Association (NFPA). 1997], 4-125. 1 Wiseman, John D., Jr., “Thornton’s Rule and the Exterior Fog Attack: A Perspective.” Fire Engineering, July 1996, 42-46. 1 MJ/kg (mega joule per kilogram) means that for every kilogram of fuel material consumed during a fire under strictly controlled conditions, one million joules of heat energy are released. A joule is an energy term (SI) and is equivalent to approximately 0.242 calories (a more familiar unit). The release of one joule per second (IJ/s) equals one watt (W). A kilowatt (kw) is 1,000 watts. A megawatt (MW) is one million watts. 1 Heat Release in Fires. V. Babrauskas and S. J. Grayson, eds. (London and New York: Elsevier Applied Science, 1992). 31. 1 Brannigan, Francis L. Building Construction for the Fire Service, Third Edition. (Quincy, Mass.: National Fire Protection Association. 1992), 387-389. 1 Telephone conversation with Deputy Chief (ret.) Vincent Dunn, Fire Department of New York. 1 Babrauskas, Vytenis, and Douglas Holmes, “Part III: Heat Release Rate-The HRR of Burning Materials Determines If Flashover Occurred.” Fire Findings, Summer 1998, 6:3, 12. 1 Custer, Richard L. P., “Dynamics of Compartment Fire Growth.” Fire Protection Handbook, 18th Edition. NFPA.: 1997, 1-85. 1 E-mail from Vytenis Babrauskas. 1 Babrauskas, Vytenis. “Upholstered Furniture and Mattresses.” Fire Protection Handbook, NFPA: 1997, 1-85. 1 NFPA data. 1 Murtagh, James J., “Fire’s Changing Signals.” WNYF, Issue 1, 1989, 9. 1 When the Fire Department of New York assembled a team of veteran fire officers to revise its bulletin outlining ladder company operations at tenement and apartment building fires (“Firefighting Procedures, Ladder Company Operations, Vol, III, Book 3, Tenements”) in 1996 specific instructions were provided for the outside ventilation (OV) firefighter confronted by EEW’s. When “venting for fire,” the bulletin states the following: “Communication with his/her company officer via handi talkie must be maintained in order to coordinate and control lateral ventilation. Ventilation may be extremely difficult due to EEW’s.” In discussing the tactic of “venting for life,” the bulletin continues by stating: “Prior to VES [vent-enter-search operations] from the fire escape, the OV must receive permission from his/her company officer via H.T. [handi talkie]. The OV might not be aware of the severity of conditions in the apartment.” 1 A very interesting article on the subject of wind and its impact on fire behavior appeared in the January 2000 issue of Fire Engineering. Entitled “Firefighting and the ‘High Pressure Backdraft,’ ” it was written by Brian M. White, a captain in the Fire Department of New York. As the author indicates, much more research needs to be done on this complex subject; hopefully his article will serve as a stepping-off point. 1 Knapp, Jerry and Christian Delisio, “Flashover Survival Strategy” Fire Engineering, August, 1996, 81-89. 1 “Demonstration of Biodegradable, Environmentally Sage, Non-Toxic Fire Suppression Liquids,” NISTOR 6191, Daniel Madrzykowski and David W. Stroup, eds., National Institute of Standards and Technology, July 1998. 1 Grimwood, Paul. Flashover & Nozzle Techniques, 1999, firetactics.com, U.K. 1 Ibid., 14 1 Fornell, David P. Fire Stream Management Handbook . (Saddle Brook, N.J.: Fire Engineering Books & Videos, 1991). 103. 1 Nelson, Floyd W. Qualitative Fire Behavior. (Ashland, Mass.: International Society of Fire Service Instructors. 1991). 105. 1 Pressler, Bob. “What Smoke Conditions Tell You.” Fire Engineering, Jan. 1999, 91-94. Additional References Babrauskas, Vytenis, Ph.D. and Douglas Holmes, MPA, “Special report: Heat Release Rate, Parts I, III.” Fire Findings, Winter, Spring, Summer, 1998. Cholin, John M., “Wood and Wood-Based Products.” In Fire Protection Handbook, 18th Edition (Quincy, Mass.: National Fire Protection Association. 1997).

Colletti, Dominic J., “Quantifying the Effects of Class a Foam in Structure Firefighting: The Salem Tests.” Fire Engineering, Feb. 1993. “Firefighter Deaths as a Result of Rapid Fire Progress in Structures 1980-1989.” National Fire Protection Association, Aug. 1990. Fredericks, Andrew A., Fire Engineering: “Return of the Solid Stream.” Sept. 1995; “Stretching and Advancing Handlines. Part 2.” April 1997; “Observations on the Engine Company,’ April 1998. Grimwood, Paul, “Water-fog in Structural Attack: A European View.” Fire Chief, Aug. 1993. Knapp, Jerry and Christian Delisio. “Survival Training in the Flashover Simulator.” Fire Engineering. June 1995. Leihbacher, Doug, “Search in the Modern Environment.” Fire Engineering, July 1999. SPFE Handbook of Fire Protection. Second Edition (Quincy, Mass.: National Fire Protection Association; Boston, Mass.: Society of Fire Protection Engineers. 1995).

PLANNING A HOSE AND NOZZLE SYSTEM FOR EFFECTIVE OPERATIONS

BY JAY COMELLA

The Oakland (CA) Fire Department (OFD) convened a Board of Inquiry to investigate the line-of-duty-death of Firefighter Tracy Toomey, who died on January 10, 1999. The fire building at 3052 Broadway was a two-story, balloon-frame building of mixed occupancy, with a residential area over the commercial premises. It was not an unusual building for Oakland.

On arrival, the first-alarm companies encountered a heavy fire condition on the first floor with extension up the stairway. They made an aggressive interior attack using multiple 11/2-inch handlines. Fire was not extinguished in time to prevent the loss of structural integrity. The resulting collapse of the second floor into the first floor killed one OFD member and left two others with career-ending injuries. One of the three direct causes the Board of Inquiry report cited for the line-of-duty death was the inability of 11/2- inch hose to flow sufficient water to extinguish the heavy volume of fire encountered.


(1) Left to right: automatic nozzle (50-350 gpm), adjustable-gallonage nozzle (30-60-90-125 gpm @ 100 psi), constant-gallonage nozzle (150 gpm @ 50 psi), and 15/16-inch smooth-bore nozzle (180 gpm @ 50 psi). (Photos by Daryl Liggins.)

The report further recommended using 13/4- inch hose to remedy insufficient fire flow volume of the 11/2- inch hose. By simply upgrading from 11/2- inch to 13/4- inch hose, the OFD could eliminate fully one- third of the direct causes cited by the Board of Inquiry. The Board of Inquiry report included findings, recommendations, and OFD res-ponses. It was published in September 2000.

The Board of Inquiry's findings were based on the assumption that the departmental target flow rate of 125 gallons per minute (gpm) through 11/2-inch hose was met. This, however, is unlikely for the following reasons:

1. Age, condition, and kinds of nozzles 2. Age and condition of hose. 3. Inaccurate pump chart that states friction loss (FL) to be 15 pounds per square inch (psi) per 100 feet to flow 125 gpm through 11/2- inch hose. This underestimates friction loss by 23 psi per 100 feet. Actual FL in 100 feet of 11/2-inch hose while flowing 125 gpm is 38 psi. 4. The pump chart underestimates accurate nozzle pressure (NP) by 20 psi. The only combination (fog) nozzles that the OFD currently employs are designed to operate at 100 psi NP. The pump chart states nozzle pressure to be 80 psi. 5. Theoretical flow at 15 psi FL per 100 feet of 11/2- inch hose is 79 gpm. 6. Recent flow tests performed with various engine companies showed flows ranging from 60 to 105 gpm. The average was about 85 gpm.

The Board of Inquiry report raises grave concerns about inadequate fire flow volumes. The fact that the actual flows were even less than the assumed 125 gpm compounds these concerns.

Today's fireground is a much more volatile environment than that of the past. The flow rate of 125 gpm was deemed to be adequate at a time when fuel loads were lighter and comprised of so-called ordinary combustibles, such as wood, paper, and cloth (cellulosic materials). Most likely, the OFD's current target flow rate was based on 1918 testing that established the standard fire time/temperature curve.

Fuel loads today are heavier and largely hydrocarbon-based (plastics). Plastics are petrochemical products that behave like solid gasoline and generate large quantities of thermal energy. One pound of cellulosic materials gives off 8,000 British thermal units (Btus) when burned, whereas plastics generate 16,000 Btus per pound of fuel. Not only do plastics produce twice the Btus, but they do so at a heat-release rate that is much faster than that of traditional fuels. Couple these factors with tighter and better insulated buildings that inhibit fire from self-venting (tight building syndrome), and the millennium engine company most definitely faces a much more dangerous enemy than it had in the past.

Since the enemy has become much more dangerous, the weapon used to combat the enemy must be upgraded accordingly. Akin to the police evolving from the 38-caliber revolver to the 40-caliber automatic, the fire department also must make a more intelligent weapon selection. The hose and nozzle system is the engine company's weapon for attacking the fire. The vast majority of the American fire service considers 150 gpm to be the minimum acceptable flow rate for interior structural fire attack. Many fire departments use a target flow rate of 180 gpm to ensure an added margin of safety.

In his brilliant treatise on the art and science of applying water on fire ("Little Drops of Water: 50 Years Later," Parts 1 and 2, Fire Engineering, February and March 2000), Andrew Fredericks, the foremost expert on engine company operations, further states that in addition to 150 gpm being the minimum acceptable flow for residential fires, 250 gpm is the minimum acceptable handline flow for operations in commercial occupancies.

OFD's target flow rate of 125 gpm is well below the nationally accepted fire service standard, and its actual flow rate of 85 gpm simply is inadequate for modern fire conditions.

The outcome of fireground operations depends on the outcome of the battle between the water the engine company delivers (gpm) and the heat (Btus) the fire generates. The flow at which the engine company can win the battle and kill the fire is defined as the critical flow rate. If the critical flow rate is not met, the battle will be lost. This dictates that the single most important characteristic of a hose and nozzle system is water flow capability. The water the engine company delivers must be sufficient to expediently kill the fire. Maneuverability of the hose and nozzle are important factors, but to sacrifice flow for ease of use has proved to be suicidal.

Although an adequate flow rate cannot be sacrificed for ease of use, handling characteristics cannot be completely overlooked either. The amount of effort required from the nozzle operator is that which is necessary to resist the nozzle reaction. Nozzle reaction is measured in pounds of force and is a function of two factors—flow rate and nozzle pressure. An increase in one or both of these factors will result in an increase in nozzle reaction force (RF). The higher the nozzle RF, the more difficult the nozzle is to control. Since adequate flow rate is the ultimate goal of a well-conceived hose and nozzle system, the logical way to keep nozzle RF within the manageable range is to keep nozzle pressures low and avoid sacrificing flow. More than 75 pounds RF is considered to be too much reaction force for a handline. However, RF less than 45 pounds is considered to be a sign of an ineffective stream.

Hoseline handling characteristics are a function of the following factors:

1. Flow rate. 2. Hose size. 3. Friction loss. 4. Pump discharge pressure.

Handline maneuverability is determined by the pressure at which a given size line must be pumped to attain a desired flow rate. If hose size remains constant and flow is increased, pump discharge pressure must be increased to account for greater friction loss. This reduces maneuverability as the line approaches the stiffness of a pipe. Conversely, if hose size increases while flow remains constant, pump discharge pressure may be reduced due to lower friction loss requirements. This results in improved maneuverability because the line becomes more bendable.

The aforementioned parameters lead to certain conclusions about what constitutes a well-planned hose and nozzle system for residential fires. The hose should be capable of flowing between 150 and 180 gpm with relatively low friction loss. The nozzle should have similar flow capability at a nozzle pressure that will maintain reaction force in the range of between 45 and 75 pounds.

Because of the pressures required to account for friction loss, the practical flow limit for 11/2-inch hose is 125 gpm, whereas the practical flow limit for 13/4-inch hose is 200 gpm (see Figure 1).

The tool at the very heart of the entire fireground operation is the nozzle. It is the weapon with which members enter into close-quarter combat with the enemy. If the nozzle malfunctions or is not used properly, all other tools and tactics on the fireground are likely to become quite limited in their effectiveness in saving life and protecting property. All kinds of nozzles perform their all- important mission by providing some rather simple, uncomplicated, albeit incredibly necessary, functions. They control flow, create shape, and provide reach. Since the functional requirements for a nozzle are relatively simple and yet immensely important, intuitively it makes sense to select the kind of nozzle with the least complicated design and the fewest moving parts. The low-tech choice in nozzle selection ensures the greatest degree of durability and reliability. Simple, durable, and low-tech are all qualities that contribute to low initial and long-term costs. More importantly, these qualities lead to reliability, which, in turn, leads to increased safety. There is an inverse relationship between nozzle cost and suitability for interior structural firefighting. Unlike so many things in modern-day, high-tech society, the best kind of nozzle actually costs substantially less than the other kinds.

NOZZLE CHARACTERISTICS

The kinds of nozzles available today, in descending order of simplicity and durability, are smooth-bore, constant-gallonage (single gallonage) fog, adjustable gallonage fog, and constant pressure (automatic) fog.

Smooth-Bore Nozzle. The smooth bore is the most low-tech of all nozzle designs. It consists of a ball valve shutoff device onto which is threaded the smooth-bore tip, which is basically a piece of tapered pipe. Together, the shutoff and tip present a very compact (73/4- inch) and lightweight (21/2 lbs.) package. Genius lies in the simplicity of its design. It has only one moving part—the ball valve.

To emphasize how difficult it is to clog a smooth-bore nozzle, Fredericks held a 15/16-inch tip up to his eye and, looking through it, he exclaimed to his lecture audience, "This is all the water sees on its way to the fire." It is the most durable and reliable of all nozzles. It requires the least maintenance of any nozzle type and has the longest service life.

Smooth-bore nozzles are by far the least expensive kind to purchase and maintain. Of all nozzles, the smooth-bore requires the least amount of training for pump and nozzle operators to become proficient. The incredible reliability of the smooth-bore nozzle is a significant safety feature. Since you can produce only a solid stream with the smooth-bore nozzle, its use ensures that members and victims will not be exposed to the potentially debilitating or lethal effects associated with introducing a fog stream into the fire area.

Emphasizing the need for durability, reliability, and low maintenance in nozzles, OFD Captain Ted Aff in Fire Stream Management Handbook by David P. Fornell (Fire Engineering, 1991) says, "If you give a fireman a 2- inch stainless steel ball bearing and put him in a bare, windowless room for an hour, when you open the door and ask about the ball bearing, he will have either bent it, broken it, or lost it." The smooth-bore nozzle is the safest and most efficient weapon for combating interior structural fires. Therefore, it is the only kind of nozzle that should be taken into the most hostile work environment on the face of the earth—the interior of a burning building. Fog nozzles should be kept in the inventory for other uses, such as flammable- liquid fires.

Constant-Gallonage Fog Nozzle, The constant-gallonage nozzle is the simplest, most reliable, least maintenance- intensive and, hence, safest member of the fog nozzle family. Of all fog nozzles, this type requires the least training. It does, however, require somewhat more training than the smooth-bore nozzle. Constant gallonage or single gallonage indicates that this nozzle is designed to flow a specific gallonage when operated at the specific pressure for which it is designed, such as 150 gpm at 100 psi NP.


(2) Oakland (CA) Fire Department (OFD) members operate a 21/2-inch hoseline with a 11/8-inch smooth-bore nozzle (266 gpm @ 50 psi) during testing and evaluation.

In addition to the 100-psi model, constant-gallonage nozzles also come in 75-psi and 50-psi models. The nozzle is 121/4 inches long and weighs 6.1 pounds. As the name suggests, there is the distinct possibility of a fog stream being introduced into the fire area. This has the potential to, in short order, turn a still-tenable environment into one that is untenable. As with all fog nozzles, when the water flows from the hose—through the shutoff, into the tip, to be broken into a spray stream—a clog point exists. The constant-gallonage nozzle is the only kind of fog nozzle that should be in an engine company's inventory.

Adjustable-Gallonage Fog Nozzle. The adjustable gallonage takes fog nozzle technology to the next level of complexity. It has more moving parts and is more maintenance- intensive than the constant-gallonage nozzle and, hence, has an increased potential for nozzle failure or malfunction. Using a flow-selection ring, the nozzle operator can choose a desired flow. This operation requires an increased level of training for nozzle and pump operators. If the nozzle operator changes the flow setting, the pump operator must be informed so he can adjust pump discharge pressure to the appropriate level for the selected flow. It is possible to put the flow-selection ring on the wrong setting, resulting in the nozzle's flowing less than the desired amount of water. So, in addition to the possibility of introducing a dangerous fog stream into the fire environment, there is a great potential to produce a flow that is less than the acceptable minimum. The adjustable-gallonage nozzle is 121/4 inches long and weighs 5.6 pounds. The adjust-able-gallonage nozzle should not be part of an engine company's nozzle inventory.

(3) The 13/4-inch hose allows significantly higher flow than the 11/2-inch line, yet size and weight differences are nominal.

Automatic Fog Nozzle. Automatic nozzles originally were de-signed in the late 1960s by Chief Clyde McMillan of the Gary Fire Task Force, an auxiliary unit of the Gary (IN) Fire Department. One of the roles of the task force was to respond to large fires and put master streams into operation. Often, initial water supply was inadequate when transitioning to defensive operations. McMillan set about de-signing a master stream appliance nozzle that would produce a stream with good reach, even at the low flows available during the transitional phases of operations. He also wanted that same nozzle to be appropriate for the high flows achievable after augmentation of the water supply.

The automatic nozzle is also called the constant-pressure nozzle. Constant pressure refers to the fact that the nozzle produces a stream of reach and appearance consistent with 100-psi tip pressure regardless of the pressure actually coming into the base of the nozzle. This is accomplished by a baffle and spring arrangement. As a given amount of water enters the nozzle base, it puts the spring under a given amount of tension. This, in turn, moves a baffle that changes the nozzle's orifice size. As the amount of water flow fluctuates, so does the orifice size. The orifice is maintained at a size that, for the given amount of water, provides approximately 100 psi NP. This creates a visually attractive stream with good reach over an extremely wide range of flows. This has prompted nozzle sales representatives to state, "The automatic nozzle will produce an effective stream no matter what the flow." Though stream quality and reach are important, stream effectiveness is determined by whether it meets the critical flow rate. Often, the stream produced by the automatic nozzle is good-looking but doesn't have much water in it.

The automatic fog nozzle is bulky (length—133/4 inches, weight— 6.5 pounds) and costly. It is at the high-tech end of the spectrum of fire service nozzles. To be used properly, it requires more training for both nozzle and pump operators than any other

nozzle type. It has the most complicated design of any nozzle and the most moving parts. It is the most maintenance- intensive and the most susceptible to failure.

To use a suitable military analogy, the automatic nozzle is to the smooth bore as the early M-16 was to the AK-47. The simple, low-tech, battle-proved AK-47 with its simple design and loose operating tolerances could handle an incredible amount of abuse in the field and still remain a very functional and effective weapon. On the other hand, the early model M-16, with its complex design, superior machining, and fine tolerances, was very susceptible to malfunction in the harsh environment of the battlefield.

Because of its design intricacy, the automatic nozzle has a high susceptibility to malfunction. It also has a propensity to mask insufficient flow by presenting an attractive stream over a wide range of flows.

THE 21/2-INCH HANDLINE

The first step in planning a hose and nozzle system is to establish the needed flow for the occupancy type in question. The flow requirement is derived by determining the flow at which the engine company most often will overwhelm the heat generated by the encountered fuel load. To deliver the desired volume of water, parameters for hose selection are based on flow and friction loss characteristics. Parameters for selecting a nozzle to couple to the business end of that hose are based on flow and reaction force characteristics. This holds true for residential occupancies and for fires in commercial buildings.

As mentioned earlier, when paraphrasing Fredericks, the minimum acceptable handline flow for operations in commercial occupancies is 250 gpm. For this type of flow, 21/2-inch hose is the line of choice. Friction loss at 250 gpm is 12 psi per 100 feet of 21/2-inch line. For the same flow in two-inch hose, the friction loss is 50 psi per 100 feet. Though a 21/2-inch line is a very substantial piece of equipment, it is not too heavy to aggressively advance as a handline, as would be the case with three- inch hose.

The key to using a 21/2-inch line efficiently is proper nozzle selection. The 100-psi combination nozzle effectively has removed the 21/2-inch line from the department's arsenal of offensive weaponry because of the astronomical nozzle reaction force of 126 pounds while flowing 250 gpm at 100-psi nozzle pressure. When pumped according to the department pump chart at 80-psi tip pressure, flow drops to 220 gpm with a still relatively high reaction force of 113 pounds. Low-pressure nozzles (50-psi tip pressure) that impart significantly less reaction force will return the venerable 21/2-inch line to its former status as a very aggressive, very offensive weapon.

Many departments successfully employ a 11/4- inch tip. Its 324-gpm flow technically classes it as a large-caliber stream, making this size tip possibly better suited for use with master stream devices. A far greater number of departments use the 11/8- inch tip. With a flow of 266 gpm at 50-psi nozzle pressure, it has a reaction force of 95 pounds. Although

it is still very important to keep nozzle reaction force low, it would be impractical to try to apply the previously cited 75-pound cap to flows from large-caliber handlines.

Paired together, the 21/2- inch line and the 11/8- inch tip create a user- friendly, offensive, large-caliber weapon. As Fredericks states in his article "The 21/2-Inch Handline" (Fire Engineering, December 1996), "No combination of smaller handlines can duplicate the volume, reach, and pure knockdown power of a single, well-placed 21/2- inch line. In addition to its high-volume flows (between 250 and 320 gpm) and long stream reach, 21/2-inch hose provides the following benefits when used with a 11/8- inch solid stream tip:

• low friction loss per 50-foot length (only about six to eight psi at 262 gpm), • exceptional penetrating power due to hydraulic force of the stream, • little premature water vaporization in highly heated fire areas, • easy reduction to smaller handline(s) after knockdown, and • much better maneuverability than three-inch hose (sometimes used as a handline)

or portable master-stream devices."


(4) An OFD member using a pitot gauge during testing and evaluation.

Using a 21/2- inch line is indicated in situations in which fire conditions are likely to overwhelm smaller handlines. Fredericks cites the oft-used mnemonic device "ADULTS," which refers to scenarios requiring the use of 21/2- inch line:

Advanced fire on arrival Defensive operations Unable to determine extent (size) of fire area Large, uncompartmented areas Tons of water Standpipe system operations

The ADULTS acronym is reminiscent of an anecdote related by retired Chicago (IL) Fire Department Battalion Chief Ray Hoff regarding proper handline selection. On seeing an

engine company stretching a 13/4- inch line toward a commercial occupancy exhibiting a heavy fire condition, Hoff requested, "Would you please put that down and bring me an adult-size line?"

When the engine company encounters advanced fire on arrival, the high flow available from 21/2-inch hose is needed for rapid control. Even a private dwelling may exhibit a fire condition heavy enough to warrant the quick knockdown power of the 21/2-inch line. This is especially true of extensive involvement of the first floor or front porch.


(5) OFD members comparing a 13/4-inch hose with a 15/16-inch smooth-bore nozzle flowing 180 gpm vs. a 11/2-inch hose with 125 gpm @ 100 psi adjustable-gallonage nozzle flowing 79 gpm (pump discharge pressure as per OFD SOPs).

Although using master stream appliances is not recommended for occupied residential buildings, the same cannot be said of 21/2- inch hose. The 21/2- inch line with 11/8- inch smooth-bore nozzle is a large-caliber weapon that is aggressive, mobile, and offensive. It can rapidly darken down a very heavy fire condition to allow an interior attack. This permits three tactical options: The 21/2- inch handline can be advanced into and through the structure; the attack can transition to the use of a smaller line with the big line left where it is; or the 21/2- inch line can be reduced down to a smaller line to press the interior attack for final extinguisment.

Whether operations are defensive initially or transition from offensive to defensive, smaller-caliber handlines should not be used. The 21/2- inch line is a much safer and more efficient alternative. The reach afforded by the large r line allows it to be operated from outside the collapse zone. Once its high-volume stream penetrates into the fire area, it has a much greater effect on conditions than does a stream from a smaller line. The 21/2-inch handlines are much more mobile and easier to deploy than master stream devices. This allows streams to be brought to bear from a greater variety of locations.

If the engine company officer is unable to determine the extent (size) of the fire area, a 21/2-inch line should be used. The high-flow stream allows for unforeseen contingencies. During the course of operations, it may be determined that the amount of fire encountered can be handled with smaller hose. As with the above-mentioned private dwelling scenario, the 21/2- inch hose can be reduced to, or replaced by, a smaller line.

Fires in large, uncompartmented areas require levels of reach, penetration, and volume that are beyond the capabilities of smaller handlines. In addition to wide-open floor plans, occupancies such as supermarkets, bowling alleys, warehouses, theaters, houses of worship, and the like often have very high ceilings. High ceilings allow massive amounts of heated fire gases to accumulate. Once these flammable vapors ignite, they may prove to be too formidable for streams from smaller lines. The reach and tremendous cooling power of the 21/2- inch line with 11/8- inch tip allows for operation from an entranceway into the rolling flame front of combustible gases beneath the ceiling. Once the hazard in the fuel- laden overhead area has been dealt with, the attack can be pressed farther into the interior of the structure.

At some fires, extinguishment simply requires tons of water. This is often the case for fires in piles of tires, junkyards, garbage dumps, and lumberyards, to name a few. A 21/2-inch line with 11/8- inch tip operating at 50 psi NP discharges more than a ton of water a minute. The use of smaller lines in this kind of situation would be an exercise in futility.

Proper consideration for members' safety demands the use of 21/2- inch hose and smooth-bore nozzles for standpipe operations. NFPA 14, Standard for Standpipe Systems, was developed based on the use of 150 feet of 21/2- inch hose equipped with a 11/8- inch smooth-bore nozzle. Depending on which of the two versions of the standard a given standpipe system was de-signed under, outlet pressures can be either 65 psi (old criteria) or 100 psi (new criteria). Outlet pressures such as these simply will not meet the friction loss requirements for smaller-diameter hose, especially in conjunction with 75-psi or 100-psi nozzles.

Many standpipe systems have pressure-reducing valves that are not field-adjust-able. This means that no matter what pressure fire department pumpers pump into the system, outlet pressure will not rise above a given outlet's rated pressure. As Fire Department of New York Battalion Chief John Norman states in Fire Officer's Handbook of Tactics (Fire Engineering, 1998), to use anything other than 21/2- inch hose and smooth-bore nozzles for standpipe operations is to use the standpipe system in a manner other than that for which it was designed. Prior to becoming a member of the professional fire service, Norman was a fire protection engineer and made his living designing sprinkler and standpipe systems.

Because of design configurations and conditions of standpipe systems, pressure problems chronically plague operations. Though certainly not an ideal situation, even at a very low outlet pressure, the combination of 21/2- inch hose and a 11/8- inch smooth-bore tip still can develop a usable fire stream.

In February 1991, the Philadelphia (PA) Fire Department had a disastrous experience dealing with a fire in the One Meridian Plaza building. At the time, the Philadelphia Fire Department used 13/4- inch hose and automatic fog nozzles for standpipe operations. At numerous sessions of the Fire Department Instructors Conference (FDIC) Engine Company Operations Class, Denver (CO) Fire Department Battalion Chief David McGrail replicated the outlet pressures (40-45 psi) that existed at the One Meridian Plaza fire. Consistently, 13/4- inch hose with an automatic tip flows less than 50 gpm while 21/2-inch line with a 11/8- inch tip achieves flows in the range of 200 to 210 gpm. This concurs with information found in Fornell's Fire Stream Management Handbook. The building eventually was demolished. The loss of the building, however, is inconsequential when compared with the loss of three members of the Philadelphia Fire Department. The tragic loss of these members was caused in no small part by poor weapons selection. The Philadelphia Fire Department now uses 21/2- inch hose and 11/8-inch smooth-bore nozzles for standpipe operations. Hopefully, it will not take more tragedies of this nature for other departments to rethink their weapons selection for standpipe operations.

SOLID STREAMS

Increased handline flows through hose and nozzle configurations that maintain maneuverability and impart manageable reaction forces will lead to more effective, more efficient, faster, and safer extinguishment operations. More expedient extinguishment, in turn, makes all other fireground operations proceed more safely and efficiently.

The solid streams produced by smooth-bore nozzles will further serve to increase the safety and efficiency of fireground operations. Solid streams are less susceptible to premature vaporization than fog streams. That is the reason solid streams are superior to fog streams in so many aspects of the fire extinguishment process. Solid streams are better able to penetrate superheated atmospheres. This, combined with the fact that their physical properties give them far superior reach, means that solid streams are much more apt to reach the seat of the fire.

With a smaller percentage of the stream vaporizing, the excess steam generation inherent in fog stream application is not present. Less steam generation means less disruption of the thermal balance of the fire compartment. Maintaining the thermal balance relatively intact preserves a condition of differentiated heat strata. Most of the heat remains in the upper levels of the fire compartment while the floor area remains relatively tenable. Visibility is less negatively affected, and the solid stream does not push products of combustion toward victims, members, or uninvolved areas of the structure.

This is in direct opposition to the conditions created by introducing a fog stream into the fire compartment. As the fog stream readily vaporizes, voluminous amounts of deadly, superheated steam are driven down to the floor. This severely increases the hostility of the environment in which members are operating, and incapacitated victims lie helplessly awaiting salvation. The use of smooth-bore nozzles will lead to safer and more efficient

fireground operations for department members. This, in turn, will lead to an increased window of survivability for victims.

The key to using a solid stream is rapid, vigorous nozzle movement to splatter the stream off the ceiling and upper walls. This method will break the stream up into large, heavy drops of water that will rain down onto the burning solid fuels. This creates conditions that Fredericks likened to "an August thunderstorm." As these large chunks of water begin their journey downward toward the seat of the fire, they simultaneously cool the upper area of the fire compartment. The upper level of the fire compartment is the birthplace of rapid fire progress phenomena, such as backdraft and flashover. The large, heavy drops of water created by smooth-bore nozzle movement have a much lower surface-to-mass ratio than the fine droplets produced by a fog nozzle. Thus, they are much less prone to premature vaporization. This makes the solid stream more efficient for extinguishment because its large drops of water cool the upper area of the fire compartment and then still are able to pass down through superheated strata to the seat of the fire—the burning solid fuels where the fuel- flame interface is located. Thus, the superheated upper portion of the fire compartment, containing massive quantities of unburned fuels, is quenched and the further distillation of flammable vapors and particulates at the fuel- flame interface is quelled in the lower level of the fire compartment. In Fire Stream Management Handbook, Fornell likens this manner of preventing further production of gaseous and particulate fuel—applying water to the seat of the fire—to turning off the valve of a leaking propane cylinder.

OPTIONS FOR IMPROVEMENT

It is incumbent on the OFD to react to the findings of the Board of Inquiry in some manner. The existing body of knowledge concerning engine company operations, coupled with the facts that have been brought to light surrounding the line-of-duty death, indicate that the status quo is simply unacceptable.

There are a number of options the OFD can employ to improve the extinguishment capabilities of its engine companies and, hence, increase the safety of all department members and the civilians whom they are sworn to protect. The following options are listed in ascending order of acceptability:

Option 1. Do nothing other than change the OFD pump chart to accurately reflect the current flow rate from 11/2- inch hose. This will ensure that members are informed regarding how much water flow (79 gpm) is at their disposal while conducting interior structural firefighting operations. This is the least acceptable option. Option 2. Issue a standard operating proceedure (SOP) stating the proper pump discharge pressures necessary to attain the flow volumes the department has long stated to be its target flows. The pump chart would need to be corrected to show true FL and NP; 40 psi (rounded up from 38 psi to make calculations easier at 02:00) FL per 100 feet of 11/2-inch hose and 100 psi NP to flow 125 gpm, and 12 psi FL per 100 feet of 21/2- inch line and 100 psi NP to flow 250 gpm. Nozzle RF would be 63 pounds and 126 pounds, respectively. Theoretically, this would meet the department target flow rate. The

practicality of meeting the target flows is questionable because a major portion of the nozzle inventory is of types and conditions that will affect flow rate negatively. There is no implementation cost. However, 11/2- inch flow still will not meet the 150-gpm minimum acceptable flow rate for interior operations in residential occupancies, and the unwieldy RF of the 21/2-inch line will cause it to be considered a static defensive weapon. Option 3. Implement Option 2. Additionally, purchase the needed quantity of 11/2- inch and 21/2-inch 100-psi fog nozzles. Purchase the constant-gallonage kind. Results would be the same as Option 2. However, the practicality of meeting target flows will be greatly improved because of the nozzle inventory. Option 4. Replace existing 11/2- inch fog nozzles with 150-gpm @ 100 psi constant-gallonage fog nozzles, which generate 76 pounds RF. Update the pump chart to show 55 psi FL per 100 feet of 11/2-inch hose to flow 150 gpm. Ensure that all 21/2- inch fog nozzles are constant gallonage. Flow, NP, and RF numbers for 21/2- inch would be the same as in Option 2. This option would allow engine companies to achieve the minimum acceptable handline flow for interior structural firefighting, 150 gpm. This improved flow, however, would come at an excessive RF. Option 5. In addition to new nozzles, purchase 13/4- inch hose. To flow 150 gpm, 13/4-inch hose is a much more practical choice than 11/2- inch. FL would be 30 psi per 100 feet of line. Option 6. With 13/4-inch and 21/2- inch hose, use 75-psi constant-gallonage fog nozzles. 150 gpm @ 75 psi NP results in 66 pounds RF. 250 gpm @ 75 psi generates 109 pounds RF. This would allow engine companies to flow 150 gpm at an RF that is in the spectrum appropriate for smaller handlines, between 45 and 70 pounds. Option 7. With 13/4-inch and 21/2- inch hose, use 50-psi constant-gallonage fog nozzles. 150 gpm @ 50 psi NP results in 54 pounds RF. 250 gpm @ 50 psi generates 89 pounds RF. Option 8. Implement one of Options 2 through 7. Additionally, issue an SOP stating that only the narrowest pattern (straight stream) on a fog nozzle shall be used for interior firefighting. Direct the Training Division staff to stop training the recruits to use a 30° fog pattern for interior fire attack. Enough members have received steam burns to question the validity of this tactic. Options 2 through 7 address safety through addressing flow. Option 8 goes a step further toward improving safety by attempting to ensure proper stream selection. However, there is the possibility that the nozzle may be left on the wrong pattern setting or the setting may be inadvertently switched as the nozzle gets bumped around during stretching and advancing. Option 9. With 13/4-inch and 21/2- inch hose, use 7/8- inch and 11/8- inch smooth-bore nozzles, respectively. A 7/8- inch smooth-bore tip will flow 160 gpm @ 50 psi NP with 57 pounds of RF. A flow of 160 gpm through 13/4- inch requires a FL of 35 psi per 100 feet

When reviewing the above- listed options, consider several factors, including how each option affects the following issues: initial and long-term costs, maintenance needs, durability, reliability, service life, effectiveness, efficiency, safety of members, and safety

of victims. In view of these considerations, the implementation of Option 10 is the best method by which to improve the arsenal of weapons at the disposal of the engine company. As was mentioned previously, effective, efficient, and safe engine company operations equal expedient extinguishment. Expedient extinguishment allows every other tactic (entry, ventilation, search, etc.) taking place on the fireground to become safer and more efficient. The tactics members implement during the fire stand between victims and mortality. More efficient fireground operations lead to a higher victim survival rate.

Hopefully, the information contained in this article will help the fire service move forward toward the goal of safer, more effective, and more efficient engine company operations.

This article is dedicated to Oakland Fire Department Hoseman Tracy Toomey, Engine Co. 6 (working in Engine Co. 12), who made the supreme sacrifice on January 10, 1999, while operating at a fire at 3052 Broadway. It is also dedicated to Firefighter (promoted posthumously to Lieutenant) Andrew Fredericks, Squad Co. 18, FDNY, who made the supreme sacrifice on September 11, 2001, while operating at the World Trade Center. Fredericks' life's work was dedicated to the betterment of the fire service and improving the safety of its members.

Thanks to the following for their assistance in preparing this article: Battalion Chief James Edwards, Battalion 2, OFD; Battalion Chief Ted Corporandy, Battalion 2, San Francisco (CA) Fire Department; District Chief David McGrail, Denver (CO) Fire Department; Lieutenant Anthony DiStefano, Engine Co. 5, OFD; Lieutenant (Ret.) Kenneth Van Gorder, Engine Co. 8, OFD; Lieutenant Richard Patterson, Division 6, FDNY; Fire-fighter Daryl Liggins, Engine Co. 16, OFD; Firefighter Mark Wesseldine, Ladder Co. 58, FDNY; and Janet Kimmerly, editor, WNYF.

JAY COMELLA is a firefighter with the Oakland (CA) Fire Department, where he has served for 13 years. He has served as a H.O.T. instructor at the FDIC and FDIC West.

Engine Company Operations: Back to the Basics

By Matt Rush

I would like to dedicate this article to my close friend, the late Andy Fredericks. I was honored to teach beside him, humbled to be his student, and honored to be his friend. Not a day goes by that I don’t think of him. God Bless Andy.

For the purposes of our discussion here, I will focus on advancing a 1¾-inch handline with a three-person nozzle team. The tactics discussed here can easily be applied to attack lines of smaller and larger diameters. Obviously, the 2½-inch “big guns” may require more personnel.

As we all know, the 1¾- inch handline has a very practical application in today’s fire service. It is lightweight, often used as a preconnect for quick attack, can be handled quite easily with smaller crews, and is used primarily as a residential line. It is critical that we get water on the fire, and to do this we must get the proper length of hose to the seat of the fire. With the widespread use of preconnects in today’s fire service, this can often times become tricky. Three simple stretch techniques can be used at every fire, no matter what type or set up of hose the engine company chooses to use. First, assess what type of situation the engine company has on arrival. Is the structure residential or commercial? Is it small or large, single-story or multi-story? Are there standpipes? You understand the picture. Choose a correct handline that will supply enough water and the proper length for the situation. Second, size up how much hose is needed from the engine to the front door (or entrance of choice) of the structure. Third, size up how much hose is needed from the front door to the seat of the fire. This obviously gets tougher as you add floors into the equation. A good rule of thumb when estimating hose on the interior is to use one length per floor plus a length on the fire floor (perhaps two in large commercial buildings). For example, a fire on the fourth floor would require four lengths of hose. One length between the first and second floors, one length between the second and third floors, one length between the third and fourth floors, and a length for the fire floor. Do not forget to add the hose needed from the engine company to the entrance point of the structure. Will your department’s preconnect reach the fire? If not, be prepared to add on to your attack line or choose a different hose load. Another good rule of thumb is to have at least 50 feet of hose when advancing into the fire area.[i] Hose stretches must be as precise as possible. If the nozzle team pulls too little hose, they will fall short; while if they pull too much hose, they will end up with a “spaghetti bowl” in their lap. Make sure you have a contingency plan should your current hose loads fall short. Train until stretching becomes second nature to the nozzle team; do not wait until entering the fireground to learn.

Due to the fire- load characteristics we face today, the recommended minimum flow for fire attack is 150 GPM in a residential setting. When firefighters from around the country

were asked what their department was flowing on a 1¾- inch handline, the unanimous answer was 100 GPM with a fog nozzle. Many firefighters may say (and have actually done so) that you can easily extinguish a residential fire with 80-95 GPM with a properly placed stream. Although true, what about having enough water in “reserve” should Murphy’s Law take effect and conditions deteriorate? What about a contingency plan for firefighter safety? Therefore 150 GPM is the minimum recommended flow for interior fire attack (more is better, but keep property conservation in mind). With a target flow of 150 GPM, we can now compare the fog nozzle with the smooth-bore nozzle. With 200 feet of 1¾- inch handline (simulating a typical preconnect) and a flow of 150 GPM, the Pump Discharge Pressure (PDP) for both 75 psi and 100 psi fog nozzles is roughly 147 psi and 172 psi, respectively. The PDP for the 7/8- inch smooth bore nozzle is 122 psi while flowing 160 GPM (a 15/16- inch smooth bore nozzle has a flow of 182 GPM at 50 psi nozzle pressure). While flowing the same GPM the obvious difference here is the PDP which correlates into a substantial difference in nozzle reaction force.

Have a three-person nozzle team advance the 200-foot, 1¾- inch handline around four corners into the back bedroom of an “apartment” with water flowing the entire time. The reason to have water flowing all of the time is to simulate a large body of fire and to negate the tactic of “spotting” as the nozzle team advances. As stated previously, the majority of firefighters are accustomed to advancing a 1¾- inch handline with a fog nozzle flowing approximately 100 GPM, which is a PDP of only 107 psi (low pressure fog) to 132 psi. The nozzle teams will encounter a much higher nozzle reaction force when advancing the fog nozzle with 150 GPM flowing. Repeat the scenario with the smooth bore nozzle and ask your crews which nozzle they prefer.

To combat the higher nozzle reaction force, lower pressures with the smooth bore, and to review basic tactics, stress nozzle team positions: the nozzle firefighter, the backup firefighter, and the door firefighter.

The Nozzle Firefighter

The nozzle firefighter will be taking the brunt of the heat and must be able to read fire conditions. For this reason, some will say that this position should be for the veteran firefighter on the team (not to include the officer). The nozzle firefighter must use good nozzle technique. This includes proper hand position and technique when putting water on the fire. With the invention of the pistol grip nozzle and higher nozzle reaction forces with the fog nozzle, proper hand position has dwindled. The ideal hand position should be to have the nozzle out in front with the nozzle firefighter’s hand away and off of the bail.

Notice the hand positioning. The nozzle firefighter’s first hand is at the coupling between the nozzle and handline. It is free of the bail to allow thorough nozzle movement and to eliminate the risk of gating down the nozzle.

Place your first hand behind the coupling that separates the nozzle and the handline. Place your second hand in a comfortable position behind the other. The bail will still be in arms reach should it need to be used. This is done for two reasons. First, it gives the nozzle firefighter more control, speed, and safety when bending the nozzle up, down, or sideways. Second, it keeps the nozzle firefighter from gating down the nozzle when his hand is not on the bail. This seems to be a natural choice when the nozzle reaction forces are high. Since we are flowing 150 GPM and predominantly used to 100 GPM, the natural reaction is to gate down because it feels as though the nozzle is getting away. Gating down the nozzle only reduces GPM, which contradicts our purpose.

To address proper nozzle technique with an aggressive interio r fire attack, I advocate the use of straight streams and solid streams ONLY. Why? First, the inventors of the fog nozzle never intended the fog pattern to be used for an aggressive interior fire attack, but for ship fires and an attack made from outside the structure (what we now refer to as an indirect attack). Second, straight and solid streams are much less dynamic when they disrupt the thermal balance. Therefore, they provide better visibility and longer reach, prevent the rapid conversion to steam close to the nozzle team, and reduce the risk of pushing fire into unwanted areas. Keeping all this is mind, proper nozzle technique dictates a straight or solid stream in a vigorous clockwise motion, often thought of as “whipping,” directed to the main body of fire. Vigorously “whip” the nozzle at the seat of the fire, walls, ceiling, and floors as you advance. The floor should be swept clear of hot water and debris, primarily sharps (sweeping the floor is also an effective way to sound for holes and walls as you advance). As my good friend Andy Fredericks used to say, “Make the room look like an August Thunderstorm.”

The Backup Firefighter:

Although some say that the nozzle position should be reserved for the veteran firefighter, others will contend that the two most important positions are the backup firefighter and the door firefighter. The backup firefighter will take the majority of the nozzle reaction forces so that the nozzle firefighter can move the nozzle about freely. The backup firefighter must anticipate which direction the advance will go and move accordingly. If the nozzle firefighter has to go left, than the backup firefighter would have to go right, and vice versa. If the nozzle firefighter goes up, than the backup firefighter must go down, and vice versa. In addition, the backup firefighter must help keep the nozzle out in front of the nozzle firefighter, as stated earlier, but be very careful not to push or pull the nozzle firefighter. The backup firefighter’s positioning should be anywhere from right behind the nozzle firefighter to one arm length, depending on preference, staffing, and reaction forces. This position also serves well to check all doors and ceiling spaces during the advance, as well as chocking any doorways. It is justifiably argued that the backup firefighter position should be the officer when a two- or three-person crew in is place.

Needless to say, the backup position is quite laborious, and therefore proper technique is important. Rather than just holding onto the hose as the team advances, the backup firefighter should use the “Seattle lock.” This enables the backup firefighter to use his or her entire body weight rather than just arm strength.

Photo 1 — Notice the backup firefighter’s position behind the nozzle firefighter. Everyone should be on the same side of the line. Should the officer be in this position, he or she will be able to evaluate conditions during the attack.

Photo 2 — A better hand position is the “Seattle lock.” The backup firefighter hooks the hose with the right arm and grasps the left forearm, which in turn takes hold of the handline. This enables the backup firefighter to use bodyweight as leverage.

The Door Firefighter:

The door firefighter plays a pivotal role in the advance of the handline. As staffing levels fall, advancing hose is becoming harder and harder. There are techniques, however, that can maximize our efforts. The door firefighter is just that; the firefighter at the door. His or her main role is to feed hose to the backup and nozzle firefighters. The door firefighter

must keep in mind that he or she may initially be standing in a large opening, a very opportune exit hole (and possibly the only exit hole until coordinated ventilation by a truck company takes place) for the products of combustion. This area is often referred to as the “chimney.” Therefore, the door firefighter should be to one side of the door and low, out of the “chimney,” so that he or she is both out of the direct path of the products of combustion and can also see what is going on around him or her. Many firefighters have found victims by simply staying low and looking under the blanket of smoke into the fire room. Once the nozzle firefighter and backup firefighter are out of sight, the door firefighter must continue to feed hose by using the “bow” technique. The “bow” technique is done by making a bow or bend at the door firefighter’s position. As the slack in that bow tightens, the door firefighter knows that the nozzle team is advancing and can create another bow. Make sure to pull hose from the outside in order to make the bow so as not to push the nozzle team towards the fire.

Keep in mind that the door firefighter will not always be at the door. Depending on how far the nozzle firefighter and backup firefighter push, the door firefighter will have to move up from corner to corner to facilitate the advance. In addition, the door firefighter may have to be responsible for walking out the kinks in the line so as not to jeopardize flow. If more personnel are available, assign them to additional door positions and maximize the advance.

Now that the nozzle team is assembled, we can advance the handline. Prior to advancing inside the fire area, the nozzle team must communicate with each other and make sure all members are ready. This may be done in any number of ways as long as all members are on the same page. A simple pat on the helmet by all nozzle team members will do. There must also be communication for water. Before personnel take the door, the nozzle firefighter must make sure that there is water at the nozzle, commonly referred to as “bleeding the hose.” This serves two purposes. First, it lets all air out of the hose so that there is a proper stream (solid or straight). Second, the nozzle firefighter will be able to tell that the pump is in gear, there is pressure, and they are not entering the fire area only at pump idle. The nozzle team must maintain control of the door. Take a minute to size up your entry point. What type of door are you dealing with? Which side of the door do you want to be on? Is the door inward or outward swinging? Is the door right or left swinging? Can you tell the basic layout of the structure, particularly the direction of the bedrooms, by looking at the opening? If the door is metal, is it swollen? If the is door wooden, is there blistering paint? Do you have smoke pushing or puffing from the door jam? These are all basic questions the nozzle team must address before opening a door.

Once the door is opened (via forcible entry, etc.), the nozzle team must maintain control of that door. Do not simply kick the door open and let it swing freely. The nozzle team must have a way to close the door should a situation prevail. By using a piece of rope, webbing, or even a hose strap around the doorknob, the nozzle team can close the door if need be. Although this may not be very important when entering a structure from the outside (keep in mind it may fuel the fire), it is vital when making entry through a door on the inside of a structure (multiple dwelling apartments with common public hallways, for example). Maintain door control — this is excellent nozzle-team discipline.

In addition to maintaining door control, the nozzle team must make every effort to chock the doorway open. This serves several purposes. First, as stated earlier, the door opening is a primary vent hole; therefore, use it as such! Second, when advancing a handline through a doorway, we always want to make sure the door does not close on the handline. This is of primary importance when entering a structure with an uncharged handline. Catastrophic results have emerged from doors closing on uncharged handlines. It is also good discipline to chock doorways when entering with charged handlines as well. This way the hose coupling will not get jammed in the door should it close. Although this may not seem life-threatening, it will save time and keep understaffed crews from sending a team member back to fix the problem.

Where and how do we chock doorways? There are several different methods. The most obvious is to use a wood chock. Proper placement of the chock, however, is critical. I do not place the chock on the ground underneath the door because it stands a promising chance of being dislodged by a boot or advancing handline. Try placing the chock above one of the hinges. This seems to work quite well.

Now that the nozzle team has entered the structure or fire room, they must advance to the seat of the fire. It is the responsibility of all nozzle team members to size up the situation. Maintain your positions! This will take communication, discipline, and training. As discussed earlier, the nozzle firefighter must use a straight or solid stream, vigorously “whip” the hose in a clockwise motion, and occasionally sweep the floor as the team advances.

Remember, there will be times when advancing that the nozzle team will be so low to the ground that they are actually on their stomachs — affectionately called the “belly” maneuver. A good technique to use, should the nozzle firefighter be in this position, is to lie on your side and use your feet to kick and slide along the floor. This way you will still have excellent control of the nozzle; control you would not have if you actually lie on your stomach on top of the hose.

As we all know, fire conditions vary from one situation to another. Fire conditions are different than they have been in previous years; they are hotter and more intense. For example, we have always been taught not to open up on smoke. Is this the best tactic today? Perhaps putting water on smoke in certain situations will protect us. No matter what the tactic may be, when advancing a handline, remember the basics. Never pass closed doors with out checking for extension. Always check the ceiling above before advancing, especially if a truck company member is not available. Put all efforts into placing that first handline in service. Know where the fire is and where it will most likely be pushed. When the nozzle team is advancing they must be cognizant of where the fire will go.

As I have mentioned before, communication is a must with all companies when advancing. Do the engine company and truck company have coordinated attack and ventilation? Does the engine company attacking the fire know if and where there are firefighters above the fire floor? If so, do they have a plan to protect them? Is a back up

line coming? Discipline is imperative on the fireground. Each unit has a job that is pivotal to the operation. Avoid the “moth to the flame” syndrome and maintain focus on the task at hand. Fire attack dictates all crews work as a finely tuned machine. If every unit on the fireground coordinates their task with each other, the end result will be a positive, safe one. Many fireground tactics are no different than they were years ago, while others are changing — make no mistake. However, it is our obligation to each other to be as safe as possible. Maintain an open mind and gain as much knowledge as possible. Continually strive to learn while never setting the basics aside. Entertain new ideas, but never forget the ideas that work. Training is the best arena to review old principles and to investigate new tactics. You will never know until you try.

Advancing the First Handline


In the firefighting business, preparation is everything. Preparation includes both regular drills and training to maintain basic skills; pre-fire planning to reduce the number of curve balls thrown at you during firefighting operations; and preparations that take place on the fireground as each important step in the fire attack process is executed. This article will concern itself with the latter — specifically the preparations necessary at the entrance to the fire area in order to ensure a safe, aggressive, and unhindered advance to the seat of the fire.

The first important consideration for the nozzle team is to ensure that at least one full length of hose is available at the entrance to the fire area. More than one length may be needed, depending on size-up or pre-fire planning information, so one length represents a minimum.

The next consideration is how this working length should be "flaked out" for an efficient advance. This depends largely on where the line is to be flaked out (the front lawn of a private house or a small stair landing in an apartment building), the layout of the fire area, and the location and direction of swing (to the left or right) of the entrance door. If sufficient room is available, the line should be neatly flaked out in a series of "S" shaped curves. Sharp bends, which will inevitably lead to kinks, should be avoided. For fires in private dwellings, the line can be flaked out on the lawn, in the driveway, on the sidewalk, or even in the street. Commercial building fires also often permit the line to be arranged neatly outside. Multiple-dwelling buildings, on the other hand, often pose difficulties due to the narrow hallways and small stair landings found in many of these buildings.

The next factor that affects how the line should be flaked out is the layout of the fire area. Will the line be turning left or right after entry? Does a long hallway lie ahead? Does the line have to advance down a set of stairs for a cellar or basement fire? Does the line have to advance up a set of stairs, as might be required for a fire in a split- level house or duplex apartment? If a hard right turn is anticipated, arrange at least part of the first length on the left side of the entrance door. Conversely, a hard left turn would warrant arranging the line to the right of the entrance door. While this is not always possible, the goal is to facilitate the advance and the smooth movement of the handline.

The swing of the entrance door may also be a factor, particularly when the door seals off a hallway leading to another part of the occupancy when it is opened. This is a common arrangement in "railroad flat" style apartments but is certainly not limited to them. If the fire is located in the area "sealed off" by the open door, the line will have to be advanced around the door — a difficult task at best. The nozzle team may have to feed part of the handline into the occupancy in a direction opposite the fire area prior to entry. This will ensure sufficient hose is available for the advance and avoid at least some of the

problems involved in trying to maneuver the line around the entrance door (possibly a 180-degree turn).

Once sufficient hose is in place, the door to the occupancy can be partially closed and the line advanced to the fire. When space is at a premium, where to put the uncharged handline can be a problem. Apartment buildings with small floor landings may require the line to be flaked out on the floor below or on the stairs leading to the floor above. When flaking the line out on a staircase, make wide turns around the newel posts, but avoid pushing the line into the corners where kinks can form. Flaking out the line on the floor below, while sometimes unavoidable, increases the difficulty of the advance because many times staffing is short and there may not be a firefighter available to feed hose up the stairs to the advancing nozzle team.

Often the best option is to flake the line out in an apartment adjacent to the fire apartment or, better still, in one across the hall. Never drape a loop of hose out of a window in order to avoid congestion on the landing. Not only does each 50-foot length of 1¾-inch hose weigh some 80 pounds when charged, a severe kink will form at the bottom of the loop.

Another effective action prior to advancing into the fire area is to take full advantage of whatever visibility exists below the smoke layer. Once the nozzle begins operating, most, if not all, visibility will be lost, so this opportunity must be seized early. In some cases, it may mean lying on the floor and directing a handlight beam into the fire area. The floor layout will be at least partially revealed, and sometimes the exact location of the fire discovered. The glow of the fire may be visible or just the shimmering reflection of the flames on a tile or hardwood floor. Either way, the advance will be much more efficient.

Another reason to look below the smoke is to increase safety. Hazards such as extension cords, sharp objects, and holes in the floor will be discovered and injuries avoided. Utilizing the visibility available at floor level is also very effective during primary search operations. At one fire, a firefighter scanning with his handlight prior to entering the fire apartment noticed a hand dangling below the smoke layer. He told his officer he was going to make a beeline for the hand and quickly discovered two children overcome on the living room couch. His officer found their mother, and the three victims were all successfully removed to the outside just as the fire entered the living room. If a few moments hadn't been taken to look below the smoke with the light, the search would have taken longer and perhaps the end results would have been different.

For fires in multiple-dwelling buildings, taking a quick look at another apartment can provide a wealth of valuable information. This might be an apartment on the floor below the fire (apartments in the same vertical line generally have the same layout from floor to floor) or an apartment adjacent to the fire apartment. Apartment units that are located side by side, particularly in older apartment buildings and garden apartment complexes, often have floor layouts that mirror one another.

At this point, the nozzle firefighter should be crouching or kneeling on the hose behind the nozzle to prevent the nozzle shut-off from being inadvertently and unknowingly

opened. Staying low and to the side of the door also protects the nozzle firefighter and other members of the nozzle team from venting heat, flame, and smoke and affords each firefighter much better control while donning gloves, face piece, and hood. The nozzle firefighter should tuck his helmet between his legs to prevent some clumsy “truckie” from inadvertently kicking it down the hallway or off the front porch and into the snow. All personal protective equipment should be quickly double-checked to ensure proper fit before the line is moved.

In the case of preconnected handlines, either the last firefighter in the stretch or the pump operator must ensure that all the hose has been removed from the apparatus. Charging a handline with hose remaining in the hosebed is not just embarrassing — it costs valuable time, which in turn increases the risks faced by the fire-attack team. As the last firefighter moves forward toward the nozzle, he must ensure the line is not stuck under any automobile tires, fence gates or doors, which will effectively become hose clamps once the line fills with water. The officer (or designated firefighter) can now call for water. As the line fills and is bled of trapped air, the second (and third) firefighters, if available, can don their face pieces and protective hoods, and make final adjustments to their turnout gear and SCBA. Once the line is charged and bled, everyone should be ready to advance.

The act of bleeding the line warrants some additional discussion. Besides exhausting the air trapped in the hose, opening the nozzle briefly prior to the advance verifies that the line is properly pressurized and a satisfactory stream is available. If the pump operator (or engineer) hasn't placed the engine into pump gear or hasn't throttled up yet, it will be quite evident when the nozzle is fully opened and an ineffectual stream results. Radio communications should quickly remedy the problem and the advance can proceed. If the problem is not at the engine, kinks in the handline may be the cause of the poor stream and will have to be straightened.

All members of the nozzle team should be positioned on the same side of the handline. Ideally, when at least two firefighters are available, the second (or “backup”) firefighter will be positioned immediately behind the nozzle firefighter to help resist the nozzle-reaction burden and provide any other necessary physical and emotional support. The latter can be an important concern when an inexperienced firefighter is assigned the nozzle position for the first time. In reality, however, due to insufficient staffing, the backup firefighter is usually forced to move between a position near the nozzle firefighter and a point several feet behind. This is necessary in order to keep the line free and moving. Due to this situation, the need to use hose-and-nozzle systems that reduce the nozzle-reaction burden without compromising flow volume and stream reach is critical and will be the topic of a future installment.

In the event a third firefighter is available, he should be positioned at the first bend or turn behind the nozzle team as the line is advanced. Staying at this position and resisting the temptation to become the “second assistant nozzleman” requires a high degree of discipline.

To ensure a smooth advance without the danger of “pushing” the nozzle firefighter forward, the “bow” technique is very effective. The third firefighter (called the “door” firefighter in FDNY) simply forms a bow in the line — either on the floor ahead, against the wall in a narrow hallway or even across a bent knee — and observes the hose. When smoke or obstructions such as walls obscure the nozzle team, a straightening of the bow indicates the line is moving. The door firefighter then feeds enough additional hose forward to restore the bow. Eventually the door firefighter must also move forward to keep up with the advancing nozzle team. In order to keep the line moving without unnecessary effort, he may elect to pull a loop of hose forward with him instead of having to go back for more line when it inevitably becomes stuck.

Although specific nozzle techniques will be covered next time, a few points bear mentioning here. One frequently asked question concerns when to open the nozzle. Generally, the nozzle should not be opened until the fire is encountered. An exception might be a situation in which the nozzle team encounters dense smoke and extremely high heat conditions. In this case, opening the nozzle briefly and sweeping the ceiling with a straight or solid stream may be the only means of preventing flashover and severe burn injuries.

If access to the fire area is difficult and fire is encountered at the entrance portal, the following techniques may prove helpful:

• The stream may be directed over the top of a partially open door. Vigorous nozzle manipulation will cause the stream to splatter off the ceiling and upper walls. Hopefully this will “darken down” the fire sufficiently to allow the door to be more fully opened and the advance continued. The stream may sometimes need to be directed through the top of a door which has partially burned away or through an open transom.

• Another effective technique is to drive the water through the space between the open door and jamb. Moving the nozzle up and down several times with the tip inserted in this gap may permit water application into this hard-to-reach area. Don't overlook breaching a wall in order to apply water on an otherwise inaccessible fire.

• If multiple rooms are involved on either side of a long hallway, they must be “knocked down” one at a time. Generally, applying water “out front and overhead” will drive back the rolling flame front at the hallway ceiling and permit water to be directed into each side room as the advance is made. Many times the stream can be applied from the door opening, making physical entrance into each room unnecessary. Be sure to control the fire in each room sufficiently to prevent its re- ignition after the line moves forward. As soon as each room “blacks out,” sweep the hallway ceiling again. If a closed door is encountered, be certain to open it and check for fire extension before moving past.

The two most frequent mistakes I observe when training firefighters in proper nozzle mechanics are these: 1.) Failure to open the nozzle fully for maximum flow and stream

reach and 2.) Being too timid when manipulating the nozzle. Previous installments have discussed why only straight or solid streams should be used for interior attack. It is vital that these streams have adequate volume, reach, and penetrating power in order to achieve rapid fire control and keep the nozzle team safe. While straight and solid streams provide many benefits for the fire attack team, the compactness of these streams requires vigorous nozzle movement in order to distribute the water efficiently over the heated fuel materials.

The first mistake, partially closing the nozzle shut off (often done in order to manage excessive nozzle reaction) will produce several negative consequences depending upon the specific type of nozzle involved. In the case of solid-stream nozzles, partially closing the shut-off not only reduces flow volume; the intrusion of the ball valve into the waterway creates significant turbulence that has a negative effect on both the reach and quality of the stream. With a combination (fog) nozzle, both flow volume and effective reach will be compromised. Automatic fog nozzles can be rather deceiving. While stream characteristics (reach, compactness) are maintained and the stream may “look good,” the consequent reduction in flow volume will lessen fire-control effectiveness.

Being overly timid when manipulating the nozzle is another common mistake. Fires are controlled quickly when an adequate volume of water is efficiently applied on the heated fuel materials. If the nozzle firefighter fails to move the nozzle in a vigorous, almost violent fashion, fire control is delayed and the risk of burn injury is increased. It seems there are two main causes for this problem. One is simply a lack of experience and/or poor training. The other is the widespread use of pistol grips. Pistol grips, particularly when installed on 100-psi fog nozzles with their high reaction forces, tend to end up alongside the nozzle firefighter's body. The arm holding the pistol grip is bent at a 90-degree angle and nozzle movement is severely restricted.

While rapid nozzle movement is important, the pattern of these movements must also be discussed. Most of us have heard at one time or another that the nozzle should be rotated with a clockwise motion. If the nozzle were to be rotated counterclockwise, heat, smoke, and flame would be drawn to the nozzle and increase the threat of burn injury. Although this phenomenon has been demonstrated repeatedly and is a proven scientific fact, it applies to fog streams, not straight or solid streams. (It should be noted that the reason for this phenomenon has been debated for many years and explanations have ranged from the effects of charged ions in the atmosphere to the Coriolis force caused by the rotation of the earth.)

In my own experience, the exact pattern of movements will depend on both the size and shape of the fire area and how close I can get to the fire before opening the nozzle. While I generally use a clockwise rotation, side-to-side movements and even up-and-down movements may also be incorporated into the mix. If one combination of movements isn't having much effect, try another. If this still proves less than satisfactory, you may need to seek another vantage point for stream application.

The nozzle should initially be pointed toward the ceiling of the fire area in order to agitate the fire gas layers and break up the stream. This creates coarse droplets that will rain down on the heated contents, efficiently knocking down the fire by eliminating the release of fuel vapors into the atmosphere. Be careful not to let the stream contact the heated ceiling and walls in your immediate vicinity, as this will cause scalding water to splatter about, increasing the burn- injury potential. As the fire “darkens down,” the nozzle angle should be reduced and the stream aimed into the lower portion of the fire area.

Once the fire is controlled sufficiently to permit the forward advance of the line, the floor must be swept with the stream. Sweeping the floor accomplishes several important safety objectives. It pushes aside sharp objects from the nozzle team's path. These may include nails, screws, glass, and hypodermic needles. It extinguishes burning carpeting and cools molten floor tiles and plastics. Sweeping with the stream also “sounds” the floor. A change in the sound of the stream will indicate the presence of an opening ahead. This opening may be the entrance to the cellar stairs, an unprotected shaft, or even a hole in the floor caused by fire burning through from below.

A new burn prevention poster sponsored jointly by the New York City Fire Department (FDNY) Safety Command and the New York Firefighters Burn Center Foundation encourages the nozzle team to “sweep-switch-squat-shift” when advancing the line. Sweeping with the stream dilutes and cools the runoff water cascading down the walls and collecting on the floor. This runoff water will be scalding hot — as high as 150 degrees Fahrenheit. Water this hot will cause a third-degree burn after only one second of contact with human skin. Even bunker pants will not protect against scald burns.

Switching knees will reduce the contact time between the heated floor and your anterior shin and knee. Consider that when you kneel, your bunker pants are stretched tight over the knee joint, eliminating the air space between the protective layers and increasing the risk of conductive heat burns. Squatting or “duck” walking is also effective, but it is rather difficult for the average firefighter to maintain this posture for an extended period.

After a fire has been knocked down, the nozzle should be closed to allow the swirling steam and smoke to "lift." In order to improve visibility still further and to reduce the heat and humidity in the fire area, a window should be located and a fog stream or broken solid stream directed through the opening. If done correctly, the negative pressure created by the stream will produce a noticeable draft into and through the fire area, effectively clearing the atmosphere of lingering combustion products. Any remaining pockets of fire will be revealed and smoldering materials will "light up" for final extinguishment.

If a combination nozzle is used, simply change from a straight stream to a fog pattern. If a solid stream nozzle is used, simply close the shutoff part way to break up the stream and effect ventilation. Removing the nozzle tip will further increase efficiency. It is best to remain several feet back from the window and to stay low in order not to impede air movement. The pattern should be adjusted until the stream fills most of the window area.

At this point, truck company personnel should enter the fire area and begin "opening up" in order to expose any hidden fire extension and to ensure complete extinguishment. During overhaul, it is usually best to remove the handline from the fire area to prevent it from being buried by sheetrock or lathe and plaster. This will also allow the secondary search to be conducted with increased efficiency.

It is tempting to open the nozzle as soon as a hole is made in a wall or the ceiling and fire is seen, but all this will do is create unwanted steam and eliminate almost all visibility. Particularly in the case of ceilings, it is best to wait until the entire ceiling has been "pulled" before operating the nozzle. An important consideration during this phase of the firefighting operation is the need to replace the initial nozzle team with fresh troops. The physical effort exerted during firefighting activities coupled with the physiological performance limitations imposed by bunker gear will rapidly fatigue these firefighters. When personnel resources are less than what they should be (as is almost always the case), the onset of fatigue will be even more rapid and the need to relieve the first due engine company becomes critical in order to avoid injuries.

The so-called "one-cylinder rule" should apply whenever possible. During overhaul, the nozzle pressure can be reduced in order to avoid unnecessary injuries to personnel and damage to property. Water point should be directed into any area of the structure or contents where the potential for a rekindle is likely. If there is any doubt, have the truck company personnel open up further or turn the pile of debris one more time.

Foamed plastic seat cushions and mattresses must be thoroughly soaked (even submerging chair cushions in the bathtub is an option to be considered) or removed to the outside for further extinguishment. NEVER enter a stairway or elevator car with a partially extinguished foamed cushion or mattress. The draft created by moving the cushion or mattress may cause the foamed insulation to burst into flame, trapping you with no escape. It is best to thoroughly soak it first, or toss it out the window to a clear area on the ground below.

In order to efficiently overhaul the exposed studs and joists in the fire room, it is best to first overhaul the contents remaining on the floor before bringing the handline back inside the room. This reduces the chances of the line sitting in smoldering debris, which could unknowingly damage the hose. Utilizing only a single firefighter (remember, the nozzle pressure has been reduced and no one really wants to get wet, particularly in winter), position at a far corner of the room with the nozzle pointed back towards the entrance. While leaning against the wall and using your leg and foot to anchor the handline and resist the nozzle reaction, sweep the stream back and forth along each joist from sidewall to sidewall. Concentrate on the joists that are the most deeply charred and don't hesitate to agitate the stream by shaking the nozzle. Once the joist bays have been washed down, perform the same operation on any studs that look charred (pay close attention to the framing around window openings) and direct the stream from ceiling to floor and back again. Let the officer take a peek, and, if all looks good, reposition the line at the door opening and repeat the process. This will ensure that both sides of each

charred joist have been washed down, as well as all affected wall studs and window framing materials.

Don't forget to drive the stream into any area where a pipe (steam, soil, or water), electrical wires, or ductwork pierces the floor above. At this point let the officer make another examination to ensure a satisfactory job has been done. This is actually a good time to bring a thermal imaging device into the room and scan the area for hot spots.

Consider, as well, the following additional points:

• Unlike fire attack operations, water application during overhaul should be very specific. Use water judiciously to avoid unnecessary property damage. Move undamaged valuables if possible.

• Reckless overhauling can destroy evidence of arson. Use care and limit water application to only what is absolutely necessary until the officer or fire investigator takes a look at the area.

• It is easy to confuse steam and smoke. If it is smoke, additional water application is necessary.

• Be cautious of holes in the floor, water accumulations, protruding nails and screws, untrimmed window glass, and other sharp objects.

• Ensure the area is properly illuminated to help avoid injuries.

FIRE STREAMS AND THE AGGRESSIVE INTERIOR ATTACK

BY ARMAND F. GUZZI JR.

EFFICIENT FIRE STREAMS ARE SOMETIMES TAKEN FOR GRANTED; THE IMPORTANCE OF ADEQUATE FIRE FLOW WITH MANAGEABLE NOZZLE REACTION IS SOMETIMES OVERLOOKED.

The hallmark of a good fire department is the ability to make an aggressive interior attack. When occupants await rescue and are trapped by fire, it is the aggressive fire department that will save them.

Whenever the topic of interior structural fire attack arises, there is always debate as to which method of fire attack is best. Some departments rely on the direct attack method. Other departments attempt an aggressive interior attack using the indirect or combination method. Then there are the departments, primarily in Europe, that rely on a theory known as "3D water fog."

So much has been written about each method over the years, and some misconceptions have developed simply out of a lack of understanding. There are so many sources from which to draw conclusions; some of the sources contain contradictions, sometimes making it difficult to know what is actually meant. A compilation of these methods "under one roof" so to speak is probably the best way to figure out how each method is to be employed.

In addition, the need for effective fire flow goes hand in hand with any fire attack strategy. Efficient fire streams are sometimes taken for granted; the importance of adequate fire flow with manageable nozzle reaction is sometimes overlooked.

WHAT TECHNIQUES SHOULD BE USED?

What techniques should we employ when aggressively attacking a building fire from within? I compiled data on the various methods of fire attack from the most qualified and highly recognized sources. Certain conclusions can be drawn from these data. In drawing these conclusions, I hope to put to rest many misconceptions.

All of the fire attack theories have a single underlying foundation: Each is designed to effect extinguishment of a fire. From this point on, each method differs from the others. This is the point at which many debates rage.

This article is geared toward the aggressive interior attack for the typical building fires fire departments across the country face every day. It is not an all- inclusive strategy and tactics text but a look at a small element of this big picture. Obviously, safety is the overriding concern at all times, since firefighting is not the safest line of work.

DIRECT ATTACK

• "The direct method of attack is simply applying water to the base of the burning material, at the flame/fuel interface, where the flammable vapors being distilled by heat from solid material ignite and burn."1

• "The direct method of attack causes little disruption of the heated combustion products. Reducing heat production by extinguishing the fire at its base stops the burning process at its source, in turn stopping the upward liberation of more heat, smoke, and gases." (1)

• "If ellipse the officer feels the overhead needs to be cooled because it is preventing the crew from moving in, a quick 2- or 3-second dash with a straight stream will provide temperature reduction without generating a massive amount of steam." (1,363)

• "Sweeping the ceiling with the stream in a side-to-side or clockwise motion also helps eliminate the threat posed by the heated gases without excessive unwanted steam production and violent disruption of the thermal balance characteristic of the indirect and combination methods."2

DIRECT ATTACK ANALYSIS

The direct attack method is designed to extinguish the fire by applying water in a straight stream (or smooth bore stream) to the base of the fire. This type of stream offers the greatest penetration of the heat being produced. A fog nozzle on the straight stream setting, or a smooth bore stream, will allow a greater distance between the fire and the nozzle than a fog nozzle on a wider setting. The stream will then strike the combustibles and cool them below their ignition temperature, thereby effecting extinguishment. It is safer to attack the fire from a greater distance than from a closer distance. These straight or smooth bore streams will produce less steam, as the water is in a tighter pattern. A wider pattern allows for a greater surface-to-mass ratio of the individual droplets, which will turn to steam more quickly.

Another point emphasized from the data accumulated concerns the application of water to the ceiling. In environments of high heat, the stream should be directed into the overhead for a period of several seconds at a time, in an effort to lower the temperature. Since the danger of flashover is very real in an enclosed area, it is important to recognize this danger and a means of preventing it. A straight or smooth bore stream to the ceiling, worked side to side, will provide more safety when there is a potential for flashover. It is important to emphasize that all the sources cited here identified excess steam as a very real danger. Therefore, it is extremely dangerous to use a wide fog pattern within an enclosed space when making an interior attack.

A stream to the ceiling can be viewed as an element of the direct attack. As the gases are potential sources of combustion, a stream directed above will keep the gases below their ignition temperature. But as with a stream directed onto other combustibles, you must limit its application to avoid the generation of excess steam. The direct attack does not advocate extinguishing the fire by generating massive amounts of steam, but by directly applying water to the seat of the flame/fuel interface. Maintaining the thermal balance is a must when making a direct attack. To do otherwise could create a dangerous imbalance in room temperature as a result of the high heat from the upper levels mixing with the lower temperatures at the floor.

Another point gathered from the data dealt with an overuse of water, even in the form of a straight or smooth bore stream. Too much water applied onto the combustibles after the initial knockdown will create excess steam that can hinder the attack.

One final point concerning the direct attack: Many of the sources stress that it is important to apply a stream of water to the ceiling. This flies in the face of some texts that say it is wasteful and that needless water damage occurs when shooting water into smoke. Remember that smoke is incomplete combustion; when present with enough heat and oxygen, smoke will ignite with catastrophic consequences. Water properly applied into the overhead provides a safety net and prevents flashover.

INDIRECT ATTACK

• "The indirect method of attack is not an interior fire attack operation."3 • "In addition to remote injection of the water fog, there are two other requirements

for success when using the indirect method. First, the ceiling temperature within the fire compartment must be at least 1,0007F to ensure ready and efficient conversion of the fog spray to steam. When a fire is in the first or early second phase of development, the direct attack with timely and adequate ventilation is preferred. Second, the fire compartment (building) must be well sealed to prevent premature leakage of valuable steam to the outside. A well ventilated fire building on the fire department's arrival warrants a direct attack, since the indirect method is only effective if the fire building remains sealed with doors and windows intact." (3)

• "Nowhere in his writings did Chief Lloyd Layman present scientific arguments that advocated spraying water over the firefighters' heads in a fire situation in order to create steam bath conditions. On the contrary, he said firefighters would be burned if they were unfortunate enough to find themselves enveloped in a hurricane of water converting to steam." (1,84)

COMBINATION ATTACK

• "Like the indirect method of attack, the combination attack was originally designed primarily for exterior application of water." (3,68)

• "The objective of the combination attack is to 'roll' the stream around the perimeter of the room, cooling the walls, ceiling, and floor with the outer edge of the stream while the inner portion of the stream cools the hot gases being produced by the

fire. Striking the heated ceiling, walls, and fuel materials produces the maximum amount of steam within the shortest period of time." (3, 70)

• "Insofar as the writings of Keith Royer and the late Floyd W. 'Bill' Nelson, of Iowa State University, are concerned, there is no mention of the impact of steam on trapped occupants. In Fire Stream Management Handbook, Fornell writes in reference to the articles and films of Royer and Nelson: 'In viewing the films and reading the results of their research, it must be noted that their tactics advocated application of water from outside the fire building. Though they did discuss interior application, the first priority in the Iowa method was to knock down visible fire before making entry. Royer says their testing did not address the problem of fire spread caused by applying streams from the outside of the building. The subject of life safety or the effects of steam on trapped victims was never addressed in the three films.' " (3,74)

INDIRECT AND COMBINATION ATTACK ANALYSIS

These theories of fire attack were never designed to be used as part of an offensive interior attack. Over the years, mainly through a lack of understanding on the part of many individuals and departments, these theories were misapplied. The data available from the original authors of these methods make it very clear that they were never designed to be used from within, what we have come to term "the aggressive interior attack."

Both the indirect and combination attack theories spell out the massive generation of steam that results from the use of these methods, and thus the danger of scalding injuries to firefighters operating within. In addition, there is the danger of spreading fire to uninvolved areas by pushing it throughout the structure with the power of a fog stream. This is not to be confused with the strategy advocated by the 3D water fog technique, which has no relation to the indirect or combination attack methods.

Layman clearly gave directions for using the indirect method. To paraphrase, Layman specifically stated that for his theory to work properly, the building must remain sealed so that steam can effect extinguishment. He went on to say that if ventilation was effected, specifically indicating that if doors and windows did not remain sealed, that a direct attack was warranted, as the steam created would exit from these same openings. Layman never stated that firefighters should make an attack from within using his theories and warned of the dangers associated with such tactics.

The combination attack, a concept experimented with heavily by Royer and Nelson in the early 1950s, brought to the forefront many new concepts. Like many other theories, departments may have used the combination attack incorrectly simply because they did not thoroughly understand the concepts.

The combination attack, like its indirect attack counterpart, is based on the belief that generating massive amounts of steam within the shortest time frame will extinguish the fire. Again, the hazard of steam and its negative effects on firefighters and victims are

apparent when used within an enclosed compartment or space. Also, the danger of spreading fire is evident if the stream pattern is set to inadvertently push the fire into uninvolved areas.

The use of a fog pattern will generate excess steam and cause a disruption in the thermal layering, creating a dangerous environment within. This is not to be confused with the concepts or methods advocated by the 3D water fog theories discussed later.

These methods are used in settings where life safety is not an issue and the compartment remains relatively sealed so as to maintain the integrity and allow the steam to do its job. As stated, these methods were never designed to be used for the aggressive interior attack because of the hazard posed by dangerous levels of scalding steam.

GAS PHASE COOLING/NEW WAVE 3D WATER FOG/OFFENSIVE WATER FOG

• "The use of three dimensional (3D) (also termed 'offensive') water- fog techniques during gaseous-phase suppression of structural fires is a most recent and innovative approach, and the reader should be clear that such applications are used not (solely) to extinguish fires but mainly to make 'safe' the approach route to the fire and reduce the likelihood of fire gas ignitions-flashovers, backdrafts, and so on."4

• "Neither are these techniques designed to replace the direct style of fire attack utilizing water in a straight-stream setting but, moreover, to complement existing forms of fire attack in an effort to increase the safety and effectiveness of firefighting teams." (4)

• "The 'pulsing' of water fog into the overhead on the approach route using short rapid bursts at the nozzle serves to 'inert' the fire gas layers and will prevent or mitigate the potential for any gas ignition of the fire gases that may lead to such a major event." (4)

• "The 'pulsing' action is created through rapid 'on-off' motions of the flow control lever or trigger. This is achieved with some practice, and some nozzles are more suited to the action than others. Ideally, individual 'pulses' should last from 0.1 to 0.5 of a second and will place a fine range of water droplets into the overhead for a brief few seconds .... Any sweeping motion of the nozzle is most likely to upset the thermal balance within the compartment and force heat down to the lower parts of the room occupied by the firefighting crew, and continuous bursts of more than a second may cause a 'piston' effect to push fire into uninvolved areas, roof spaces, etc."5

GAS PHASE COOLING/NEW WAVE 3D WATER FOG/OFFENSIVE WATER FOG ANALYSIS

Gas phase cooling, or 3D water fog, is designed to protect firefighters most notably from the dangers of flashover. It advocates spraying water in a fog pattern of specific dimensions into the overhead for very brief periods of less than one second at a time (referred to as "pulsing" the nozzle). This method's theorists acknowledge that water will expand to steam rapidly. Yet, if used sparingly, the technique will make the atmosphere

safer by cooling the overhead combustible fire gases, which will allow the attack team to continue its approach to the seat of the fire.

This method does not advocate the massive application of water fog with the intention of creating steam for fire extinguishment. It recognizes the dangers associated with steam and pushing fire into uninvolved areas. The technique stresses that it is in no way similar to the strategy of the indirect attack founded in the 1940s and 1950s.

The 3D water fog strategy relies on the direct attack method with a straight stream from a fog nozzle once the fire is located. It seeks to apply water directly to the flame/fuel interface to effect final extinguishment.

FIRE FLOWS AND NOZZLE REACTIONS 13/4-Inch Handlines

For the purpose of this article, we will use the 13/4-inch medium-diameter handline, since it is popular and can deliver flows of up to 185 gallons per minute efficiently in stretches of about 200 feet. Other benefits of the 13/4-inch handline are that it takes less time to deploy than the 21/2-inch handline and fewer firefighters are needed to staff it efficiently. One and a half- inch handlines, while not as popular as 13/4-inch lines, can flow about 125 gpm efficiently in stretches up to 200 feet. A larger-diameter line must be used to fill out stretches longer than 200 feet- for example, 21/2-inch hose to a reducer or a wye followed up by the 11/2-inch or 13/4-inch handline tasked with extinguishment. Simply put, friction loss becomes a major factor in the longer stretches, and pump efficiency and capability then become factors. This is a topic unto itself and will not be fully discussed here.

Also, for this article, water is the extinguishing agent; a discussion of Class A foam is outside the scope of the article.

NOZZLE REACTION AND FIRE FLOWS

Are your medium-diameter handlines being used to their maximum capability? Although they can deliver flows of up to 185 gallons per minute, most departments are not flowing anywhere near this simply because of the very high nozzle reactions they are encountering.

Probably, the most important point to keep in mind is that in the interest of safety and efficiency, a sufficient volume of water must be available through medium-diameter attack handlines. Small-diameter lines of less than 11/2 inch are not suitable for interior fire attack operations. Although there is no doubt that many fires can be handled with the limited flows of a one- inch booster line (about 40 gpm), no additional flow will be available should it be needed.

As important as adequate flow is to fire suppression operations, you must remember that nozzle reaction is the ultimate decider of effective fire flows for handlines. In other words, if the nozzle reaction is significant, the nozzle operator will do one of two things: If he cannot control the nozzle reaction exhibited by the stream, he will gate down to deliver a lesser flow with more manageable nozzle reaction, or the nozzle operator will simply lose control of the handline and suffer the corresponding deadly consequences. Nozzle reaction is directly attributed to nozzle pressure and flow (measured in gallons per minute). The end result is nozzle reaction measured in pounds force.

Realistically, a two- person nozzle team (consisting of a firefighter assigned to the nozzle and a second member in a backup position) can safely and effectively control somewhere between 65 to 70 pounds force of nozzle reaction. The higher the nozzle pressures at a given flow, the greater the nozzle reaction. The table below lists flows and reactions from a variety of nozzle types.

Note that the lower the nozzle pressure, the less nozzle reaction at a given flow. A lower reaction with a higher flowing handline means greater safety and more water delivered in a shorter time. Several formulas are available for computing flow and reaction, which may cause the figures to vary slightly when compared with various charts of major nozzle manufacturers.

Remember that to extinguish any given Class A fire requires that you deliver the flow rate needed to absorb the given Btus. If the volume of water needed is not delivered, the fire will continue to grow until it consumes all the given combustibles within its reach. As the fire eventually burns itself out, the Btus given off will be absorbed by the flow rate being delivered, and the fire will be extinguished. As an example, if a fire requires a flow rate of 200 gallons per minute for extinguishment and only 40 gpm are delivered, the fire will not go out. It will continue to burn until the Btus given off are low enough to be absorbed by the 40-gpm flow rate. This is simply a matter of physics and cannot be changed.

How then can we deliver a flow sufficient to accomplish rapid extinguishment without endangering ourselves? Ultimately, we want to deliver as great a flow as possible in the shortest period of time and in the safest and most effective manner. To do this, we must strive for high flows with limited nozzle reactions and consistent application of the fire stream in a safe manner.

What flows are considered best for our medium-diameter handlines? As a rule, the more water a suppression team has available, the more fire it can extinguish and the safer the incident will be. How much water to flow should be based on the consideration of how much nozzle reaction you can safely handle. If your nozzle team can control the line safely up to 65 to 70 pounds of force reaction, base the flow volume on that value.

Note that in the chart, 185 gpm through a 50-psi smooth bore exhibits a reaction of 69 pounds of reaction. A 100-psi fog nozzle flowing 125 gpm has a reaction of 63 pounds force, whereas the 75-psi low-pressure fog nozzle can flow about 150 gpm with a

reaction of 66 pounds force. Note: A major nozzle manufacturer offers an emergency low-pressure feature for its line of automatic nozzles. When the feature is activated, a nozzle pressure of about 50 psi, instead of 100 psi, will be provided; nozzle reactions will be comparable to the smooth bore counterpart. Flow is the key to fire extinguishment, but without pressure to project this flow, the water available is irrelevant.

Even if nozzle reaction is held to a manageable level, it is still imperative that a firefighter be assigned to the backup position. Although not the most glamorous position, it is a most critical one. The backup person is responsible for absorbing the great majority of the reaction, which allows an adequate amount of water to be delivered. Without the backup person, the attack becomes less efficient and safety is compromised. Obviously, the more members assigned to the stretch, the more efficient and safer the fire attack.

WATER DAMAGE

Water damage is not caused by flow rate but by prolonged application of water by an untrained nozzle team that does not know when to shut off the line. A stream flowing 60 gpm for 25 minutes will cause more water damage than a stream flowing 200 gpm for one minute. An effective nozzle team knows when to open and shut down a line and what stream patterns and techniques to use.

CONCLUSIONS

With regard to fire suppression strategies for interior firefighting, the biggest conclusion that can be drawn is that the generation of steam within a confined area can prove detrimental and dangerous to all inside the structure. The original theories of the indirect and combination methods made it very clear that massive amounts of steam had to be generated. In addition, the techniques used in the 3D water fog approach also make it very clear that too much steam will have negative consequences. Water dispersed in a fog (spray) pattern will turn to steam more quickly than water confined within a straight stream. This rapid expansion in a very high heat environment can cause injuries.

Another conclusion drawn from the various forms of attack is that the wide fog pattern used in all but the short "pulses" advocated in the 3D water fog technique can push fire and heat into uninvolved areas.

Ultimately, the data available show that the direct method, which relies on the straight (or solid) stream, is the most effective pattern for fire extinguishment. The 3D water fog strategy also relies on the direct attack method, but, as stated, using a fog pattern in short applications renders the approach safe. Overuse of water, regardless of the pattern used, can inhibit the attack by creating excess steam and disrupting the thermal balance.

Another clear fact that emerged is that more water can be safely delivered at a lower nozzle pressure simply because you will have to contend with less nozzle reaction. The fog nozzle vs. smooth bore nozzle debate has been covered extensively in other articles.

VENTILATION

Ventilation is paramount to any interior attack. Even though it is not the theme of this article, it must be included. Combustible gases are inherently dangerous and await only a sufficient amount of heat and oxygen to ignite. It is imperative that the products of combustion be allowed to exit. For the members inside making their attack, these combustible gases are better off outside the building than inside with them.

Sometimes, ventilation is not easy to accomplish. When this happens, the threat of flashover is very real, and getting water into the hot gases will delay or eliminate this threat. Direct attack advocates say that it is important to get a stream into the overhead area when there is intense heat even though no fire has been encountered. A stream into the overhead for a period of several seconds will delay flashover while the advance to the seat of the fire continues.

Flashover mitigation and fire extinguishment can take place with the indirect and combination attack, but these methods were never designed for inside application when victims or firefighters are present. Again, the massive generation of steam would cause extreme problems for those inside.

Preventing flashover was a primary goal of the 3D water fog advocates, who specify that water be applied into the overhead for a very, very brief time and then be followed up with a direct attack from a straight stream onto the seat of the fire.

Personnel using the 3D water fog technique must be properly trained in this application. Sustained use of the wide fog pattern within an enclosed area could adversely affect the firefighters making the interior attack. Massive quantities of scalding steam could be generated, and the fire could be pushed into uninvolved spaces.

References

1. Fornell, David. Fire Stream Management Handbook. 1991. (Saddle Brook, NJ: Fire Engineering-Pennwell Publishing Company, 1991), 78.

2. "Little Drops of Water: 50 Years Later, Part 2," Andrew A. Fredericks, Fire Engineering, March 2000, 132.

3. "Little Drops of Water: 50 Years Later, Part 1," Andrew A. Fredericks, Fire Engineering, February 2000, 66.

4. www.firetactics.com, a British Web site with in-depth information on the 3D Water-Fog Technique.

5. Grimwood, Paul. Flashover and Nozzle Techniques. May 25, 2000. Available through www.firetactics.com.

The above authors have made significant contributions to the field. Fire service professionals should read their works.

ARMAND F. GUZZI JR. has been a member of the fire service since 1987. He is a career firefighter with the Fire Department of the City of Long Branch (NJ) and has been an instructor at the Monmouth County (NJ) Fire Academy since 1990. He has degrees in fire science, education, and business administration.

Firefighting Nozzle Reaction

PAUL GRIMWOOD

In 1990 I completed a research project (Fire Magazine UK - November 1992) that evaluated the operational capability of fire fighting hand-line streams as used by London Fire Brigade. At that time we had main-line options of 45mm (1 3/4") hose-lines with 12.5mm (1/2") nozzles and 70mm (2 3/4") hose-lines with either 20mm (3/4") or 25mm (1") nozzle options. One of the basic laws of physics - Newton's third law - states that for every action there is an equal and opposite reaction. Quite simply, to the firefighter this means that as water is projected from a nozzle to form a 'jet' or firefighting stream, the nozzle tends to recoil in the opposite direction. This effect, termed nozzle or jet reaction (or kick-back) requires the firefighters at the nozzle to exert sufficient effort into over-coming this reaction force. The entire force of this reaction takes place as the water leaves the nozzle and whether or not the fire stream strikes a nearby object has no effect on the reaction. Thus, whether or not a hose-line's stream is allowed to strike a wall whilst a firefighter is working it from the top of a ladder is immaterial to his stability on the ladder, which is governed solely by the reaction at the nozzle.

By evaluating maximum flow capability for a hose-line that could be effectively directed and safely handled whilst advancing and working inside a fire-involved structure It was observed that there was a maximum nozzle reaction force that could be handled by one, two and three firefighters as follows -

One firefighter - 266N (60 lbf)

Two firefighters - 333N (75 lbf)

Three firefighters - 422N (95 lbf)

These were interesting findings and from these I was able to establish baseline flows for interior firefighting operations. To achieve this it became necessary to take acceptable pumping practice into consideration without contravening the limitations placed upon european pumps, hoses and equipment available at that time. This resulted in baseline flows of 277 lpm (73 gpm) on 45mm hose-lines with 12.5mm nozzles, 650 lpm (172 gpm) on 70mm hose-lines with 20mm nozzles and 750 lpm (200 gpm) on 70mm hose-lines with 25mm nozzles, as advanced by two-man crews.

However, these 'base-line' flows were rarely, if ever, achieved in practice as tradition had established a base-line pumping pressure of 3-4 bars (45-60 lbs psi) to which a small adjustment may have sometimes been made for frictional loss and pressure head. Actual firefighting flow-rates were in fact far lower than had been previously thought. - Ref: SRDB Codes of the period.

Interestingly, similar research has been carried out by other fire departments, notably San Francisco, Los Angeles and Chicago, who proposed that a safe and practical baseline flow for a workable firefighting hand-line would be around 550 lpm (150 gpm). More recently (1996), the City of St. Petersburg in Florida USA have established that, for their purposes, the ideal

baseline flow is around 600 lpm (160 gpm) using a 7/8" (22mm) nozzle with a 50 lbs psi nozzle pressure on a 45mm (1 3/4") hose-line. This set-up will create an acceptable reaction force of 266N (60 lbf) and offers a hose-line that is easily advanced and maneuvered for interior position.

However, the change to combination fog/straight-stream or automatic nozzles brings a demand for higher nozzle pressures to achieve similar flows and with that comes an increased reaction force. A baseline flow of 600 lpm (160 gpm) being discharged from a combination/automatic type nozzle operating at 7 bars (100 psi) NP will produce a reaction force of 356N (80 lbs lbf) which would cause a two-man team to struggle with any workable advance of the line. There are combination/automatic nozzles available that have been adjusted to provide rated flows at lower nozzle pressures but be sure to test these yourself as manufacturer's 'rated' flows are sometimes unachievable! Top US branded nozzles must meet the stringent demands of NFPA standards and Low-Pressure combination nozzles are able to achieve their rated flow-rates at factory-set nozzle pressures of just 5 bars. This would enable a flow of 600 lpm (160 gpm) to be achieved with a reaction force of just 303N (68 lbs lbf) which is more easily handled and advanced by a two-man team.

The firefighter is able to calculate the amount of nozzle reaction (NR) by resorting to various formulae -

NR (Newtons) = 1.57 x NP x d squared/10 (European Smooth-bore), or;

NR (Newtons) = 0.22563 x lpm x Sq.root of NP (European Combination fog/jet or automatic Nozzles)

These are metric formulae where P = Nozzle Pressure; d = Nozzle Diameter; lpm = Flow in Litres Per Minute and NR is in Newtons.

In the USA different formulae are used as follows -

NR (lbf) = 1.57 x d squared x NP (US Smooth-bore), or;

NR (lbf) = 0.0505 x gpm x square root of NP (US Combination fog/straight or automatic Nozzles)

FOG NOZZLES

GALLONS PER MINUTE (GPM) POUNDS REACTION FORCE† (RF)

NOZZLE PRESSURE AT INLET IN PSI GPM SETTING

50

55

60

65

70

75

80

85

90

95

100

105

110

115

120

125

13

9 3

10 4

10 4

10 4

11 5

11 5

12 5

12 6

12 6

13 6

13 7

13 7

14 7

14 8

14 8

15 8

gpm rf

20

14 5

15 6

15 6

16 7

17 7

17 8

18 8

18 9

19 9

19 10

20 10

20 11

21 11

21 12

22 12

22 13

gpm rf

25

18 6

19 7

19 7

20 8

21 9

22 10

22 10

23 11

24 11

24 12

25 13

26 13

26 14

27 15

27 15

28 16

gpm rf

30

21 8

22 8

23 9

24 10

25 11

26 11

27 12

28 13

28 14

29 14

30 15

31 16

31 17

32 17

33 18

34 19

gpm rf

40

28 10

30 11

31 12

32 13

33 14

35 15

36 16

37 17

38 18

39 19

40 20

41 21

42 22

43 23

44 24

45 25

gpm rf

60

42 15

44 17

46 18

48 20

50 21

52 23

54 24

55 26

57 27

58 29

60 30

61 32

63 33

64 35

66 36

67 38

gpm rf

95

67 24

70 26

74 29

77 31

79 34

82 36

85 38

88 41

90 43

93 46

95 48

97 50

100 53

102 55

104 58

106 60

gpm rf

100

71 25

74 28

77 30

81 33

84 35

87 38

89 40

92 43

95 45

97 48

100 51

102 53

105 56

107 58

110 61

112 63

gpm rf

125

88 32

93 35

97 38

101 41

105 44

108 47

112 51

115 54

119 57

122 60

125 63

128 66

131 69

134 73

137 76

140 79

gpm rf

150

106 38

111 42

116 45

121 49

125 53

130 57

134 61

138 64

142 68

146 72

150 76

154 80

157 83

161 87

164 91

168 95

gpm rf

200

141 51

148 56

155 61

161 66

167 71

173 76

179 81

184 86

190 91

195 96

200 101

205 106

210 111

214 116

219 121

224 126

gpm rf

SOLID BORE NOZZLES

GALLONS PER MINUTE (GPM) POUNDS REACTION FORCE† (RF)

SOLID BORE DIAMETER (INCHES) NOZZLE PRESSURE*

3/8" 1/2" 5/8" 3/4" 7/8" 15/16" 1" 1 1/8" 1 1/4" 1 3/8" 1 1/2" 1 3/4" 2" 2 1/4" 2 1/2" 2 3/4" 40 26

9

47 16

73 25

106 35

144 48

165 55

188 63

238 79

294 98

355 119

423 141

575 192

752 251

951 318

1174 393

1421 475

gpm rf

45 28 10

50 18

78 28

112 40

153 54

175 62

199 71

252 89

311 110

377 134

448 159

610 216

797 283

1009 358

1246 442

1507 534

gpm rf

50 30 11

53 20

82 31

118 44

161 60

185 69

210 79

266 99

328 123

397 148

473 177

643 240

840 314

1064 397

1313 491

1589 594

gpm rf

55 31 12

55 22

86 34

124 49

169 66

194 76

220 86

279 109

344 135

417 163

496 194

675 264

881 345

1115 437

1377 540

1666 653

gpm rf

60 32 13

58 24

90 37

129 53

176 72

202 83

230 94

291 119

360 147

435 178

518 212

705 288

921 377

1165 477

1438 589

1740 712

gpm rf

65 34 14

60 26

94 40

135 57

183 78

211 90

240 102

303 129

374 159

453 193

539 230

734 313

958 408

1213 517

1497 638

1811 772

gpm rf

70 35 15

62 27

97 43

140 62

190 84

218 97

249 110

315 139

388 172

470 208

559 247

761 337

994 440

1258 556

1554 687

1880 831

gpm rf

75 36 17

64 29

101 46

145 66

197 90

226 103

257 118

326 149

402 184

486 223

579 265

788 361

1029 471

1303 596

1608 736

1946 890

gpm rf

80 37 18

66 31

104 49

149 71

203 96

234 110

266 126

336 159

415 196

502 237

598 283

814 385

1063 502

1345 636

1661 785

2010 950

gpm rf

85 39 19

68 33

107 52

154 75

210 102

241 117

274 133

347 169

428 209

518 252

616 300

839 409

1096 534

1387 676

1712 834

2071 1009

gpm rf

90 40 20

70 35

110 55

159 79

216 108

248 124

282 141

357 179

440 221

533 267

634 318

863 433

1127 565

1427 715

1762 883

2132 1069

gpm rf

95 41 21

72 37

113 58

163 84

222 114

255 131

290 149

366 189

452 233

547 282

652 336

887 457

1158 597

1466 755

1810 932

2190 1128

gpm rf

100 42 22

74 39

116 61

167 88

227 120

261 138

297 157

376 199

464 245

562 297

668 353

910 481

1188 628

1504 795

1857 981

2247 1187

gpm rf

105 43 23

76 41

119 64

171 93

233 126

268 145

304 165

385 209

476 258

576 312

685 371

932 505

1218 659

1541 835

1903 1030

2302 1247

gpm rf

110 44 24

78 43

122 67

175 97

239 132

274 152

312 173

394 219

487 270

589 327

701 389

954 529

1246 691

1577 874

1948 1079

2356 1306

gpm rf

115 45 25

80 45

124 71

179 102

244 138

280 159

319 181

403 229

498 282

602 341

717 406

976 553

1274 722

1613 914

1991 1128

2409 1365

gpm rf

120 46 26

81 47

127 74

183 106

249 144

286 166

325 188

412 238

509 294

615 356

732 424

997 577

1302 754

1648 954

2034 1178

2461 1425

gpm rf

125 47 28

83 49

130 77

187 110

254 150

292 172

332 196

420 248

519 307

628 371

747 442

1017 601

1329 785

1682 994

2076 1227

2512 1484

gpm rf

130 48 29

85 51

132 80

191 115

259 156

298 179

339 204

429 258

529 319

640 386

762 459

1037 625

1355 816

1715 1033

2117 1276

2562 1544

gpm rf

135 49 30

86 53

135 83

194 119

264 162

303 186

345 212

437 268

539 331

653 401

777 477

1057 649

1381 848

1748 1073

2157 1325

2611 1603

gpm rf

140 49 31

88 55

137 86

198 124

269 168

309 193

352 220

445 278

549 343

665 416

791 495

1077 673

1406 879

1780 1113

2197 1374

2658 1662

gpm rf

145 50 32

89 57

140 89

201 128

274 174

314 200

358 228

453 288

559 356

676 430

805 512

1096 697

1431 911

1811 1152

2236 1423

2706 1722

gpm rf

150 51 33

91 59

142 92

205 132

279 180

320 207

364 236

461 298

569 368

688 445

819 530

1114 721

1455 942

1842 1192

2274 1472

2752 1781

gpm rf

175 55 39

98 69

154 107

221 155

301 210

345 241

393 275

497 348

614 429

743 519

884 618

1204 841

1572 1099

1990 1391

2456 1717

2972 2078

gpm rf

200 59 44

105 79

164 123

236 177

322 240

369 276

420 314

532 397

657 491

794 594

945 707

1287 962

1681 1256

2127 1590

2626 1963

3177 2375

gpm rf

References: National Fire Protection Association (NFPA) Fire Protection Handbook - 17th Edition

International Fire Service Training Association (IFSTA) Fire Protection Publications - Fire Stream Practices - 7th Edition * Nozzle Pressure Measured with Pitot Gauge, † Reaction force measured in pounds

Low Pressure Fog Nozzles

By David Polikoff

About a year ago I was interested to find out what kind of nozzles were out on the market and can they perform better than the nozzles that my station was using. I wanted a nozzle that would give me maximum GPM with reduced nozzle reaction. You see my department runs with only 3 on an engine, this includes the driver. unfortunately most companies in the U.S. are short staffed like this, some even worse. At that present time we were using the TFT break away nozzle. I was never a big fan of a nozzle that will give you 50 to 350 GPM I wanted a nozzle that would give me X and only X. I called my local fire equipment dealer and he suggested I call Nelson Miller from Elk Heart Brass. I talked to Nelson for about an hour and he educated me about nozzles, not just nozzles from his companies but all nozzles. He told me that most of the time the TFT nozzles are not maintained like they should be and that there will be reduced GPM due to the internal parts not moving like they should. The nozzles need to be cleaned and lubed after each use, or at a min. of once a month. as far as I know this was never done. After my conversation with Nelson I did some more digging. I called Capt. Joe Bruni from the St. Petersburg Fire Dept. He had done extensive nozzle test in the past so I wanted to get his opinion. He told me most of what Nelson had told me, so now I knew I was on the right track. I shared my findings with my Captain and he agreed we need to rethink our nozzles. I was back on the phone with Nelson to arrange a demo with the Elk Heart low pressure nozzles. we decided that we wanted to go with the 150GPM at 75lbs nozzle pressure.

Test day

Nelson came to my station for the demo I invited every station in our county 7 stations out of 19 showed up. To start the test we used a class "A" pumper with 200 feet of 1 3/4 inch hose no elevation. we hooked the TFT nozzle up to a flow meter and charged the attack line to 160psi this should give us 150GPM (30psi FL per 100 ft. plus 100psi for the nozzle) my suspicions were correct we were only getting 80 GPM from our TFT. we changed to a different TFT nozzle and the result was the same. We switched nozzles to the Elk Heart low pressure nozzle we charged the line to 135psi to get 150 GPM (30psi FL per 100 ft. plus 75 for the nozzle) the flow meter hit 150 GPM. I will admit the the nozzle reaction seemed a bit more with the low pressure nozzles. I ask Nelson why was this? he told me that we were only getting 80 to 90 GPM from the TFT, and when we got the GPM we were supposed to get, of course there is more nozzle reaction. there was more GPM!

Bottom line

We decided to go with the Elk Heart low pressure nozzle (150 GPM at 75lbs nozzle psi) I wanted to have a minimum fire ground GPM for my company we decided to go with 150 GPM, but I also wanted the capability to get more water with out having to pull a second line. I decided to have a smooth bore slug tip permanently mounted on the break away portion. We went with the 15/16", this gave us 180 GPM at 50 psi. this added a little more in the nozzle reaction but it is something the average firefighter can handle. After playing with the nozzle we found that we can pump the engine at 140psi through 200 ft 1 3/4 inch hose and leave it there for the low pressure fog or the smooth bore (the fog will be 160 GPM and the smooth bore will be 180 GPM) I now feel comfortable going in with our new nozzles knowing that the guys will get the correct GPM. I prefer the smooth bore portion it is very ease to unscrew the fog and go in and make the attack.

Low pressure nozzle (150 GPM @75lbs nozzle psi) Same nozzle broken down on the left is the15/16" slug tip

NOZZLES AND HANDLINES FOR INTERIOR OPERATIONS

NOZZLES AND HANDLINES FOR INTERIOR OPERATIONS

BY DAVID WOOD

The phrase "aggressive interior attack" is used frequently in the fire service, but what does it really mean? It implies that the first-due engine company`s primary function is to push a handline into the structure and control the fire. Separating the burning area from the uninvolved rooms that must be searched for occupants is the most vital function of the engine company. Putting water on the seat of the fire is the very heart of what we do. An old adage says that a properly placed hose stream will save more lives than any other action taken on the fireground. In these days of reduced staffing, it is all the more true. With today`s emphasis on technical rescue and EMS, basic engine company work is often overlooked and taken for granted. Do your engine companies truly have the ability to perform an aggressive interior attack? Establishing a minimum gallons-per-minute flow for interior handlines, flow testing the nozzles and handlines your engines are currently using, and assessing the actual handline practices your engine companies are employing must all be considered before you can answer this question.

MINIMUM GPM FOR INTERIOR HANDLINES

Has your department established a minimum gpm standard operating procedure (SOP) for interior handlines? If so, are you sure your firefighters are actually flowing it on the fireground? Is it based on experience and research and made after carefully considering the needs of engine companies operating inside burning structures? Is the gpm flow always available to the nozzleman, or does he have to turn a ring on the nozzle or call the pump operator for more water? Is the volume adequate to allow a nozzle team to rapidly advance through more than one burning room? Does it have a safety factor for those jobs where conditions deteriorate or when more fire than expected is encountered? If you cannot answer yes to all these questions, your engine companies may not be prepared for an interior attack on more than one room of fire. They may also be in danger.

Several formulas are used to calculate the minimum gpm required to extinguish a given volume of fire. The Iowa State formula (L 2 W 2 H / 100 4 gpm) has been taught to new firefighters since it was developed at Iowa State University in the 1950s. It calculates 13.44 gpm as the minimum required to control a fire in a 12- 2 14-foot room with eight-foot ceilings. Anyone who has responded to a fire at which a civilian with a garden hose has knocked down a room of fire through the window would most likely agree. Most firefighters, presuming they can crawl down the hall to the door of a burning room, would also agree that a 13-gpm stream would probably knock down the fire. While this may be technically correct, the formula does not provide a margin for error or a safety factor for the engine company using such a tactic from an interior position. Suppose that the engine company makes the door of the fire room just as an aerosol can full of a flammable propellant causes a BLEVE (boiling- liquid, expanding-vapor explosion). A window or sliding glass door that vents as the crew is advancing will allow the fire to quickly intensify. If the wind is blowing against the engine company, the results can be

catastrophic. A fire presumed to involve only one room may have extended into the attic and is now roaring overhead, unknown to the firefighters below.

As more is learned about flashover, it becomes obvious that an engine crew armed with only a 13-gpm stream is in grave peril if the area in which they are located reaches flashover. A program about this phenomenon aired on educational TV graphically represents this. In just a few minutes, one small burning chair causes a room to flash over, and the fire quickly extends to adjacent areas. The prevalence of synthetic materials in our society makes the danger of flashover a real possibility at any fire to which we respond. Our engine companies must have enough water immediately available to protect themselves.

If we apply the Iowa State University formula to a fire scenario involving multiple rooms, the required minimum gpm will increase. A fire in the three bedrooms and hallway in my home would require a stream of 40 gpm to extinguish, according to the formula. This does not take into consideration the fact that a nozzle team would have to extinguish and cool the hall rapidly enough to crawl down its 20-foot length to reach the two rooms at the end. They would also have to knock down one room midway and then pass it as they pushed on.

To extinguish this fire, the nozzle team must have a stream with enough volume to cool the rooms quickly enough to occupy them and continue to advance the nozzle. They must be reasonably confident that the room they knocked down and passed will not light up behind them. In the real world in which engine companies operate, 40 gpm will not be effective or safe for extinguishing this fire.

Another formula, developed at the National Fire Academy (NFA), states the minimum gpm required to extinguish a given fire can be determined by dividing the square feet of the fire area by 3 (L 2 W / 3 4 gpm). It calculates the minimum flow for the same one-bedroom fire as 56 gpm.

Although this is more than four times the volume of the Iowa State formula, it is barely above the flow from a one- inch booster line. It will certainly extinguish the fire in the room, but the safety factor is nonexistent. In the scenario involving three bedrooms and the hall, the NFA formula calls for 167 gpm. This is a safer, more realistic figure and may account for the extensive amount of synthetic materials that makes today`s fires hotter and quicker to flash over than fires 30 years ago. An experienced engine company should be able to advance a stream flowing 167 gpm down the hallway and extinguish three rooms without a great deal of difficulty.

This is the principle behind setting a minimum gpm SOP for interior handlines. The nozzle team should have enough water available at all times to extinguish multiple rooms of fire. For those fires involving just the mattress or a corner of the room, the nozzleman applies a short burst from the stream. If the burning area involves one room, the nozzleman opens the nozzle a little longer. If multiple rooms of fire are encountered, the nozzle team can flow enough gpm to allow them to occupy the space that was just

burning and move forward. Always having enough water available at the nozzle for the multiple-room fire provides the engine company with a safety factor for the unexpected. It also puts the control in the brain and hands of the nozzleman. A small fire requires just a dash, while the full gpm is instantly available when needed.

Some departments use nozzles that allow the nozzleman to increase the gpm by turning a selector ring on the nozzle. These nozzles usually work well, and the theory is sound most of the time. This system requires coordination, though, and leaves a chance for error. What works well at company drills is not always practical under fire conditions. There is a huge difference between practicing in the parking lot vs. advancing a handline down a burning hall and extinguishing three rooms. There is a possibility that the nozzle flow selector may be set at or changed accidentally to an insufficient gpm. If it occurs before the engine advances down the hall, the nozzleman may recognize that something is wrong. If it occurs during the advance, as the crew is crawling and falling over everything that gets in their way at a tough job, it may be difficult to recognize and correct. Halfway down the hall under brutal conditions and zero visibility is not the time to have to try and change the gpm setting.

Some fire departments assume that the nozzle team can request a boost in gpm by radio if the line cannot be advanced: The engine officer simply calls the pump operator on the radio and requests more gpm. This may work if the radios are working and if the officer can get through the busy radio traffic. If by chance the pump operator happens to hear and understand the officer`s request, the nozzle team might get the desired gpm. The point is, too many things can go wrong. If engine companies always have sufficient gpm available at the nozzle, they will be able to operate more safely and efficiently from interior positions.

WHAT GPM IS ADEQUATE?

The question then is, What minimum gpm flow is adequate and safe for interior firefighting operations? The answer, to a degree, will vary according to your department`s needs. As a member of a Fire Department of New York (FDNY) engine company for four years, I learned the value of a stream with a minimum flow of 180 gpm. Although higher flows may sometimes be required, the FDNY minimum flow SOP provides the engine company with a fire stream with three vital characteristics.

First, it gives the nozzle team the punch to extinguish the majority of multiple-room fires. A properly applied stream flowing 180 gpm will control most fires involving as many as five rooms, barring unusual circumstances such as strong winds. Multiple rooms of fire are extinguished by controlling one area or room at a time and keeping the nozzle moving forward. A stream of 180 gpm should allow the nozzle team to cool a room and rapidly advance into it and gain control of it. The nozzle team must keep advancing to extinguish the remaining rooms. If a room must be darkened down and then passed, as when advancing down a hall, the volume applied must be enough to keep the room from lighting back up. It is important for one member to monitor a passed room so that the nozzle team can be warned if the fire in the room reintensifies.

Second, a stream flowing 180 gpm gives a good indication of the severity of the situation. It is a potent offensive weapon in experienced hands. If an engine company is unable to advance a nozzle it knows is flowing 180 gpm, a different tactic may be called for. As John Norman writes in his Fire Officer`s Handbook of Tactics, Second Edition (Fire Engineering, 1998), more water, more ventilation, or both, may be called for. If this doesn`t allow the nozzle to advance, a change of tactics--from offensive to defensive, for example--may be necessary.

Third, 180 gpm provide a safety factor for the nozzle team and any truck personnel in the nozzle`s vicinity. If more fire than anticipated is met or conditions deteriorate, the flow will be sufficient to extinguish the fire or at least protect the members as they retreat. In most cases, if the area flashes over, the power of the stream will allow the engine company to save themselves. In this age of energy-efficient buildings full of synthetic wall/floor coverings and furnishings, this factor can be critical.

FDNY Firefighter Andrew Fredericks has well documented the capabilities of a stream flowing 180 gpm in his article "The 212-Inch Handline" (Fire Engineering, December 1996). All departments should develop a gpm SOP based on actual fireground experience and their specific needs. It should provide all the qualities previously discussed. The FDNY SOP of 180 gpm may not be exactly right for your fire department, but it will not be far off. The goal is to set a standard minimum gpm based on analysis of your fire situation and make a conscious decision with the effectiveness and safety of your engine companies in mind.

A disturbing trend has developed in which many departments` engine companies assume that they are flowing enough water from their handlines but actually are not. Many firefighters have no idea of, and have never thought about, how much water they have available at the nozzle. Since most of our fires involve one room or less, we have become overconfident. We usually get away with relatively low flows, becoming victims of our own success. The times we are driven out of the building, we blame it on too much fire. Was it actually the volume of fire that drove us off the fire floor or the inability to advance the nozzle because of insufficient flow? To be able to answer this question accurately, you must not only establish a minimum gpm but also ensure that your companies are flowing it.

FLOW TESTING

To accomplish this objective, you must actually flow test the nozzles and handlines currently used in your department. It is the only way to accurately assess how much your engine crews are flowing. You can use an engine with onboard flowmeters or a portable flowmeter. The portable unit (several brands are available) allows more versatility in testing. You will need also a pitot gauge and a smooth-bore nozzle of a known flow at a given nozzle pressure. These devices will be used to calibrate the flowmeter and ensure that the readings are accurate. An inline pressure gauge that can be inserted between the nozzle and the last coupling will give you an idea of the nozzle pressure, but it is not essential.

To use the portable flowmeter, connect a supply line directly to a hydrant and into the inlet end of the meter`s flow tube. Connect another line from the outlet end of the flow tube into the auxiliary inlet on the pump. Attach the wire that transmits the flow reading between the flow tube and the flowmeter. Once the supply line from the hydrant is charged and the flowmeter is calibrated, the gpm flow of any handline off the engine can be easily determined. With this arrangement, multiple lines can be quickly flowed and tested. Every handline on the apparatus can be stretched. As long as only one line at a time is flowing, the gpm reading will be for that individual nozzle and hoseline. The gpm of water entering the pump will equal the volume flowing from the nozzle. This also allows rapid comparison between streams from different nozzles without disconnecting each time.

Another advantage of connecting the flowmeter on the inlet side of the pump is that it allows you to observe the correct pump discharge pressure needed to supply your target gpm to a specific nozzle/hoseline combination. Since the flow tube is on the inlet side of the pump, no additional friction loss occurs from a test device in the handline being flow tested. The alternative is to place the flow tube on a pump discharge. This will also work, but it allows testing of only the nozzle and line connected directly to the flow tube. Different nozzles and hoses must be disconnected and reconnected each time.

Once the flowmeter is in place, charge the supply line from the hydrant to the pump, and connect a handline with a smooth-bore nozzle to a discharge. A smooth bore is required for calibrating the meter, since a fog nozzle can`t be accurately measured with a pitot gauge. The gpm flow of the smooth bore at a given nozzle pressure must be known. For our purposes, a 1516- inch tip is connected to 134- inch hose. Have the pump operator start water in the handline and throttle up to a pump discharge pressure that will approximate 180 gpm (the flow of a 1516- inch tip at 50 psi). With the nozzle wide open, insert the pitot tube into the stream, and take a reading. Adjust the pump discharge pressure until the pitot gauge reads 50 psi. Now, without shutting down the nozzle or changing the pump discharge pressure, adjust the flowmeter until it reads 180 gpm. This calibrates the flowmeter and verifies that the flow reading is correct. If we were using a 78- inch tip, the flowmeter would be set at 160 gpm (the flow of a 78- inch tip at 50 psi). Once the meter has been calibrated to a smooth-bore nozzle, the flow from any nozzle and handline combination connected to the pump will be accurately displayed on the flowmeter.

A newer type of portable flowmeter, controlled by a computer chip, has made calibration easier. The unit can be calibrated by programming it for the size of the flow tube without flowing water. To use this type of meter, hook it up as described above. Increase the flow to the 1516- inch smooth bore until the flowmeter reads 180 gpm. At this point, the stream from the nozzle should be measured with a pitot gauge to verify the flow reading. The pitot gauge should indicate 50 psi nozzle pressure if the flowmeter has been correctly calibrated. If it does not, consult the operator`s manual, and make the necessary adjustments.

A good place to begin assessing your current handline practices is to give an engine company a fire scenario. With a flowmeter in place, have the members stretch a handline

and flow water. To be as realistic and informative as possible, ask them to duplicate what they would actually do under fireground conditions. Repeat the test with several engine companies, and analyze the results. Is every unit meeting, or at least close to, the gpm flow established as the department required minimum? If so, you have verified that you are operating as the department has stipulated. All that is left to do is to make sure that all your engine companies continue to follow the SOP when operating. This can be accomplished through training and implementing a formal policy for interior handline operations.

If your engine companies are not flowing the desired gpm, you must investigate further. There may be several reasons for this. It may simply be a matter of education and training. Engine companies may be using low gpm flows based on the success they have had with one-room fires. Explain the need for having an adequate flow available immediately, as discussed earlier. Another reason may be that they simply don`t know what they are flowing. Since they usually get away with a low gpm, they have not considered the need for more. A more common reason may be the handling characteristics of the nozzle at flows sufficient to extinguish multiple rooms of fire.

HANDLING CHARACTERISTICS

Nozzle Reaction

Nozzle reaction is measured in pounds of force and determines how difficult a stream is to control. The higher the nozzle reaction, the harder the stream is to control. The lower the nozzle reaction, the easier the stream is to control. Nozzle reaction depends on the gpm flowing and the nozzle pressure at which it is flowed. It is roughly the same for a smooth-bore and a fog nozzle in the straight-stream position, if both the flow and nozzle pressure are the same. For our discussion, let`s assume that interior operations will be conducted with a solid-stream or fog nozzle in the straight-stream position.

There are different formulas to calculate nozzle reaction for smooth-bore and fog nozzles. All we need to know is that at a given flow (180 gpm in this case), the nozzle reaction will vary directly with the nozzle pressure. If the flow in gpm is held constant while the nozzle pressure is lowered, the nozzle reaction will be less, and the stream will be easier to control. The more the nozzle pressure is reduced at a given flow, the easier the stream will be to handle. As long as the stream has adequate reach and shape, the lower the nozzle pressure, the better. Fog nozzles that operate at low pressures also produce a straight stream with larger droplets than nozzles that operate at 100 psi. This allows a tighter straight-stream pattern that approaches the quality of a smooth bore in some low-pressure nozzles.

The other factor that must be considered is the pump discharge pressure needed to supply our target flow at the correct nozzle pressure. Simply put, nozzles that operate at 100 psi require higher pump discharge pressures. This means the hose will be stiffer and less maneuverable and the nozzle reaction at our target flow will be higher. Nozzles that operate at pressures lower than 100 psi require lower pump discharge pressures. The hose

will be more maneuverable, and the nozzle reaction at our target flow will be less. The more we lower the pressure at which the nozzle operates, the more maneuverable the line and the lower the nozzle reaction. Kinks can be a problem, though, and must be managed.

Specific Nozzles

The smooth-bore, automatic- fog, and low-pressure fog nozzles are commonly used by engine companies. For our purposes, we will assume the following for each of these types of nozzles: a minimum flow of 180 gpm for all nozzles (if the desired gpm flow is different, adjust your testing and research accordingly; the principles em-ployed will be the same), and the nozzles will be used on 134- inch hose, which will allow flows of 180 gpm at relatively low pump discharge pressures.

The smooth-bore nozzle. This nozzle type has been around for many years. It is still a popular choice because of its ability to deliver high gpm with low nozzle reaction at 50 psi nozzle pressure. A 1516- inch smooth bore delivers 180 gpm at 50 psi. The nozzle reaction is 69 pounds. In Fire Stream Management Handbook (Fire Engineering, 1991), David Fornell states that one firefighter can safely and comfortably control approximately 70 pounds of nozzle reaction. The 1516- inch smooth bore on 134- inch hose is a popular combination in many departments for this reason. It delivers 180 gpm with manageable nozzle reaction at relatively low pump discharge pressures. A 78- inch tip is another popular choice of smooth-bore advocates, delivering 161 gpm at 50 psi nozzle pressure with 60 pounds of nozzle reaction.

Automatic fog nozzles. Also used widely in departments, this type of nozzle operates through a range of gpms. A typical automatic for handlines may have a range of from 60 to 200 gpm. The nozzle has a large spring inside the barrel, which helps to shape the stream. At the upper end of the gpm range, the spring is compressed, allowing the deflector stem to move out. This increases the nozzle orifice and allows more water to flow from the nozzle. At the lower end of the nozzle`s gpm range, the spring is not compressed. This keeps the deflector stem in close, reducing the nozzle orifice and giving the stream good reach at low flows. This is exactly what the nozzle is designed to do. It is widely believed that automatic fog nozzles "automatically" maintain 100 psi nozzle pressure. This is not entirely true. The data sheet provided with the automatic nozzles used by my department shows that they operate through a range of nozzle pressures as well. At 60 gpm, these automatics have 65 psi of nozzle pressure and 24 pounds of nozzle reaction. At our target flow of 180 gpm, these automatics have 95 psi nozzle pressure and approximately 95 pounds of nozzle reaction. This is well above the 70-pound reaction that is readily controlled by one firefighter.

Engine companies must be aware of how automatic fog nozzles work to avoid the possibility of unknowingly flowing a dangerously low gpm. The nozzle reaction at 180 gpm is substantial and difficult to control. Firefighters are ingenious and quickly learn that lowering the pump discharge pressure still gives an adequate stream (or so they think) and one that is now manageable. They are being deceived into thinking that a low flow stream is adequate, because of the spring in the barrel of the nozzle, which provides

a stream with good reach at 60 gpm. An analogy would be placing your thumb over the end of a garden hose. The stream will have good reach, but you still have a garden hose. This situation occurred in my own department. It was determined through flow testing that our engine companies were operating in interior positions with as little as 60 to 80 gpm. In talking with Fornell, who has done nozzle consulting all over the country, I learned that this is a common occurrence.

The key to operating an automatic nozzle at 180 gpm is to relieve the nozzle reaction from the nozzleman. In the FDNY Training Academy, I was taught that at least two firefighters are needed to control the nozzle reaction from an automatic at 180 gpm. We were taught that, as a rule of thumb, if one firefighter can easily control the nozzle, the flow is inadequate. At the time, I was not fully aware of the implications. The FDNY solution to absorb the nozzle reaction is the two-firefighter method, or nozzle-team concept. The backup firefighter must be on the same side of the hose as the nozzleman and must maintain physical contact with him. He turns his arms backward, clamping his hands on the hose and pulling against the nozzle reaction. He leans into the nozzleman with his body weight, which relieves almost all the reaction from the nozzleman. The backup man must be careful not to push the nozzleman faster than he wants to go. They must truly work together as a team. If the nozzleman moves left, around a corner, the backup man moves right. When the nozzleman directs the stream up, the backup man must keep the hose low. The technique works so well that it is also used with the smooth-bore nozzle. Although the smooth-bore reaction is considerably less than that of an automatic at the same flow, 180 gpm is a potent stream. The two-firefighter method is preferred with flows of 180 gpm, regardless of the type of nozzle used.

The low-pressure fog nozzle. If a standard fog nozzle operates at 100 psi, a low-pressure nozzle operates at pressures below 100 psi. As previously discussed, the lower we can get the nozzle pressure while maintaining gpm, the lower the nozzle reaction will be. As long as the stream has adequate reach and shape, the lower the pressure at which the nozzle operates, the better it will be for the nozzle team. Consider three nozzles. Each flows 180 gpm at 100 psi, 75 psi, and 50 psi, respectively. The nozzle that flows 180 gpm at 50-psi nozzle pressure will be the easiest to control.

Low-pressure fog nozzles have been around for many years and are becoming very popular. Fire departments reluctant to switch to smooth-bore nozzles are learning that they can have the same easy handling characteristics for which the smooth bore is known, but with fog capability. Many different flow/pressure combinations are available. The following rated nozzles are common and are growing in use by many good fire departments: 150 gpm at 75 psi (stated as 150@75), 175@75, and 200@75. Other low-pressure nozzles are also available.

Quite by accident, while talking to a nozzle vendor, I came across the low-pressure nozzle to which my department is switching. It is rated as a 250@100 psi nozzle. If it is rated at 100 psi, you may ask, how is it a low-pressure nozzle? The answer is that we "underpump" the nozzle to deliver 180 gpm at 50 psi nozzle pressure. Do those numbers sound familiar? They are the same as those of a 1516- inch smooth-bore nozzle with fog

capability. The straight-stream pattern, which we use for most of our interior firefighting, is the closest to a smooth-bore stream I have ever seen. A vendor that sells nozzles to the Memphis Fire Department tells me that it is doing something very similar. It is underpumping a 200@75 to deliver 160@50. The concept is the same, only the target gpm is lower. The Memphis Fire Department has recognized the need to select a minimum standard gpm and reduce the nozzle pressure at which it is flowed.

At ratings above 175 gpm, the different manufacturers increase the size of the nozzle body to accommodate the higher flows. At first glance, these nozzles look quite large and unwieldy. Nozzles should be purchased based on how they perform, not on how they look.

The initial impression of the awkward appearance of the 250@100 nozzles disappears the moment you flow 180 gpm through one of the nozzles. I believe it is the large barrel size that produces the excellent streams it delivers. Without a doubt, it produces a 180-gpm stream that is superior to any fog nozzle I have ever tested. The heavy droplets produced by the low nozzle pressure deliver a straight-stream pattern that rivals any smooth bore, with almost identical handling characteristics. The deflector stem is easily changed to convert a 250@100 to a 200@75.

We have discussed the characteristics of a fire stream that will allow our engine companies to extinguish multiple rooms of fire from interior positions. Adequate volume and reach are vital for allowing the engine to push a handline into the seat of the fire. Using the two-firefighter nozzle-team concept, a stream that is adequate and safe for interior operations can be delivered by a smooth-bore, automatic-fog, or low-pressure fog nozzle. Nozzles that flow a given gpm at a lower nozzle pressure are easier to handle. Keep this in mind as you evaluate the way your engine companies are operating and consider new equipment purchases. For fire departments that do not have the luxury of six-firefighter ladder companies, the engine company`s ability to get a handline inside the structure and control the fire may be their only chance to save lives.

Don`t assume that your handline practices are effective or safe just because you are good at one-room fires. Every fire department should set a minimum gpm SOP for interior handlines and ensure that the engine companies are meeting it. This SOP should be based on experience and analysis, not on the basis of "because we`ve always done it that way." The standard should be established by conscious decision and not be allowed to just happen. The only way to know for sure is to perform actual flow tests and train. Engine companies must know exactly what their handlines are flowing to be effective and safe while operating inside burning buildings.

DAVID WOOD is a captain with Metro-Dade Fire Rescue in Miami, Florida, where he has served 17 of his 23 years in the fire service. He spent four years in the Fire Department of New York, assigned to Engine 53 in Spanish Harlem. He has an associate`s degree in fire science technology from Miami-Dade Community College and is a Florida State-certified fire instructor.

Fire Engineering April, 1999

PRESELECTING PUMP DISCHARGE PRESSURES FOR PRECONNECTED HANDLINES

PRESELECTING PUMP DISCHARGE PRESSURES FOR PRECONNECTED HANDLINES

BY DOUGLAS LEIHBACHER

When pump discharge pressures are not carefully chosen, the nozzle team may attempt an aggressive interior attack with an inadequate water supply. This could place the team in danger and render its effort ineffective.

To illustrate the importance of optimal flow, consider the following scenario: Your engine company arrives first-due to a fire in a three-story frame apartment building. Dark brown smoke is showing from the top floor and eaves as you arrive. A ladder company arrives behind your engine and begins to raise its aerial to the roof to effect vertical ventilation. When you step off the apparatus, your lieutenant directs you to stretch a 250-foot 134- inch preconnected handline to the top floor. After donning your SCBA, you walk to the rear of the apparatus. Passing your arm through the top row of extended hose loops, you grasp the nozzle and step back from the tailboard. With this length of hose over your arm, you approach the fire building. A fellow crew member, who will back you up on the line, grabs the second set of long loops and sees that all the remaining hose has been removed from the hosebed. This backup firefighter discards the hose one loop at a time while stretching to the fire floor. In contrast, you carry your folds of hose with you until you reach the fire floor.

On your arrival at the top floor, you en-counter a smoke condition. You remain in the stairwell below the level of the smoke momentarily to don your face piece. With the face piece in place, you begin flaking out the hoseline. As you do, you overhear roof team members on your portable radio reporting that they opened the scuttle and have fire in the cockloft.

Your lieutenant arrives on the top floor along with a forcible entry team and radios the pump operator to start water. As you kneel to one side of the apartment door to bleed the air from the line, you can hear the roof team starting the power saws above. From experience, you know that the vent hole they are cutting will make your job much easier.

When the door is forced open, the hallway becomes charged with smoke, and visibility is lost. As you enter the apartment, you sweep the floor quickly with the hose stream and shut it down. This will cool the floor and remove any sharp debris. After moving in several feet, you encounter severe heat and can see some flame activity in the smoke overhead. Your lieutenant is at your side and orders you to open up the nozzle and aim at the ceiling in front of you to cool the hot gases overhead. When you do, the heat intensifies as the smoke be-comes impregnated with steam. You can hear crashing in front of you as wet plaster falls from the ceiling and hits the floor, re-vealing flames

rolling across the cockloft. As you direct the stream upward, the heat continues to build. The line is flexible and easy to maneuver under your arm, but the flames will not darken down, and the punishing heat drives you closer to the floor. In an effort to hold your position, you keep the nozzle moving back and forth over your head. You cannot advance because the flames continue to roll above you. The heat continues to intensify, and your lieutenant orders you to back out. As you exit the fire apartment, you pull the hose back into the hallway and close the apartment door. The interior operation is abandoned, and a de-fensive attack will be initiated outside the building using master streams. As you back the hose downstairs, you wonder what went wrong. You`ve moved in on fires like this before and knocked them right down.

THE CRITIQUE

On returning to quarters after the fire, your lieutenant holds a critique of the operation. During the discussion, the lieutenant asks the pump operator what pump discharge pressure was used to supply the handline. The pump operator answers that the pressure was about 100 psi. The lieutenant reminds the pump operator that 100 psi is needed at the nozzle and that, because of the impact of friction loss and head loss, the nozzle pressure was probably considerably less. He states that he will preplan an initial pump discharge pressure for future operations, which will ensure that the nozzle is supplied with the correct pressure.

THE PUMP OPERATOR

The pump operator is one of the most important individuals on the fireground, regardless of rank. His ability to provide instantly a volume of water commensurate with the amount of fire encountered is the key to successfully containing the fire. Without this expertise, the most aggressive hose teams would be unable to advance. Likewise, search and rescue operations may have to be cut short or abandoned entirely. Remember, a nozzle team is only effective when it has enough water to "overpower" the fire it encounters. When it opens the nozzle and directs its stream into the flame zone, it must penetrate deeply so that the fire will darken down somewhat quickly and allow the team to advance its line farther.

To be a proficient pump operator, it is necessary to understand hydraulic principles. However, the pump operator should not be expected to perform complicated hydraulic calculations during initial fireground operations, which are bewildering enough in their own right. The pump operator has enough to be concerned with in positioning the apparatus properly, shifting into pump, engaging the proper transmission gear, and opening the correct discharges.

PRESELECTING PUMP DISCHARGE PRESSURES

One way to simplify operations for the pump operator, while making conditions safer for crew members operating inside the structure, is to preselect the pump discharge pressures for all preconnected hoselines carried on the apparatus and to mark them for immediate

reference. One of the benefits of preconnected lines is that all features except head pressure remain constant; the length of the stretch, the diameter of the hose, the type of nozzle, and even the handle on the pump panel always remain the same. Thus, the friction loss will also remain the same. This makes it possible to determine the optimum pump pressure for each preconnected handline on the engine ahead of time and eliminate the guesswork on the fireground.

The charts shown on page 35 are simple to use and can be used to determine optimal pump discharge pressures for handlines employing 100 psi fog or automatic nozzles. The formula used to develop the charts is FL = 2Q2KL (FL--friction loss; Q--gpm flowing/100; K--conversion factor for hose diameter other than 212 inches; L--length of hose). Figures can vary with the age and make of the hose. They are based on two fundamental hydraulic principles:

1. Friction (FL) varies with the number of gallons per minute (gpm) flowing through the hoseline. As the flow increases, the FL will also increase for a given diameter of hose. For example, if 200 gpm are flowing through a 212- inch line, and that flow is increased to 250 gpm, the FL will correspondingly increase [from approximately eights pounds per square inch (psi) to 11 psi in this example].

2. FL varies with the length of hose stretched. Thus, there would be more FL in a 200-foot preconnect than in a 150-foot preconnect.

To select pump discharge pressures for 134- inch preconnected handlines, use the top chart. To select pump discharge pressures for two- inch preconnected handlines, use the middle chart and for 212- inch preconnects, use the bottom chart. To use the charts, simply choose the desired gpm flow in the column on the left and read across to the pump pressure column on the right, which matches the length of the preconnect on your engine.

For example: If you ride with a 150-foot 134- inch preconnect and want to flow 175 gpm through it, simply locate 175 in the gpm column on the left and read across to the first column on the right, which represents 150-foot preconnects. The needed pump discharge pressure for this flow will be 170 psi.

For engines outfitted with flowmeters instead of pressure gauges, the process is even simpler. It is necessary only to choose the gpm flow you wish in the left-hand column.

When choosing optimal pump discharge pressures as described above, remember that the greater the gpm flow, the better the chance of controlling the fire. [For guidelines on minimum gpm flow for interior structural firefighting operations, refer to "The 212-Inch Handline" by Andrew A. Fredericks (December 1996, page 36).] However, nozzle reaction will increase as well. Thus, consider your staffing level. If too much water is flowing for the number of firefighters assigned to the hoseline, they may be unable to overcome nozzle reaction and will tire quickly.

If, for example, your company responds with 134- inch preconnects and a one-person nozzle crew, 100 to 110 gpm (yielding a nozzle reaction of approximately 50 pounds) may be your optimum practical discharge even though a higher flow would be more effective. In turn, a nozzle crew of two firefighters could handle a nozzle discharging 150 to 160 gpm (nozzle reaction of around 75 pounds), and a three-person hose crew could control an even greater discharge without tiring.

For this reason, it would be wise to field test the pump discharge pressures you have selected with your personnel. In many cases, you will find that an increase in flow is manageable without causing undue strain for the hose team. For the greatest effectiveness, choose the highest flow fo r which your staffing will allow.

Once you have chosen pump discharge pressures for all preconnected lines, be sure to mark them conspicuously on the apparatus. An ideal location for labeling each pump pressure is on the discharge gauge corresponding to each preconnect. An equally good place to label is the handle of the pump discharge gate for each preconnect. Finally, the inside of the pump operator`s compartment door also provides a handy, out-of-the-way place to list pump pressures.

Lastly, if your company uses constant-flow fog nozzles, be sure to choose a pump pressure within the range of the nozzle`s capacity, and remember to reset the ring on the nozzle to correspond with the chosen gpm flow.

In addition to simplifying the pump op-erator`s job, preselecting pump discharge pressures can also make interior firefighting safer. To advance their lines within the structure, hose teams must discharge enough water to be capable of darkening down the fire they encounter. When there is too much fire to advance, they must have enough water to hold their position to protect search teams. Most veteran firefighters have been admonished never to stretch a booster line into a building fire. The reason for this is the limited discharge capability of a booster line. With only 30 to 40 gallons or less per minute available, a booster will be ineffective within a structure, given the volume of heat and flame likely to be encountered. Yet, stretching a 134- inch line into a structure and supplying it with only 80 to 90 gallons per minute is tantamount to stretching a booster line. There will be times when you will get away with it, but the line will be ineffective when you encounter heavy fire conditions.

Without preselected pump pressures, many pump operators will be impelled to make an educated guess and await further instructions. This is not the best option. The reason is illustrated by an article published recently by IFSTA in its quarterly magazine Speaking of Fire. The article describes a study conducted by the National Institute of Standards and Technology. The study shows that over the past 50 years, the fire load (lbs./sq. ft.) found in residential buildings has more than doubled. Additionally, the use of synthetic materials, such as polyurethane foam, in home furnishings cause hotter, longer-burning fires than did the ordinary combustibles used earlier in this century. Add to these findings the advent of thermal-pane windows, which hold heat in, and it is easy to see why higher flow rates are becoming more essential to controlling structure fires.

Although the amount of fire encountered will vary with the fire loading of each structure fire, the amount of water the hose team can expect for its line should remain constant and not vary from pump operator to pump operator. The optimum pump discharge pressure, then, for an aggressive interior attack should be a standard pressure preselected by the company officer that will make full use of the flow capability of the preconnect being stretched, within the constraints of staffing levels. When only a minor fire condition is encountered, it is the nozzle team`s job to control the amount of water it uses, and the company officer always has the option of directing the pump operator to reduce the pressure. But more importantly, nozzle teams must be confident that they are using their optimal flow in cases when they encounter fire that will not darken down and they cannot advance. This is the time to consider altering tactics.

WATER DAMAGE

It would seem that an increase in discharge would increase the amount of water damage. That is not necessarily the case. In fact, the amount of water damage may actually decline. Having enough water to control a fire with an interior attack eliminates the need to fall back on an outside attack using master streams.

During an interior attack, water must be applied properly. Occasionally, it is applied unnecessarily before reaching the proximity of the fire. Once the fire is encountered, experienced engine companies advance by a series of stops and starts whenever possible. Once the fire darkens down, they shut down the nozzle and move forward to a better position. The faster the fire darkens, the sooner the nozzle can be shut off. In fact, most water damage occurs when the nozzle is kept open long after flames have darkened down. Additionally, during overhaul, steam rising from structural members is often mistaken for smoke and is washed down excessively. This is rarely necessary. Applying water properly and using it sparingly during overhaul are the best ways to minimize water damage.

In summary, preselecting pump discharge pressures for preconnected handlines provides two significant benefits. It simplifies initial operations for the pump operator and improves the fire flow capabilities so that interior hose operations are safer and more effective. It may still be necessary for the pump operator to make adjustments for changes in nozzle elevation (65 psi per story, to overcome head pressure) or reduce pump pressure during overhaul to prevent water damage, but the process will be simplified and the initial flows will be sufficient to effect a quick knockdown more often.

DOUGLAS LEIHBACHER, a 15-year veteran of the fire service, is a captain in the Yonkers (NY) Fire Department. He is a New York state-certified fire instructor.

Smoothbore Nozzle Basics

By Tim Adams

As smoothbore nozzles work their way back on to hoselines all across the country at an increasing rate, many of the born-and-bred combination nozzlemen are finding themselves with a new tool in their hands. To most, this has become the vogue. A good portion of these firefighters have failed to realize that with a change from fog patterns and combination nozzles comes a new challenge: to properly apply the solid stream safely and effectively from the smoothbores. This unfamiliarity has left them either unconvinced, partially burned or just plain confused and unsuccessful.

With the popularity of smoothbores expanding, the theories surrounding the use of solid streams have been well documented. This raises an interesting question. Have we changed the way we apply water to compensate for this “new nozzle”? Are we using the stream correctly and taking advantage of a solid stream’s true capabilities? I think not. In order to maximize it’s potential and truly reap the benefits, certain basic skills must be modified and perfected when fighting interior fires using handlines equipped with smooth-bore nozzles. As basic as they may seem, these four simple steps will insure a successful transition.

1) CHASE THE KINKS — Lower nozzle pressures mean more kinks. It is important that we remove the kinks to maintain proper flows and nozzle pressures. This starts with making a good stretch from the hose bed and flaking the hose properly before charging. A few extra seconds here leads to minutes saved as the line is advanced. Place the nozzle down a short distance from the point of entry after stretching the line (off the porch, allowing for easier forced entry). The nozzle and the coupling (50 feet back) are side by side with a bend pulled straight back away from the entry point. This method allows the line to be advanced through the door with less effort because we are not putting needless bends in the line, and a straight hose can be advanced inside without binding on the door jam.

2) SOLID STREAMS OFFER REACH — Use this to your advantage. While it is imperative that the nozzle make the doorway quickly, once in position, use the stream's reach to cover the entire room. Break up the fire burning overhead, cool down the contents, then sweep the floor and move in. Hit all six sides when necessary.

3) POSITION THE NOZZLE OUT FRONT AND MOVE THE STREAM AROUND, A LOT! — I feel that this is the skill that is being overlooked and ignored the most by the newly converted fog generation. In order to take advantage of the cooling capabilities of water, it must be applied to the burning material to cool it below its ignition temperature. This requires the nozzleman to aggressively work the stream over the entire burning area. Too many times the nozzle is held too close to the body and directed into the fire area with little or no movement. Do your department a favor, remove those pistol grips. With the tip held approximately two feet in front of the body, the nozzle is easily directed in all directions quickly with less effort and maximum cooling efficiency. Break up the stream

into large droplets off the ceiling and walls. Fog patterns give us the false security of quick extinguishment simply because of the large amount of steam generated. It appears to be darkening down the fire when in reality the steam is merely hiding the seat. Precious time passes before the fire is exposed again and the process starts over, delaying search.

4) DARKEN DOWN, SHUT DOWN — While the solid or straight stream doesn’t usually offer the appearance of instant extinguishment, it does extinguish more quickly with less disruption of thermal balance. Still, too much of a good thing can be bad, and this holds true with water. Remember, hit the seat hard with sufficient GPM quickly, then shut down the nozzle, wait a second, and move in, observing the conditions, then completing extinguishment.

The fact is that most fires can be extinguished no matter how we apply the water. The true test remains with whether lives are saved. I am convinced smoothbore nozzles used to extinguish interior fires always save lives if used properly. We have to approach each fire situation with the idea that we will need to save a life. If the structure turns out to be unoccupied, then we are that much more prepared for the next fire when it truly matters and lives are at stake, including our own. If you want your engine companies using straight streams inside, give them a smoothbore and take the guess work and temptation out of the mix.

A solidstream is the best straight-stream

Stream Selection


What type of fire stream should be used during interior fire attack? This remains one of the most hotly debated issues in the fire service and to understand why requires that we briefly examine the history of fire attack methods in use since the end of World War II.

Up until the late 1940’s, structure fires were fought directly using solid streams. Although significant experimentation with fog streams had been underway for some time, their role was limited to fires involving oils and other combustible liquids. Then the late Chief Lloyd Layman introduced his “indirect method of attack” as a means of efficiently controlling fires in structures using the cooling and smothering effects of expanding steam. This launched a revolution, and within a short time the fire service was divided into two camps. One continued to advocate the use of solid streams; the other embraced the use of fog and spray streams.

Those who argued for the use of fog streams were further buoyed by the introduction of the so-called “combination attack” in the late 1950’s. Developed by Keith Royer and the late Floyd W. “Bill” Nelson of Iowa State University’s Fire Service Extension, combination attack theory did not necessarily mandate the use of fog streams. Royer and Nelson’s main concerns were the rate of flow in gallons per minute and the efficiency of water distribution within the involved area. The form of the applied water was secondary, but fog stream proponents largely ignored this point.

The 1950’s also saw nozzle manufacturers begin to tout the advantages of their new (and more expensive) fog nozzles. Scanning the pages of Fire Engineering and Firemen magazines from the 1950’s and 1960’s, one gets the impression that to use anything other than water fog would brand you a tactical dinosaur.

Other influences were at work as well. The insurance industry viewed fog streams as a near miraculous remedy for water damage. Acting with the passion of religious zealots, representatives of various fire insurance rating bureaus managed to convince scores of fire chiefs that the greatest threat on the fireground was not the fire, but rather the water used to control it! By the time the late 1960’s arrived, the majority of fire departments had replaced their solid bore tips with fog nozzles and the ranks of solid-stream advocates had grown desperately thin.

In the last several years, however, the fire service has undergone a rebirth of sorts in how it approaches interior firefighting. Not only have many fire departments abandoned the use of fog patterns during interior fire attack, solid stream nozzles are reappearing on handlines from coast to coast. While I personally advocate the use of solid streams, if a

combination (fog) nozzle is the only option, it should be used in straight-stream position. With an adequate rate of flow (at least 150 gpm for residential fires), a solid and/or straight stream will provide for rapid knockdown with less violent disruption of the thermal layering in the fire area. More importantly, the use of solid and/or straight streams can dramatically lessen the risk of burn injuries caused by unwanted and unnecessary steam creation.

What is “unnecessary” steam? We have been brainwashed into believing that fog streams are efficient because small droplets convert to steam more readily than large ones. While a fog stream will vaporize more quickly than a solid or straight stream, does the efficient conversion of these small droplets to steam necessarily equate to efficient fire extinguishment? The answer is no.

The goal of interior fire attack should not be to rapidly absorb heat energy from vapors burning remotely from the seat of the fire, but rather to apply water on the heated solid materials and prevent release of these volatile fuel vapors in the first place. By cooling the mattress, sofa, desk, or stuffed chair burning in the lower portion of a room, the dangers posed by the accumulation of flammable vapors in the upper portion of the room is eliminated.

Another argument against the use of solid and straight streams involves the compactness of the streams themselves. Fog streams are better, it is said, even when being applied directly to the burning solid materials, because the wider pattern covers a much greater surface area. The problem, however, is that many times, little if any part of the fog pattern actually contacts the heated surfaces. Solid streams and straight streams are more likely to reach the seat of the fire because they are less prone to suffer premature conversion to steam or be carried away by convection currents. In addition, their long reach provides a greater margin of safety by permitting stream operations to commence at a safe distance. This is particularly important when a high heat condition makes a close approach to the fire impossible. The stream should be directed “out front and all around” in order to distribute water over the burning materials, using the ceiling and upper walls as baffles to splatter water into areas otherwise difficult to reach and to agitate (not overcool) the burning vapors at the ceiling.

Still others argue against solid and straight streams (solid streams in particular) because they lack the “protection” offered by fog streams. Although the nozzle team may feel secure behind this wall of water droplets, what is occurring on the other side of the fog pattern? Is the fire being driven into remote areas of the building or structure? Is the fire being pushed towards firefighters performing search operations? In many cases, it is the nozzle crew itself that receives steam burns. On still other occasions, the fire is forced over and around the fog pattern, causing burn injuries or possibly jeopardizing the nozzle team’s escape route.

Fog streams have their place, but not during interior firefighting. The safety of both building occupants and firefighters rests on the success of the first handline. An adequate

flow volume delivered in the form of a straight or solid stream is the best means of ensuring this success

The late ANDREW FREDERICKS was a firefighter in the City of New York (NY) Fire Department (FDNY) assigned to Squad Company 18 in Manhattan, one of five squad companies high inside the First World Trade Center tower rescuing people when it collapsed on September 11, 2001. A member of the fire service for 21 years, Mr. Fredericks was a New York State certified fire instructor (Level II) at the Rockland County Fire Training Center in Pomona, NY, an adjunct instructor at the New York State Academy of Fire Science, a field instructor for the Illinois Fire Service Institute, an instructor for the New York State Association of Fire Chief's, and an adjunct lecturer at John Jay College of Criminal Justice in New York City. Mr. Fredericks was co-author of FDNY's engine company operations manual. He was a member of the Editorial Advisory Board of Fire Engineering and the FDIC Educational Advisory Board. He was president of Andrew A. Fredericks & Associates, Inc., a firm specializing in municipal fire service training and consulting. Mr. Fredericks held a bachelor of arts in political science, a bachelor of science in public safety/fire science, and a master's degree in fire protection management.

Structural Fire Attack: Misinterpretations and Misapplications

By Troy Cool

Many articles have been written explaining the different methods of fire attack and options for applying water during fire fighting operations. However, to this day the debate continues and few topics stir more emotion at the firehouse kitchen table than the age-old question: “What is the best way to ext inguish a fire when conducting an aggressive, interior structural fire attack?”

The purpose of this article is not to simply duplicate the efforts of others but to possibly provide a different way of looking at one of the most basic methods of structural fire attack and the confusion behind its application. In addition to this clarification, this article will provide a possible explanation for the popularity of potentially unsafe firefighting practices still being taught at many fire academies, training institutions and used by many fire departments across the country.

First, let us review the three most commonly accepted and applied methods of structural fire attack. Prior to the mid-1950’s, most fire departments practiced direct fire attack using primarily smooth bore nozzles producing a solid stream. The essence of direct attack is simple — apply water in the form of a straight or solid stream directly onto burning fuel in an effort to cool it below the point at which the fuel produces flammable vapors. The concept is very simple: if more water (GPM) is applied to the burning fuel than heat (BTU’s) being produced by the fire and a negative heat balance is achieved, the fire will go out! The other key factor to consider when making a direct attack is whether or not the water is actually reaching the burning fuel, emphasizing the importance of reach and penetration when attacking a fire using the direct method.

During World War II, Chief Lloyd Laymen developed a method of fire attack using water fog to extinguish fuel oil fires on ships. This method was developed on a decommissioned Liberty Ship by Laymen’s forces in the Coast Guard fire fighting school. Following the war, Laymen refined this method to be used for structural fire attack. In 1950, at the FDIC in Memphis, Tenn., Laymen introduced this indirect method of fire attack. The premise behind the success of the indirect method of attack is the rapid production of large quantities of steam within a relatively confined environment with little or no ventilation. This method of attack was primarily designed to be initiated from outside, remote positions through a window into the fire area. The indirect attack was not intended to be used for aggressive interior structural fire attack. In fact, Lloyd Laymen, the father of fog firefighting, warned of the potential danger to the nozzle team if this method is applied from interior positions, due to thermal balance disruption and the hurricane of scalding steam that is produced.

Following Laymen’s work, Keith Royer and Floyd W. “Bill” Nelson conducted pioneering research at Iowa State University into the use of water fog to extinguish

structural fires. Royer and Nelson introduced a variation of the indirect attack using water fog — the combination attack. Instead of keeping the nozzle in a fixed position like in the indirect attack, the idea behind the combination attack is to “roll” the stream around the room to improve the steam conversion. The common factor between the two methods is rapid steam conversion by the water fog as it is injected into a superheated, well-sealed fire compartment.

As was true for the indirect attack, the combination attack was primarily designed as an exterior method of fire attack. The first priority when employing an indirect or combination attack, as intended by its inventors, was to knock down all visible fire from the outside prior to making entry into the fire building. This concept was not that much different than the standard firefighting practices of the 1950’s when turnout gear offered a much lower level of thermal protection and SCBA use was not as common. The only difference was that fog nozzles were substituted for the smooth-bore nozzles that had been in use for the hundreds of years prior. As turnout gear improved and SCBA use became mandatory, most fire departments routinely entered burning buildings to initiate fire attack from the inside in an effort to save more lives and property; and the misapplication of the “interior” indirect and combination attacks began.

This information is readily available from many sources, but few have clarified and explained the different methods of structural fire attack and their proper application as clearly as the two-part article series published in Fire Engineering, “Little Drops of Water – 50 Years Later” by the late Andrew Fredricks. These two articles are probably the best, most comprehensive pieces written on the topic of applying water to fire and should be considered required reading for anyone who may find themselves on the business end of an attack line.

There seems to be a great deal of misunderstanding about the most basic, yet most effective and safest, method of applying water from an interior position — the Direct Method. Some texts will describe a direct attack as simply applying water directly on the seat of the fire. In its most basic form, this is correct; but it does not completely describe the direct attack. If a fire is small, localized water may be applied directly to the seat of the fire. This will work very well and is the most efficient use of water. However, not all fires are controlled in the incipient phase. In fact, the modern fire environment is extremely volatile and produces fires that can reach flashover conditions within minutes. If a fire is encountered that fully involves a room and its contents, then the water, in the form of a straight or solid stream, should be distributed throughout the room by sweeping the ceiling and the floor and rotating the nozzle vigorously in an effort to apply the water in the form of large droplets directly onto the burning fuel.

This aggressive, circular nozzle rotation is what often is mistaken for and described as a combination attack. You must remember the intention and essence of each form of fire attack. By definition, the direct method involves applying water in a straight or solid stream directly onto the burning fuel with the intent being to simply cool the fuel to eliminate flammable vapor production. It makes no difference whether the fuel is a small rubbish pile, a piece of furniture or a complete room, or fire is rolling across the ceiling

of the involved room or rooms and down the hall — it’s still a direct attack! Just because the nozzle is swept or rotated to improve distribution and drive the fire back does not mean that the attack is a combination method where a fog stream and massive steam production are the tools of choice. A direct attack will produce most of its steam at the fuel source where it will be of the most benefit, not prematurely where it will likely be carried away by heat currents and have little actual cooling effect on the burning solid fuel.

A direct method of attack with a straight or solid stream will certainly not produce steam in the quantity that will rapidly fill the fire compartment, creating an untenable environment for the nozzle crew or any victims due to the presence of moisture with high heat and thermal imbalance. While some deterioration of visibility is to be expected when creating steam within a burning building, the direct attack will help maintain any visibility present prior to opening the nozzle.

As stated earlier, many fire academies teach, and fire departments use (misuse), the indirect and combination methods of attack as a primary method of interior structural fire attack. One possible explanation for this misuse is the method of instruction and application taught during structural fire attack training. Many firefighters have been taught during live fire training to employ these techniques. Such training is in many cases inadequate and unrealistic. Students are taught to use a combination attack with a 30- to 60-degree fog stream while crouched directly outside of the burning room that usually has a limited amount of fuel and windows that are sealed, allowing little or no ventilation. Under these circumstances the combination attack will be fairly effective, even though all visibility is lost and conditions for the nozzle team become very uncomfortable. What we should be teaching is using the proper method of attack flowing adequate GPM’s coordinated with well-timed, well-placed ventilation.

If the residents of your response area are considerate enough to call you before they have a fire so you can control the amount and type of fuel burning and stretch your attack lines into a position just outside the fire room so the fire can be quickly controlled, then a combination attack may be fairly safe and effective. However, if that’s not the case and your engine companies routinely enter burning buildings to battle fires against unknown, sometimes large, fuel loads and you may have to fight your way into the front door, down the hall(s) and then advance into the burning room or rooms to complete extinguishment, then a direct attack with a straight or solid stream is the most effective and safest choice. Any attempt at advancing down multiple hallways or through multiple rooms of fire using a combination attack with low to moderate GPM flow, as is being taught, will likely result in painful burn injuries for the nozzle crew and a lost fire building.

Many will argue that the majority of the fires fought across the country involve only a single room and contents and, due to inadequate staffing or poor tactics, ventilation of the fire room is often delayed. Under these conditions, an “interior” indirect or combination attack will usually be effective. However, even under these very limited fire conditions, a direct attack with a straight or solid stream and adequate GPM flow will achieve faster, more complete knockdown, using less total water resulting in less water runoff and less

excess damage. The direct attack will also maintain better visibility and create less thermal balance disruption.

Then there is the enemy to consider. What protection is a fog stream with inadequate volume going to provide from an unexpected flashover or rapid fire progress event?

Another bit of bad information that has been taught for many years goes to the basics of how fog nozzle pattern adjustment has been taught. “Right to fight or right for reach and left for life” is totally misleading. What we should be teaching is “left for lobster,” because that’s exactly what happens to the nozzle crew and anyone else in the surrounding area when a fog stream is injected into the superheated air of a burning structure. It is a well known fact that a water curtain of fog is not effective for protecting an exposure, since radiant heat will penetrate through the fog stream and continue to heat the exposure. This concept holds true inside a fire building as well. This magical force-field of fog will not protect you inside a burning building any better than it protects an exposure outside. The best protection from flashover or other rapid-fire-progress events is to simply knock down or extinguish the fire using a direct attack with a straight or solid stream flowing adequate GPM’s. Fog streams used inside a burning building are more likely to burn you than protect you!

In conclusion, there is no nozzle or method of fire attack that will work best in every situation for every application. However, the historical documentation, combined with practical experience, clearly shows that the most effective and safest method of aggressive, interior structural fire attack is made using a direct attack with a straight or solid stream flowing adequate GPM’s. The result will be a faster and more effective knockdown of the fire and a more tenable environment for the nozzle crew as well as any victims who may be trapped within the burning building.

The Evolution of the Combination Nozzle

By Tim Adams

While smooth-bore nozzles have undergone minimal change during the past 25 years, the combination nozzle has continued to evolve with new technology. The fog nozzles used during the 1960's were designed to break the water up into very tiny droplets discharged at a very high pressure. Cities such as Chicago and Oakland used pumpers with up to six stages that could pump through booster lines at up to 800 psi.

The theories presented by Lloyd Laymen were in full force in many cities across the U.S. The idea was low g.p.m. (40 to 80) at high pressures delivered into the super-heated upper atmosphere and converted to steam to cool and suffocate the fire. The fog stream was very effective in pushing fire away from the hose team as they advanced into a ventilated room and contents fire. Self-contained breathing apparatus was left on the engine for the next generation of firefighters.

Gradually, the flow rates for combination nozzles were increased in connection with the acceptance of the adjustable gallonage combination nozzle. The nozzle pressures were an industry standard 100 p.s.i. and droplet size was increased to allow for greater reach and penetration. Based on the research by Keith Royer and Bill Nelson of Iowa State University’s Fire Training Institute, rate of flow and water distribution were identified as the two most important factors affecting fire extinguishment. Provided critical rate of flow was met and the stream penetrated the area of involvement, their tactics favored violent movement of a combination nozzle applied through the window set on a medium wide fog. Most of their principles found there way into the mainstream of firefighting teachings. Automatic nozzles were introduced next and this lasted until just recently as fire departments started realizing that the cost far outweighed the lack of benefit.

The latest generation of combination nozzles introduced to the fire service by nozzle manufacturers is the fixed-gallonage, low-pressure version. These nozzles offer many outstanding features that make them a favorite of many fire departments. Because fixed-gallonage nozzles have fewer moving parts than automatic or adjustable-gallonage models, they have a lower repair frequency and cost. The most popular flow-rates chosen by today’s fire service is considerably higher, ranging from 150 to 250 g.p.m. for handlines. These were achieved by redesigning combination nozzles to flow at pressures from 50 to 75 p.s.i.. instead of 100 p.s.i. The demand for higher flows, to combat larger and hotter burning fuel loads in residential fires, could only be accomplished by reducing the nozzle reaction created by the increased g.p.m. Lastly, water droplet size was drastically increased to produce better reach and penetration, more effectively cooling the burning material below its ignition temperature.

So here we are, in 2004, with the most advanced combination nozzle money can buy; high flow, low pressure, larger droplets, low maintenance, and reduced cost. Funny, but if I didn’t know better, I would say it sounds like the description of a smooth-bore nozzle.

Every recent change by manufacturers has been to emulate the performance of a smooth-bore. In fact, the latest nozzle to hit the market is a combination nozzle that shoots a fog pattern and solid stream simultaneously. For the most part, regarding nozzle development, manufacturers use feedback from the professional firefighters from across the United States. Larger cities with high fire activity do much of the testing. If it is solid stream performance that is trying to be achieved, why not put down the combination nozzle that the fire service has become so comfortable with. See if the protection for the nozzle team can be achieved by a quick, complete knock down from a smooth-bore while using the water in its most effective extinguishing form, solid.

Let's agree on two facts: 1) fog patterns move air and push fire and smoke away from the nozzle and this could be catastrophic to civilians trapped or firefighters searching behind the fire, and 2) a solid stream will penetrate a higher heat area without converting to steam more effectively than a straight stream from a combination nozzle. Salesmen will try to show you in the parking lot how the straight stream and solid stream are hard to tell apart side by side. I don’t want to put out parking lot fires. Heat is the true test of the stream. Will it penetrate and reach the burning solid fuel in the highest of heat conditions? This is the factor that makes the smooth-bore nozzle the most valuable. One fire ... quicker knock down ... one life saved. Isn’t that what it’s truly all about? We are trained to minimize risk, we just did.

I’m really not trying to continue the great debate, but facts are facts. The greatest amount of opposition that I have heard concerning smooth-bores has come strictly from those who have never used a solid stream in a working fire and had a chance to experience its capabilities. Two firefighters in Sacramento were recently heard at two different fires saying that they would have liked to have had the opportunity to see what difference a smooth-bore would have made during their aggressive interior attacks. High heat and heavy fire rendered their streams ineffective from the combination nozzles they were using. Use the 7/8-inch smooth-bore tip (160 g.p.m. @ 50 p.s.i.) in training and practice breaking the stream into large droplets off the ceiling and walls. Practice sweeping the floor and moving in with the nozzle out in front working in circles. Then take it inside a working fire, learn what it can do and get good at using it.

The Retooling of the 1" Smooth-bore Tip By Capt. Joe Bruni &Lt.Rob Edwards

The Research

In 1996, the City of St. Petersburg, Florida, Fire and Rescue Department began an in-depth research project. This research took a detailed look at nozzles, fire streams, and the gallons per minute that were being delivered during fireground operations. It was discovered that we were only delivering approximately 90 to 110 gallons per minute from our 1-3/4" handlines and approximately 200 gallons per minute from our 2-1/2" handlines. The research began with a basic flow meter which had been kept in the Safety and Training Division. All handlines that were 1-3/4" in the city had either an adjustable gallonage combination nozzle or a combination nozzle that could flow anywhere from 50 to 300 gallons per minute. The 2-1/2" handlines had either a 250 gallon per minute adjustable gallonage combination nozzle or a stacked-tip smooth-bore which were comprised of a 1", 1-1/8", and 1-1/4" tips.

This project started out as a basic look at gallons per minute delivered. It turned into a nine-month research project that not only took a hard look at gallons per minute delivered, but also which was the best type of fire stream and attack (direct, indirect, and combination) for interior structural firefighting. This research project showed St. Petersburg Fire and Rescue that we needed to take a good hard look at one of the most critical tools used for fire suppression, the nozzle.

Different Nozzles Tested

The first nozzles we tested were low-pressure combination nozzles that required 75

pounds of nozzle pressure to reach their required flow. These nozzles are available with different stems which are threaded into the head of the nozzle. The different stems can

flow anywhere from 125 to 300 gallons per minute. The low-pressure nozzles proved to be very satisfactory; however, it was discovered flows greater than approximately 150

gallons per minute required at least two firefighters on the line to effectively deal with the back pressure generated. A problem was occurring with one firefighter on the nozzle

using a straight stream. The reaction force generated from a 100 psi combination nozzle flowing more than 125 gallons per minute was too much for one firefighter which was requiring the officer to become more of a firefighter than a supervisor. After all, the

officer must be able to observe conditions, direct the firefighters, and keep everyone's safety first and foremost. It was also discovered, a firefighter would either gate-down the bail of any nozzle where they could not handle the reaction force. Or, a firefighter will use the nozzle on the narrow-angle fog setting to help reduce the reaction force. We

discovered most firefighters did not feel comfortable with reaction forces higher than 60

to 65 pounds. This gating down action resulted in flows of less than 125 gallons per minute, even with 1-3/4" hose. We were defeating the reason why 1-3/4" hose came into the fire service, to generate higher flows with reduced friction loss. It was time to try a

different approach.

Shortly after the low-pressure tests the Safety and Training Division looked into our fire service casualty reports. It was discovered over a two-year time frame that St. Petersburg Fire and Rescue had nine firefighters with reported steam burn injuries that required medical attention. These injuries occurred during interior structural firefighting. This did not include the firefighters who had felt the effects of steam, but did not receive any blistering injuries where a casualty report had to be generated.

We learned in the fire academy that the narrow-angle fog stream would protect us during flashover or rollover should either occur. What we discovered is that the fog stream was not protecting us inside the structure. Granted, the steam burns may not have occurred if adequate ventilation had taken place on the opposite side of the fire but with the reduced manning of the 90's, the personnel who performed ventilation were no longer or seldom able to perform this critical task. Other factors today include: double and triple-pane energy efficient windows which do not fail quickly under fire conditions, energy efficient construction, and materials inside the structure that burn hotter than ever before. St. Petersburg Fire and Rescue discovered direct attack with a straight or solid stream inside the fire room, or just outside of it, proved to be the most effective and safest type of fire attack nine-five percent of the time. We were over-using the fog stream.

Testing of the Smooth-bore Tips

Many different firefighters and fire departments were contacted about their use of smooth-bore nozzles for interior fire attack and it was decided to give them a serious evaluation. We discovered that it is a rare occurrence for a firefighter to have the opportunity to be on a nozzle, even in the busiest fire departments. The experience level on the nozzle has diminished in the fire service of America. This is partly be due to a drop in the number of structure fires in this country. Statistics report structure fires down forty-six percent.

The first smooth-bore nozzle tip we tested on the 1-3/4" handline was the 15/16" tip. This nozzle proved to be a great tip for knockdown because of the gallons per minute it flowed at 50 psi nozzle pressure (180 gpm), but it was still very difficult for one firefighter to handle that much reaction force. This size tip also did not offer a very wide window of error for the driver/engineer if it was slightly under-pumped or over-pumped. Over-pump this tip and the firefighter was faced with a serious and unmanageable reaction force to contend with, under-pump this tip and the hoseline had a kinking problem. We decided that the 15/16" tip was a great tip for the firefighting crew which worked together every shift with the same crew and driver/engineer. This was not the case in St. Petersburg. We decided to try another size tip on our 1-3/4" handlines.

The next tip tested was the 7/8" tip. This tip flowed 160 gallons per minute at 50 pounds nozzle pressure and had a reaction force of 60 to 65 pounds; therefore, we found this reaction force manageable by one firefighter and the window of error for the driver/engineer was la rger than with the 15/16" tip. Over-pump this tip or under-pump it a little and it is no big deal. We were getting the same reaction force from the 7/8" tip that was generated from a 100 psi combination nozzle flowing 125 gallons per minute. This size tip proved very effective for quick fire knockdown because of the punch it delivered with its direct attack and added gallons per minute. This is when our firefighters and company officers discovered that the direct attack inside the fire room, or just outside of it, with a 7/8" smooth-bore nozzle proved to be the correct choice for almost every interior structural firefighting operation where the seat of the fire could be reached. Could the same thing be accomplished with a combination nozzle set on straight stream? It certainly could, but not with the reduced reaction force and additional gallons per minute available from the smooth-bore nozzle. Keep in mind, it is gallons per minute that extinguishes fire. Plain and simple, the higher Btu's of today's structure fires requires more water. Did the smooth-bore provide us with any protection inside the structure? If you keep the upper atmosphere from reaching the 1,200 degree mark (the point which flashover occurs). We found that not only did flashover not occur, but we were putting out interior fires with less water than if we were using a combination nozzle set on a narrow angle fog pattern that flowed the same gallons per minute. The theory taught about fog streams went right out the window. There was no protection offered from fog streams inside the structure. The fog stream inside an unventilated structure did not protect the firefighters, it burned them. Lloyd Layman discovered during his study of fog streams that if they are used inside an unventilated fire building, they will drive interior crews out of the structure. Fog streams can also burn any trapped victims inside the structure and push fire to uninvolved areas of the structure. This is due to the large volume of air they move. We have witnessed many fire victims with their skin hanging off. After nine months of research it was time to put the 7/8" smooth-bore on one 1-3/4" handline and a combination nozzle on the other 1-3/4" handline, (preferably a low-pressure combination nozzle that could flow 150 ga llons per minute). We were now confronted with a problem, how to purchase the nozzles. This was a year that the department did not budget enough money under the nozzle category to accomplish this.

The 2-1/2" Stack-tip Nozzle

It was time to examine the 2-1/2" stack tip nozzles as well. The department had been using chrome-plated, heavy brass nozzles for years. While many of the firefighters in St. Petersburg had used and fought fire with these nozzles, it was discovered through a department survey that only one firefighter ever remembered removing the 1" tip from the stack to go with the next tip size to increase gallons per minute. This was amazing that firefighters went through the trouble of pulling a 2-1/2" line but were only flowing 200 gallons per minute with a 1" tip. Why were we going through the hassle of pulling a large line if we are not going to get the most gallons per minute out of it? The City of St. Petersburg has a more than adequate water system. So, it was at this time we decided to

remove the 1" and the 1-1/8" tips from our 2-1/2" nozzles and start off with the 1-1/4" tip for initial fire attack. This proved to be very effective when we needed to flow big water on a big fire. The 330 gallons per minute at 50 pounds nozzle pressure delivered from the 1-1/4" tip was extremely effective when it came to quick knockdown of a large fire. The 1-1/4" tip also has the same reaction force as a combination fog tip flowing only 220 gallons per minute.

A Lieutenant from station 6, who was actively involved in the testing and evaluation of our nozzles, came up with a unique idea at this time. He asked, why put those 1" and 1-1/8" tips away on a shelf somewhere? Let me take them home and convert the 1" tips into 7/8" tips with my lathe. Our purchasing problem seemed to be solved.

The Retooling of the 1" Tips

The 1" tip was placed in the chuck of a lathe and the inside bore roughed up with some emery paper to help the epoxy bonding agent adhere the aluminum insert to the 1" tip. This also removed any dirt or corrosion. A 1" inch (outside diameter) piece of solid aluminum rod was cleaned up with emery paper, coated with a structural epoxy adhesive, and then pressed into the 1" tip and allowed to dry. Once the epoxy had dried, a 1/16" hole was drilled through the side of the 1" tip and into the 1" aluminum rod insert. A 1/16" aluminum pin was epoxied into this hole for added strength and to further secure the 1" aluminum insert. The tip was reset into the chuck of the lathe and a 3/4" drill bit was used to drill a hole through the 1" insert. A boring tool was then used to bring the hole out to 7/8". At the orifice opening, a recess was now cut into the end to prevent damage from use. At this point the tip was now turned around in the chuck to center the hole and to cut a taper inside of the thread side of the tip which provided a smooth tapered hole. The chrome was now machined off and some polishing done to complete the job. The tip was stamped 7/8", mated to the 1-1/8" tip, and added to a ball-valve-shut-off already carried inside a compartment on every engine. This shut-off was part of our air-aspirating foam nozzle assembly. To change to a foam operation, the smooth-bore tip is simply removed and the air aspirating foam tube is added to the ball-valve-shut-off. This has proved to be a very effective way of doing business and the City of St. Petersburg Fire/Rescue Department has not suffered any steam-burn injuries to the firefighters or any trapped victims since the implementation of the 7/8" smooth-bore nozzle. We now have two documented rescues of trapped victims from structure fires after use of a smooth-bore nozzle. Neither of these victims suffered steam burns that may have occurred from the use of a narrow-angle fog stream. Our firefighters have discovered that the direct attack offered from a solid-stream or a straight stream is the safest and most effective way to attack ninety-five percent of our structure fires, providing you can reach the seat of the fire to use a direct attack.

Bio:

Joe Bruni is the Captain of station 12C with the City of St. Petersburg Fire and Rescue Department. He has a total of 23 years in the fire service. He has an A.S. in Fire Administration He has served two years in the Safety and Training Division as a department Training Officer. He is an instructor with the Pinellas County Fire Academy and St. Petersburg Junior College. He is currently on track to complete a B.A.degree in Organizational Studies with a Public Leadership track. Questions and comments can be sent to him at [email protected].

Rob Edwards is a Lieutenant at station 6B with the City of St. Petersburg Fire/Rescue Department. He has a total of 20 years in the fire service. He is an instructor with the Pinellas County Fire Academy and is a Florida State certified smoke diver.

Why Fires Are More Dangerous Today


For several years now we have been told that fires are more dangerous — hotter, less predictable — than they were 50 or even 25 years ago. The primary reason given for this is the ever-expanding use of plastics in our homes and businesses. Others have countered that this is simply not true, because it is the available oxygen that regulates the heat produced by any compartment (room) fire. For each cubic foot of oxygen “consumed” in the combustion process — regardless of the fuel involved — a fairly uniform 535 BTU's of heat is produced. Since all interior fires are oxygen- or ventilation-regulated, in theory, the heat produced by burning a one-pound block of polystyrene will be almost exactly the same as the heat produced by burning a one-pound block of oak.

The problem with this explanation, however, and one of the reasons why fires are more dangerous today, is that it ignores differences in the heat release rates of plastics and “traditional” or cellulosic fuels. Plastics, in general, have much higher heat release rates. Early in the development of a compartment fire, it is not the oxygen available for consumption that controls the burning rate, but the characteristics of the fuel itself. If the materials burning have higher rates of heat release, we can expect a more rapid build up of heat within the fire area and a reduced time frame until a flashover or other “rapid fire development” event occurs. As Tom Brennan points out: fires may be fewer today (compared to the peak fire activity years of the 1970s), but the incidence of flashover is greater. The dangers posed to firefighters operating in this volatile environment are very real. But an increasing number of flashovers is only part of the story. Smoke conditions have worsened as well.

The dark, choking smoke characteristic of fires involving petrochemicals has become a signature of the modern structure fire as petrochemical derivatives (plastics) now represent the single greatest portion of residential and commercial fire loads. One of the dangers posed by volumes of dense smoke is the ease with which a firefighter or team of firefighters can become disoriented and lost. Incidences of firefighters becoming lost in the smoke and subsequently dying from asphyxiation or from burns caused by rapid fire spread have become tragically common. In some cases, the firefighters had a charged handline with them when they entered the burning structure, but somehow became separated from the line and subsequently died. In other cases, firefighters have been severely burned while clinging to the handline, and the reason for this phenomenon requires a closer look at smoke and its makeup.

Smoke is made up of solid particulates and aerosols carried along by convected air and carbon monoxide gas. When you ask firefighters about carbon monoxide (CO) and its attendant hazards, most will reply by rote that it's colorless, odorless, and tasteless. While

these characteristics are important, there are three others that cause death and injury to operating firefighters: CO is highly flammable; it has a wide explosive range (12.5% to 74%); it ignites at about 1,128 degrees Fahrenheit (a temperature quickly attained in many room fires). Although the lower explosive limit (LEL) of CO is high when compared to other flammable gases, once the LEL is achieved, CO remains within its flammable limits over a wide range of fireground conditions.

When pockets of CO ignite, firefighters performing searches and even those advancing handlines are often burned. Insulated by modern bunker gear and protective hoods from the heat radiating downward from the smoke above them and blinded to rollover by the dark smoke that surrounds them, the critical warning signs of impending flashover go unnoticed. Even “state of the art” turnout clothing cannot protect against burns caused by flashover. Remember too that a charged handline can't offer protection if it isn’t in operation. Perhaps opening the nozzle on smoke, despite what we have been taught, is something we should consider in some cases. If we can reduce the volatility of the smoke, we can prevent burn injuries. Fires involving commercial occupancies, cellars, and confined spaces should be considered prime candidates for applying “water on smoke.”

Still another issue involves the types of buildings and structures we fight fires in today. Void spaces are commonplace in new construction. Voids have also become a problem in buildings that are renovated using “lightweight” components and assemblies. Voids create ideal places for CO to collect and build-up dangerous temperatures and pressures that often result in collapse, smoke explosions or other rapid fire progress events. Buildings are also more insulated today and smoke and heat seepage to the outside is often eliminated. Without benefit of a fire that has “self-vented” prior to the arrival of the first due fire companies, firefighters are frequently subjected to extreme punishment while performing primary search duties and advancing the initial attack handline.

So it is true — fires are more dangerous today. Unfortunately, both human evolution and fireground tactics haven’t kept pace with changes in the modern fireground environment and advances in modern turnout gear. Firefighters still get burned at the same temperatures today as generation ago. Although modern protective clothing has reduced the incidence of many types of burns, when firefighters do get burned, the severity is often very high. Aggressive interior fire attack is the hallmark of a good fire department, yet in an increasing number of instances, it is incompatible with the volatile, well-insulated, lightweight fireground of today. What then, is the answer?

It is not one answer, but several. Here are five to start with:

• First, let's restore firefighting to its proper place at the head of the fire department table. Service diversity has in many cases created mediocrity on the fireground.

• Second, lets utilize our protective equipment wisely and gain a better understanding of its limitations — physical, physiological, and psychological.

• Third, lets train more realistically. Use acquired structures whenever possible and forget the propane simulators and “theater” smoke.

• Fourth, make sure we know how much water we're flowing on our fires. The only way to do this is to measure it and make sure we are achieving minimum flows and reach with manageable nozzle reaction burdens.

• Fifth, increase staffing. As retired FDNY Deputy Chief Vincent Dunn has pointed out, we often have most of our too-few personnel on the fireground assigned to every task imaginable except stretching and operating the life-saving first handline. Amen for NFPA 1710. The road just ahead may be a little rocky, but the long-term benefits will be tremendous.

i Cohn, Bert M., “Plastics and Rubber,” Fire Protection Handbook , 18th Edition [Quincy, Mass.: National Fire Protection Association (NFPA). 1997], 4-125. ii Wiseman, John D., Jr., “Thornton’s Rule and the Exterior Fog Attack: A Perspective.” Fire Engineering, July 1996, 42-46. iii MJ/kg (mega joule per kilogram) means that for every kilogram of fuel material consumed during a fire under strictly controlled conditions, one million joules of heat energy are released. A joule is an energy term (SI) and is equivalent to approximately 0.242 calories (a more familiar unit). The release of one joule per second (IJ/s) equals one watt (W). A kilowatt (kw) is 1,000 watts. A megawatt (MW) is one million watts. iv Heat Release in Fires. V. Babrauskas and S. J. Grayson, eds. (London and New York: Elsevier Applied Science, 1992). 31. v Brannigan, Francis L. Building Construction for the Fire Service, Third Edition. (Quincy, Mass.: National Fire Protection Association. 1992), 387-389. vi Telephone conversation with Deputy Chief (ret.) Vincent Dunn, Fire Department of New York. vii Babrauskas, Vytenis, and Douglas Holmes, “Part III: Heat Release Rate-The HRR of Burning Materials Determines If Flashover Occurred.” Fire Findings, Summer 1998, 6:3, 12. viii Custer, Richard L. P., “Dynamics of Compartment Fire Growth.” Fire Protection Handbook, 18th Edition . NFPA.: 1997, 1-85. ix E-mail from Vytenis Babrauskas. x Babrauskas, Vytenis. “Upholstered Furniture and Mattresses.” Fire Protection Handbook, NFPA: 1997, 1-85. xi NFPA data. xii Murtagh, James J., “Fire’s Changing Signals.” WNYF, Issue 1, 1989, 9. xiii When the Fire Department of New York assembled a team of veteran fire officers to revise its bulletin outlining ladder company operations at tenement and apartment building fires (“Firefighting Procedures, Ladder Company Operations, Vol, III, Book 3, Tenements”) in 1996 specific instructions were provided for the outside ventilation (OV) firefighter confronted by EEW’s. When “venting for fire,” the bulletin states the following: “Communication with his/her company officer via handi talkie must be maintained in order to coordinate and control lateral ventilation. Ventilation may be extremely difficult due to EEW’s.” In discussing the tactic of “venting for life,” the bulletin continues by stating: “Prior to VES [vent-enter-search operations] from the fire escape, the OV must receive permission from his/her company officer via H.T. [handi talkie]. The OV might not be aware of the severity of conditions in the apartment.” xiv A very interesting article on the subject of wind and its impact on fire behavior appeared in the January 2000 issue of Fire Engineering. Entitled “Firefighting and the ‘High Pressure Backdraft,’ ” it was written by Brian M. White, a captain in the Fire Department of New York. As the author indicates, much more research needs to be done on this complex subject; hopefully his article will serve as a stepping-off point. xv Knapp, Jerry and Christian Delisio, “Flashover Survival Strategy” Fire Engineering, August, 1996, 81-89. xvi “Demonstration of Biodegradable, Environmentally Sage, Non-Toxic Fire Suppression Liquids,” NISTOR 6191, Daniel Madrzykowski and David W. Stroup, eds., National Institute of Standards and Technology, July 1998.

xvii Grimwood, Paul. Flashover & Nozzle Techniques, 1999, firetactics.com, U.K. xviii Ibid., 14 xix Fornell, David P. Fire Stream Management Handbook . (Saddle Brook, N.J.: Fire Engineering Books & Videos, 1991). 103. xx Nelson, Floyd W. Qualitative Fire Behavior. (Ashland, Mass.: International Society of Fire Service Instructors. 1991). 105. xxi Pressler, Bob. “What Smoke Conditions Tell You.” Fire Engineering, Jan. 1999, 91-94. Additional References Babrauskas, Vytenis, Ph.D. and Douglas Holmes, MPA, “Special report: Heat Release Rate, Parts I, III.” Fire Findings, Winter, Spring, Summer, 1998. Cholin, John M., “Wood and Wood-Based Products.” In Fire Protection Handbook, 18th Edition (Quincy, Mass.: National Fire Protection Association. 1997). Colletti, Dominic J., “Quantifying the Effects of Class a Foam in Structure Firefighting: The Salem Tests.” Fire Engineering, Feb. 1993. “Firefighter Deaths as a Result of Rapid Fire Progress in Structures 1980-1989.” National Fire Protection Association, Aug. 1990. Fredericks, Andrew A., Fire Engineering: “Return of the Solid Stream.” Sept. 1995; “Stretching and Advancing Handlines. Part 2.” April 1997; “Observations on the Engine Company,’ April 1998. Grimwood, Paul, “Water-fog in Structural Attack: A European View.” Fire Chief, Aug. 1993. Knapp, Jerry and Christian Delisio. “Survival Training in the Flashover Simulator.” Fire Engineering. June 1995. Leihbacher, Doug, “Search in the Modern Environment.” Fire Engineering, July 1999. SPFE Handbook of Fire Protection. Second Edition (Quincy, Mass.: National Fire Protection Association; Boston, Mass.: Society of Fire Protection Engineers. 1995).

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