Ventilation Principles & Practices FDIC 2011 - … Principles & Practices FDIC 2011 Lieutenant Brian...

Ventilation Principles & Practices

FDIC 2011Lieutenant Brian Brush

West Metro Fire Rescue - Lakewood, Colorado

The opportunity to be here is not one that I take lightly and I am honored by the company. I am a

presenter not an instructor, my goal is to share a package of information I developed from that

which has been shared with me. The list of resources is long and compiled over the years from

greater firefighters then I will ever be, and from departments and organizations across the

country. To continue to honor our profession all of my material is available for your use either in

this form or any that you request. Please feel free to contact me directly. I hope that you find

something in this program to help you or your department.

Lieutenant Brian Brush

West Metro Fire Rescue Lakewood, Colorado

[email protected]

What's Changed?

For the guys in this picture, properly ventilating the structure was the only way any firefighters

were going to work. In the absence of SCBA and PPE releasing heat and getting smoke to lift

had to be done first in order for any interior operation to take place. That is in large part why

there are nine guys on this truck company.

Fast forward 100 years and we are in a very dangerous place. We get to fires faster thanks to cell

phone notification, computer aided dispatch and Quantum pumpers. We are dressed and fully

encapsulated when we step off the rig. We quickly stretch a pre-plumbed cross lay to the front

door. This all comes together for “fast attack”, putting interior crews all to often in the transition

stage of fire behavior from growth to fully developed.

The fires we are fighting are consuming more synthetic and petroleum based materials than

natural products. This new fuel is causing hotter environments and more toxic, explosive

byproducts with dirtier smoke. They burn in structures that are being built tighter and more

energy efficient than ever before. Secured to a greater degree than ever before and built out of

lighter weight materials with the poorest quality construction methods ever.

The simple point is that technology has advanced us in our abilities' as much as it has advanced

our opponent. Therefore the need for addressing ventilation needs early and often maybe really

hasn‟t changed that much over the years.

Fires are more dangerous

• Increase in fuel loading and higher

BTU‟s

• Lightweight building materials

• Increase in occupancy insulation

values resulting in tighter structures

• Smoke is more explosive due to

higher percentage of petroleum

based products

Am I repeating myself? Yes, and for good reason. Commit this to memory – As we get better it

gets worse! Once we acknowledge this as truth we will stop asking the infamous line of duty

death question. “In this day and age why are we still killing so many firefighters?”. Wake up! We

are the “we” that is “killing” firefighters when “we” place false hopes in the fact that technology

will give us an edge. We have response time statistics, staffing level studies, fire codes all

showing how we are better today at what we do. Guess what? The statistics prove that fire is

getting better at what it does too. Fire is causing more damage and killing civilians and fire

fighters more efficiently every day.

NFPA 2008 Fire Loss Report www.nfpa.org/assets/files/PDF/OS.fireloss.pdf

•In 2008 there were 515,000 structure fires. Down 3% from 2007 and the lowest number since

NFPA began collecting data in 1977.

•This is less than half the 1,098,000 structure fires that occurred in 1977

•At the same time the death rate per 1,000 home fires was 8.1 in 1977 and 7.2 in 2008 for a

decrease of only 11%.

•When property loss is adjusted for inflation, the increase in the average structure fire loss

between 1977 and 2008 is 80%.

• In 1977 156 firefighters died in the line of duty. 118 LODD in 2008. Only a 24% decrease

despite over a 50% reduction in structure fires.

Lack of understanding is costing us our lives

• NIOSH LODD 2010-10

– “During this incident, uncoordinated ventilation occurred while the hoseline and search and rescue crews were inside the house. The victim and other fire fighters, within the small house, were between the fire and the ventilation source. One fire fighter accounts heavy, turbulent, black smoke pushing from a window on the B-side after it was broken. Shortly after, the house sustained an apparent ventilation-induced flashover.”

At our department we review a LODD report once a month. 100% of the time some says “Hey

that could have been us.”. The statement should be rephrased because our nation‟s fire service

and it‟s losses are “Us”. Every time a firefighter is lost it did happen to the collective “Us”.

When the loss of a life presents a lesson it is in the learning that we honor our heroes. Do not let

a critic claim that a brother‟s life was given in vain to save property. Mourn their loss as

unnecessary as it may be it shall never be in vain. Education and the potential prevention of

further loss through training in their name ensure that they gave themselves for “Us”.

Top 25 factors present at firefighter

fatalities“Staffing and Tactics for Firefighter

Survival”

Lt. Jeffery S. Parker Fire Engineering

April 2010

Lack of understanding is costing us our lives

In his April 2010 article for Fire Engineering Lt. Parker of Fort Thomas, Kentucky submitted his

research on key contributing factors associated with NIOSH firefighter fatality reports. His

report drives home the fact that we are truly misunderstanding and misusing the tactic of

ventilation. “Ventilation is often not done because of staffing shortages, or gets modified to the

point that it fits the tactic that can be performed with less equipment or less staffing and this is

killing us.” (Parker 2010)

When we look at the graph he presented of the top 25 factors ventilation is #3. If we take a closer

look it is far and away the primary factor related to fire behavior and the most common tactical

factor. This is extremely frustrating because it is something that in many cases can control

through staffing, training and education.

Cause and Effect

That change begins here with a review of fire behavior. Ventilation of fires in enclosed structures

is a necessity for a safe, effective interior fire attack. Enclosed environments compound the

effects of heat, pressure, steam and increase the rate at which oxygen is consumed by fire.

Translation: every second a fire burns without ventilation our job is getting harder and the

potential of occupants surviving is drastically reduced.

Opening up an enclosed structure in any manner will change conditions and fire dynamics.

Homes and businesses are not controlled environments and, we truly will never know the

makeup of the fire area or what is occurring. For this reason we must accept the simple fact that

all our actions have effects. Sometimes they are the desired effect and sometimes they are the

unexpected effect. Anticipating and looking for change good or bad after each action is

professional work and will make follow up actions more informed.

Few of us arriving at this structure fire and opening this front door would associate it with initial

ventilation. Most of us would call it gaining entry, if we really took the time. These two

firefighters certainly did not think beyond the act of opening the door. With the failure to give

consideration to the effects of their action they did not recognize the changing conditions and

unprepared for the event that followed.

Traditional Fire Behavior

How do we prepare ourselves to anticipate and recognize change in conditions? We study fire

behavior. This chart is the basics and shows the four phases of fire behavior. What it doesn‟t

show is that fire can also come back. If fire decay is a result of lack of oxygen then our

ventilation actions may provide “growth” back to a “fully developed” fire. Fires in enclosed

structures are ventilation controlled. If I could I would make that simple sentence a mandatory

reminder on every fire dispatch.

Fire Behavior

These two videos show various fuel packages, arrangements and variables. There is no limit to

the amount of information that can be covered in these demonstrations. The observation of

mushrooming and radiant heat build up with resultant flashover in real time will be the main

focus.

We must look at the room and recognize that it is the radiant heat trapped at the lid of the room

reflecting down on the contents which causes flashover. The point is visually represented at 30

seconds into the first video with the ignition of the lamp and the surface of the coffee table. The

point is even clearer in the second video at the 3:00 mark when the top of the couch remote from

the area of origin ignites before the arm of the couch in close proximity to the area of origin.

The key points I want to address are those we can change through ventilation tactics. Prevention

of mushrooming, smoke propagation and release of radiant heat from the “lid” of the room to

prevent flash over.

Hierarchy of Ventilation

• Heat – Most predictable

– Fewest variables

– Limited opportunities

• Pressure– Fairly Predictable

– Layout and environment are

significant variables

– Greater opportunity

• Mechanical– Use of a machine to overcome fire

behavior

– Highest percentage of unknowns

– Safety requires significant planning

In its simplest form the reason we ventilate is to relieve heat and pressure. Therefore our decision

making process should be rooted in the why.

Of all the different techniques of ventilation there are only 3 root methods. The ventilation tactic

of cutting a hole over a room and contents fire is using heat to ventilate the structure. Taking a

window to vent horizontally is using pressure differentials. When we cannot take advantage of

fire behavior to ventilate we need to employ a mechanical means to overpower natural fire

behavior in order to vent.

When we start to consider our ventilation options we should take into account our odds of

success. The “hierarchy of ventilation” reinforces the thought process of using the most reliable

method with the least variables first and using the least reliable method with the most variables

as a last resort.

Heat• Using the thermal column

created by the fire to vent a

compartment and support

attack

• IFSTA-Chimney Effect

Heat is a fire‟s greatest strength and most predictable attribute, it wants to go up. Using the

thermal column to ventilate fires has allowed us to live and work around fires in enclosed spaces

for thousands of years. Because of the simplicity and reliability of the chimney effect, using heat

to ventilate should be the first option considered.

Heat

Here we have an excellent example of vertically ventilating a room and contents fire to utilize

the chimney effect. In the first picture it is clear the fire is confined to an interior room and not in

the attic. Using a pike pole the firefighter punches in the “lid” of the room providing all the

stored up heat and energy a direct path up and out. In the second picture you can observe two key

elements in the fire behavior, heat and efficiency. Out of that ventilation opening a significant

amount of fire/heat is being released with that there is very little if any smoke. Inside that room

conditions have without a doubt improved tenfold.

Heat

This video from Houston Fire Department provides the example in real time. The cut of the

decking is made releasing the smoke that was charged in the attic this smoke is relatively “lazy”.

You can see the clear difference in the velocity when the firefighter punches in the ceiling and

the thermal column develops. That chimney effect develops allowing for cleaner burning and

fresh air entrainment. From the hole we see a clean flame; in the room you can see the seat of the

fire.

What is happening?

• Room temperatures drastically

reduced

• Radiant heat released

• Fresh air entrainment allows for

cleaner burn reducing potential

explosion

• Mushrooming is mitigated providing

better visibility and more tenable

conditions

Using the innate need for heat to rise as a ventilation method is by far the most reliable. When

we open up an enclosed fire over the top we stand to mitigate a long list of problems with one

tactic. It is understood there is certainly more to consider in the operation however, at this point

in the program we are speaking specifically on ventilation principles.

Pressure

• Heat and gas production from

fire increase the ambient

pressure in structures with every

second

• Ventilation of an enclosed

structure to the outside creates a

pressure gradient.

• A pressure gradient is the

movement of air in response to

pressure differences, blowing

from high to low.

Fire creates heat and pressure while consuming property and oxygen. We already covered the

fact that heat wants to rise and how we use that to our benefit. When we release heat of an

enclosed space out a vertical ventilation opening we are also taking advantage of the pressure the

fire has built up as well.

The high pressure environment of a fire area wants to seek out lower pressures as bad as the heat

wants to rise. This is why when we open the door to a house with a fire in it we need to expect

that conditions will change. More than likely that change will occur in our direction. Many

people claim that the reason conditions change and we see the smoke and fire show at the front

door just after opening is because “it needs oxygen”. Yes and no.

The pressure gradient brought that nasty smoke and heat from the fire area to the front door, not

a thirst for oxygen. When we open a door to a fire room, fresh air is entrained along the floor and

built up heat and smoke (pressure) moves out at the “lid” seeking areas of lower pressure. When

those byproducts of incomplete combustion move into areas that have more oxygen available it

may or may not still be hot enough to combust. This flash or ignition is secondary to the driving

force (pressure) that is moving the smoke.

This fire department does a great job of opening up the store front to provide the ventilation

opening. It is clear the smoke and heat is pushing hard out the front even against the operating

hose lines.

Stop and think about this. We removed the glass from the store front so we could relieve the built

up pressure and create a ventilation opening to get smoke to lift. Perfect plan, immediately set

back when we flow our streams into that opening preventing smoke release and now causing

steam conversion which increases compartmental pressure.

Don‟t forget the basics due to the occupancy type. We use pressure differential and unburned to

burned tactics in coordination all the time by taking windows in room and contents fires and

pushing out. This is a larger and more dangerous structure which is all the more reason for

slower more coordinated action.

Pressure

Attic fires are very difficult for many reasons. One of the greatest challenges of attic fires is fire

location. Due to the lack of windows and the fact that it is an uncompartmentalized space, the

odds of cutting a hole over the seat of the fire is like finding a needle in a hay stack. So when an

attic space is vented the main goal is to relieve the pressure to prevent the catastrophic event

rather than seeking to create the thermal column.

Think about what we are taught to do when we identify a back draft situation. The textbook

answer is to vertically ventilate before initiating any interior operations. An attic fire is a back

draft / smoke explosion in the making. There are countless reports of firefighters killed or injured

in smoke explosions every year. The most common report is that the firefighter entered the

structure and upon pulling ceiling a smoke explosion occurred. Why? Because the pulled ceiling

became the ventilation opening for all the heat and pressure built up in that confined space. By

being more disciplined on these fires we can prevent these cases by directing everything up and

out.

Another video out of Houston provides an amazing example. Arriving companies find a single

family dwelling with an attic fire. The smoke is under so much pressure it has been forced from

the attic space out eves, and into the residence. Early pictures completely obscure the front of the

house and the place looks like it is ready to explode.

No need to panic- The attic fire is identified and vertical ventilation is performed relieving the

pressure, clearing the occupancy and allowing hoselines to move in and attack it from

underneath. Professional work.

Mechanical

• Pre control pressurization

– Stairwells

– Zone pressurization

• Positive Pressure Attack

• Post control ventilation

– HVAC / Smoke ejector• Negative Pressure / Pull smoke

– PPV• Positive Pressure / Push Smoke

– Hydraulic Ventilation

Why does mechanical ventilation end up last on the decision tree? If we are using mechanical

ventilation we have made a decision that we need a machine to overpower natural fire behavior

(the heat and pressure). In this framing it should make us all a little more cautious.

Of course, there are situations where we must rely on mechanical ventilation. So we need

training education and plans to put the tactic to use. We never employ the tactic to compensate

we employ the tactic because the situation calls for it.

When it comes to mechanical ventilation the tactic can be divided up in to 3 areas.

•Pre-control pressurization uses a mechanical means to increase the atmospheric pressure of an

area above that of the fire area prevent the natural pressure gradient from moving smoke.

• Positive pressure attack uses a fan to support the offensive fire attack in situations where

conventional ventilation methods are not an option.

•Post control mechanical ventilation is for all intensive purposes is a salvage operation to remove

smoke from a structure.

Pre-Control Pressurization

This video shows the use of a fan for pre-control pressurization. A 27” gas fan is used to

pressurize a stairwell of a 16 story building. The camera is focused on the door to third floor .

Approximately 25 feet down a public hallway from this door there is a well involved apartment

fire working with the door open. This video is in real time and it starts with the start of the fan.

Even though the stairwell is 16 stories the volume of the space isn‟t that great, this coupled with

the fact that there is no exhaust opening the atmospheric pressure of the area is raised in short

order.

The higher pressure stairwell has now erased the pressure gradient normally created between the

fire are and remote areas. The pressure barrier prevents smoke movement into the stairwell and

make conditions tenable.

It seems like magic, but it is really very simple. We should always be aware that should we loose

that pressure by fan failure or creation of an exhaust opening conditions will return to the zero

visibility and high heat we started with. No different than searching with a TIC that looses

battery, the technology only give us an edge when it works.

Zone Pressurization

• Using the building

system to pressurize

separate floors or

zones to isolate

smoke.

Zone pressurization is very similar to and may include stairwell pressurization. The way it works

is air coming into the zone is continued while return dampers are shut increasing the pressure in

that area. This creates a pressure barrier to prevent smoke travel into these areas. The specifics

and capabilities of this tactic depend on the building and the system. Typically a zone is an entire

floor, stairwell or elevator shaft. Some of the more modern systems at larger malls can actually

pressurize separate zones on the same floor.

Positive Pressure Ventilation

• PPV is not all encompassing– Positive Pressure Attack (PPA)

– Smoke removal

• Current national trend is PPV for use as a post control

ventilation method– Uncontrolled variables

– Threat of extension

– CFM overkill

• Our fans 10 – 15,000 CFM

• Single story 1500 sq ft residence is 12,000 Cubic feet stark empty.

– Common SOP

• Main body of fire under control

• Primary searches clear

• Overhaul initiated and no other fire locations found

To sum up positive pressure ventilation we need to split it in two. PPV can be used to support a

positive pressure attack which has specific criteria and requires precision coordination. PPV can

also be used for smoke removal post control which is by enlarge the common place.

Nationally there is a move away from “fan and a line to the front door”. With the greater

understanding that years of experience has brought us PPV is now primarily a post control

ventilation method. The key reasons for this change are as follows.

• With certain layouts under certain conditions PPV will absolutely perform as advertised.

Unfortunately the number of uncontrolled variables in a house fire and on a fire ground is

impossible to account for safely.

• Any time we intensify fire behavior the threat for extension increases.

• CFM overkill is just as it sounds. These high volume fans, on paper appear to match the volume

of the occupancy take for example a 1500 square foot house with an 8 foot ceiling (12,000 cubic

feet). What is not considered is that once a few rooms are closed and others are filled with

furniture, partition walls and cabinets the volume of the occupancy can be immediately reduced

by at least 1/3. If we run that 15,000 CFM fan into a residence that only stands with 9,000 CF of

air. With just a 12 Sq. Ft exhaust opening the pressure throughout that fire area is going to be

well beyond what is necessary. Now fire and byproducts are being forced into low pressure areas

like walls, ceilings and closed rooms through light fixtures and outlets and door jambs.

Positive Pressure Attack

This video was produced by the Tempest Fan Company in conjunction with the Salt Lake City

Fire Department during their testing of PPA tactics in acquired structures in the early 90‟s. This

video and the use of positive pressure fans became wildly popular.

“Pressure Precepts” Fire Chief Magazine December 2006Battalion Chief Kriss Garcia & Battalion Chief Reinhard Kauffmann Salt Lake City Fire

• “As incident commanders turn to positive-pressure as part of their firefighting attack strategy, the potential for injuries rises.”

• “ A recent NIOSH report underscores the importance of completely understanding the precautions required to safely use PPV. „Unless PPV has been started in coordination with the initial attack , it shouldn’t be initiated until all interior crews have exited the structure’.”

• “There are many PPV situations where precautions are necessary. Firefighters should watch out for the following situations:”

– When there are or is the potential for victims, or firefighters standing at windows or other exhaust openings.

– When firefighters have entered the structure prior to the PPV being used.

– When backdraft conditions are observed

– When exhaust openings cannot match fire loading

– When exposures may be threatened by “blow torching”

Positive Pressure Attack Today

Chief Garcia and Chief Kauffmann are more or less considered the positive pressure gurus. In

the early 1990‟s they developed the Positive Pressure Attack method after weeks of testing in

acquired structures in Salt Lake with the assistance of Tempest Fans. Part of that work was the

video we just watched which sold countless departments on the value of PPV. The plan seemed

so simple, fan blows in and fire blows out giving attack crews a clear, cool path to the fire.

Time has taught us once again that technology was not quite as promised. This 2006 article was

written by Chief Garcia and Chief Kauffmann to address a fire which severely burned a crew

while searching fire building when a fan was started. Their goal was to pass on the lessons

learned by their department over the years and how their operations have changed regarding PPV

use.

Chief Garcia and Kauffmann are still considered subject matter experts on positive pressure

ventilation and they continue to tour the country teaching and testing. What gives them continued

credibility is that they are teaching from what has been learned rather than sticking to their

original position and ignoring the hazards.

The slide above outlines what they believe to be critical criteria to with hold positive pressure

ventilation.

Hydraulic Ventilation

•Nozzle set to wide fog

•At least 2 feet back from

the window or door

Our last method mechanical ventilation to discuss is hydraulic ventilation. Tried, true and simple.

While hydraulic ventilation won‟t clear out a big box structure the CFM that it will move is more

than adequate for post control room clearing.

Smooth bore 625 CFM

Straight stream 800 CFM

Smooth bore with ½ open bale 3000CFM

30 degree fog 5000 CFM

Typical Bedroom without furniture 10 x 10 x 8 = 800 CF

What else moves smoke?

• Stairwells

• Shafts

• Air handling

• Auto Exposure

• Wind

• Misplaced fire

tactics

To conclude the ventilation principles component I always like to inquire “What else moves

smoke?”. These responses are the most common. All good thoughts, however the point of the

question is to remind us to focus on the principles and not the tools. Smoke is moved by heat,

pressure and mechanical means.

Decision MakingWhat to use and When

• Location and extent of

the fire

• Location of occupants

and firefighters

• Building construction

• Exposures and

Environmental

conditions

With a sound understanding of ventilation principles, the “why”. We can now look to putting our

tactics to work, the “what, how, where and when”. The balance of this training program will

focus on ventilation practices. We all have different size up methods based on our own style,

education and experiences. The goal of this program is to provide education and experience to

assist in decision making, not change your methods. These four points are just a few of hundreds

of factors to consider when making ventilation decisions. As we work through the rest of this

program, size up will be addressed on a point by point basis to strengthen the association with

lesson specifics.

Coordination is Key

We simply can‟t speak to this enough. Back to the first video we watched of the firefighters

opening the door. The lesson remains that fires in enclosed structures are mainly ventilation

controlled. We must recognize the potential in all the actions we take on the fire ground to have

an impact on ventilation.

Today‟s fires are an uphill battle for all the reasons we presented earlier. From synthetic materials

to lightweight construction and reduced staffing we do not need to add to the imbalance by

letting uncoordinated actions give these fires even more ammo.

The first video is from the dash camera of San Bernardino City Battalion Chief Mike Alder‟s

vehicle. This is a working fire in a first floor apartment of a two story multi-family dwelling. At

this time there is one engine crew interior stretching an 1 ¾” to the fire and a second on the

outside stretching a backup line. The one truck company is split. Two from the truck are starting

a search on the second floor and the other two are working their way around the structure as an

outside vent team. That outside vent team is who we want to watch. As they round the corner of

the structure and come into view the engine company calls for the windows. You can see the

officer with the radio confirming the order, followed by his firefighter taking the windows. They

have a significant pressure release which surprises a civilian and a photographer but not the truck

crew. Seconds later, steam conversion and hose stream. Textbook coordination.

Coordinated Actions

Uncoordinated Ventilation

This fire is in a vacant single story single family dwelling. The incident commander has made the

call to vertically ventilate the structure first then, if conditions allow initiate an interior attack.

When the video starts there is a truck company on the roof starting to cut a hole. Two engine

crews have stretched lines to the rear and a RIT team is working to “soften” the building before

attack. What sounds like a well planned and coordinated fire literally changes in a flash. The RIT

firefighter cutting plywood off windows fails to consider the effects of his actions on the fire.

The horizontal ventilation he provides causes the entire first floor to light off. This fire event

chases the truck crew off the roof completely ruining the opportunity for them to direct that

energy up and out as planned.

Vertical Ventilation

“Up and Out”

When vertical ventilation tactics are appropriate and can be performed safely it is the best

method of ventilating enclosed structures. Releasing heat, pressure and toxic gases from a

structure at a high point makes our floor level operations safer, cooler and more efficient.

Vertical Ventilation

• Curb to the cut thought process

– Access

– Wall indicators

– Roof Type

• Pitched / Flat / Arched

• Roof System

– Structure:

» Conventional

» Lightweight

– Covering type

• Fire walls

• Roof top indicators/poke through

• Sounding and “Reading your feet”

Don‟t put the cut ahead of the horse, we have a lot of work to do before we make any carts. Bad

joke, important point. A systematic approach to your tactic that includes collecting information

makes for safer and more confident operations. That being said, if your observations are

indicating the tactic is unsafe you should be equally confident in the decision to stop the

operation. During a class on ventilation at FDIC an instructor made a statement that a good

firefighter takes in everything he can from the “curb to the cut”. He may or may not have meant

for that point to stick but it did.

Here is an example of what my curb to cut thought process looks like if upon arrival of a fire on

Truck X the IC assigned me vertical ventilation.

• How are we going to get on and off the roof – Front, rear, sides? Aerial, ground ladders,

neighboring structure?

• As the ladders go up what are the walls telling me? Frame, masonry? Smoke from eaves? Drain

scuppers in parapets? Reinforcement iron?

• Roof type may be obvious when we pull up. Other times we find out from the tip of a ladder.

• Look over the whole roof before you commit. Tunnel vision quickly sets in once the feet hit the

roof. Consider: layout, access/egress, fire walls, existing openings, vent pipes

• At the wall to roof transition look for construction clues? The roof to wall connection is the

safest and easiest point to check. Open up soffits, expose seams in material even make inspection

cuts.

• When moving on the roof practice solid consistent sounding techniques paying close attention

to feedback through your feet.

Peaked Roofs

Peaked roofs are the most common. There are a number of different styles of peaked roofs

however the common construction element is the downward sloping roof decking from a high

point “ridge” to the exterior walls. There are two additional points on peaked roof design features

to make here. The first is on the safest areas of operation. Roof to wall transitions, valleys, ridges

and hips all offer much greater weight distribution than operating in the field of the roof decking.

While vertical ventilation operations commonly occur in the field of the roof we should aim to

use these construction strengths for access and egress. Secondly, peaked roofs by design act as

funnels. Regardless of what point in the attic space extension occurs smoke, heat and fire quickly

builds and spreads across the highest, narrowest point of construction, the ridge.

What do we have?

Here we have two single family dwellings with peaked roofs. The one on the left was built in the

mid 1980‟s and the one on the right was built around 1920. From the “curb” we can start to

identify elements of the structure including age that can help us determine what we will

encounter when we are operating on the roof.

As a side note the structure on the right was the scene a fire which claimed the life of Denver

Fire Department Lieutenant Richard Montoya. Lt. Montoya was conducting a search of a second

floor bedroom when he became trapped.

Conventional Peaked Roof

Conventional peaked roof construction methods are most prevalent in buildings built prior to the

1970‟s. The use of rafters and ridge beams with quality dimensional lumber makes this roof

system a solid platform that holds up well to time and fire. Unfortunately since the 1970‟s

technology and “value engineering” has made this type of roof construction rarer in modern

peaked roof structures.

Lightweight Roof Construction

Lightweight truss construction methods save builders money and materials while costing

firefighter‟s time and opportunity. The concept is simple, our structural components “trusses”

have a much higher surface to mass ratio than with conventional methods. As you can see in the

picture to the right even the arrangement of the trusses creates an excellent kindling package for

fires in these areas.

Does this mean that we shouldn‟t operate on truss roofs? No! Roofs are systems designed to

support loads. The truss is a critical structural component however it is just one piece. Sheer

support of roof decking, the triangle design and engineered roof to wall connections all come

together for a solid system. What does this mean for us as firefighters operating on peaked roofs.

Thanks to technology vertical ventilation is actually more critical to operations and must be

performed in a much tighter window of opportunity.

Balloon Frame

While balloon frame construction utilizes conventional roof construction the walls of the

structure are built without fire stopping which allows for unchecked vertical fire spread. For this

reason as with truss construction vertical ventilation is more critical to operations and must be

performed in a much tighter window of opportunity.

Ridge Hip Valley Gable

These terms have already been introduced through this program however when it comes to

operations we need to understand that they don‟t just describe construction features they identify

landmarks. Good common terminology can help when the roof crew makes the call for a

“secondary means of egress to the gable end on the bravo side”.

Reading the Structure

The aforementioned landmarks are critical for directing simultaneous operations in separate

locations on incidents occurring in complex structures like this. Shortly after this footage vertical

venting was performed over both exposure occupancies. The video was shot by a bystander on a

second alarm fire in a townhouse complex. The use of this video at this point is for identifying

and naming construction features in real time with real conditions.

Reading the structure

Clearly the task is much simpler with a clear picture and without the distraction of a well

involved occupancy. We can now see that the town home complex is actually two and three unit

adjoining structures not as single units or a common structure.

Roof Ladder Cuts

Since we are on the topic of construction features and we are using this fire it is a good

opportunity to cover roof ladder cuts. The reason we use roof ladders is to improve our situation.

Roof ladders help distribute the live load we place on the roof and improve footing on steep

pitches or bad conditions like snow or rain.

This picture shows the hole cut to provide ventilation of the attic space for the Bravo exposure of

the fire we just reviewed. Roof ladder placement makes accessing the ridge on a steep roof pitch

possible. More specifically the roof ladder placement location next to the chimney takes

advantage of construction features and known framing to improve the safety factor.

Reading the Soffit

In the previous slide the chimney presents us with a clear indicator of where our rafters are for

good roof ladder placement. In the absence of landmark like we can look for other clues in soffits

or even nail patterns in gutters.

Flat Roofs

Flat roofs present the most complex, challenging and time consuming ventilation operations. The

good news is that they also cover larger commercial occupancies with greater fire loads in busy

parts of town. This makes them excellent candidates for signage and cell sites which add

significant loads that the building was never designed to support. I wish this was just a fun little

joke but as you can tell from the picture it is very true. This building which is at least 60 to 70

years old was certainly never designed to support this kind of load on its roof. The bottom line

when dealing with flat roofs is to expect the worst. More than likely that‟s what you‟ll find.

Typical Flat Roof?

According to IFSTA this is “typical” flat roof construction. I will tell you that there is not a

“typical” flat roof. What we could call “typical” is pretty much limited to components. There will

be a structural system that supports some form of decking which allows for application of some

type of water proofing.

Up on the Roof

• Top Side Size-Up

• Primary flat roof duties

– 360 : Look Listen Feel

– Ventilation using existing openings

• Secondary flat roof duties

– Making the cuts

• Inspection Cut

• Ventilation Cut

Flat roofs might as well be called hidden roofs. You cannot properly size up a flat roof from the

ground. We might get some clues from the ground level about the type of roof system by taking a

peek inside the structure. We might be able to determine roof height from the location of drains

all good information but we have to be top side to do a good size up.

What do we have?

By now you should be on to the game. I set you up with some information then I show you a

picture or a video to prove my point.

What do we have? Appears to be a commercial building with a single occupancy? It is tough to

tell because of the poor picture quality but, there may be some type of division in the wall where

the sign is. This wall does not have any visible drains to indicate roof level. The point is that

from here we don‟t know what we have. What we do know is that we need to “expect the

unexpected”.

Go find out

Now what do we have? The unexpected! The wall division has no relation to the structure and

come to find out we actually have two totally different roof systems.

Existing Openings

From the earlier slide we broke up roof duties into primary and secondary. The primary duties

included our size up and ventilation using existing openings. Ventilation using existing openings

is considered a primary duty if they will support the incident and are done in coordination with

other operations just like all ventilation. The reason we put existing openings ahead of cutting a

hole is purely convenience. If we can take advantage of something that is already in place that

may even provide some added level of control like a bulkhead door or roof hatch it saves us time

and resources. Compare it to the “try before you pry” adage for forcible entry.

Even if these existing opening are where we need them they still might not be ideal. When we

went to the roof of this structure our hope was that this 3‟ x 6‟ opening was just that. Come to

find out underneath it we only had two 2‟x 2‟ louvered vents into duct work. While this existing

opening did not provide a ventilation opening we were we did get information. From this

opening we were able to determine rafter direction and depth of roofing material.

Concrete Roofs

As there are times when existing openings aren‟t enough, there are also times when that is all we

got. Twin tee concrete roofs like this one are a prime example. Remember that the lack of

vertical options doesn‟t mean that we are without options. We now need to move on to using

pressure and horizontal openings or when all else fails consider mechanical means.

Arched Roofs

Bowstring construction and arched roofs tend to be considered the worst roofs we will encounter.

This reputation is misplaced, from a time in the fire service where we placed blame on things

that were beyond our control in order to avoid responsibility. The driving force behind this

theory is the Hackensack Tragedy.

Height – Volume - Fire load

Height – The reason occupancies are constructed in the arch style is to provide height. This

added height must be one of the first things we consider in our evaluation of these occupancies.

A floor level investigation may not reveal anything, all the while conditions over head could be a

nightmare. Look Up.

Volume- Once again the wide open space that these structures provide is a desired construction

feature. It also means that lack of partitions allow for rapid fire spread.

Fire Load- The picture above is of a local indoor pool. It doesn‟t matter what type of roof you

put over a pool. We know the fire load in there is so low we should be able to operate for a while

before we have any concerns. The same is true for the auto dealership fire except on the other

side of the spectrum. Structural steel, bowstring or heavy timber, heavy fire conditions feed by

vehicles and auto repair materials will destroy any roof system or material in short order. In

closing, vertical ventilation evaluation and operations do not need to change for bowstring

construction as long as we pay attention to what we know about arched roofs and what the

incident is telling us.

Basements

• Earlier consideration

– Bad environments

– Bad access

– Bad place

• Flat roof ventilation

Causing damage for some reason makes the “customer” service; I mean the fire service really

nervous. The only thing that scares customer servers more than cutting holes in customers roof‟s

is cutting holes in customers floors. We must overcome this aversion and recognize the high risks

of a basement fire. Basements are poorly ventilated, poorly accessed and the roof of the

basement (the first floor) typically bears the greatest load. If we plan this operation early, select a

good location like along an exterior wall below a bay window, vertically venting basements can

be done quickly and safely by following flat roof procedures. Bottom line – If you would cut a

hole in the floor to support a RIT operation why wouldn‟t you cut a hole in the floor to prevent

RIT activation.

We love to brag about out the beating we take on basement fires. Funny thing is we only get the

chance to brag about taking a beating when we make it. Don‟t make your kids orphans for

bragging rights-

Horizontal Vent

• Opening Doors

• Taking windows

• Gable Vents?

Horizontal ventilation is considered the quickest and easiest way to relieve structures and

provide ventilation. This combined with the fact that we operate horizontally in structures means

that we must coordinate and communicate all our actions and not let independent actions in the

heat of the moment compromise safety.

Horizontal VentilationSometimes it‟s all you need

It just simply takes more to horizontally ventilate a structure. This video is Houston Fire

Department arriving at a room and contents fire in a small single family dwelling. Upon arrival

there is about a 10 x 10 room well involved with fire out 3 windows. You can see that fire is very

active and it is clean burning indicating it is well vented. The engine crew advances in and makes

quick work of the room.

Two things to note on this fire in particular. The first is that this small room has 3 windows. This

is fairly uncommon for a room of this size however we see that this is necessary to properly open

this room up. If you were to vertically ventilate this room a hole the size of only one of these

windows would be more than adequate. The second point to note is that although the room is

well ventilated for smoke and steam conversion the room is holding a ton of heat. Shortly after

the initial knockdown the fire flares back up. As long as windows are below the ceiling level heat

will remain trapped in the lid.

This fire is about as straight forward as we could ask. Well ventilated ahead of the attack upon

arrival. The small fire area and 3 windows is all we need.

Horizontal VentilationSometimes it‟s just the first step

Row houses, townhomes, strip malls or apartments, any adjoining structures present us with

limited ventilation opportunities. For this occupancy and fire location we have, front, rear and

top as our options. Based on initial smoke conditions this place needs to be opened up right now!

Time sensitivity forces our hand; we need to provide initial ventilation as soon as possible

opposite the entry point to reduce the potential for a significant event in the direction of the entry

crews. Two firefighters ladder the porch roof and take second story windows on the A side.

This is quick, well placed and extremely effective. As good of an example as this is, it is just the

first step. The initial horizontal ventilation improved conditions dramatically however these two

windows aren‟t going to be enough to release the heat of a well involved top floor. A follow up

vertical ventilation hole over the fire rooms would be ideal.

Before I move on there is always a question of “how is this opposite of the attack?” Inside the

front door of nearly all 2 story row houses, condos or town homes you find the stairs. 1st floor

stairs on the a-side bring you up to the 2nd

floor on the c-side. Therefore the 2nd

floor fire attack

at this occupancy will be from the rear out the front.

Taking Windows

• Window Size Up– Location, Location, Location!

• Fire room

• Opposite attack

• Living space

• Exposures

– Conditions

• Fire

• Wind

– Window Type

• Operable versus Non-operable

• Size

• Mechanics

Windows are the most common opening in structures. The quick access, good location and

typical ease of removal make them an extremely tempting choice. As professionals we must

exercise good discipline here. Take into consideration the location and extent of the fire, current

and future operations then size up your window choices. With a good thought process and

informed plan the ventilation operation is then communicated and coordinated.

Taking Windows

Location - This picture is the rear of a strip mall. The 1950‟s era strip mall is constructed around

this 1890‟s era single family. You could fill a day just discussing this one occupancy. For right

now the focus is location. When a location is given “Take the windows in the Bravo Charlie

corner second floor” we have to consider the source and make sure we are targeting the same

area. If command is giving this order a quick face to face or request for him to point out or light

up the location may be a quick and easy way to clear this up. If an interior crew is giving this

order finding out which “Bravo Charlie corner” they are talking about is going to take some

work.

Taking Windows

Location- Apartments like these for the most part give us two options for horizontal ventilation.

The downside is we only have two options, the upside is this is a dead giveaway for apartment

layout. On the left side of this picture you see the stairs that provide access to the apartment

doors. This should be no surprise because we can see that to both sides of the stairs are the

balcony‟s which are accessed by sliding doors off the living areas of the apartments found just

inside the front door that faces the stairs. These sliders are option one and we know what rooms

they serve. On the right side of the picture we can see option 2. These one bedroom apartments

have a single window for the bedroom. We need to start looking at windows for what they serve

even if it is just as simple as identifying common area versus sleeping area.

Taking Windows

Because of the cheap construction methods in modern buildings window types give us even more

clues. As a disclaimer these are just clues to layout they are not guarantees. The home on the left

shows us two windows on the Charlie Side. Without the distraction of fire and our minds tuned

to windows and building layout we should be able to quickly identify clues offered by both. The

first floor window sill is at counter height (bathroom or kitchen) the window size is consistent

with a larger room (kitchen). The second floor window is large (bigger room), has screens

(operable) and on the second story (master bedroom). The home on the right gives us a good

example of clues provided by cost saving contractors. On the first floor we see a large window

with standard height sill. Directly above it, on the second floor (where we would expect the

sleeping areas) there is a single, smaller non-operable window. This first and second floor set up

is the same to the right just outside of the picture. What does this tell us about layout?

Contractors don‟t want to spend the extra money on operable windows for an area that occupants

can‟t access. If we believe that the area represented by the first floor windows is a living room

then we can start to think that this living room is open to the second story. This is important for

us to recognize because it provides a high point to ventilate horizontally. This could be the best

point to initially vent a first floor fire.

Taking Windows

Another new construction residence that helps to clears up the non-operable window clue. Just

over the front door and first floor window we see 3 non-operable windows. If we take a quick

look down the Bravo side and see more non-operable windows in this AB corner or no windows

we know with almost complete certainty that this is a vaulted space and not a living area.

Commercial Occupancies

What are we

walking

into?

Earlier in the class we looked at commercial occupancies with store fronts and discussed

ventilation tactics using pressure gradients. Unfortunately if we look at all our commercial

occupancies the ones with store fronts only make up a small percentage.

Taking Windows

For the majority of commercial occupancies, windows are typically undersized for the area they

serve.

Taking Windows

The window on the left is a modern sliding vinyl window. These windows are a firefighter‟s

dream. Putting a Haligan to work on the frame we can remove full panes faster than we can

break and clear out the window. The window on the right is a firefighter‟s nightmare and it has

nothing to do with the bars on the outside. These windows are the “old school” steel frame

casement windows. The glass in these windows is out quick but, the frame is a beast. Clearing

these windows requires a sledge or a saw. A row of these windows like we see on this wall is

going to take a considerable amount of time and resources to clear. The point of this slide is

recognize and plan. An outside vent team on a building with the vinyl windows can be two guys

with hand tools. If you start your 360 and find these steel frame windows with bars, assign a full

company with tools and a saw.

Gable Vents

• Horizontal vent of an attic?

• Typically inadequate opening based on volume of attic

• Must be coordinated to prevent rapid spread.

• Use gables for access not ventilation

Gable vents are designed and installed in attics to allow natural air movement consistent with

natural heating and cooling of the space. The use of gable vents to vent an attic space under fire

conditions is counterproductive. Gable vents are poorly placed and undersized for fire

ventilation.

The picture on the left is a prime example and can be compared to the video of the firefighters

opening the door we watched earlier. If we arrive at an attic fire and take a gable vent for

ventilation this is what we will get; a massive push out that opening as we just provided a low

pressure magnet. Consider how quickly conditions are being compounded in that enclosed space.

If we also think of the heat built up along the ridge the last thing we want to do is pull everything

horizontally. When possible, attic spaces need to be vertically ventilated. Use gable vents or

rooms underneath as access for your hoselines.

Wind

The true effects of wind on interior operations are just now starting to be fully understood. In

recent years there has been extensive research by NIST, FDNY and Chicago Fire Department.

The information collected from testing has indicated that exterior wind speeds as low as 5 miles

per hour through a window can create wind driven fire conditions on the fire floor. Additionally,

these studies have prompted NIOSH to investigate environmental conditions and their impact on

LODD cases both current and past.

6th and Simms

• The wind at ground level was negligible. The window with fire showing is about

25 feet. With negligible winds at ground level, the winds 25 feet off the ground

were significant enough to overcome the pressure of the fire inside this room.

Our department certainly doesn‟t need a new study to show us that wind conditions outside the

fire room can make operations more challenging. These photos are from the live burns we

conducted in 2005. This window is the only opening for a well involved hotel room. Wind was

reported as very light at ground level however at the third floor it was holding the fire to the wall

and even with the steam expansion very little made it exterior.

FDNY Wind Tests

If a picture is worth a thousand words this video is priceless. This apartment building in New

York was used over a month by FDNY and NIST to study wind driven fires. Here we have a well

involved bedroom fire, door closed in a 3rd

floor apartment. The video was used in a class at

FDIC given by one of the NIST scientists on the project. He described the puffing action as

“over pressurization” of the fire compartment. Imagine where all that energy would be going if

the door to that bedroom opened.

NIST Wind Video

Here is a video complete with thermal imaging of what happens when the door to the fire room is

open with a 20 mile an hour wind. Let‟s see if this is the wind driven fire you pictured.

The scenario prepared by NIST is a fire that starts on a mattress in a one bedroom apartment. The

occupant discovers the fire and evacuates leaving the doors open on the way out. As the fire

builds in the room, the window for that room fails and the exterior wind at 20 miles per hour is

introduced.

The footage is of the four simultaneously running cameras. The upper left view is of the fire

room from the bedroom door. The upper right view is of the common area of the apartment from

the apartment door. The lower left camera is looking at the open apartment door from the public

hallway and the lower right view is a thermal imaging camera at that same angle. The thermal

imaging camera also provides us a surface temperature reading of the masonry wall 3 feet off the

ground at the apartment door.

For the first two minutes we observe fire growth and can see smoke and heat move through the

apartment and out into the hallway. At 2:21 the window fails and the wind impacts the fire. At

2:30 the wall temperature is 80 degrees over the next minute that wall temperature reaches over

900 degrees at 3 feet off the ground. At just over 3 minutes all the protected conventional

cameras have failed due to high temperatures. Additionally all of the thermocouples they placed

were destroyed after maxing out at 2500 degrees including the one at the ceiling in the public

hallway.

When possible wind conditions must be evaluated at the window prior to taking it.

Operations

This firefighter is going to work. Carrying two ladders he is a very determined man. Sure there

are easier and more organized ways to move equipment. Yes, the top floor of that building is well

involved, and certainly the guy holding the camera could help him out. The point is this is a cool

picture of a guy carrying two ladders.

Getting it Done

Study – Practice – Drill – Preplan

The last picture was a guy going to work in stereo typical “Truckie” fashion. This picture is a

professional crew, working with purpose in an organized fashion just as they have trained. They

accessed the roof to a structurally sound point at the ridge. They brought appropriate tools

including a roof ladder at the ready. The sounding firefighter is leading the operation and

popping vents as he goes, while the saw man is keeping an eye on his partner and awaiting cut

direction.

My chief looked at this picture and saw a firefighter not wearing gloves. I look at this picture and

see two firefighters working as a team. Both confident and efficient in their assigned tasks,

functioning with discipline in a safe well coordinated manner. In today‟s fire service with fire

incidents declining every year this level of proficiency can only come from practice.

Professional Work

Another video from San Bernardino City Fire. This one provides us with real time footage of

operations. The key point of focus will be the first arriving 4 person truck company that is sent to

the roof to ventilate. We will see the truck officer and two firefighters at the base of ladder on the

Alpha Bravo corner. What we can‟t see is the fourth firefighter from the truck throwing an egress

ladder on the Charlie side.

First up the ladder is the sounding firefighter with the hook. It is difficult to see but when he gets

on the roof he immediately begins sounding over to the fire occupancy to determine cut location.

Next up the ladder is the saw firefighter. By the time he gets to his partner it is time to cut. The

saw man is 100% task oriented with the running saw in his hands so the sounding man becomes

his back up. Just as the officer starts up the ladder he is joined by his fourth firefighter. When the

officer gets on the roof he keeps a slight distance to keep an eye on both the operation and fire

conditions.

The first hole is a success and provides good ventilation but the officer determines more is

needed and calls for a second hole. The two person team drops back, the sounding man selects

cut location and the process repeats itself. The second hole complete and the officer calls it good.

You can see that smoke conditions at the windows have improved. The crew reassembles, heads

up and over the ridge sounding as they go to the egress ladder. Why doesn‟t the crew leave the

roof the way they came? One simple wind change and that ladder could have been a nasty place.

With the primary ladder providing the quickest access to the cut it is the most vulnerable after the

cut. The added safety and protection of the long way off may be quicker in the end. Furthermore

the repetition of using egress ladders for egress sets up best practices.

Be safe by thinking ahead

Steam conversion is a good thing to see at a fire and it means we are making progress. It also

may obscure places that were clear earlier, just the same as a wind shift. Plan ahead and call for

more ladders, two is not enough for this situation.

How many firefighters does it take?

There are places where you can have too much of a good thing, even staffing. Under certain

conditions it can be argued that we need more people to improve safety. For the most part I agree

as long as roles and responsibilities are clear. In the San Bernardino City video we just watched

in that occupancy with those fire conditions sending a full crew to the roof is a good call. The

tactic of the actual cut only requires two people. The safety of the operation is improved when

the additional show good discipline and stay in a position to evaluate the bigger picture.

This video from Houston show us that no matter how many people are involved if the tunnel

vision is on, no one is maintaining situational awareness.

The access ladder is thrown to a corner which is common practice because it is easily

landmarked and it s a structurally sound point. The downside to laddering a corner is that it is a

point where two walls come together and on the roof walls are edges. The firefighter who fell

should have been well aware of his proximity to the edge when he stepped on to the roof

however the tunnel vision of the task cost him his situational awareness.

The Cuts

The first thing we tend to think of when we hear “ventilation” is cutting roofs. So why is it the

last thing we are going to talk about? Because, as soon as you get your hand on that saw, your

world becomes small and loud. This is the worst time to start and stop, or try to communicate

plans. The goal is that the training you have done combined with the information you take in and

process up to that point you can comfortably and confidently put your head down and go to work

without interruption.

4 x 4 Vent Holes

• History of 4x4 holes– From the pre-saw fire service

– Rafter and plank roof construction

– Single family homes were more typically about 1000 Sq ft

– Contents of homes were mainly Class A combustibles

• Today‟s use of 4x4 holes– Field cuts for smaller single room

vertical ventilation

– Considered the minimum • Modern construction has larger more open

floor plans

• Fuels burn hotter and less completely

• Structural members are lighter weight

The old standard 4x4 hole for vertical ventilation is just that, an old standard. Today most of our

vertical ventilation operations will require more square footage. That said, a 4x4 hole may be

more than adequate on the next fire you go on. The point is that we think of it as a minimum and

not the goal. Training should be focused on cutting 4x4 holes and planning for the potential that

more may be required. This helps us develop a good visual gauge of size and time as well as

keeping a thought process that is towards planning ahead.

Hand Tools

• Roof Pitch

• Access

• Saw failure

With a steep pitch and tight valley a the roof ladder or chainsaw may just crowd the situation.

Going to work with hand tools at times may be the best route. The final and obvious situation for

hand tools is saw failure. Make a back up cutting tool part of your package.

Why A Specific Cut Order?

• Simple - Consistent – Safe

– The cut order is designed to keep members out of

the cut areas and working towards their means of

egress or windward side. During the loud

operational period it also decreases the need for

communication between crew members as to what

will need to be done next.

From this point forward we will focus on one cut order. This cut order can be expanded as

needed from a simple peaked roof field cut, to a large scale flat roof operation. With a common

cut order for all our operations we help reduce communication, keep operations consistent and

improve overall safety. With that being said this is not a requirement as much as it is an option

and recommended practice. Our experience shapes our practices and if you have a sound method

that keeps you safe, out of cut material and working towards your egress you do not have to

change. We do ask that you preplan your cuts with your partner so needs can be anticipated and

the operation is not delayed.

Single Rafter Louver

1

2

3

4

5

EGRESS

Here is the modified “single rafter louver” cut pattern we will be teaching. These five cuts will

be the base of all our ventilation cuts. The reasoning behind this order as we discussed before is

simplicity, safety and consistency.

The Cuts:

• The operation begins with a diagonal cut starting near and high proceeding down and away

until a structural member is met. This cut will serve to create a knockout to assist in

louvering the deck.

• The second cut is top down, along side the structural member at least 4‟ in length

• The third cut will be our top cut which will roll at least one rafter.

• The fourth cut is the bottom cut and will also roll at least one rafter.

• The fifth cut will be a vertical, top to bottom along side the structural member if this is

adequate width.

An example of the “single rafter louver” at a garage fire. This roof is of truss construction with

structural members on 24” centers. A single rafter louver in this roof provides us with almost the

full 48” width.

Field Cut

• Over the fire room

• Create the “Chimney Effect”

When it comes to peaked roof ventilation we are going to talk about field cuts and ridge cuts.

The field cut refers to the cut location being in the field of the roof. Since most rooms are located

along exterior walls the holes we cut to vent them will fall in the field. As we showed in earlier

slides field cuts will be a two step process. Cutting the decking of the roof then punching the lid

of the room to release the heat and create the chimney effect.

This video demonstrates the expanded cut and a few other points can be discussed.

• The diagonal cut and first vertical are made with the same hand position. The hand position

is changed for the next two horizontal cuts. This process repeats itself for as cuts change

from vertical to horizontal this limits the need for the firefighter to change body position and

prevents work over the cuts.

• With both crew members understanding the cut order no verbal communication is required

during the operation. The sounding firefighter determines cut location and indicates with the

tool where he wants the hole with the angled motion. He then moves into a position to back

up the saw man until he sees that the saw man is about to make the 5th

cut. As the saw man

makes the 5th

cut the sounding firefighter gets his hook into place to prevent drop in and

awaits the saw firefighter to complete the cut before opening up. Once the saw man starts on

the second louver the sounding firefighter opens up and initiates ventilation.

Ridge Cut

• Peaked roof

construction

• Attic fires require

larger holes

• Hallway vent

• Increased obstruction

potential

• Use construction

features to your

advantage

The second peaked roof cut is the ridge cut. The ridge is the location to vent attic fires, larger

rooms that may take up more than half the occupancy or fires that involve center hallways.

If you are venting a room or hallway from the ridge there are two major considerations. First is

to have a hook of appropriate length to reach the lid of the room. The second is to be prepared to

encounter stored belongings which may completely negate this ventilation option.

Single Rafter Louver Expanded

3

1

2

Repeat as necessary

EGRESS

5

4

As mentioned earlier a 4‟ by 4‟ hole is the minimum not the goal. By running the third cut long,

rolling two rafters and moving the fifth cut between the two rafters you can double the size of the

hole with just two more cuts.

Ridge Cut

Here is a perfect example of the funnel effect of peaked roofs. This vehicle fire in Castle Rock

extended to the attic of this structure through the eaves. The truck company quickly accesses the

ridge via the aerial and with a well placed hole relieves a significant amount of heat and pressure.

This is a reminder that regardless of the point which the extension is introduced to the attic space

the ridge must be addressed. Many times I have heard concerns that venting at the ridge will

draw the fire to that location. The simple fact is that heat and peaked roof construction is what

draws the fire to the ridge. Cutting a hole early is the only way to prevent lateral spread once it

gets there.

With about a 2500 Sq Ft. footprint this attic needs a significant hole to properly

ventilate the volume it holds. At least a 4 x 8 to 4 x 12 depending on fire extent

remembering when expanding your hole do so along the ridgeline in a rectangle.

Large Area Peaked Roof

Plan ahead, then plan ahead and when you‟re done, plan ahead. With good saw techniques hole

can quickly be expanded. When we are venting attics at the ridge the hole does not need to be

continuous. If the initial hole appears to be insufficient you can drop back to a safer location and

make additional holes as long as they remain at the ridge


1

2

3

Repeat as necessary

EGRESS

ROOF PEAK

Soffit

One more look at an option for expanding our ventilation opening.

Here is an excellent example. The first hole is well placed but the hole appears to be

overwhelmed. The crew drops back a few feet and starts another hole still working towards their

egress as a team of two with the officer providing eyes over the whole operation.

Boise Fire 2 Story MFDArrival Alpha Side

Boise Engine 4 arrived to find this working fire in a second story apartment. On the A-side is the

open stairwell to a short open hall which access the two second floor apartments.

Charlie Side

From the Charlie side we have a well involved bedroom fire out the window in the Bravo Charlie

corner. If a crew was on the roof at this moment a good sized field cut over the room would be

perfect. Looking at this from the dashboard of the truck company pulling up, I would plan on

getting to the ridge and venting for an attic fire. The auto exposure of the eaves will be into that

attic space in short order.

Flat Roofs

• Property conservation venting?

• Vertical ventilation need is greater yet window

of opportunity is smaller

Recently I was told that putting firefighters on flat roofs was ridiculous since it is just “property

conservation venting”. I believe he was speaking about unoccupied commercial structures. If

that was the case and he was speaking about risk versus benefit considerations, I guess I agree

with him. That said, there are a lot of assumptions and I hope that what he said was not what he

meant.

While the majority of flat roof occupancies are commercial, a fair amount of multi-family and

extended care facilities with flat roofs. We are also going to see fires in commercial occupancies

that we can safely operate in with ventilation. We should be safe and constantly perform risk

benefit analysis. This does not mean we take defensive positions as soon as we hear everyone is

out of a structure.

Inspection Cuts

• Construction materials

• Rafter direction

• Depth of cut

• Initial indication of

conditions

• Early and often on

questionable roofs

Inspection cuts are great opportunities for us to slow down and pick up a little more info before

we fully commit to the ventilation operation. A simple 3 sided cut that is large enough to fit your

arm through. Cutting an inspection cut at our roof to wall transition will keep us in a structurally

sound position, tell us the depth of roofing material and may even reveal rafter direction. Once

we are out over the field, if the inspection cut shows good smoke we just expand our cuts from

there and it becomes the knock out for opening up.

Don‟t fear the saw

Respect and Understanding•Know the tool

•Know the task

•Know the situation

There is a direct coloration between risk of injury and comfort level. We are the most dangerous

when we fear an operation (uncomfortable) and when we are complacent in an operation (too

comfortable). Aim for the middle by respecting the tools and tactics

Know the tool:

•Our circular saws with a warthog blade are an impressive machine and for most operations the

saw requires very little help other than direction and drag.

•With the inboard mounting the blade is inline with the handle, as our hand goes the cut goes.

Keep body weight off the saw and positioned behind the handle so that as structural members

are encountered the difference is easily sensed.

• Know the task:

•Having the cut order and length planned will limit starts and stops.

• Know the situation:

•Fire conditions and location

•Your location on the roof

•Egress direction- Obstructions – Edges

•Roof construction

•Depth of material – Type of structural members

•In built-up roofs burying the saw may not be enough to reach the decking, requiring

more cuts

CIRCULAR SAWS WITH RUNNING BLADES DO NOT COME OFF THE DECK

Lack of a break, the saw power and blade mass exaggerate movement in free space make them

very dangerous when operated outside of material

7 9 8 cut / Coffin Cut


EGRESS

The most common flat roof cuts are the 7 9 8 cut and the Coffin cut. Both these cut processes

are essentially just an expanded version of the single rafter louver. Once again if you are trained

and consistent in these other cut methods please continue. The single rafter louver base and

common cut order for all roofs will continue to be our teaching method for the afore mentioned

reasons.

Let‟s walk through the cut process:

Up to this point the sounding man has determined cut location and indicated to the saw man

where he wants it by marking the diagonal. The saw man dropped in a diagonal cut until he felt

the resistance of the structural member an stopped. His next cut is along the structural member to

a length he feels appropriate then he stops and moves to the full length top cut where we pick

him up in this picture. Note the firefighter has good positioning with the saw. His body weight is

entirely behind the saw and in line with the blade. With the power of the saw and aggressive cut

of the Warthog blade we as operators simply mind the saw as we drag it through the material.

This “light” touch will prevent binding and help us detect structural members.

With the full length top cut complete we can see the knock out cut has dropped in and the overall

cut looks like a 7. The next series of cuts will be done two at a time alternating from horizontal to

vertical.

The horizontal cut rolls one rafter and runs up to the next structural member then stops. The saw

man then repositions and drops his vertical cut in between the two rafters to facilitate the first

louver.

The next cut follows suit and may be continued for several more if necessary.

Opening up

Trying to louver a large section of flat roof can be a difficult task. This first section may be

particularly difficult due to the fact that it is a full bay width on the one side and only a half bay

on the other. Be prepared with a long hook to keep you out of the opening. Most importantly do

not be to proud to ask for help. The saw man is going to be task oriented and will not see you

struggling. We have to get ventilation started if that means we have to stop a cut for a few

seconds it is well worth it.

Here we have the saw man finishing his cutting operation. He is showing good body positioning

and simply minding the saw through the material. The sounding man has opened up as they‟ve

gone and with the completion of this cut and final louver they will be done and off.

We can see to his right that the vent hole has run out of real estate due to the location of the roof

top unit. Fortunately the hole he has cut is of good size and his operation is done.

The Trench Cut

Defensive tactic to create a fire break in the roof.

The trench cut is very misunderstood. The trench component of the trench cut is to create a fire

break and provide access for fire streams not ventilate the cockloft.

• Order of operation:

• Large vent hole over fire area

• Observation cuts

• Cut trench at narrow point and pull ceiling but do not pull the trench

• Position hose lines underneath and above

• When fire shows from the observation cuts pull the trench and operate hose lines into the trench

The trench cut was developed during the 1960‟s in New York city during an exceptionally busy

fire era. The tactic was brought outside the city when the first edition of John Norman‟s Fire

Officers Handbook was published. This slide outlines the requirements for a trench cut operation.

Note that the first order of business is a large vent hole over the fire area. The key points seem

simple, clearly explained in his text and logical given certain situations, so why the confusion.

At about the same time John Norman published his book, John Mittendorf also published a book

on truck company operations which describes “strip ventilation”. Strip ventilation is essentially

what we described earlier as expanding the louvered cuts or adjusting your louvered cuts to the

roof layout. Strip ventilation is a ventilation opening for the purpose of venting. An expanded

single rafter louver cut that runs 8 to 10 feet along the ridge of the roof could be considered

“strip” ventilation.

Trench Cut in a Strip-mall

More labor intensive due to the fact it requires two trenches and the absence of a narrow point to aid in

you cut.

MAIN

VENT

Observation cuts

T

R

E

N

C

H

T

R

E

N

C

H

EXPOSURE D EXPOSURE B

Some may ask since we don‟t have H or E type tenement buildings when we would use trench

cuts. Any type of flat roof on a “winged” building will work however the most common

application in most suburban departments is limiting extension in strip-malls. This would be an

example of set-up for a center unit.

Trench Cut in a Strip-mall

Here we have the side view of a trench operation. The main vent over the fire area may be burn

through or a hole cut by firefighters. Observation cuts are placed between the main hole and the

trench to provide indication of fire travel . Then lastly we have the trench cut which is that fire

break in an area which hoselines can be safely staffed and operated. The trench cut is not to be

opened until the observation cuts are indicating the fire is moving towards the trench. With the

common cockloft early opening of the trench will potentially draw fire.

Trench cuts are not peaked roof operations

In the top left picture we can see fire burning through the ridge with nothing showing at the

eaves. This is a great picture to demonstrate the funnel or heat trap effect of peaked roofs.

In the bottom right we see the “trench cut” crews created in the roof to prevent fire spread.

Knowing what we know about peaked roofs and seeing the picture on the left it should be clear

that the further we get from the ridge when venting attic spaces more time and energy is being

wasted.

For attic fires, heat and pressure build at the highest point. In a peaked roof it is the

ridge in a flat roof it is the deck. For this reason time and efforts are completely

wasted the further from the ridge we work. To prevent horizontal fire spread in a

common peaked roof attic space vent along the ridge.

“Strip Ventilation”

Here we have a graphic to show a good “Strip Vent” location along the ridge. Due to the high

and narrow point of the ridge this is where fire will be moving horizontally first. It will take a

very long time for fire to show at the eaves. In flat roofs a strip vent can go in any orientation

simply because in flat roof constriction the roof decking is the lid of the cock loft.

Strip Vent

Single Rafter Louver

1

2

Repeat as necessary

EGRESS

ROOF PEAK

Soffit

As we mentioned before, plan ahead. By running the top cut long the hole is easily expanded one

rafter at a time with the horizontal then vertical cuts.

Final Notes

Trench Cut and Strip Vent

• Strip Ventilation

– Used for Venting fire and smoke

– At the ridge in peaked roofs

– Any orientation on flat roofs

• Trench Cut

– Associate Trench with Fire Break

– Used for hoseline access

– Last stand location

Getting it Done

• Ventilation size up

– Building Construction

– Fire Behavior

• Ventilation safety considerations

• Plan your exit before you need it

• Always have two ways off

• Delegate more ladders if needed

Time to start wrapping this up. Hopefully at this point with the principles and examples we have

presented you have developed a ventilation size up that works for you. Do not forget the risks

associated with these operations. Support each other. The saw man is the extra eyes for the

sounding firefighter as he works his way across the roof. The sounding firefighter becomes the

back up for the saw man when the saw is running and his blinders are up. Plan your exit, plan

ahead and for everything have a plan B.

Getting on the Same PageThe pre-game starts with common terminology

– Construction

• Ridge, Hip, Valley, Gable, Eaves

• Slider, Double Hung, Casement

– Equipment

• Saws

• Tools

• Primary Ladder, Secondary Ladder

– Operation

• Inside Team, Outside Team

• Saw man, Sounding man, OVM

Start by ensuring you are speaking the same language. Acronyms and slang may be our curse. I

tend to just refer to the roof saw as the Warthog and when I think of a hook I immediately think

of a 6 foot steel Halligan hook. Most of my crew understands this but a newer firefighter or even

a very senior firefighter who hasn‟t worked with me may not know what I am asking for.

Something as simple as rounding the truck, tower or ladder, whatever you call it may help to

clear some things up.

Company Level Expectations

Tower X Fire Ground Responsibilities

Inside Team

Gain primary access

Conduct search

Fire – Victims – Extension

Pre and post-control overhaul

Salvage of property

Outside Team

Provide for secondary access/egress

Perform 360‟ and topside size-up if

necessary

Laddering

Fire Floor – Floor Above - Roof -

Opposites

Most company officers discuss expectations with their crews. Adding a fire ground

responsibilities component to it can help crews anticipate what should be done next. Something

as simple as a priorities list can go along way in reducing communication and the delay in

moving from task to task.

Tactical Action Plans / Job Sheet

Ventilation-

– Horizontal

» Must have direct communication

» Confirmed and Coordinated

» Considerations

• Size up

• Fire conditions

• Wind

• Exposures

– Vertical

» FF1

• Primary ladder, Sounding tool

• Leads to and directs cuts

» FF2

• Secondary ladder

• Saw and Secondary cutting tool

• Performs cut

» Additional members

• Operational oversight/safety

• Labor assistance

Tactical action plans or job sheets are the key to doing as we drill. Take what we have covered

today to your crew and develop drills that become your system for operation. This is a simple

example it can easily be expanded or reduced to fit crew specifics.

Tool Assignment Example:2 Person Vertical Vent (Typical Single Family)

FF #1 – Primary ladder and sounding tool/hook

Putting it on paper means nothing until we do it. Take the time practice your plan and see what

works. Officers, take the time to show your expectations not just speak them.

Tool Assignment Example:2 Person Vertical Vent (Typical Single Family)

FF #2 – Secondary ladder, saw and back up cutting tool

Questions?

Compiling this information into one program has been a lot of work however, the work is not

done and I look to you for help to improve it. Please be honest and constructive in your feedback

so we can provide better programs in the future. In closing the information presented in this class

is 99.9% collected and .1% created. Recognizing that this class would not exist without others

sharing information with me, I will make this entire class, videos, pictures and resources fully

available for you to pass on as you see fit.

Ventilation Principles & Practices FDIC 2011 - … Principles & Practices FDIC 2011 Lieutenant Brian...

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