Ch 05 Features of Fire Protection
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Transcript of Ch 05 Features of Fire Protection
5 Features
of Fire Protection
Objectives (1 of 2)
• Understand the basic concepts of fire protection and building construction
• Identify the basics of fire behavior, including fire spread
5
• Explain the ways in which smoke and fire containment is achieved
• Describe the various types of fire protection systems
Objectives (2 of 2)
5
Building Fire Protection: A Short History (1 of 2)
• Historically, fire containment was a primary objective of the fire fighter.
• Modern building codes reduce conflagrations.
• Reduced conflagrations contributed directly to human safety.
5
Building Fire Protection: A Short History (2 of 2)
• Compartmentation also contributed to human safety.
• Firefighting concerns
• Egress for occupants
• Fire fighter safety
5
Fire Terminology (1 of 3)
• Noncombustible Buildings
• Material that does not aid combustion
• Buildings contain noncombustible and combustible components
5
Fire Terminology (2 of 3)
• Fire-rating
• Fireproof
• Flameproof
• Self-extinguishing
• Flammable
• Fire retardant
• Fire resistance
5
Fire Terminology (3 of 3)
• The meaning of fire terms vary.
• The conditions of testing vary.
• Inflammable
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Fire Resistance Distinguished (1 of 2)
• Rated fire resistance
• Inherent fire resistance
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Fire Resistance Distinguished (2 of 2)
• The criteria for fire resistance are imprecise.
• Risk/benefit calculation often cannot be done.
• The protected combustible classification provides no safety for the fire fighter.
5
Fire Behavior, Fire Fighters, and Buildings
• Concealed Fire
• Bursts out of a hidden void
• As dangerous as a building collapse
• Difficult to simulate in training exercises
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Rapid Development of a Fire
• Flashovers
• Backdrafts
• Flameovers
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Preventing Fatalities
• Ventilation is essential in limiting risks to fire fighters operating inside the building.
• Ventilation can cause backdrafts, flashovers, or flameovers.
5
After a Fire
• Research abnormal situations
• Investigate unusual heat, smoke, or burning
• Revamp fire command and attack procedures
5
Fire Growth
• Influenced by building construction
• Influenced by the materials lining the walls and ceilings of the space
5
Flame Spread
• Also known as fire growth
• Still a problem for fire prevention staffs
5
Examples of Fire Growth
• Cocoanut Grove nightclub fire in Boston
• Soldier’s hostel in Newfoundland
• Mercy Hospital in Iowa
• Dorothy Mae Apartments
• Elliott Chambers Boarding House
5
Combustible Tile Ceilings
• Suspended from ceiling
• Creates a void in which explosive carbon monoxide gas can be generated and stored
• Creates a violent explosion
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Examples of Fires Involving Combustible Tile Ceilings
• Silver Spring, Maryland, in 1977
• Orlando, Florida
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Building or Content Hazard? (1 of 2)
• Building Problem
• Hidden
• Exposed
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Building or Content Hazard? (2 of 2)
• Contents Problem
• Furnishings
• Interior finish, including decorations
• Mercantile stock
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Hidden Building Elements
• Batt Insulation
• Is fiberglass or rock-wool insulation with various thicknesses
• Laid in ceilings and must be kept free of light fixtures
• The paper vapor seal gives a phenomenal flame spread.
5
Other Hidden Building Elements and Examples (1 of 3)
• A supermarket with a combustible ceiling
• An electrical fire that ignited the vapor seal of the insulation
• A torch set fire to the paper vapor seal on the insulation
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Other Hidden Building Elements and Examples (2 of 3)
• Combustible fiberboard
• Foamed-plastic insulation
• Old air-duct insulation
• Electrical insulation
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Other Hidden Building Elements and Examples (3 of 3)
• Tennessee Valley Authority’s Browns Ferry Nuclear Power reactor fire
• Telephone company building, New York City, 1975
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Interior Finish
• Plaster
• Matchboarding
5
Modern Interior Finishes
• Increase fire extension by surface flame spread
• Generate smoke and toxic gases
• Add fuel to the fire
5
Low-Density Fiberboard
• Bagasse
• Often erroneously ignited by a plumber’s torch
• Fire often goes undetected until it erupts violently.
5
Combustible Acoustical Tile
• Fiberboard punched with holes
• Used to cover deteriorated plaster ceilings
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Industry Opposition
• St. Anthony’s Hospital fire
• April 1949
• 74 deaths in the fire, mostly infants
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Void Spaces
• Formed by suspended ceilings of combustible tile
• Fire can burn undetected until it bursts out furiously.
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Remodeled Ceiling Hazards
• Code requires that a new ceiling meet flame spread requirements.
• Code does not require the removal of the old ceiling.
• Fire can build and burst out from between the old and new ceilings.
5
Adhesive
• Corridor ceilings made of combustible acoustical tile glued to gypsum board
• The MGM Grand Hotel fire in 1980 was linked to the 12 tons of adhesive used to attach tiles to the ceiling.
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High Density Fiberboard• Rocky Flats Nuclear Weapons Plant
• Very dense fiberboard was selected for radiation shielding.
• Tested via the blow torch test, which is considered inadequate
• Long continued heat from spontaneously ignited plutonium ignited the fiberboard.
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Paper• U.S. Atomic Energy Commission
• Project had a temporary snow roof of hemp-reinforced bituminous impregnated paper.
• This paper has a very high flame spread rating.
• A stove could have ignited the materials, but was removed.
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Fabrics
• Flames spread rapidly on gasoline- and paraffin-impregnated canvas.
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Cork and Rattan
• Cork on the ceiling as decoration
• Cork paneling
• Rattan ceilings
5
Wood
• Very popular and common
• The unexposed side of plywood can burn unobserved and protected from fire department streams.
5
Plastics
• Rigid-foamed polyurethane
• Used for interior finish in many houses
5
Plastics Related Fires
• 1971 fire in a French nightclub
• Fire in a disco in Dublin, Ireland
• Expo ’67 in Montreal, Canada
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Aircraft Interiors
• Aircraft fires are exacerbated by plastic seats and other interior fittings.
• August 1990; FAA standards increased for fire and heat resistance.
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Acoustical Treatment
• Flame spread consequences of materials used are not always known.
• Station nightclub in West Warwick, Rhode Island
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Open-Plan Offices
• Where do the corridors begin and end?
• Corridors should have rated walls and doors.
• “If there is no wall there is no room.”
• It is all a corridor.
5
Carpeting
• Now used on walls and ceilings
• 1980 fire in the Las Vegas Hilton Hotel
• Carpeting on daycare center walls is dangerous.
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Alterations
• Be aware of building alterations with interior finish materials that would not have been permitted during construction.
• Combustible paneling
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Decorations and Contents
• Christmas trees were common fire hazards.
• Decorations and furniture are difficult to control from a fire prevention perspective.
• Halloween haunted houses are a concern.
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Fires from Decorations
• Six Flags Haunted Castle in New Jersey
• Girls’ dormitory in Rhode Island
• A water treatment plant under construction
• Smithsonian Institution National Museum of Science and Technology
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Today’s Fire Loads
• Both fire loads and rates of heat release are increasing.
• Solid and foamed plastics replacing wood, cotton, wool, and other materials have often unrecognized hazards.
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First Interstate Bank Fire
• Floor had open spaces crammed with computers and related equipment.
• Rapid fire spread
• Fire Research Division of the National Institute of Standards and Technology (NIST) report discusses this fire.
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Hotel Remodeling
• Mattresses and furniture are removed from rooms and stored in hallways.
• Targets for arson
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Regulations
• Little on national level, but some state and municipal involvement
• State of California
• City of Boston
• Port Authority of New York and New Jersey
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Certification of Interior Designers
• New York State requires two examinations
• One on interior design itself
• The other on building codes and fire safety
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Residential Fire Tests
• National Bureau of Standards (NBS)
• Conducted fire tests on the contents of typical residential basement recreation rooms
• Study the full report.
5
Available Films
• National Fire Protection Association (NFPA) produced movies
• Fire: Countdown to Disaster
• Fire Power
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Difficulties
• Materials used in building interiors can be confusing.
• Specific information is required to make an accurate assessment.
• Don’t make assumptions.
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Control of Rapid Fire Growth (1 of 4)
• Eliminate high flame-spread surfaces.
• Foreign ships may contain combustible trim and veneer.
• U.S. merchant ships severely limit the combustibility of construction materials and surface finishes.
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Control of Rapid Fire Growth (2 of 4)
• Cut off extensions
• Some codes require a metal door sill separating more flammable materials.
• Effective only if the door is closed
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Control of Rapid Fire Growth (3 of 4)
• Coat the material
• Fire-retardant surface coatings are effective only if applied as specified and not too thinly.
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Control of Rapid Fire Growth (4 of 4)
• Wooden materials can also be formulated to be flame resistant.
• One manufacturer has produced structural glass-fiber-reinforced plastics.
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Testing and Rating Materials
• First attempts at testing
• Failed due to inexact, legally unenforceable language
• Developing adequate tests
• Tests must be consistent
• Tests also should be reproducible
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NFPA 255• Commonly referred to as the Steiner
Tunnel Test
• Sample 25 feet long and 2 feet wide forms the top of a tunnel or long box.
• A gas fire is lighted at one end; fire progresses along the underside.
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NFPA 255 Test Results
• Class A: 0–25
• Class B: 26–75
• Class C: 76–200
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Building Codes
• Most rely on the tunnel test standard
• Class A flame-spread rating for corridors and exit ways
• Less restrictive requirements for offices
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Running the Tunnel Test
• “Smoke developed” is measured and indexed.
• Calculated by measuring the obscuration as the smoke passes a photoelectric cell
• Materials with ratings of 300 or more generate substantial amounts of smoke.
• This testing standard is widely accepted.
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Fire Rated
• Term often causes confusion in the building trades.
• Term is without a specific meaning.
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The Radiant Panel Test
• NBS developed the American Society of Testing and Materials (ASTM) E162, Radiant Panel Flame Spread Test.
• Samples measure only 6 by 18 inches.
• Is more fully described in the NFPA Fire Protection Handbook
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Factory Mutual Corner Test
• Corner test • Simulates an actual
fire within the corner of a building
• Walls are up to 25 feet high.
• The exposure fire is a pile of pallets.
5
Carpet Tests
• Floor covering is contributing factor in a number of serious fires.
• Current standards require the passing of the screening test.
• Seven out of eight samples must pass the test.
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Test for Spreading Flames
• NFPA 253: Standard Method of Test for Critical Radiant Flux of Floor Covering Systems Using a Radiant Heat Energy Source
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Radiant Flux Test
• Radiant Flux Test (NFPA 253) measures resistance to flame spread.
• Test gives the critical radiant flux (CRF) of the sample.
• The higher the CRF number, the less flammable the carpeting
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Classes of Interior Floor Finish Ratings
• Class I: ≥ CRF minimum of 0.45 watt/sq cm
• Class II: ≥ CRF minimum of 0.22 watt/sq cm
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Don’t Be Mousetrapped
• Be wary of conducting your own tests.
• Leave testing to the experts.
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Research
• Present efforts to improve building codes
• Continued challenges
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Fire and Smoke Containment
• Products of Combustion
• Distinctions must be made among smoke, particles, and fire gases.
• Smoke and toxic gases are more significant as fire killers than is thermal exposure.
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Smoke
• First warning of most fires
• Does considerable damage
• May reduces visibility to zero
5
Gases
• Can cause injury or death
• Carbon monoxide (CO) can paralyze or slow human ability to function or escape.
• Hydrogen Cyanide (HCN) is as great a danger as CO.
5
Toxic Effect of Gas
• A product of concentration and exposure time
• Habel’s Rule
• CO is the most common toxic fire gas.
5
Other Fire Gases
• Nitric acid and hydrochloric acid
• Polyvinyl chloride (PVC)
• Nitrocellulose base film in commercial motion pictures and x-rays
5
Flammability
• Gases can accumulate in any enclosed area.
• Overpressures occur when gases ignite.
• Gas ignites when sufficient oxygen is available.
• CO detonation can blow buildings apart.
• CO is flammable.
5
Smoke vs. Gases
• Have different physical effects on people.
• Old-style filter masks let odorless CO through.
• CO can stratify above a fire, creating death clouds.
• Smoke particles can plug up screens.
5
Smoke Damage
• Water damage is often considered the most expensive byproduct of fire suppression.
• Smoke damage may be the most expensive byproduct of a fire.
5
Contaminated Smoke
• Cost of cleanup can be astronomical.
• Radioactive material can damage living tissue.
• Polychlorinated biphenyls (PCBs)
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Corrosion
• Equipment, brickwork, and concrete can be damaged by corrosive products of combustion.
• Plastics can form corrosive acids when combined with hydrogen and oxygen.
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Gravity
• Pulls down on surrounding heavier, colder air, causing lighter, heated air to rise upward
• Gravity vents
• Mechanical vents
5
Containment of Fire (1 of 4)
• Compartmentation
• Creating fire areas no larger than one floor
• All connections between floors designed to stop the spread of fires.
5
Containment of Fire (2 of 4)
• Sprinklers above stairway openings
• Required by some fire departments
• No proof that this will prevent the extension of fire
• Will not stop smoke and gases
5
Containment of Fire (3 of 4)
• Self-closing doors
• Considered a nuisance
• Stairway doors are often blocked open with wooden wedges.
5
Containment of Fire (4 of 4)
• Enclosing stairways
• Open grand staircase was a crowning architectural feature.
• After 1940s, an effort was made to enclose open stairways.
• Stairway is a transmitter of smoke and heat.
5
Fire Door Closure Devices
• Self-closing
• Automatic
5
Inspections of Closure Devices
• Should include
• Operating fire doors and shutters
• Counterweights
• Doors
• Hardware
• Fusible links
5
Problems with Closure Devices
• Closure devices may be completely inadequate to control smoke movement.
• Many people block open self-closing doors.
5
Smoke-Sensitive Releases
• Door latch system can be triggered automatically.
• Heavy doors are held by mechanical latches.
• Doors can be controlled individually.
5
Horizontal Exits and Smoke Barriers
• Horizontal exits reduce travel distances and subdivide floors.
• Smoke barriers give occupants a smoke-free area
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Escalators
• Strong resistance to enclosing escalators
• Water spray nozzles can be directed downward through the opening.
• A line of sprinklers can be located around the escalators.
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Public Education
• Misinformation from movies and TV• Backdraft
• Defending Your Life
5
Smoke Detectors
• Detectors are often missing or out of service.
• Two types: ionization and photoelectric
• Fire protection and fire detection are not synonymous.
5
Unwarranted Alarms
• Alarms transmitted erroneously
• Some cities have instituted penalties for repeated, unwarranted alarms.
• Can be a disincentive for reporting a fire
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Ventilation (1 of 2)
• Compartmentation
• Can cut off a fire
• Can create unventilated compartments
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Ventilation (2 of 2)
• Makes building habitable for occupants and fire fighters
• New Law Tenement House Act
5
Fire
• Book published in 1903 included
• A design for automatic vents tripped by fusible links
• Exception to “Don’t vent till you have water.”
5
Theaters
• Designed so that a fire could occur and the occupants would be protected from the combustion products.
• Automatic vents above the stage reduce the pressure on the proscenium fire curtain.
5
Holland Tunnel
• Designed to reduce the maximum amount of CO that could be generated by auto exhausts to an acceptable level
• Airflow required would be 50 mph.
• Triple tunnel arrangement
5
Eurotunnel “Chunnel”
• A service tunnel between the two train tunnels is kept at a higher pressure than the train tunnels to exclude smoke.
• Access is provided through “smokeproof” doors.
5
Fire Department Ventilation
• Consisted of opening and breaking windows and cutting holes in the roof
• Smoke ejectors were developed to increase the volume of airflow.
• Fans were used to exhaust smoke, generally during overhaul.
5
Fire Protection Systems
• Automatic sprinkler systems
• Standpipe systems
• Fire Alarm detection and communication systems
• Smoke management systems
• Other fire protection systems
5
Automatic Sprinkler Systems
• Sprinklers were once almost exclusively installed in factory and mercantile buildings.
• Now, sprinkler designs have been developed specifically for multiple dwellings and single-family homes.
5
Types of Sprinkler Systems
• Wet pipe
• Dry pipe
• Preaction
• Deluge
5
Design and Operation of Sprinkler Systems
• Hydraulically designed
• Only a certain number of heads operating
• Each head flows a specific amount of water
• Prewetting
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Density and Demand
• Density is the unit rate of water application to an area or surface; expressed in gallons per minute per square foot (gpm/ft2)[(L/min)/m2].
• Demand area is the gpm/ft2 required within a sprinkler system.
5
Sprinkler Installation Incentives (1 of 3)
• Typical code incentives• Heights and areas
• Construction of corridors and tenant separations
• Interior finishes
• Travel distances to exits and exit widths
• Standpipe requirements
• Fire detection systems and draftstopping in attic spaces
5
Sprinkler Installation Incentives (2 of 3)
• Site development incentives• Fewer fire hydrants with greater spacing
• Reduced fire flow, small supply pipe
• Increased allowable distance from public access way
• Street width reduction
• Cul-de-sac allowances
5
Sprinkler Installation Incentives (3 of 3)
• Tax or insurance incentives• Elimination of value of sprinkler system from
assessed valuation
• Property tax rebates
• Elimination of water department fees
• Insurance premium reductions
5
Opposition to Sprinklers
• Not everyone supports automatic sprinklers.
• Some claim that sprinklers are ugly.
5
Popular Misconceptions About Sprinkler Systems (1 of 2)
• The sprinkler system will discharge on even a trifling fire.
• The entire building will be drowned when the sprinklers go off.
• The pulling of a manual fire alarm box will set off all the sprinklers.
• The pipes might leak.
5
Popular Misconceptions About Sprinkler Systems (2 of 2)
• Smoke is the big killer so smoke detectors are better than sprinklers.
• We have smoke detectors and the fire department is right down the block.
• Sprinklers cause damage to libraries.
• Smoke detectors set off all the sprinklers.
5
Fire Activities to Correct Erroneous Opinions
• Sprinkler demonstrations
• Sprinklers and flammable liquids
5
Fire Service Misconceptions (1 of 2)
• Building is sprinklered; there is no problem.
• Supplying the fire department connection (FDC) is a secondary operation.
5
Fire Service Misconceptions (2 of 2)
• Sprinklers should be shut down as soon as possible to prevent excessive water damage or to clear the air.
• Residential sprinklers are the same as other sprinkler systems.
5
The Fire Department and Sprinklers
• Fire chiefs support automatic sprinklers.
• Sprinkler protection often is traded off for concessions.
• Fire department should take action when notified of a sprinkler shutoff or other disabling functions.
5
Non-Working Sprinklers
• What should happen when the fire department learns that a sprinkler system is out of service?
• Fire department should have no hesitation in shutting a building until sprinklers are fixed.
5
Why Were Sprinklers Installed?
• Determine reasons for installation.
• What might happen if system not working?
• Don’t hesitate to close building until system problems are corrected.
5
Fire Department Policy
• Fire department notification
• Formal legal action
• Informal action
• Authority to modify requirements
• Formal personnel instruction
5
Fire Department Instruction
• Should provide an understanding of why sprinklers were installed
• Should cover fire department policy
• Should provide knowledge of situations that decrease efficiency of sprinklers
5
Company-Level Inspections
• Water supply or water distribution problems
• Some systems depend solely on the city water main pressure to provide adequate sprinkler flow.
5
Sprinkler Fraud
• A sprinkler contractor in California was discovered to have installed unconnected sprinklers that were simply glued to the ceiling.
• Inspection of sprinkler systems should look beyond the obvious.
5
Management
• Management is managing the fire department, rather than managing the fire problem.
• Have sprinkler system protocols in your standard operating procedures (SOPs).
5
Special Situations• Most flammable liquids float on water. • Flammable liquids have a high Btu (British
thermal unit) content.• Flammable liquid containers can result in a
BLEVE (boiling liquid expanding vapor explosion).
• Runoff water may create a significant contamination problem.
5
Protection of Glass Fire Barriers
• Wetting must occur early to avoid thermal shock to hot glass.
• Window treatments should not be installed between the glass and the sprinklers.
5
Early Suppression Fast Response (ESFR) Sprinklers
• Early discharge of a larger quantity of water
• Sprinkler orifice is 0.75 inches; conventional sprinklers are 0.5 inches.
5
Standpipe Systems
• Fixed networks of piping and hose valves
• Installed in tall and/or large buildings to provide quick fire attack
• Classes are I through III.
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Standpipe Operations
• Class I through III used throughout 1980s.
• One Meridian Plaza fire
• Need for thorough preplanning
5
Standpipes Water Supply Classifications
• Automatic-wet standpipe system
• Semiautomatic-dry standpipe system
• Manual-dry standpipe system
• Manual-wet standpipe system
5
NFPA 72: National Fire Alarm Code Initiating Devices (1 of 2)
• Manual pull stations
• Spot type smoke detectors
• Line type smoke detectors
• Duct smoke detectors
• Spot type heat detectors
5
NFPA 72: National Fire Alarm Code Initiating Devices (2 of 2)
• Line type heat detectors
• Gas detectors
• Flame detectors
• Water flow switches and water pressure switches
• Supervisory switches
5
Indicating Devices
• Strobes, horns, chimes, buzzers, and sirens
• Speakers and lamps
5
Panels
• No design standards
• Small red and yellow lights may give you information.
• Devices often are grouped by zones.
• Fire alarm systems that are positioned with fire fighter communication systems are not very useful.
5
Preplanning Considerations
• Area(s) protected by the system
• Types of detection and other initiating devices
• Location of alarm panel and any remote annunciators
• Type of panel and type of zoning
• Silence switch
5
Smoke Management Systems
• Smoke control
• Purge
• Zoned smoke control
• Air flow
• Original design and testing criteria
5
Design Requirements and Guidelines
• International Building Code
• NFPA 92A
• NFPA 92B
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Control Panel
• Most use toggle switches to turn on/off various parts of the system
• Beware of a wrong flip of a switch.
5
Preplanning Knowledge• System and the type of smoke
management
• Location and extent of system
• System design criteria
• A step-by-step sequence of system operation
• Location and description of control panel
5
Firefighting Considerations
• Assess the system operation.
• When activating a system manually, let all fire fighters know so they will not be endangered.
• Leave a fire fighter with a radio at the system controls.
5
Other Fire Protection Systems
• Dry chemical and foam
• Carbon dioxide and clean agent
• Halon
• Water mist or water spray
• Total flooding or local
5
Summary (1 of 3)
• Fire containment is a primary objective of fire fighters.
• Terms describing combustibility and flammability are not always used accurately or in a technically accurate way.
5
Summary (2 of 3)
• Collapsing buildings are a hazard to fire fighters, but concealed fires and rapid fire spread are also very hazardous.
• Fire growth and spread are influenced by building construction.
• Fire loads and rates of heat release are higher today.
Summary (3 of 3)
• Compartmentation creates fire areas no larger than one floor.
• Venting makes the conditions inside a fire building somewhat habitable.
• Fire suppression and detection systems are critical to fire protection.