Safety and Survival on the Fireground-CH.22_split_1.pdf

22 FIRE HAZARD IDENTIFICATION At the beginning of this book, a risk/frequency matrix evaluated firefighting tactics in a visual way to show that some firefighting assignments are more danger- ous than others. In addition to our tactical operation dang...

22 FIRE HAZARD IDENTIFICATION At the beginning of this book, a risk/frequency matrix evaluated firefighting tactics in a visual way to show that some firefighting assignments are more danger- ous than others. In addition to our tactical operation dangers, a burning building environment provides its own dangers. We must never forget the fire environmentisa deadly place and an uncontrollable environment. The closest thing to the fireground is a battleground. THIRTEEN FIRE ENVIRONMENT DANGERS The dangers of a fire environment include explosion, collapse, fall hazards, falling objects, rollover, flameover, flashover, backdraft, fire, smoke, heat, disorientation, and electrocution. These perilous dangers are part of a firefighter’s everyday workplace; they threaten every firefighter, performing every fire task, at every fire. Any of these deadly hazards can kill or injure a firefighter operating inside or outside of a burning building. Following are some facts about these 13 deadly fireground hazards: 1. Gas explosion happens instantly, with no warning. Explosions are often caused by leaking natural gas, propane tank blasts (boiling liquid expand- ing vapor explosion), and backdrafts (fig. 22-1). During an explosion there are shock waves, flying shards of glass and other shrapnel, structure collapse, and fire spread.’ 349 AND ASSESSMENT SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition n. 2. Collapse of burning buildings often kills more than one firefighter. Most firefighters die from floor, roof, wall, and ceiling collapse, in that order. When an entire building collapses, it is a global collapse (fig. 22-2). 350 2l Two firefighters caught in the fireball of a propane gas explosic.. e T Sliprari A structure collapse often kills more than one firefighter.  Chapter22 | Fire Hazard Identification and Assessment 3. While firefighters can fall climbing fire escapes, ladders, and during roof operations, sometimes suffering serious injury or death, most falls on the fireground occur at ground level (fig. 22-3). Falls from slips and tripping are leading causes of death and injury in society at large. In darkness and smoke, firefighters trip over objects or slip on ice rushing to get into posi- tion to fight a fire. Tunnel vision due to stress can blind firefighters to tripping hazards, as can working in darkness, in poor weather conditions, and when blinded by smoke. Wl INWS W YV INE D WIS WI WIS Wl Wi 1 WJFIND.3 VY EIWE ] WAl Il.3 i WSS WS Wl 351 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition 4. Objects falling from buildings kill and injure firefighters working around the perimeter of a burning building. Building fragments, falling glass, shingles, chimney tops, thrown objects, falling people, dropped tools, and burned objects thrown from heights are all classified as falling objects. To protect themselves against falling objects, firefighters should either go inside the building during offensive operations or stay outside the collapse zone around the perimeter during defensive operations. Before anything is thrown from a window, the incident commander must assign a firefighter guide at street level (fig. 22-4). 352 S8 Falling objects are a danger around the perimeter of a burning building.  Chapter22 | Fire Hazard Identification and Assessment 5. Rollover is one of the three flash phenomena, the other two being flameover and flashover. Rollover can happen before flashover and is considered a warning sign that flashover may follow. Rollover is flashes of flame mixed with smoke at ceiling level or extending from the top of a door or window opening (fig. 22-5). 353 Rollover is a warning sign of flashover. SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition 6. Flameover is rapid flame spreading over the surface of walls, ceilings, and/ or floors of a burning building caused by flammable coatings or cover- ings such as oil-based paints or wall or ceiling coverings made of plastics (fig. 22-6). It is a rapidly spreading surface fire that can cause large life loss during fires in public assembly buildings or high-density occupancies.? 354  ceilings, %) i = © = = =} @ o © AL — 2 ] ) £ 5 — @ > o o = =] @© o} — a ) © E ) - = h=y a © — 2 — ) > [} m T Q9 L o Fig.22-6  Chapter22 | Fire Hazard Identification and Assessment 7. Flashover is a term used to describe a smoke-filled room that suddenly bursts into flame. The trigger for flashover is heat; the heat buildup and re-radiation back into a room filled with combustible smoke. Flashover usually happens during the growth stage of a fire. The temperature in a room during flashover can reach 1,000°F (fig. 22-7). - e 355 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition 8. A backdraft is a smoke explosion triggered by the sudden introduction of oxygen. A backdraft explosion can occur when searching firefighters enter a smoke-filled room and introduce fresh air to an oxygen-deficient atmo- sphere of combustible smoke particles; a combination of pyrolyzate, carbon monoxide, and heat (fig. 22-8). 356 A backdraft is a smoke explosion.  Chapter22 | Fire Hazard Identification and Assessment 9. Fire traps and kills firefighters. The mantra is “firefighters should not pass fire or go above a fire.” Flame can cut off escape routes and trap and kill those who forget this warning during firefighting operations (fig. 22-9). 357 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition 10. Smoke is what actually kills most people trapped in fire (fig. 22-10). Smoke is the solid particles of soot produced by combustion and held aloft and combined with the gases released from heating or burning material. Smoke obscures vision and can cause firefighters to become disoriented and trapped in fire, it is toxic and hot, and it can explode and cause burns.? ghters trapped in fire. 11. Heat of a fire increases a firefighter’s body temperature and causes stress- related injuries including heart attack, heat stroke, heat exhaustion, and hyperthermia. Protective clothing cannot stop heat. Rotating firefighters to a rehabilitation unit for temporary rest periods during a fire protects fire- fighters from heat exhaustion (fig. 22-11). iS No PO - I (-3 358 slsplsl Smoke kills both victims and firef  Chapter22 | Fire Hazard Identification and Assessment 12. Disorientation is defined as the loss of direction due to the loss ofvision or visual clues about the surrounding environment. Disorientation during firefighting can result from darkness, smoke, and a structure’s maze-like partitions of interior spaces. Firefighters who lose their sense of direction searching in smoke can be caught and trapped by fire and smoke or buried in a collapse (fig. 22-12). 13. Electric shock is a fireground killer both inside and outside a burning build- ing. Firefighters using metal ladders, tools, and hose streams near overhead wires are in the greatest danger of electrocution. Electric utilities should be shut down by utility personnel before overhauling begins, not by firefight- ers. The action shown in figure 21-13 is obviously an unsafe act. Some of the 13 fireground hazards listed above are more dangerous than others; some happen more frequently than others. A risk assessment of degree of danger and frequency of occurrence will further help us evaluate our work hazards. Firefighters identify the dangers first. They then determine which hazards are more dangerous and which are less hazardous, and can evaluate which hazards are more likely to occur during a fire and which are less likely to occur. The following are two lists of fireground hazards: one shows degree of danger, the other shows the frequency of occurrence. 359 sl vi Disorientation is the loss of direction. SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition 1 000w I/ Wil W ISl W Wi e Degree of danger The following lists the estimated degree of danger during structural firefighting in an urban area population of over 250,000 from highest (1) to lowest (13). The variables considered in this prioritization are as follows: speed of occurrence, area of hazardous event, warning signs before event, frequency of occurrence, effectiveness of firefighter protection equipment, and defensive measures known and trained for. Gas explosion—shock waves, shrapnel, fire, collapse Db Electrocution—voice immobilization, locked muscles Collapse—frequency of collapse of floor, wall, roof Fire—caught and trapped beyond and above flames Nk Heat stress—heart attack, hyperthermia, exhaustion Flashover—1000°F heat, burns, the point of no return o Disorientation—falls, asphyxiation, burns N Smoke—carbon monoxide inhalation, heat, disorientation Falls and slips—surfaces, stairs, ladders Y Falling objects—perimeter of building danger area pk < Backdraft explosion—investigation, gas, arson, BLEVE [ P 360  Chapter22 | Fire Hazard Identification and Assessment 12. Rollover—size-up, warning sign of flashover 13. Flameover—stairs, hall, lobby, means of egress, danger area Frequency of danger In the following list, the estimated frequency of occurrence of fire dangers on structure firefighting in an urban area with population of over 250,000 are shown from most frequent (1) to least frequent (13). Falls Lk Heat stress Falling objects Smoke inhalation Rollover Disorientation NS Fire Flashover WX Electric shock Collapse pk <. Gas explosion (WY (WY Backdraft pk b 13. Flameover The risk and frequency matrix graph in figure 21-14 further illustrates the above lists of degree of danger and frequency of occurrence. It can be used as part of a risk management plan to help identify, recognize, and evaluate actual and potential fire- ground hazards. This should be only a first step effort to evaluate fire dangers; the frequency and degree ofdangers stated here are only estimates. Use this graph to help initiate discussions about the dangers and to better evaluate these fireground risks in your fire department. Your safety officers should review, modify, and update this risk graph to reflect the death and injury experiences in your response area. 361 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition High Frequency Less Risk High Risk Smoke n Disorientation Flashover Ellectric shock Backdraft (smoke) explosion ) Gas explosion f] collapse ([} Flameover m Low Frequency Imn Risk/frequency graph of fireground hazards TACTICS FOR AVOIDING FIREGROUND ENVIRONMENT DANGERS Now that we better understand the list ofmost common hazards, their frequency ofoccurrence, and their degree ofdanger, let’s look at each one and go over some tips to help firefighters avoid them. 362  Chapter22 | Fire Hazard Identification and Assessment NUMBER 1—EXPLOSIONS Explosions are part of the deadly, uncontrolled environment called the fire- ground. Fire protection engineers define the term explosion as an effect produced by a sudden and violent expansion of gases. An explosion can produce a loud blast, shock waves, searing heat, balls offlame, and flying glass and shrapnel. Fire protection engineers group explosions into three broad categories: e Physical explosions e Physical/chemical explosions e Chemical explosions A water heater boiler rupture would be a physical explosion. The container would rupture but there would be no ensuing explosion ofthe content (the water). A propane cylinder BLEVE (boiling liquid expanding vapor explosion) would be a physical/chem- ical explosion. There would be a physical explosion—a rupture of the cylinder—and then an instant chemical explosion ofthe flammable propane. A smoke (or backdraft) explosion would be classified as a chemical explosion: the smoke and gas that react with oxygen and heat in a burning room. The chemical reaction and explosive ingredients present in a natural gas explo- sion are the same as in any ordinary combustion explosion: fuel, oxygen, and heat. For example, the fuel in a combustion engine explosion driving an automobile is gasoline. The fuel in a gas explosion might be methane or some other flammable gas. The fuel in a backdraft or smoke explosion is the by-product of incomplete combus- tion—carbon monoxide (CO). CO has an explosive range of from 12% to 74% when mixed with air. There are many types of explosion at fires. Firefighters operate at manhole explo- sions, gas main explosions, flammable liquid and gas cylinder explosions, oil burner explosions, vehicle gas tank explosions, terrorist bomb explosions, and smoke explo- sions. The four most common explosions at structure fires are explosions caused by leaking gas piping, BLEVES of propane gas cylinders, flammable vapors released from an arsonist’s accelerant, and bombs. Smoke explosions are much less common. Before a fire investigator declares the cause of an explosion at a structure fire, he or she must rule out all other possibilities. For example, if the gas piping is intact, there are no ruptured propane cylinders found, and there are no traces of an accelerant flammable liquid residue or bomb fragments, then the explosion may be recorded as a smoke explosion (backdraft). There are three important facts firefighters should know about any type ofexplo- sion. One is that a room or fire area that explodes requires only 25% of its space to contain the explosive mixture. If the explosive mixture is in one corner of a large, smoke-filled room, the entire area could explode when firefighters enter to search, allowing fresh air to enter with them. A second fact firefighters should know is that it does not take much explosive pressure to cause destruction and death. The higher the peak pressure developed 363 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition by the explosion, the more deadly the blast.* Listed below are the destructive effects caused by explosion pressures: Effect ofExplosion Destructive Peak Pressure Glass shattering 0-5 psi Firefighter knock down 1 psi Wood partition collapse 1-2 psi Cinder block wall collapse 2-3 psi Brick wall collapse 7-8 psi Firefighter lung damage 15 psi Threshold for fatalities 35 psi 50% fatalities 50 psi 99% fatalities 6S psi A third fact firefighters should know about explosions is there are several phases of an explosion. In the first phase is the original shock wave blast of the explosion; next is the flying shrapnel of the exploding container; third is the blast, carrying with it parts of enclosing walls, roof, floors, doors, windows, and ceilings. At ground zero, whether from a terrorist bomb or an explosion in a manhole between buildings, the shock waves of the blast rise up and outward. In some cases, a vacuum and implosion may be created, causing atmospheric pressure inside nearby buildings to blow out glass and walls back onto the sidewalk and street. And finally, firefighters should know that the generated heat of a blast may cause secondary fires and secondary structural collapse. Ground shock waves may break gas, water, electric, and sewer pipes, and subway tunnels and building foundations are sometimes affected. Firefighting tips when operating at potential explosions 1. Explosions happen suddenly and are unpredictable. They cannot be prevented during a fire. Explosions are a constant part of firefighter’s work environment. 2. Firefighters are trained when fighting gas fires to shut off the supply and let the fire burn. Never extinguish a gas fire with a hose stream. Let the gas fire burn and protect exposures from fire until the gas can be shut off. 3. Before overhauling begins, gas and electric supplies should be shut off. Fire- fighters should be aware of the smell of leaking gas at any fire and report this to the incident commander. During a serious fire, gas pipe joints may fail and leak gas. 4. When encountering a burning propane cylinder, to prevent a BLEVE, follow these steps: a. Cool the vapor space in the upper portion of the cylinder. b. Shut off the gas by the control handle if possible. 364  Chapter22 | Fire Hazard Identification and Assessment c. If the flow of burning gas cannot be shut off; allow the propane to burn after withdrawing everyone to a safe distance. After a fire is extinguished, if flammable liquid residue left by an arsonist is discovered in the burned-out rubble, firefighters should not disturb the area. Instead, withdraw, do not overhaul, and notify the fire investigators to respond. Firefighters should identify the occupancies where explosions are most likely to occur and develop preplan strategies. These preplans must include specific methods of horizontal and vertical venting. Explosion occurs in store occupancies more than in residence occupancies. Stores that are more likely to contain explosive and flammable solids, liquids, and gases are paint stores, hardware stores, woodworking shops, motor vehicle garages, restau- rant kitchens, construction shacks, flower and garden shops, and stores under renovation. Occupancies containing an explosion potential should be required to install fire extinguishing systems. When manhole or sewer covers in a street are emitting smoke and popping off, firefighters should stretch a hose and stand a safe distance away from all nearby manhole covers. Do not park fire apparatus in the street near other covers. Check nearby cellars for fire origin or spread to or from the street manhole through electric or gas conduits in the utility room. Call the utility company to the scene and have firefighters await electric supply shut- off before extinguishment. When extinguishing a vehicle fire and the vehicle has the potential to explode, use the reach of a hose stream and stand away from fuel tanks and explosive bumpers. When an explosive such as a stick of dynamite or terrorist bomb or device is found at the scene of a fire or emergency, firefighters should not disturb the explosive. Instead, evacuate the civilians, withdraw all fire personnel to a safe area, notify the bomb squad, and stretch a hoseline in preparation for an explosion, collapse, and fire. 10. When taking precautions against possible explosion, shrapnel should be foremost in the minds of firefighters operating at a scene of a potential explosion. Realize that flying fragments such as glass, brick, and shards of splintered wood and glass cause the most injuries. All protective cloth- ing should be worn. The perimeter of a burning building is a deadly area. A high peak pressure explosion will collapse walls out into the street. Firefighters should be away from a building a distance at least equal to the twice the height of the building wall to have a chance of surviving an explosion. It is rare to know when or if an explosion may occur during a fire operation; however, when there is a definite warning or evidence of an explosion about to occur, firefighters should evacuate the area completely. NFPA recommends withdrawing 2,000 ft away from the area.’ If this is not possible, take cover around a corner structure or behind a building or fire apparatus. Explosion protection of last resort is a firefighter’s full protective 365 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition gear. A helmet, eye shield, hood, gloves, boots, bunker pants, coat, and face mask may be hot, cumbersome, and slow you down, but if you are caught in an explosion, they may mean your survival. NUMBER 2—ELECTROCUTION The Occupational Safety and Health Agency (OSHA) has tips for firefighters when working near fires in and around electrical equipment: e Shut off the electric power before extinguishment. e Assume that all electric wiring in a burned-out building is energized at lethal voltages. e Stay at least 10 ft (3 m) away from overhead wires. e When raising aerial or ground ladders, first survey the overhead area for the presence of overhead wires before raising. e Ifan overhead wire falls across a moving fire vehicle when responding, drive away from the fallen line. If the fire truck is positioned and cannot be moved, do not leave the vehicle. e Never operate near electrical equipment while you are standing in water. Shut off utilities before overhauling. Firefighters electrocuted while fighting fires are often raising metal ladders or using metal tools near line electricity. Although much information is written about use of hose streams near electric equipment, it is raising, operating on, or moving metal aerials near overhead wires that kills most firefighters on the fireground. Follow- ing are just two examples of firefighters being electrocuted: o A firefighter was electrocuted when repositioning a metal ground ladder and it struck an overhead wire. e Three firefighters were carrying the ladder vertically; one slipped on ice, causing the ladder to sway and the tip to hit a nearby overhead electric wire on a utility pole. Two of the firefighters were electrocuted. Before starting to raise aerial ladders or ground ladders, survey the area for the presence of overhead wires. In most instances, electric overhead power cannot be shut down during the early stages ofa fire. When there is a working structure fire, an electrician from the local utility company should be called to respond and report to the officer in command. The utility company employee should be equipped and know how to remove power to a burning building by disconnecting wires from a utility pole or street shutoff. When a utility company cannot guarantee 24-hour, 7-day-a-week availability to respond to fires, they should be requested to provide training for firefighters on how to safely and effectively perform the procedure. These trained firefighters should then be certified by the utility company. 366  Chapter22 | Fire Hazard Identification and Assessment At a structure fire, electric power should remain on for as long as safety permits. Electricity provides power for lights, which assists search and rescue operations and visibility at night, and it keeps fire pumps running for fire extinguishment and eleva- tors operating ifneeded by firefighters for firefighting and evacuation. However, there are certain times during a fire or emergency operation when electric power must be immediately removed to protect firefighters and trapped victims. 1. At most fires, electricity should be cut off before overhaul starts. Normal current in a residential building can kill firefighters. During overhaul, walls, ceilings, and floors are sometimes opened in order to search for hidden fire. Metal tools can come in contact with electric wires behind these walls and ceilings. Firefighters standing on a wet floor in a burned-out room can entangle their metal tools in a live wire, causing the person to be elec- trocuted or severely shocked. Thus, after a fire is extinguished and before overhaul is about to start, electric power should be shut off. 2. When electricity is the source of heat causing the fire, power must be immediately cut off. Also, if a victim is being electrocuted, power must be removed from the wire or appliance before the person can be safely aided. To handle this type of fire or emergency, firefighters must be trained to safely shut off electricity to residential buildings. Utility companies cannot respond quickly enough to do the job. 3. After an explosion, power should be shut off before collapse search and rescue begins. Explosions can cause structural collapse, ripping open walls, ceilings, and floors of a structure. Live electric wires are often threaded throughout the rubble, hanging dangerously in midair, and lying on the ground. When shutting electric power offbefore overhauling, the fire officer should limit the area ofelectric power loss to as small an area as possible: one room, one apartment, one floor, one building section. Also, the electric power should be cut off as near the area ofoperations as possible. For example, first consider removing apartment fuses or opening circuit breakers. If this is not possible, consider shutting off the power from apartment’s electrical panel, or if necessary shut the electricity off from the electric panel box in the basement. Only utility company employees or trained firefighters should be permitted to pull meters outside a residence or cut electric wires. Firefighters ordered to remove electric power should know the hazards they face. For example, firefighters sent to a dark or smoky basement to pull the switch on an electric panel box have been severely injured by walking into live electrical equipment. If the cover to the electric equipment has been left open or removed, firefighters who come in contact with the equipment can be burned or electrocuted. Also, when pulling the switch to open the circuit, if the cover to the electrical panel is open or removed, an arc or electric flame can explode outward and burn the firefighters standing in front of the panel box. To protect yourself when pulling a switch to an electric panel box, use a light to locate the box, make sure the panel box cover is closed, and stand away from the electric panel. After the switch is opened, an arc explosion inside the enclosed box 367 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition can blow the cover or panel off the wall. Eye shields should be donned or an SCBA face mask worn. Meters outside private dwellings should only be removed when life is threatened and the inside service switch box in the basement cannot be reached; there is a real danger ofarcing during the meter removal from the panel. Actually, whenever electric current is interrupted, an arc can be produced. The arc is an explosion, like a flash ofblinding light, that can be accompanied by hot sparks and splattering molten metal. Safety precautions used by utility company personnel when pulling meters outside a private dwelling include using protective linesman gloves, eye shields, rubber matting or dry wood surfaces to isolate the worker from grounding, and keeping the face and body away from the meter in case there is an arc. A study by the Occupational Safety and Health Agency revealed that incidents of electrocution occur most often around normal house current of 110 to 120 volts. The study also revealed that many personnel did not realize that contact with 110/120 volts could cause death. Fire departments should establish preplanned emergency responses with local utility companies or determine whether they should train and certify firefighters to perform these tasks. NUMBER 3—COLLAPSE A study by the National Fire Protection Association (NFPA) titled “Fire Ground Fatalities as a Result of Structural Collapse: 1990-1999” revealed that 56 firefighters died in burning building collapses during that 10-year period.® The causes ofcollapse showed that floor collapse was the most deadly, killing 21 firefighters. The next most deadly type ofburning building collapse was roofcollapse, killing 19 firefighters. Then came wall collapse, killing 14 firefighters operating around the outside of burning buildings. And finally, ceiling collapse killed 2 firefighters. An important discovery of this study about structural failure during fire operations is of the 19 firefighters who died from roof collapse, 15 were operating inside the building—the roof came crashing down and trapped them. These firefighters were searching and operating hoselines below the roof, inside the building. Firefighters must realize that the inside of a burning building is the most deadly area on the fireground; it is much more deadly than operating on the roof or around the perimeter of the burning building. In addition to knowing what parts of a burning building collapse and kill fire- fighters, they must know how different types ofbuilding construction fail during fire. The following are the specific recurring collapse hazards associated with each of the five basic construction types. Type Il: Fire resistive—floor collapse The collapse danger ofType I fire resistive buildings is chiefly floor collapse. In a skeleton steel, high-rise, fire resistive building, the floor is constructed oflight gauge corrugated steel sheets that support several inches of concrete floor. Steel beams 368  Chapter22 | Fire Hazard Identification and Assessment spaced 10 or 12 ft apart support the corrugated steel. At a serious fire in a fire resis- tive building, first the ceiling collapses and flames attack the underside of the floor. If the spray-on fire retardant is absent or falls off, the steel beams buckle, warp, and sag when heated to 1,100°F. Then the concrete floor sections above crack and collapse, either heaving upward or sagging downward. Floors may sag 6 to 12 in. at the center span between the supporting beams below. Ifthe fire burns for several hours, the floor sections can collapse down into the floor below. Flames may spread vertically in a fire resistive building through the cracked and sagging floors. At a high-rise fire in New York City in 1993, in a fire resistive office building, a fire officer searching the floor above the blaze reported that drawers to file cabinets suddenly started to open. Entire lengths of files rolled outward, fully exposing file folders. After the fire was extinguished, the cause was found to be due to sagging and collapsing floors. As the concrete and steel floor sections sagged downward, the file cabinet drawers slanted downward and the pull of gravity opened the doors and roiled them out. In Quebec, Canada an entire slab of concrete collapsed down to the floor below during a fire in a fire resistive high-rise building. Whena fire officer searching the floor above a serious fire in a fire resistive build- ing discovers cracked or sagging floors, small flames rising through broken sections of flooring, or concrete floor heaved up several inches, he or she must recognize these as collapse warning signs. This information should be reported to the officer in command and all firefighters ordered off the floor above the fire into the stairway enclosure to operate hand lines, and/or the entire building should be evacuated and outside master streams used to extinguish the fire. Type ll: Noncombustible—roof collapse The collapse danger of a Type II noncombustible building is roof collapse. In a noncombustible building, the roof usually consists of layers of felt paper insulation, asphalt waterproofing, and corrugated steel sheet roof deck, all supported by light- weight steel bar joists. An unprotected lightweight steel bar joist truss can collapse after 5 to 10 minutes of fire exposure. This rapid failure rate of bar joists has been reported in the NFPA Handbook for the past 50 years. (Steel bar joist was the floor construction ofthe twin World Trade Center towers that collapsed so rapidly on 9/11.) This is an extremely unsafe roof during a fire. Flames attacking the lightweight steel bar joist can cause it to rapidly sag, warp, and collapse downward. The spray-on fire retardant does not adhere well to the thin round bars of the truss. The roof deck above a fire can then collapse in sections depending on the number of lightweight trusses that fail. A section of roof deck will hinge downward and firefighters operat- ing on the roofwill slide down the sloping roof deck into the fire or become trapped inside the burning building. Safe operating practices recommend, “If the fire is serious enough to require roof venting, then it is too dangerous to go on top of the roof.” When a fire involves a Type II noncombustible building and venting is required, there are other options. Fire offi- cers should instead use horizontal venting techniques. Open up doors and windows on two or more sides, or use mechanical fans to vent smoke and heat. When horizontal 369 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition ventilation is ineffective, the incident commander should withdraw firefighters and extinguish the fire using an outside attack with master streams. Life safety is more important than fire containment or saving property. Type lll: Ordinary—wall collapse The collapse danger of a Type III ordinary constructed building is wall collapse. Masonry walls of a Type III ordinary constructed building can be 4, 8, or 12 in. thick and made of brick, concrete block, or stone bonded with mortar. Masonry walls fail during a fire because the interior structural framework fails, shifts, or expands, and this pushes out a wall. In other words, the interior of a burning building causes the exterior to collapse. A brick wall is 50 times stronger in resisting compression (down- ward) loads than tension (horizontal) loads. Masonry walls are designed to resist loads applied from the top, not from the side. A lateral load or side pressure will collapse a wall, a vertical or top load will not. For example, brick parapet walls, which are exterior walls that extend above a roof, often collapse during fires. Extending several feet above the roof, a parapet wall is a freestanding unstable wall. These walls are sometimes weakened even before a fire occurs as they are exposed on three sides—front, top, and rear—to rain and wind that weaken the mortar between the bricks over the years. Even a strong gust of wind can collapse a parapet wall. During a fire in a one-story row of stores, when the roofburns and the interior structural framework shifts, or if there is a backdraft or explosion, the parapet wall can collapse. Parapet walls should always be checked for stability. If necessary, a collapse danger zone should be established. Firefighters should be withdrawn from an unstable wall for a distance equal to at least the height of the wall and up to twice the height. For example, if the wall is 20 ft high, firefighters should operate hose streams 30 to 40 ft away from the wall. If the wall suddenly collapses, firefighters will be outside the danger zone. Bricks may roll outward beyond the zone, but the falling wall will crash down within the collapse danger zone established, not on top of the firefighters. Type IV: Heavy timber—structure framing and wall collapse The collapse danger of a Type IV heavy timber building lies in structural frame- work collapse. The structural frame of a Type IV heavy timber building consists of wood columns not less than 8 in. thick, wood beams not less than 6 in. thick, and wood floors not less than 4 in. thick. The weakest points ofthe heavy timber structure are the connections and joints. Duringa fire, the connections fail before the timber does. The structural framework of a heavy timber building can be of solid wood trusses or glued laminated lumber. Trusses of glued laminated lumber have more connecting points than solid timber. Ifa fire is not extinguished inside a heavy timber building by an interior attack and the flames spread from floor to floor, an explosive fire will occur, requiring firefighters to be withdrawn to safety. The radiated heat from a fully involved heavy timber build- 370  Chapter22 | Fire Hazard Identification and Assessment ing is tremendous. Withdrawal offirefighters and apparatus and protecting exposures is the strategy used when an interior attack fails. During a fully involved, heavy timber building fire, when all floors are freely burning, the structural framework will fail. The floors will start to collapse and then the walls will fail, sending bricks and timbers crashing into the street and spraying chunks of masonry across side streets. Very few firefighters are killed by collapsing walls of heavy timber buildings because radiated heat waves from the fire forces them to withdraw a safe distance from the burning building. When we look at the fireground around a heavy timber building from a bird’s-eye view, we see there are four relatively safe areas in which to position fire trucks and master streams. Ifthe walls ofa heavy timber building collapse outward, the areas where the fewest bricks land are at each of the four corners. The probability of surviving a wall collapse is greater for firefighters ifthey position appa- ratus and operate master streams from these corner areas. If the corner section of a building appears unstable, however, withdraw from the area. Firefighters can still be killed by collapsing walls in these corner “safe” areas! Note that the weakest part of a masonry wall is the center, where the windows are located. Type V: Wood frame—wall and floor collapse The collapse danger of a Type V wood frame building is wall collapse. Unlike any other construction type, a wood frame building’s walls may burn and collapse when exposed to flame. Flames blowing out of a window and spreading up the combustible walls of a Type V wood frame building must be considered a collapse warning sign. The most dangerous wood frame building from a collapse point of view is a three- story, corner building known as a “triple decker.” Because of its height and the lack of support on the outside corner, when a fire occurs on a lower floor, all three or four sides of the structure collapse outward together then the floors pancake down on top of each other. Firefighters operating anywhere around a collapsing wood frame building can be buried by the wall falling outward. A wood frame building is the only burning building that can have three or four walls collapse outward simultaneously. When a collapse danger zone is established for a wood frame building, it must extend around the entire building. Fireground commanders must size up a fire building. We must know the parts and how each building type can collapse duringa fire. NUMBER 4—FIRE According to the U.S. Fire Administration, from 2000 through 2011, fire killed more than 3,000 men, women, and children and injured another 16,500 to 18,000 people each year. On average, more than 100 firefighters were killed annually during that period.” The dangers of fire are among the first things a firefighter must learn about in order to stay safe and perform the job. To survive in this profession we must 371 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition know everything there is to know about fire—the enemy. We must know exactly what fire is, how it spreads, how it can kill us, and how fire can be extinguished. Fire has several definitions. First, it is a chemical reaction, combining oxygen, fuel, and heat. Second, it is an oxidation reaction that emits heat and light. Third, it is called an exothermic reaction because it creates a substance—char and ash—that contains less energy than the original burned combustible material. Fourth, fire is called combustion and it produces four deadly products—heat, flame, smoke, and gases—that kill and injure people. There are two types of fire: flameless surface fire and flaming fire. Firefighters encounter flameless fire during overhauling. It is a smoldering, glowing, or deep- seated burning, generally found in porous materials. Upholstered furniture, cotton batting, coal, sawdust, and polyurethane foam mattresses can burn without flame. This type of smoldering or flameless fire can cause a fire to rekindle. A flaming type fire happens when a material is heated by an external source and emits combustible gases. If there is flame nearby, it could ignite these combustible gases. Once ignition occurs, flames grow and cover the area of the material that has been heated. The basic combustion process takes place in the area where the combustible gases mix with oxygen. The heat of these flames is passed offinto the atmosphere and radiated back to the material. If sufficient heat 1s radiated back to the combustible material, which some estimate as one-third, the fire will continue to burn and grow. If most of the heat is passed off into the atmosphere, the fire may go out. A fire that is growing inside a room has three identifiable stages: growth, fully developed, and decay. A fire may smolder for some time, but when it begins growing inside a room, a firefighter can use these three visible stages for risk assessment. The three stages of fire growth are usually measured by a time/temperature curve. In the first stage of a fire—the growth stage—an extreme upward temperature rise can be seen. A fire in a small room will complete the growth stage more quickly than a fire in a large room with the same fuel, oxygen supply, and shape. Oxygen supplied to a fire determines its rate ofburning: the more oxygen supplied, the faster the fire burns. Because of our goal of rapid response time, with the first fire unit’s arrival within 4 minutes, most fires we respond to and extinguish are in the growth stage and flash- over has not happened. The second stage of a fire—the fully developed stage—happens after flashover. It is observed in a time/temperature curve by the leveling off of the temperature rise. The highest temperature of a fire is reached in this second, or active flaming stage of combustion. When there is a delayed alarm, firefighters arrive during the fully devel- oped stage of the fire. Firefighting is more difficult now and the chances of rescuing survivors becomes less likely. If on arrival firefighters see the windows have been broken by the heat and flames can be seen, this fire is in the second stage of growth development, also known as the fully developed or active flaming phase. The time an uncontrolled fire remains in the second or fully developed stage depends on the amount ofcombustible material inside the room. While the duration ofthe first stage depends on the type offuel, oxygen, and size of room, the duration ofthe second stage is determined by how much fuel there is to burn. 372  Chapter22 | Fire Hazard Identification and Assessment The third stage of a fire—the decay stage—is shown as the downward portion of the time/temperature curve. This stage begins after most of the fuel in the room has burned and after the highest temperature is reached. After this peak, the tempera- ture starts to decline. The flames decrease in size and eventually only white smoke is produced by the remaining char and ashes. The duration of the decay stage depends on whether the fire burns out by itself slowly, or if the fire department extinguishes the blaze quickly. New research testing by the Underwriters Laboratories shows that with fires in the growth stage and not yet vented, the initial entry of firefighters opening a door to begin a search supplies oxygen to the fire and rapidly increases the growth rate up to flashover.® This research reinforces the need for the first arriving firefighters to coordinate searching and venting with the advance of the first hose team in order to reduce the danger of becoming caught and trapped by fire. Flashover, which signals the transition ofa room fire from the growth stage to the fully developed stage, is the most dangerous part of a fire and is one of the causes of firefighters becoming caught and trapped. This sudden conversion ofsmoke and heat into flame can be caused by a smoldering chair that ignites into flame and produces a column of smoke and heat up to the ceiling. The smoke and heat then extends outward along the underside of the ceiling to the outer walls of the room, at which point the smoke and heat start to descend downward. Now there is a transfer of heat from the descending superheated smoke into the ceiling and upper walls and in some cases a retransfer of this heat back into the burning room from the ceiling and upper walls. When this retransfer of heat, also known as radiation feedback, raises the temperature ofthe combustible gases and furnishings in the burning room to the autoignition temperature, flashover can occur. The room suddenly bursts into flame. Flashover doesn’t occur at every fire, but it is an ever-present danger that firefighters should be aware of. Rollover is a warning sign that flashover may occur. Rollover is fire department jargon used to describe the sporadic flashes offlame mixed with smoke that sometimes occurs at ceiling level, either in a hallway right outside a burning room’s doorway or extending out an open door or window. Rollover is caused by heated combustible gases, escaping through the door or window of a burning room, that mix with air. It usually precedes flashover, a more deadly event. Rollover sometimes occurs when a fire inside a room is in the growth stage and firefighters are still outside in a hall, wait- ing for the hoseline to be charged and about to attack the blaze. Firefighters should always check the smoke and heat above them that is escaping out of a doorway for rollover flames as the rollover may allow fire to spread behind them. Rollover may also trap firefighters searching on the floor above the fire. To prevent rollover when outside the burning room, close the door to the room if possible, preferably with a pike pole or at least a gloved hand. Rollover and high temperature smoke should be considered warning signs of flashover about to happen. 373 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition NUMBER 5—HEAT Heat buildup in the human body causes dehydration; it can also cause heat exhaustion, heat stroke, loss of consciousness, and cardiac arrest. Inhaled heat can asphyxiate by blockage of the respiratory tract due to swelling. Heat can cause death by hyperthermia when the body absorbs heat faster than it can be dissipated. And heat kills by burns. Third-degree burns over 50% of a firefighter’s body are usually fatal. What exactly is heat? Heat can be defined as a form of energy produced by accel- erated vibration of molecules or as a form of energy that raises temperature. Heat is measured by both quantity (amount) and intensity (temperature). For example, if the heat of two separate fires fills two rooms, one room twice as large as the other, and if both room temperatures reach 1,000°F, the rooms have the same heat intensity, but the larger room has twice the quantity of heat. Firefighters are mainly concerned with heat intensity. Heat temperature’s destruc- tive effects tell us valuable information about a fire. Heat in smoke is a warning sign of flashover about to happen. It also tells us we are getting close to the fire when searching in smoke. During an investigation, heat markings help us determine how a fire has spread and its origin. The following are important benchmark temperatures firefighters should know, published in the Fire Protection Handbook:’ e Most solid materials ignite and burn when heated to 572°F. e Ordinary single-pane window glass breaks and flames spread when the glass 1s heated to 550°F to 660°F; double-pane glass requires much higher temperatures to break. e Cast-iron columns heated to 800°F can collapse if struck by a hose stream. o DPrestressed concrete “spalls” (delaminates and breaks apart due to the expansion of entrapped moisture) at 800°F. o Steel fails at 1,000°F to 1,100°F. e Flashover occurs in a room heated to 1,100°F. ¢ The maximum room temperature at a fire involving ordinary furnishings ranges between 1,400°F and 1,800°F. e Wired-glass windows deform and drop out of their frames at 1,600°F. When we look at these temperatures that are reached at a fire and how they distort ordinary building materials and spread fire, we must realize the object that has the least resistance to the heat of a fire is a firefighter’s body. Our bodies can be injured by heat very quickly and at low relatively low temperatures. For example, studies by NFPA show the unprotected skin ofa firefighter suffers second-degree burns when exposed to 160°F for 60 seconds, 180°F for 30 seconds, or 212°F for 15 seconds. Also, that 300°F is considered the maximum survivable breathable temperature. One or two minutes of breathing air heated to 300°F after your tank runs out can burn the respiratory tract and cause death. 374  Chapter22 | Fire Hazard Identification and Assessment There are several visible color warning signs of superheated air that firefighters can use to help avoid injury: e The red or yellow flame of a flashover can be 1,000°F. e Black or brown smoke without flame found near the fire origin, called the hot smoke zone, can be S00°F to 1,000°F. e White steam, generated when a hose stream extinguishes a fire, can be 500°F and can conduct through a firefighter’s turnout, causing second- degree burns. When water absorbs heat it evaporates and expands into steam, expanding in volume 1,700 times. Steam is generated quickly during fire extinguishment by a hose stream, and if the steam expansion is not vented or contained, it will burn firefighters even if they are wearing bunker gear through what is known as a steam conduction burn. To illustrate this, consider a real event in which a rookie firefighter crawled inside an unvented, burning room in order to get a better angle for the hose stream and for a close approach before water was supplied to the nozzle. When water was finally supplied and the nozzle opened, the content fire was quickly extinguished but steam filled up the room and burned the firefighter through his turnout and hood. The lesson learned was that the fire room was not vented, and the expanding, confined steam burned the firefighter. The firefighter was also too aggressive with the hoseline advance. To avoid this type of steam burn, the incident commander should order fire- fighters to coordinate window venting with the advance of any hoseline. Venting will dissipate much of the steam buildup and prevent the confinement. Windows must be vented during a hoseline advance so heat can be released. Also, the hose attack team officer should order the hose stream to be directed to first hit the fire from the doorway. The standard operating procedure is “over your head, all around” initially with the stream to cool down the upper levels of the room where heat has stratified and let the venting work, then, when heat coming from the doorway subsides, advance into the room for final extinguishment. It is difficult to sense the heat of a fire through protective clothing. To reduce the danger of heat burn injuries—especially with firefighters wearing bunker gear, hoods, and masks—officers and experienced firefighters should encourage rookies to slow down. Remind them to use the reach of the hose stream. The objective is safety, not speed when advancing an attack hoseline. As many in the fire service agree, we have gone as far as possible with providing protective equipment to firefighters. Now we must look at our firefighting tactics. There should be a re-evaluation of our present, high-risk, aggressive firefighting tactics that were developed in the last century when a firefighter’s life was not considered a high priority. The heat of a fire causes severe burns. Burns are classified as first degree, second degree, and third degree. A first-degree burn involves only the outer layer of skin, and presents as red, painful, and swollen tissue due to an accumulation of fluids near the burn. Second-degree burns penetrate more deeply. Here the tissue of the burn area becomes pink, swollen, and blistered. A third-degree burn is the most serious burn as it penetrates beneath the skin. The burn area is dry, white, or charred. (Note: There 375 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition have been reports in the news media of firefighters receiving “fourth-degree bums,” described as burns destroying all skin down to the bone. The medical profession and first aid books do not recognize a fourth-degree burn; this is a media term only.) First- aid treatment for firefighters at a fire scene is the same for first- and second-degree burns: Immerse the burn area in cool water or run cool water over the burn area for 10 to 15 minutes, then dry and cover with a lint free, sterile dressing. First aid for third-degree burns involves wrapping the burn area in a sterile dressing and treating the victim for shock. Immediate medical attention is required. In an effort to reduce injuries due to heat stress, many fire departments have cre- ated rehabilitation (rehab) units. These units respond to the scene of an incident and allow firefighters to temporarily rest and receive treatment for heat exhaustion. They can also provide a mask change to firefighters before they go back into action. Rehab units aren’t intended to treat firefighters who are injured; injured firefighters are treated by medical personnel. At the rehab unit, firefighters can receive cooling treat- ment with ice-cold towels, cool water to replace body fluids, misting fans that help reduce body temperature, a shaded area for relieffrom exposure to the sun, or they can remove their fire gear and rest for several minutes before resuming firefighting. There is no protection from heat inside a burning building. Firefighters wear masks for protection from toxic smoke and fire-retardant turnout gear for protection against flame, but there is no protection against the effects ofheat. In fact, the protec- tive equipment we use to shield us from toxic smoke and flame increases our heat stress. To reduce the effects of heat exposure to firefighters, the incident commander may use one or all of the following procedures: 1. Grant a rest period when leaving the scene of a fire or emergency that has been an exhausting, long-duration operation. 2. After a fire is extinguished, have another company called to the scene to perform the overhaul or salvage work. 3. When releasing companies from the scene, allow the companies that were first arriving to leave first and keep the firefighters that arrived later to overhaul. 4. Call extra units to the scene of a fire or emergency in order to distribute work among more units or to relieve tired and exhausted firefighters. 5. Call the rehab unit before the need arises. NUMBER 6—FLASHOVER Flashover—sudden conversion of smoke and heat into flame—is the most danger- ous time of a fire. Firefighters are caught and trapped by flashover. Fire protection engineers tell us flashover is caused by radiation feedback; when heat being radi- ated back into a burning room raises the combustible gases and furnishings to their autoignition temperature, flashover occurs. The room suddenly bursts into flame. 376  Chapter22 | Fire Hazard Identification and Assessment When a growing fire goes from its first or growth stage to the second, fully developed stage, flashover may happen and this can be sudden, unexpected, and deadly for a searching firefighter. Flashover signals several dramatic changes in a fire: it is the end of an effective search and rescue in a room, it means the death of any person trapped in the blaz- ing room, and it ends the possibility of using a portable extinguisher to quench the fire. After a room flashes over and explodes into flame, an attack hoseline is required and windows must be vented to release heat. The fire is now in the fully developed or active flaming stage and changes from a contents fire to a structure fire; flames that began in the furnishings are now attacking the structure. This is the beginning of a collapse danger. When operating at a fire, the strategy of a fire officer is to delay flashover inside a burning room. By delaying flashover you can buy time, which may save lives. For example, you may want to delay flashover to make a search and rescue of the burning room or to allow firefighters to go above a fire to rescue a trapped victim. Or you may want to delay flashover if there is a delay in stretching the first attack hoseline. The following tactics can be used to help delay flashover; however, ifyou want to prevent a flashover, you must extinguish the fire with a hose stream. The best protection against flashover is to advance a hoseline discharging 180 gallons of water a minute on the fire. Three strategies to delay flashover e Venting. At a small content fire, venting windows can release the buildup of heat in room. Venting delays the fire’s radiation feedback process and also improves visibility by removing smoke. e Restricting venting. At a serious fire, restricting the amount of available oxygen by closing the door to the burning room can delay flashover. By not venting, you starve the fire of the oxygen it requires, which slows down the combustion rate, which in turn slows down the buildup of heat in the room. This strategy may be needed when there is a delay in stretching a hoseline and all persons are out of the burning room. At a serious fire, searching should be coordinated with hoseline advance. e Using a portable extinguisher. At a small content fire, the discharge of a portable extinguisher can temporarily reduce the amount of heat in a burn- ing room and delay flashover. Warning signs of flashover To avoid becoming trapped by a sudden flashover, firefighters must know the two warning signs: heat mixed with smoke and rollover. e Heat. When superheated smoke in a room forces firefighters to crouch down on hands and knees to get beneath the temperature stratification in 377 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition order to perform search and rescue, this must be considered a warning sign that flashover may occur. Heat 1s the triggering event for flashover—the radiation feedback from ceiling and walls. e Rollover. Rollover is defined as sporadic flashes of flame mixed with smoke at the ceiling level or extending out of a door or window of a burning room. Fire protection engineers tell us rollover is caused by heated combustible gases in smoke that ignite into flashes of flame when mixed with oxygen. There are two defensive search procedures that can be used to reduce the risk of death and injury from flashover. Both rely on limiting the distance firefighters enter into the area on fire when there are warning signs of flashover. The first procedure is used when entering from a doorway. In this case, the firefighter should check behind the door for victims, then enter the room no more than S ft. At that point, call out and listen for a response, at the same time sweeping the floor for unconscious persons. If no response is forthcoming and no victims are found, close the door and wait for the hoseline. Once the attack hoseline is in place and operating, conduct a search and rescue behind the line, searching the room and space outward from the hoseline. The second procedure is used when access is from a window—either at ground level or from a ladder. Instead of entering the room, firefighters should check for victims by crouching down below the heat, reaching in with a tool, and sweeping the area below the windowsill. When attempting to save themselves, occupants who cannot exit through a doorway will attempt to open or escape through a window. Fire- fighters often find these victims collapsed and unconscious next to or at the window. If a victim is found, a firefighter can crouch below the heated smoke and flashes of flames mixed with smoke coming out the window and pull the victim to safety. Point of no return There is a so-called “point of no return” when searching inside a burning room. This point ofno return is a point beyond which a searching firefighter will not be able to escape ifa flashover happens. If the room suddenly bursts into flame, the firefighter must be able to reach the door or window he or she entered in time to prevent being burned by the flashover’s extreme temperature rise. How far inside a burning room that is about to flashover is the point ofno return? That is the life and death question. We can calculate this distance by putting together several facts: how exposure to high temperatures affects the human body, the expected temperature encoun- tered, and the speed at which a firefighter can escape the room. NIST reports on fire dynamics show that temperature of 131°F to 162°F cause intense pain and damage to exposed skin and that temperatures in a post-flashover room can be as high as 1111°F (600°C)." Even with great protective equipment, firefighters cannot survive this temperature. Time and motion tests found in the Fire Protection Handbook reveal that the average person moves at 2% ft per second when walking. Factor in the possi- bility that firefighters may be carrying 70 lbs of equipment, which will likely slow down their rate of movement. 378  Chapter22 | Fire Hazard Identification and Assessment So the question is how long can a firefighter be exposed to 900°F heat and not suffer second-degree burns? I say it is 2 seconds. If a burning room has just flashed over and a firefighter is S ft inside the room, and crawls back to the doorway at 2% ft per second, he or she will be in an environment of 900°F for 2 seconds and probably not suffer burns. But if the firefighter is 10 or 20 ft into the room and the room flashes over, he or she will be exposed to this heat for 4 or 8 seconds. What seems like a very short amount of time becomes an eternity when your life is in immediate danger. Firefighters should know the definition of flashover. They should know the warn- ing signs of this danger: heat in smoke and rollover. Firefighters must also know how to delay flashover. And most important, they must know the point of no return and how to conduct a safe defensive firefighting search. NUMBER 7—DISORIENTATION Disorientation is the loss of sense of direction, usually due to loss ofvisibility in darkness or in smoke. When firefighters experience disorientation, especially when searching a smoke-filled room, the result can be deadly. Some say we should be called smoke fighters instead of firefighters, as there is much more smoke than flame at most structure fires. Smoke is the greatest product of combustion—not flame—and the thick, black clouds of combustible gases given off at fires quickly obscures our vision during firefighting operations. When firefighters become disoriented by losing their sense ofdirection in a smoky environment and cannot escape to safety, they risk injury and death by other fire- ground dangers such as flashover, asphyxiation, burns, heat, falls, or being buried in a collapse. One of these may be listed as the cause, but a post-fire investigation may reveal that disorientation happened first. When conducting firefighter injury and fatality investigations, it is important to know whether disorientation is a contrib- uting factor. This is especially important in helping improve safety records and in developing safe firefighting procedures. One contributing cause of disorientation is due to the increasingly common use of plastics in furnishings and construction materials. Plastics, which are for the most part made from petroleum products, produce large quantities of black smoke when they burn and can create total, rapid darkness in a burning room. Unlike the smoke from burning wood, paper, or cotton, there are no gradations of smoke or gradual darkening of smoke levels from plastics; the black smoke can almost instantly obscure vision within the room. Plastic furnishings have contributed to the increased number of firefighters disoriented and trapped by smoke during search operations. The following examples of firefighter fatality investigations show howa firefighter can become disoriented in dense smoke, suffer a loss ofvision and direction, and then be killed by another event. 379 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition Flashover A fire officer reportedly killed by burns suffered from a flashover actually had been disoriented by smoke and become trapped behind a long, low bookcase that divided a large room. He could not get back to the entranceway and was killed by flashover. Asphyxiation A firefighter reportedly killed by toxic smoke actually first had been disoriented by smoke in a large commercial occupancy. He lost his sense of direction, could not retrace his steps to a point of entry, ran out of air in his SCBA, and was killed by toxic smoke. Falling A firefighter reportedly killed in a fall had first become disoriented by rapid buildup of smoke and heat in a room. Searching for a way out in the dense smoke, he tripped over a low windowsill and fell from the window to his death. Collapse A firefighter reportedly killed in a collapsed building actually had first become disoriented in smoke while searching an upper floor above a serious fire. He soon became lost and could not find his way out. The fire grew until it involved the entire building, the structure collapsed, and the firefighter was killed. Firefighters searching for the location of a fire before the positioning of initial attack hoselines and those searching above a fire are especially in danger of becom- ing disoriented by smoke and trapped. Searching during the growth stage of a fire, whether alone or in pairs, is particularly dangerous because of the potential rapid generation of large quantities of smoke and heat just before flashover occurs. To avoid the danger of disorientation, firefighters should stop, think, and plan before beginning a search. Size up the situation yourself rather than relying on somebody else’s size-up,and train on the common procedures used to avoid disorientation: preplanning, hands-on exercises, and the use of safety equipment. Even before responding to a fire, a company’s training sessions should include the study of floor plans of buildings in the response district. In a high-rise building, if you are unfamiliar with the layout of the smoke-filled area to be searched, make a quick check of the floor below. Knowledge of the layout of the apartment or rooms on the floor below can give you information to keep you from becoming disoriented when searching the fire floor and give you confidence while searching in smoke. Conduct training sessions in the firehouse using masks with facepieces blacked out to give firefighters experience in the use of search ropes in zero visibility environ- ments. Your department should have mask confidence training sessions for rookie 380  Chapter22 | Fire Hazard Identification and Assessment firefighters and refresher courses for veteran firefighters that address disorientation dangers. Firefighters stretching hoselines must stay close to the hose as they search. You can use the hose to find your way out, but should also realize that the hose can be a cause of disorientation. For example, a firefighter may follow the curled up lines of small diameter hose or stretches that lead to a dead end room instead of directly to the exit. Always search in teams and, when entering small, smoke-filled rooms, search in an organized manner. Move around the room in a clockwise or counterclockwise direction and try to maintain contact with a wall. When entering a smoky hallway for a search, keep one shoulder against the wall while advancing. When returning to your point of entry, keep the other shoulder against the same wall. Maze-like rooms with many partitions, cubicles, or office workstation dividers or rooms that are subdivided into illegal single occupancies must be searched with a search rope. The combination of this type of complex floor layout and a smoke-filled interior make disorientation an extreme danger. Before entering the fire area, tie one end of a search rope to a secure object in a hall or stairway and play out the rope as you search. As a last resort, ifyou do become disoriented, activate your PASS (personal alert safety system) device. NUMBER 8—SMOKE Smoke is one of the deadly by-products of combustion. It kills more people than flames, heat, or fire gases. Smoke inhalation accounts for 75% of all fire deaths in America each year. Smoke is technically defined as finely divided particles of soot and suspended liquid droplets known as aerosols. It is formed during incomplete combustion—burning in an oxygen-deficient atmosphere. Firefighters know smoke as the deadly and dark gases in the air produced in abundance by fire that prevents them from locating the origin of the blaze, blinds them, causes them to lose direction and, if they are not careful, traps and kills them. The mixture ofhot vapors and gases produced by the combustion process is the first and most deadly hazard to appear during a fire, and it kills and injures in several ways: e Smoke causes disorientation. e Smoke 1s blinding and irritating to unprotected eyes. e Hot smoke when inhaled can cause burns to the throat and lungs, resulting in swelling and death. e Toxic smoke can kill quickly by asphyxiation. e Smoke can become combustible and explode. 381 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition Disorientation Firefighters who become lost and disoriented when searching in a smoky room and who cannot find their way out may first experience a sense of panic and attempt to escape blindly in any direction. If they are lucky they stumble back to safety; if they are unlucky they crawl into a corner or closet, become entangled, or either pull their masks off or run out of air and die. This description of firefighter fatality is called being caught and trapped by smoke, but it is really the disorientation that kills the firefighter. As described above, firefighters should train in mask confidence, searches in smoke, organized search techniques, use oflife lines, and, most importantly, study floor plans and layouts ofvarious occupancies. Eye injuries Exposure to smoke leads to several debilitating injuries to unprotected eyes, including inflammation, irritation, infection, and loss of vision—either temporary or permanent. The most common firefighting eye injury is conjunctivitis—an infec- tion caused by inflammation ofthe conjunctiva of the eye. Soot in smoke also irritates the nerve endings in the eyes, causing pain, blinking, and tearing. Without the use of protective equipment, firefighters cannot effectively search in smoke. For example, before the widespread use of masks, firefighters had to either keep their eyes open to look for victims or close their eyes and attempt to search by feel. The eye pain caused by the smoke quickly ended a search, and the loss ofvision also led to immobilization of both firefighters and victims—in some cases long enough for toxic gas or flame to overtake them. The use ofself-contained breathing apparatus (SCBA) has become one ofthe most effective ways to prevent eye injuries caused by exposure to smoke. Today, thanks to NFPA 1500, all firefighters entering burning buildings have and wear SCBA. The face masks not only protect them from injuries to the lungs from toxic gas inhalation, but also from the irritating effects of smoke and more serious eye injuries. Lung injuries The energy-efficient, insulated walls and ceilings of apartments and homes built and renovated during the energy crisis of the 1970s and continuing today has created a new hazard to firefighters: hot smoke. Apartments and homes are tightly sealed to conserve heat during winter. Rooms have double-pane windows, insulated walls and ceilings, and airtight doors. When a fire occurs inside such an energy-efficient space that is unoccupied, it is contained and burns for a long time before smoke or flame become visible on the outside, it is discovered by someone, and the fire department is called. The longer a fire burns in a tightly sealed room, the more the smoke is heated, and can reach temperatures as high as 900°F. A firefighter’s skin or lungs exposed to heated smoke will be severely injured. Scientific tests show that smoke generated at a fire can be divided into two general areas: a hot smoke zone and a cool smoke zone. The hot smoke zone includes those 382  Chapter22 | Fire Hazard Identification and Assessment areas in a burning building where the temperature ofthe smoke is high and the smoke movement is caused by the heat. As heated air expands it becomes lighter than the surrounding air and rises. Every firefighter knows the hot smoke is near the ceiling and that’s why you stay low when searching. If a fire is confined in a sealed and insulated room long enough, the hot smoke at the ceiling will eventually descend to the floor level, filling the entire room with superheated smoke. The hot smoke zone usually exists in the room of fire origin. The cool smoke zone includes those areas distant from the fire in a burning building where the heated smoke has been cooled by entrained air. The walls and ceilings absorb the heat of smoke as it is vented and flows out of the room of origin. Smoke that has stratified or is being moved by the stack effect, wind, or mechanical air moving systems, is in a cool smoke zone. Years ago, the fire service used to say, “Do not use a hose stream on smoke—wait until you see the flame.” Years ago, firefighters did not enter the superheated environments we do today. Today the saying is, “Use the hose stream on super-hot smoke to cool the atmosphere down.” Firefighters today enter hot smoke zones. They cool down the smoke to avoid smoke burns, even while realizing that cool smoke is still toxic smoke. Asphyxiation When smoke mixes with air it displaces the oxygen available and required by the human body. Air is approximately 21% oxygen, and if the amount of oxygen in air is reduced, displaced by smoke, the human body suffers. If a firefighter is not wearing a self-contained breathing mask and the oxygen in a burning room drops to 17%, motor coordination becomes impaired; at 10% to 14%, fatigue and faulty judgment take place; and at 6% to 10%, a firefighter loses consciousness and dies. In addition to displacing oxygen, smoke contains deadly toxic gases. Carbon monoxide (CO) and hydrogen cyanide are two common toxic gases found in smoke that kills firefighters. As it is not possible to tell the toxicity of smoke by its color or quantity, assume the worst and wear your mask. While CO is not the most toxic, it is the major threat because it is the most abun- dant toxic gas generated by fire and found mixed with smoke. The toxicity of CO is due to its affinity to combine with hemoglobin in the blood, restricting its ability to deliver oxygen to cells. Hydrogen cyanide (HCN), another gas commonly produced by fire, is about 20 times more toxic than CO. Ina fire, it is produced from the burning of both natural and artificial materials containing nitrogen such as polyurethane, nylon, acrylonitrile, wool, silk, and even wood. This toxic gas does not combine with the hemoglobin like carbon monoxide. Instead, it inhibits the use of oxygen by the body’s cells, a process known as histotoxic hypoxia. Explosion When smoke explodes, it is referred to by firefighters as a backdraft or a combus- tion explosion. The same chemical reaction and explosive ingredients are present in a smoke explosion as are in any ordinary combustion explosion: fuel, oxygen, and 383 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition heat. The fuel in a combustion engine explosion powering an automobile is gasoline. The fuel in a backdraft is smoke—combustible smoke particles of pyrolyzate and carbon monoxide (CO) that have an explosive range of 12% to 74% when mixed with air. Smoke explosions do not happen often. In fact, leaking gas, flammable liquid container ruptures, and flammable vapors from an arsonist’s accelerant cause most of the explosions at fires. However, a backdraft can occur anytime there is smoke and heat in a partially closed room. During a structure fire, an explosion caused by explosive levels of carbon monox- ide (CO) and pyrolyzate happens as the result of a sequence of events. It begins in a burning room, when carbon monoxide gas and pyrolyzate are produced by incomplete combustion after most of the oxygen is used up by the fire. Now the sealed-up room is filled with combustible product but little oxygen, although it still has remaining sparks and embers and heat. When firefighters enter after forcing entry or to search, they introduce oxygen. This oxygen in the air combines with the explosive atmosphere and smoldering sparks and triggers the fire triangle of air, fuel, and heat, causing a backdraft or smoke explosion. NUMBER 9—FALLS Falling is the second leading cause of accidental death after auto accidents and is a leading cause offirefighting injury. The latest NFPA statistics (2009) reveal there were 78,150 firefighters injured, and that 22% ofthese were caused by falls, slips, and jumps. Muyths about fall injuries There are some misconceptions about how and where firefighters suffer falls during fires. Most falls are not from heights; instead, they take place at ground level. Firefighters slip on icy streets or paved areas when stretching hose or raising ladders; we trip over hoses or unseen obstructions at night fires. During a fire, firefighters are under stress. The physical and emotional stress of firefighting makes us vulnerable to the hazards of falls. Stress causes tunnel vision or narrows our concentration on the flames or the location of our assigned duties we must quickly get to in order to complete our mission. As we concentrate on a specific point or object, we block out surrounding hazards, which can cause us to fall, slip, or misjudge a jump. While more serious fall injuries are from heights, most of the falls are from distances of 10 ft or less. Falls can occur from something as simple as misjudging the motion of a moving fire apparatus or an error in following safety procedures, such as standing on an unstable surface or object that collapses during the overhauling stage instead of getting a ladder into position. Even short falls can be deadly. A veteran firefighter who fell a distance of only 10 ft from a window after a flashover in a burning store landed on his head and died. It’s not the height you fall that determines your injury, it’s how you strike the ground. Falls occur most often at ground level and on stairs and ladders. 384  Chapter22 | Fire Hazard Identification and Assessment Since 9/11, the increasing amount of gear and equipment firefighters carry and wear is beginning to be seen as a contributor to falling. For example, a NIOSH 1inves- tigation ofa firefighter fatality caused by a fall from a roof cited the amount ofweight the firefighter was carrying when he lost balance was over 100 lbs. When the weight of a saw carried by a sling over his shoulder shifted, the firefighter fell five stories down from the rooftop. As the amount of equipment weight carried by firefighters is increasing, this is becoming a bigger safety issue and one that must be addressed. Fall prevention Military personnel, martial arts students, and athletes are taught falling skills to reduce their risk of injury. Firefighters should also know these techniques and means of protection during a fall. For example, firefighters must know how to protect the most vulnerable parts of the body during a fall: the head, spinal column, and joints (wrists, elbows, and knees). During a fall, try to land on your feet with your legs bent at the knees. As you strike the ground, protect your head by “tucking” to the side and toward your armpit, away from the fall. Even with a helmet on your head, this advice can reduce the injury. Protect your spinal column when falling backward by attempting to turn and twist to your side when falling. Strike the ground on your side with your buttocks, thigh, and shoulder instead of your back. To protect your joints during a fall, do not stiff-arm the ground. Instead, bend your elbows and slap the surface just before striking the ground. Hit it before it hits you. Injury prevention To reduce the dangers of falls on the fireground, use the following tips: 1. Firefighters should learn to pace themselves during the hectic, early stages of a fire. This will reduce stress and vulnerability to tripping hazards. Size up your surroundings in addition to sizing up the fire. Dependability, not speed, is the key to firefighting effectiveness. 2. Light up the fire scene. Floodlights should illuminate the front of the fire building and spotlights should illuminate specific areas, such as the window at which a ladder is placed, a hole in a floor or sidewalk, or the front entrance stairs. 3. During the winter, firefighters should carry salt or sand on every apparatus. Chauffeurs should spread it out on the front entrance steps and surround- ing streets and sidewalk before a firefighter has a chance to fall on any icy and slippery surface. During my career as a fireground commander, I have witnessed one type of fall injury over and over again. That injury occurs in the winter, after firefighters stretch an attack hoseline into a burning building and extin- guish a blaze. The freezing air and ground temperatures can quickly freeze the water that seeps from the building, especially at the entrance and steps leading to it. After the fire, firefighters come out of the building entrance 385 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition doorway and slip on the icy stairs, falling down two or three steps. To prevent these falls, I started ordering each company to carry a box of salt or sand onboard the apparatus and instructed the chauffeur of the engine companies to spread salt on the steps of every building during freezing weather so the exiting firefighters would not slip. 4. Firefighters should carry a flashlight at all times. 5. When disoriented or blinded by smoke, do not attempt to walk to an exit or window. Instead, get down on your hands and knees and crawl, feeling the floor or surface in front of you as you move. 6. Last, but not least, wear properly fitted gear. Turnout clothing provides a slight cushioning effect, and a helmet with a tightened chin strap can save your life. Several years ago, I investigated a fall injury. A firefighter fell five stories from a fire escape into the back yard of a tenement. On his way down, he hit and broke a clothesline and a telephone cable attached between two buildings and miraculously survived. His helmet stayed on during the fall and saved his life. OSHA Analysis of Fall Injuries Work Surface Involved Percentage ofInjuries Floor 51.4% Stairs 13.2% Ladders 10.5% Others (roof, scaffold, ramp, walkway) (accumulated) 24.8% Source: Federal Register Vol. 55, No. 69, April 10, 1990. NUMBER 10—FALLING OBJECTS Several years ago, a fire company extinguished a small blaze that started in a stuffed chair. Firefighters removed a badly burned man who had fallen asleep in the chair with a lit cigarette. They then dragged the smoldering chair to a window, pushed it out onto a fire escape, yelled “Watch out below!”, and threw it over the rail into the back yard. Unfortunately, a firefighter who was assigned the outside vent position was in the rear yard about to climb the fire escape and was struck by the smoldering chair. The man was knocked unconscious, suffered a disabling head injury, and was forced to leave the fire service. All kinds of things fall from burning buildings, ranging from objects or tools thrown from a roof or window to portions of the building that are knocked loose or seared or melted away from their attachments and even people jumping to escape a fire. Unfortunately, these deadly airborne missiles falling from above can strike anyone going into, coming out of, or operating around the perimeter of a burning building—including firefighters—and can result in deaths and injuries. 386  Chapter22 | Fire Hazard Identification and Assessment The front sidewalk, side alleys, and rear yard, which are the danger zones for falling objects, are also where firefighters have to work to raise ladders, operate hose streams, vent windows, and conduct forcible entry. Because of the danger of falling objects, they must be aware of and train on how to avoid injury when working the perimeter of a burning building. One important safety action is to either go into the burning building or withdraw from the perimeter of the burning building once the assigned task is complete. Limit the time and risk of injury at this position to that required to accomplish the mission. Broken glass from windows being vented is the most common falling object at a structure fire. When firefighters are searching for trapped victims in a smoke-filled building, windows must often be vented to clear smoke and increase visibility for the search. In many cases, this means breaking the glass, as the windows in older build- ings may have many coats of paint that prevent opening the window or they may be obstructed by bars or gratings for protection against burglary. Firefighters performing a primary search in a burning building can create a rainstorm of falling glass around the front, sides, or rear of a building, and the size and thickness of the broken glass can range from sheets large enough to decapitate to tiny shards that can blind fire- fighters working below. The glazing in windows of residential buildings is usually 1/16 in. to 1/8 in. thick and of standard glass; the glazing in windows in commercial buildings ranges from % in. to %2 in. thick and may be tempered, safety, or standard glass. Regardless of the type or thickness, though, when falling from a height of 40 or 60 ft, it is likely to injure someone. A case study of an injury to a firefighter from falling glass was conducted in the FDNY. The report detailed how a firefighter was connecting a supply hoseline to a standpipe inlet near a high-rise residence building. Firefighters above were venting windows at a particularly smoky fire, and glass shards were falling near the connec- tion hose to the standpipe. Even though the pump operator firefighter was wearing protective equipment and a helmet, as he was bending over to connect the supply line to a 3 in. siamese inlet connection on the standpipe, a sliver of falling glass went through his turnout coat and severed part of his spinal column. The firefighter fell to the ground and could not get up. Thankfully, he was quickly carried to a stretcher and rushed to the hospital, where a 3 hour operation was performed to remove the glass and prevent permanent paralysis. Glass is heavy. Commercial building window glass that is % to %2 in. thick weighs between 22 and S lbs per sq ft. A show window that is 8 ft x 4 ft and of %2 in. glass could weigh 160 lbs. Follow all safety precautions when breaking windows for venting, especially on a window of that size, and anticipate the number and sizes of razor-sharp pieces of glass that may fall. Safety procedures Who 1s responsible for an injury that occurs after the fire has been controlled, when during overhauling operations a smoldering object is thrown out of a window or glass is knocked out of a window frame and it strikes a firefighter below? Is it the responsibility of the firefighter inside or the firefighter outside? The answer is the 387 SAFETY AND SURVIVAL ON THE FIREGROUND | Second Edition firefighter inside is responsible because the firefighter operating inside the building is not working in a life-threatening environment. The fire is out, the rescue opera- tions have ended, and now firefighting actions must be more controlled. Firefighters inside a burned-out structure performing overhaul and salvage should never throw any smoldering object out a window or remove glass shards by knocking them outside unless the area below has been cleared and a firefighter is standing guard outside at ground level. It is not sufficient to yell “Watch out below!” and then throw a smolder- ing chair or mattress out a window. When an object must be thrown out ofa window during overhauling, follow these procedures: 1. Obtain permission from the officer in command of the fire. “Ladder 2 to Command. I have to discard material out a window on the C side.” Notify or assign a firefighter outside the building to clear the area of civil- ians and act as a safety guard. “Command to Ladder 2. I have sent Engine 1 pump operator to act as your safety guide.” 3. After the area is clear, the firefighter acting as guard signals when to throw the smoldering objects out or break off the jagged glass shards. “Engine 1 to Ladder 2. It is all clear below.” When all objects have been discarded out the window, notify the firefighter below assigned as a safety guard. “Ladder 2 to Engine 1. That’s it; all mate- rial is outside.”. When operations are complete, the safety guide notifies the incident commander. “Engine 1 pump operator to Command. Operations complete. The material has been discarded. I am going to wet it down with a booster line.” Following are safety procedures that should be followed: When trimming broken glass from windows, knock the glass shards inside, not outside. When assigned to operate around the perimeter of a burning building, be aware of the danger of falling objects and wear proper protective clothing. When venting windows from inside, attempt to open the window before breaking glass. Double paned windows in new and renovated buildings can be more quickly and fully vented by opening them manually than by break- ing glass. To warn firefighters outside and below when venting a window from the inside, break a small section first. Be alert to the sound of the glass breaking as it should act as a warning of more to come. If it 1s not possible to safely discard a smoldering object through a window and it must be carried out of the building, be aware that exposing the object to fresh air—either in the hallway or in the street—can cause the object to burst into flame. Have a portable extinguisher or hoseline ready to quench a flash fire. 388  Chapter22 | Fire Hazard Identification and Assessment e Realize that commercial glass is more dangerous when broken then residen- tial glass. The thickness and weight of falling glass pieces can cause serious lacerations and cut hoselines. e The perimeter of a burning building is a dangerous place. After complet- ing your assignment there, go inside the building or withdraw outside the collapse danger zone. NUMBER 11—BACKDRAFT While they may be rare or difficult to identify, backdraft and smoke explosions can and do happen, and the fire service must investigate any explosion and determine its cause. Before a fire chief declares an explosion to be a backdraft, there must be an investigation to rule out all other explosion causes. If the gas piping is intact, if there are no ruptured containers found, and if there are no traces of an accelerant residue, then the explosion can be designated a backdraft. Fire protection engineers classify explosions into two broad categories: a physical explosion such as a BLEVE (boiling liquid expanding vapor explosion) and a chemical explosion such as a combustion explosion. A backdraft would be classified as a chemi- cal explosion. The same chemical reaction and explosive ingredients are present in a backdraft as are in any ordinary combustion explosion: fuel, oxygen, and heat. The fuel in a combustion engine explosion driving an automobile is gasoline; the fuel in a backdraft explosion is smoke. An explosion is defined as an effect produced by a sudden violent expansion of gases. Some effects of an explosion include shock waves that shatter windows, blow down firefighters, and collapse