Fire officer handbook of tactics chapter 22

• Structural collapse is a major concern for firefighters due to its potential for fatalities and multiple-casualty incidents.
• Changes in construction methods, which prioritize lightweight materials and lower costs, are increasing the risk of collapse during fires.
• Firefighters should learn to recognize warning signs and causes of collapses, and prepare for rescue operations.
• Recognizing building types help predict collapse behavior during fires.

Historical Collapses with Significant Firefighter Fatalities:

• Chicago Stockyards warehouse (1910): 23 deaths
• New York City, 23rd Street building (1966): 12 deaths
• Boston, Vendome Hotel (1972): 9 deaths
• Brooklyn, Waldbaum’s Supermarket (1978): 6 deaths
• Hackensack, NJ, Ford dealership (1988): 5 deaths
• Wichita, KS, Chevrolet dealership (1968): 4 deaths
• Brackenridge, PA, two-story building (1991): 4 deaths
• World Trade Center (WTC) (2001): 343 deaths

Building Classifications and Collapse Resistance:

• Buildings can be ranked by collapse resistance to estimate structural stability and interior firefighting time.

Class 1: Fireproof Construction

• High fire-resistance ratings (up to 4 hours)
• Typically uses a skeletal framework of poured concrete or steel I-beams
• Collapse is usually localized (concrete spalling or I-beam sagging)
• Designed to allow time for evacuation and fire control during heavy fires
• Lightweight construction in modern buildings may not provide sufficient evacuation time
• Examples of collapses: WTC 1, 2, and 7
• Other high-rise fires, like One Meridian Plaza in Philadelphia, resulted in near collapse due to standpipe malfunction
• Windsor Building in Madrid (2005) had a partial collapse of steel-framed areas after a severe fire
• Concrete core remained standing
• Severe collapse danger in poured-in-place concrete buildings under construction when fire involves wooden formwork

Class 4: Heavy-Timber Construction

• Generally stable due to large load-bearing members (12x12 wooden columns and brick walls)
• Manual firefighting usually shifts to exterior operations before collapse becomes a danger
• Repeated fires in abandoned industrial buildings are an exception
• Collapses are often large-scale, affecting walls and floors
• Apparatus should be removed from the collapse zone, 1½ times the height of the wall.

Class 3: Ordinary Construction

• Standard brick and wood joist construction
• More prone to burn-through than collapse under normal floor-load limits
• Danger of unusually high floor loads (plumbing warehouses) and concentrated loads (roof-mounted AC)
• Concentrated loads can cause early localized failure
• Lateral loads on walls can cause wall failure

Class 5: Wood-Frame Buildings

• More likely to burn through than collapse under standard construction methods
• Does not apply to lightweight truss-construction methods
• Lightweight and truss-construction methods should be considered a special category for collapse resistance.

Class 2: Metal or Noncombustible

• Least resistant to collapse when exposed to fire
• Uses large quantities of unprotected steel
• Steel expands when heated (9½ inches for a 100-ft beam at 1,000°F)
• At 1,500°F, steel loses half its strength, causing sagging or twisting
• Cooled steel contracts but retains its distorted shape, leading to further collapse

Framed Structures:

• Have protected steel or concrete supporting systems
• Resist total collapse effectively
• Collapses are localized between supporting members

Unframed Structures:

• Rely on bearing walls for weight support
• Bearing wall collapse causes extensive damage by removing floor supports

Structural Member Failure Priority:

• Bearing walls (most important)
• Columns
• Girders
• Beams and joists
• Floor or roof decking (least important)
• Failure of vertical members (columns, walls) is typically more serious than failure of horizontal members (beams)

Common Causes of Structural Collapse On The Fireground:

• Structural weakness (design flaws, poor workmanship, improper renovations)
• Fire damage to wooden structural members (burn-through rate: 1 inch per 45 minutes)
• Heating of unprotected steel (lightweight steel-bar joists can fail in 5-10 minutes)
• Failure of highly heated cast-iron columns or facades (cast iron is brittle and can shatter when cooled)
• Explosions of fuels/explosives/backdraft(1 psi lateral force can topple a brick wall)
• Overloading of the floor (water-absorbent materials or excessive hose stream runoff of 1,000-gpm adds approximately 8,500 lb to weight of structure per minute)
• Cutting/removing structural members during overhaul
• Vibration and impact load (avoid jumping or causing impact loads on damaged areas, shut down external sources of vibrations)
• Miscellaneous causes (high winds, flooding, water main damage, old age)

Warning Collapse Indicators:

• Occupancy by problem businesses (plumbing supply stores, supermarkets, truss construction buildings)
• Construction type: truss construction is a serious warning sign
• Overloaded floors (heavy equipment, absorbent stock, built-up water)
• Heavy fire burning for more than 20 minutes (5 minutes for lightweight construction)
• No appreciable runoff from hose streams
• Cracks or bulges in walls (monitor expanding cracks)
• Water or smoke seeping through a solid brick wall
• Roof pulling away from the wall.
• Roof sagging or feeling abnormally soft or spongy
• Any obvious movement of floors, walls, or roofs
• Noises (creaking, groaning, cracking timbers, rumbling)
• Plaster sliding off walls or plaster dust in the air

Establishing Collapse Zones:

• The Incident Commander (IC) must remove everyone from the potential collapse path.
• Use portable radios to issue evacuation orders and confirm receipt.
• Use audible warning devices for those without radios (sirens, air horns).
• Establish safe exterior collapse zones to protect from falling walls and debris.
• Collapse zone size: at least 1½ times the height of the facing wall for its full length.
• Include areas inside adjacent buildings due to potential roof collapse.
• Avoid positioning aerial devices too close to buildings.

Bowstring Truss Roofs:

• Hip rafters can act as levers, causing walls to be propelled outward with explosive force upon truss failure.
• Ground-level forces must withdraw to a distance at least 2½ times the height of the wall.
• Flanking positions or positions above the wall (elevating platform) may be necessary.
• Sudden release of a huge fireball upon roof collapse.
• The total elapsed time from flashover to collapse can be approximately 8 minutes.

Five Types of Collapses:

• V-shape
• A-frame
• Supported lean-to
• Unsupported lean-to (cantilever)
• Pancake
• Styles are likely to occur in specific building construction classes

V-Shaped Collapses:

• Usually occur in Class 3 or 5 buildings with wooden floor joists
• The outer edges of the joists remain supported at the exterior walls while the center portion collapses
• Victims on the collapsing floor, not in the vicinity of the collapse, will be thrown toward the center along with loose debris
• Victims directly below the collapse will have the least chance of survival, while those along the perimeters will have the greatest chance of survival

A-Frame Collapses:

• Result when a strong center object hold up the center portion of a structure, while the outer ends of floors or roof fall, resulting in a tent-like structure in the center of the debris pile
• Void areas in this case are close to the remaining center obstruction: bearing wall or column line
• Those along the outer edges will have a lower chance of survival than those near the center supporting structures

Supported Lean-To Collapse:

• Results from the failure of the support at one end of a floor or roof
• One bearing wall blows out while the other remains intact
• Everything that was on top of the floor will be thrown into a heap at the low end

Unsupported Lean-To Collapses:

• Result from similar events that cause the supported lean-to, but the floor or roof joists end up dangling in midair, held only by their attachment at the remaining standing wall
• The low end is totally unsupported, creating a severe danger of further collapse
• Search of the voids under these overhanging floors is extremely dangerous

Pancake Collapses:

• The floors of the structure fall in layers, resembling a stack of pancakes
• The floors are very often resting directly on the floor below it
• Numerous rescues have been made from pancake collapses in Class 3 and Class 5 buildings

Individual Voids:

• Result from spaces formed by a series of strong objects that prevent collapse into that particular are and may be found in any type of collapse
• Victims aren’t as likely to be thrown to a side or end as they would if the floor were to incline

Collapse Rescue Operations:

• Actions during the aftermath determine the survival of trapped firefighters
• Bring as many streams to bear in the affected area as possible, using a tower ladder
• Use the tower ladder's boom as a tie-off point for hoisting objects (if necessary)
• Remove weight from the boom, including tools and personnel.
• Deploy rapid intervention teams (RITs) to be specially selected and equipped with radios, masks, forcible-entry tools, lights, TIC, and a search rope to locate downed members
• Utilize emergency medical service (EMS) units, prepared for advanced life support
• Do not send every available member rushing in to join the search
• Backup team should remain in a safe area to wait for first team to locate victim
• Conduct a roll call and verify all personnel are accounted for
• Attack support functions can be beneficial to the rescue effort
• Use high-expansion foam in below-grade areas to protect firefighters

Five Stages of the Collapse Rescue Plan:

• Reconnaissance and size-up
• Accounting for and removal of the surface victims
• Searching voids
• Selected debris removal and tunneling
• General debris removal

Reconnaissance and Size-Up:

• Determine what happened, where, who’s missing, where they were last seen, and if they can be alive.
• Assess construction type, problem occupancies, and problems with utilities.
• Request utility repair crews to shut off services in the street.

Accounting for and Removal of the Surface Victims:

• Remove lightly pinned victims and provide examination and treatment.
• Designate a victim tracking coordinator to record names, locations, and injuries.
• Conduct a roll call to identify missing members.

Searching Voids:

• Search void spaces created by strong items holding up debris.
• Provide pinned persons with spare SCBA, RIT-Paks, or hoseline-supplied air source.
• Attach a search line to lead others directly to them.
• If entanglement is extensive, amputation may be necessary.

Selected Debris Removal and Tunneling:

• Cut or move structural elements to remove trapped victims.
• Use tools like TICs, acoustic and seismic listening devices, and remotely operated cameras.
• Use extreme care and permit only specially trained members to perform these tasks.
• Prevent fatalities by rotating crews to prevent fatigue.
• Multiple avenues of approach are useful.
• When possible, chose electric tools, sawzalls etc.
• Provide sufficient lighting.
• Rope off affected area, shore up area, or tie off debris, as necessary.
• Only remove the equipment shoring up the area after the operation is complete.

General Debris Removal:

• Begin after completing the first four stages.
• Use heavy equipment under fire department direction to find survivors.
• Employ specially trained search dogs and acoustic/seismic sensors.
• Secure the search area to eliminate all vibrations and noise.
• Search area for body parts before debris removal and deposition in the designated examination area.

Street Management At Collapses:

• Put essential units in the right place and keep unnecessary units out of the way.
• Older, densely populated areas are subject to gridlock conditions in which requires coordination and cooperation of all responding agencies for positive outcomes.
• Ensure continued smooth access to the site by positioning units appropriately.
• Position first-alarm engine companies to protect trapped persons and rescuers against fire.
• Stretch precautionary lines and ensure a continuous water supply.
• Position pumpers outside the fire block to keep the front clear and maintain the water supply.
• The third and fourth engines should take similar positions at the rear of the structure.
• Set up staging areas with secure parking spaces for vehicles that aren’t in use.
• Keep aerial ladders away from the front of the building unless needed for rescue
• Prioritize elevating platforms for highly maneuverable master streams and rescues from heights or deep within destroyed areas.
• Position heavy-rescue apparatus and collapse shoring vehicles close to the operations area but outside the collapse zone
• Split up ambulances based on function (triage and treatment vs. patient transport) and establish medical command.
• Secure access to the site for heavy equipment (cranes, front-end loaders, dump trucks).
• Utilize crowd control, traffic control, and armed sentries to prioritize the safety of all involved.

Safety Precautions During Collapse Operations:

• Shut down all utilities.
• Monitor the atmosphere for flammable or toxic gases.
• Prohibit smoking.
• Remove all nonessential personnel.
• Control the spread of fire.
• Maintain constant surveillance of weakened building components, using surveyor's transit.
• Eliminate all vibrations.
• Avoid cutting/removing major supports; brace and shore if necessary.
• Rotate personnel frequently (every half hour or less).
• Maintain communications.
• Seek expert assistance.
• Report to the officer in command any conditions that may be warning of a possible collapse