Chapter 16: Fireground Collapse Zone Planning

Where must a collapse zone be established?

Adjacent to exposed exterior walls that present a collapse hazard.

Where should apparatus and personnel operating master streams be positioned?

Outside the collapse zone.

What traditional collapse-zone distance does the chapter give?

At least 1.5 times the structure's height, measured outward from its base.

What collapse-zone distance corresponds to a 30-foot-high structure?

At least 45 feet, using the chapter's 1.5-times-height estimate.

Why can collapse-zone planning become more difficult for taller structures?

The traditional height-based distance can consume a very large area and limit defensive operations.

What conditions call for establishing a collapse zone?

Evidence of weakening from prolonged heat, adoption of a defensive strategy, or circumstances that do not justify interior operations.

What factors must be considered when sizing a collapse zone?

Construction type, other exposures, and safe locations for apparatus and personnel.

How far along an affected wall does the collapse zone extend?

The full length of the affected wall.

What defensive position does the chapter describe near building corners?

The area within a 90-degree arc from the wall intersection, provided personnel and apparatus remain far enough away to avoid flying debris.

What is the first action when collapse is suspected to be imminent or likely?

Exit with the crew while informing Command and everyone still inside.

What follows withdrawal and notification when collapse is likely?

Establish and clear the collapse zone as soon as possible.

What limited collapse-zone exception does the chapter describe for master streams?

Cautiously placing an unstaffed master-stream device, then immediately withdrawing once it is operating; personnel must not remain in the zone.

What accountability action follows evacuation for collapse danger?

Conduct a roll call or personnel accountability report (PAR) to verify all personnel are safe.

What emergency signals must firefighters know and obey?

Their department's evacuation and other emergency signals.

What two broad dangerous-building conditions does the chapter distinguish?

Conditions that increase fire spread or intensity and conditions that make the structure susceptible to collapse.

How are fire spread and collapse hazards related?

Conditions that increase the fire's spread and intensity also increase structural damage and collapse potential.

Why should construction type be considered together with elapsed fire time?

Together they give a rough estimate of structural integrity.

How does the chapter define fuel load?

The maximum heat that could be produced if all combustible contents and building materials in a given area burned.

How does a greater or more combustible fuel load affect a fire?

It can make the fire burn hotter and longer.

What is building compartmentation?

The arrangement and separation of rooms and spaces within a building.

How do compartmented layouts compare with open floor plans in fire spread?

More compartments provide more barriers; open layouts can permit greater fire spread.

What are interstitial spaces, and why do they matter in a fire?

Concealed spaces within walls, floors, or ceilings that can provide paths for hidden fire travel.

How can insulation and lightweight engineered features worsen fire conditions?

Insulation can retain heat, while lightweight or engineered members may fail quickly and unexpectedly under that exposure.

Why are buildings under construction or renovation more vulnerable to fire spread?

Normal barriers may be incomplete and systems such as sprinklers or fire department connections may not be operational.

What missing features can increase hazards in abandoned or demolition-stage buildings?

Doors or walls that normally limit fire spread may be missing, and structural components may be unsound.

What does HVAC stand for, and what is its normal function?

Heating, ventilation, and air conditioning; it moves heated or cooled air through the building, commonly through ducts.

How can HVAC ducts spread fire hazards?

They can carry heated air and combustion products from an involved compartment into other areas.

How can hot gases carried through ducts start fire in another compartment?

They can heat materials to ignition, or flammable gases may ignite after mixing with fresh oxygen.

How do purpose-designed smoke evacuation systems differ from ordinary HVAC operation?

They isolate normal HVAC functions and can remove smoke/fire gases or control building pressurization.

Who should operate a building's smoke evacuation system during a fire?

Trained personnel acting under the incident commander's direction.

How do smoke detectors and dampers help limit spread through HVAC ducts?

Smoke detection activates dampers that close and block airflow through affected ducts.

Why can suppression water increase collapse risk?

Water retained in the building adds weight to already weakened structural members.

What approximate weight per U.S. gallon of water does the chapter use for estimating added load?

About 8-10 pounds per U.S. gallon, as a rounded chapter estimate.

What approximate water load does the chapter associate with a 250-gpm stream?

About 1 ton per minute, if the water accumulates in the structure.

What collapse patterns can added suppression-water weight cause?

Floors may pancake downward or walls may be pushed outward, potentially causing complete structural failure.

Why do fireground operations continue after extinguishment?

Salvage protects contents, overhaul confirms extinguishment and prevents rekindling, and the structure must be secured before handoff.

How can firefighting operations damage a structure beyond the fire's original damage?

Forcible entry, large quantities of water, and damage to load-bearing components during salvage or overhaul can increase collapse risk.

What must firefighters avoid when opening or cutting walls during overhaul?

Cutting load-bearing components.

What should be checked before moving heavy property during salvage?

Floors and stairs must be examined to determine whether they can support the load and movement.

How may lumber such as 2-by-4s be used after a fire?

To reinforce or anchor damaged structural components such as walls and floors.

How may plywood or OSB be used to secure a fire-damaged building?

To cover doors, windows, and holes in walls or roofs.