A building under construction is at its most vulnerable to fire. Framing and sheathing are exposed, sprinklers and fire-rated assemblies are not yet working, combustible packaging and debris pile up, and hot work, temporary heat and temporary power are all in use. Our guide to construction fire prevention planning covers how to keep fires from starting. This article focuses on readiness and response: what has to be in place before a fire, what crews should do in the first minutes, and what to do afterward to protect people, the project and the insurance claim.

Know the rules that apply

Federal OSHA's construction fire protection standard is 29 CFR 1926.150. In Washington, the equivalent rule is WAC 296-155-260, enforced by the Department of Labor & Industries. Local fire codes, usually based on the International Fire Code, add requirements for site access, water supply and fire safety plans, and many fire marshals reference NFPA 241, the standard for safeguarding construction, alteration and demolition operations. Hot work is governed by NFPA 51B as adopted locally. Check with the local fire marshal early; some jurisdictions require a written construction fire safety plan before permits are issued.

RequirementWhat the rules say
Water supplyOSHA requires a water supply for firefighting as soon as combustible materials accumulate. Washington requires a supply of sufficient volume, duration and pressure to operate firefighting equipment.
Portable extinguishersAt least one 2A-rated extinguisher for each 3,000 square feet of protected building area, with no more than 100 feet of travel to the nearest one. OSHA also requires at least one on each floor, next to a stairway in multistory buildings.
Flammable liquids and gasA 10B-rated extinguisher within 50 feet of where more than 5 gallons of flammable or combustible liquids, or 5 pounds of flammable gas, are being used.
StandpipesIn multistory buildings, standpipes brought up as construction progresses, as soon as applicable laws permit, with fire department connections at street level.
Alarm and reportingWashington requires an alarm system that can alert workers on site and the local fire department, with the alarm code and reporting instructions posted at phones and employee entrances.

Before a fire: get the site ready

  • Name a fire prevention program manager. NFPA 241 calls for the owner to designate a person responsible for the site fire prevention program. On most projects that role falls to the general contractor's superintendent. The person should know the applicable fire standards, the site's protection systems and how to inspect for hazards.
  • Keep fire department access open. Fire codes commonly require access roads wide enough and strong enough for apparatus, with adequate vertical clearance, from the start of the project to the end. Keep hydrants, standpipe connections and sprinkler connections clear of materials, fencing and parked equipment.
  • Plan the alarm. Decide how workers will be alerted (air horn, radio call, temporary alarm system), make sure every crew knows the signal, and post the site address and emergency number at every entrance and phone.
  • Stage extinguishers. Place and inspect extinguishers to meet the spacing above, plus one at every hot work location, near fuel storage and on equipment.
  • Set assembly points. Choose an assembly area away from the structure and away from fire department access routes, and decide who takes the headcount.
  • Brief the fire department. Invite the local station to walk the site, especially on large wood-frame or multistory projects, so crews know where access, water and hazards are.
  • Secure the site after hours. Fencing, lighting, cameras or monitored security reduce arson and trespass, which are common causes of fires on idle sites.

Pull these items into your site emergency action plan. See our guide to emergency action plans for what that plan should cover.

Hot work and fire watch

Welding, cutting, torch-applied roofing and grinding cause many construction fires. Use a written hot work permit for every job, signed by the person authorizing the work, with combustibles removed or protected within the work area.

Fire watch timing. Under the 2019 edition of NFPA 51B, a fire watch must continue for at least one hour after hot work is completed, and the person authorizing the permit may require fire monitoring for up to three additional hours. Smoldering fires in concealed spaces often show up after crews have left, so the watch and the final walk-through matter. Your local fire code, owner requirements or insurance policy may require more.

During a fire: the first minutes

  1. Sound the alarm. Anyone who sees fire or smoke triggers the site alarm and tells the nearest supervisor.
  2. Call 911. Give the address, the entrance to use, what is burning and whether anyone is missing or trapped. Do not wait to see whether an extinguisher works.
  3. Evacuate and account. Crews leave by the nearest safe route and go to the assembly point. Foremen account for their crews and subcontractors and report anyone missing to the superintendent.
  4. Fight only small fires, only if trained. A trained worker may use an extinguisher on a small, early-stage fire with a clear exit behind them. If the fire is spreading, involves the structure or produces heavy smoke, leave.
  5. Meet the fire department. A designated person meets the first engine with site plans, the location of the fire, hazardous materials (fuel, gas cylinders, chemicals) and the headcount.
  6. Shut off utilities only if safe. Temporary power, gas and fuel supplies should be shut off by trained people if it can be done without risk.

After the fire: protect people, the project and the claim

  • Get medical care for anyone hurt and report serious injuries to OSHA, or in Washington to L&I, within the required time.
  • Do not re-enter until the fire department releases the site, and have the structure assessed before work resumes.
  • Notify your insurance carrier and broker right away, along with the owner and lender if the contract requires it.
  • Take reasonable steps to prevent further damage, such as securing openings, covering exposed areas and pumping water, and keep receipts.
  • Preserve evidence: hot work permits, fire watch logs, daily reports, delivery records, photos and video. Do not discard damaged equipment or materials until the adjuster has seen them.
  • Investigate the cause and update your procedures. Share what was learned at the next safety meeting.

Where insurance fits

A construction fire can trigger several policies at once. Which one responds depends on contract terms and policy language, which vary by carrier.

LossCoverage that may respondPoints to check
Damage to the building under construction and materials on siteBuilder's riskWho buys it under the contract, whether it covers materials in transit or stored off site, soft costs and delay in completion, and any hot work or protective safeguard conditions
Fire spreads to a neighboring property or injures the publicGeneral liability and umbrellaAdditional insured requirements, subcontractor coverage and limits
Tools and equipment destroyedContractor's equipment (inland marine)Scheduled versus blanket limits, rented equipment, replacement cost or actual cash value
Workers injuredWorkers' compensationIn Washington, coverage is through L&I or self-insurance

Builder's risk policies sometimes include conditions, such as security, fire watch or hot work permit requirements, that can affect a claim if not followed. Read them before the project starts and build them into your site plan. If subcontractors do hot work, confirm their insurance and require them to follow your permit system; see subcontractor insurance requirements.

When to call a broker

Call us before you sign a contract that assigns builder's risk, before you start a large wood-frame or multistory project, or when an owner or lender requires specific fire protection measures. We can review how your construction insurance program handles fire across builder's risk, liability, equipment and workers' compensation.

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