Field

What is a fire watch in construction?

A fire watch is a person assigned to watch for and respond to fire during hot work such as welding and cutting, and for a period afterward, or while a building's fire protection systems are out of service.

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Hot work starts fires. Sparks and slag from welding, cutting, and grinding can travel well beyond the work area and smolder in insulation, dust, or packaging for a long time before anyone sees flame. A fire watch is the person whose only job is to look for that, have an extinguisher in hand, and raise the alarm. On construction sites, OSHA requires one when normal precautions are not enough, and many owners, insurers, and fire officials require one more broadly.

What OSHA requires

For construction, 29 CFR 1926.352 covers fire prevention during welding and cutting. It requires suitable fire extinguishing equipment to be immediately available in the work area. Under paragraph (e), when the normal fire prevention precautions are not sufficient, additional personnel must be assigned to guard against fire while the work is being done and for a sufficient period of time after it is completed. Those people must be told about the specific fire hazards and how to use the firefighting equipment provided.

The general industry welding standard, 29 CFR 1910.252, is more specific and is often used as a practical guide on construction sites too. It requires fire watchers where other than a minor fire might develop, including where appreciable combustible material is closer than 35 feet to the work, and it requires the fire watch to be kept for at least a half hour after welding or cutting is finished to catch smoldering fires. Fire watchers must have extinguishing equipment ready, be trained to use it, and know how to sound the alarm.

Fire watch duties at a glance
DutyWhy it matters
Stay with the hot work and watch all exposed areas, including below and behind wallsSparks travel through openings and gaps
Keep a suitable extinguisher ready and know how to use itSmall fires are only small for a minute
Know how to sound the alarm and call the fire departmentSome fires cannot be put out with an extinguisher
Stay after the work ends for the required periodSmoldering material can ignite well after the torch is off

How it works on a real job

Say a mechanical sub is welding pipe hangers in an occupied office building during a $750,000 tenant improvement. The building owner requires a hot work permit. The foreman fills out the permit, moves the cardboard and ceiling tile scraps away from the work, covers what cannot be moved with a welding blanket, and assigns an apprentice as fire watch with a charged extinguisher. The apprentice checks the floor below, because the hangers are going in over a floor penetration. When the welder finishes at 3:15, the apprentice stays, walks the area again, and the foreman closes the permit after the watch period required by the permit and the owner's program.

Fire watches also come up when sprinklers or alarms are impaired, for example during a tie-in or a renovation. Fire codes and local fire officials often require a fire watch patrol during those outages. The requirements vary, so check with the authority having jurisdiction.

Common mistakes

  1. Assigning the welder's helper as fire watch while also asking them to fetch material. A fire watch should have no other duties.
  2. Leaving when the welding stops.
  3. No extinguisher at the watch position, or an extinguisher that has not been inspected.
  4. Ignoring the floor below and the far side of walls.
  5. No written hot work permit when the owner or insurer requires one.

Related terms

See safety data sheet, OSHA 300 log, job site, and site logistics plan. For inspections, read how to run a jobsite safety inspection.

Frequently asked questions

How long must a fire watch stay after welding?

The construction standard, 29 CFR 1926.352(e), says for a sufficient period after the work. The general industry standard, 29 CFR 1910.252, sets at least a half hour. Owners and insurers may require longer.

Who can be a fire watch?

A person trained to use the extinguishing equipment provided, familiar with how to sound the alarm, and told about the specific fire hazards. They should not have other duties during the watch.

Is a fire watch required for all hot work?

Not always under OSHA's construction rule, which requires extra personnel when normal precautions are not sufficient. Many owners, insurers, and fire codes require one for all hot work.

Do I need a fire watch when sprinklers are shut off?

Often, yes. Fire codes and local fire officials commonly require a fire watch during fire protection impairments. Check with the local fire authority.

Sources

  1. Cornell Law School LII: 29 CFR 1926.352 Fire prevention
  2. GovInfo: 29 CFR 1910.252 General requirements (welding, cutting, and brazing), 2024 edition
Written and edited by

Maurice Francois writes and edits construction operations guides for Smart Business Automator. More from Maurice on the Scaling Legends podcast.

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