A fire watch is a trained person assigned to watch for and respond to fires during hot work such as welding, cutting, brazing and grinding, and for a set time after the work ends. The fire watch has extinguishing equipment ready, knows how to raise the alarm, and has the authority to stop the work if conditions become unsafe.
Fire watches matter because sparks and slag can travel well beyond the work area, fall through floor openings or land behind walls, and smolder unseen for a long time before flames appear. Many hot work fires start after the welder has packed up and left. A dedicated fire watch catches these fires while they are still small enough to put out.
What Is a Fire Watch?
In hot work, a fire watch is a person whose only job during the work is to look for fires in all exposed areas and respond to them. OSHA's general industry welding standard, 29 CFR 1910.252(a)(2)(iii), sets when fire watchers are required and what they must do. Construction and shipyard work have their own rules, and NFPA 51B, the National Fire Protection Association standard for fire prevention during hot work, adds widely used requirements.
The term is also used in fire codes for a different situation: patrols posted when a building's fire alarm or sprinkler system is impaired. That type of fire watch is described later in this article.
When OSHA Requires a Fire Watch
General industry
Under 1910.252(a)(2)(iii)(A), fire watchers are required whenever welding or cutting is performed where other than a minor fire might develop, or where any of these conditions exist:
- Appreciable combustible material, in building construction or contents, is closer than 35 feet to the point of operation.
- Appreciable combustibles are more than 35 feet away but are easily ignited by sparks.
- Wall or floor openings within a 35-foot radius expose combustible material in adjacent areas, including concealed spaces in walls or floors.
- Combustible materials are adjacent to the opposite side of metal partitions, walls, ceilings or roofs and are likely to be ignited by conduction or radiation.
Construction
Under 29 CFR 1926.352(e), when normal fire prevention precautions are not sufficient, additional personnel must be assigned to guard against fire during welding, cutting or heating and for a sufficient period after the work to ensure no possibility of fire exists. They must be instructed in the specific fire hazards and in using the firefighting equipment provided.
Shipyards
Shipyard employment has detailed fire watch rules in 29 CFR 1915.504, including that a fire watch must not be assigned other duties while hot work is in progress. Under 1915.508, fire watches must be trained before assignment and at least annually.
How Long a Fire Watch Must Last
- OSHA general industry: a fire watch must be maintained for at least a half hour after welding or cutting is completed, to detect and extinguish possible smoldering fires.
- OSHA shipyards: the fire watch must remain at least 30 minutes after hot work ends, unless the employer surveys the area and determines there is no further fire hazard.
- NFPA 51B: the 2019 edition increased the post-work fire watch to a minimum of 1 hour and added fire monitoring of the area for up to an additional 3 hours, as decided by the permit authorizing individual. Check which edition your jurisdiction, insurer or company has adopted.
Many employers apply the stricter NFPA 51B time on their hot work permit because insurers and local fire codes often reference it.
Fire Watch Duties
- Keep suitable fire extinguishing equipment readily available and know how to use it.
- Know where and how to sound the fire alarm.
- Watch all exposed areas, including floors below, adjacent rooms and the far side of walls.
- Try to put out a fire only when it is obviously within the capacity of the equipment available; otherwise sound the alarm.
- Stop the hot work if unsafe conditions develop.
- Stay in the area for the full required time after the work ends.
Impaired System Fire Watches
Fire codes commonly require a fire watch when a building's sprinkler or fire alarm system is out of service, for example during repairs. In this case trained people patrol the affected areas, look for fires and notify the fire department and occupants if one is found. Requirements, such as when the watch is triggered and how patrols are logged, come from the fire code adopted by your jurisdiction and from the authority having jurisdiction, so confirm local rules before an impairment begins.
How to Set Up a Fire Watch Step by Step
- Assess the hot work area. Inspect for combustibles within 35 feet, openings, and materials behind walls or floors.
- Issue a permit. Document the precautions and the fire watch requirement on a hot work permit.
- Assign a trained person. Choose someone trained in extinguisher use and alarm procedures, with no other duties during the work.
- Provide equipment. Place suitable extinguishers or hose lines at the work location and confirm they are charged and inspected.
- Cover all exposed areas. Add more fire watchers if one person cannot see every exposed area, such as the floor below.
- Maintain the post-work watch. Keep the fire watch in place for the full required period after work ends.
- Close out the permit. Do a final inspection and record the time the watch ended.
Common Mistakes to Avoid
- Giving the fire watch other tasks, such as helping the welder.
- Ending the watch as soon as the welder leaves.
- Not checking the floor below or the far side of walls and partitions.
- Using an untrained person or one without a working extinguisher.
- Failing to document the fire watch on the permit.
How SMS360 Helps
SMS360's Work Permits module supports digital hot work permits that record precautions, the assigned fire watch and close-out times. Training Management tracks fire watch and extinguisher training, and Audits & Inspections supports extinguisher and hot work area checklists.
For OSHA's text, see 29 CFR 1910.252 and 29 CFR 1915 Subpart P on eCFR. See also our page on welding, cutting and hot work regulations.
Frequently Asked Questions
How long does a fire watch need to last after hot work?
OSHA requires at least 30 minutes after welding or cutting in general industry. NFPA 51B (2019 edition) requires at least 1 hour, with possible additional monitoring of up to 3 hours. Follow the strictest requirement that applies to you.
Can the welder be the fire watch?
No. A fire watch must focus on watching for fires, and in shipyards OSHA prohibits assigning other duties while hot work is in progress. The person doing the hot work cannot watch all exposed areas at the same time.
What training does a fire watch need?
Fire watchers must be trained in using the fire extinguishing equipment and familiar with how to sound the alarm. In shipyards, training is required before assignment and annually.
When is a fire watch required for an impaired sprinkler system?
Fire codes generally require a fire watch when a required sprinkler or alarm system is out of service. Specific triggers vary by jurisdiction, so check your local fire code and fire marshal.
