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March 2019: Hot Work

As noted in the most recent NFPA Research Report "Structure Fires Started by Hot Work," Hot Work remains to be a leading ignition source for structure fires. NFPA estimates that during the five-year period of 2010-2014 local fire departments responded to an estimated average of 4,440 structure fires per year involving equipment associated with hot work. These fires caused an average of 12 civilian deaths, 208 civilian injuries and $287 million in direct property damage per year.

A frequent misconception is that hot work is only welding. Brazing, cutting, grinding, soldering, thawing pipe, torch-applied roofing and welding are all examples of hot work. These are operations that involve open flames or produce heat and/or sparks.

By taking certain safeguards, you can help to decrease and possibly prevent property losses and on the job injuries, avoid costly business downtime, retain market share and keep experienced employees at work. Even when a fire is not prevented, proper hot work procedures will help to minimize damage, with monitoring and quick response. Whether the work is being performed by outside contractors or in-house employees, a formal Hot Work Permit System will help ensure proper precautions and safeguards are taken during these potentially hazardous operations.

As we noted in our October 2014 web article, you may think that hot work operations are well controlled at your facility since you have a permit system in place; however, many facilities could improve their hot work programs.

Two of the most critical parts of a Hot Work Permit System are training and preplanning. Educate employees, and sometimes contractors, about hot work precautions and let them know their responsibilities when hot work is performed on site. Before issuing a permit or starting any hot work, ask yourself is it possible to complete the job without performing any hot work? Can the work be conducted in the maintenance shop or other safe location? Is there a safer way? There may be some instances when hot work must be prohibited because an area cannot be made safe (i.e., processes involving flammable liquids, gases and dusts, on walls and partitions of combustible sandwich-type construction, etc.).

If hot work operations are necessary, an appropriate supervisor or permit authorizing individual (PAI) should confirm the checklist of precautions on the permit are being taken. The PAI should fill out the permit and issue Part 2 to the person(s) doing the work. The supervisor should retain part 1 until the job is complete.

Precautions to take for hot work operations are also often not fully understood. One item often missed is clearing combustibles for 35 ft. (11 m) around the work area. This means that all combustibles within a 35 ft. radius of the work area should be removed. It is critical to relocate any flammable or combustible liquids or flammable gases from the work area. Flammable or combustible liquids were first ignited in 15% of the non-residential fires recorded in the aforementioned NFPA Research Report.

If relocating combustibles is not practical (i.e., working on roofs with combustible covering and/or insulation), then combustibles should be protected by a listed welding curtain, welding blanket, or welding pad.

Personnel sometimes view combustibles as only paper or wood. Items such as plastics, fabrics, many powders, liquids, gases, etc. are also combustible. Thus, it is important to ensure that personnel understand what items are combustible and must be addressed.

A fire watch is required during all hot work operations where combustibles are present or where other than a minor fire might develop. The fire watch position should be that person’s only duty. This person should have an appropriate fire extinguisher ready if needed; scan the area to ensure that combustibles are not introduced to the area once the work starts; scan the area for any smoldering, smoke, and any other signs of fire; and take appropriate actions as needed.

In addition, a fire watch should be maintained after completion of hot work operations to detect and extinguish smoldering fires. Careful inspection of the work and adjacent areas should be made at this time. This inspection should also include adjacent rooms and the floors above and below the work area (if walls or floors were worked on).

The 2019 edition of NFPA 51B, Standard for Fire Prevention during Welding, Cutting and Other Hot Work, increased the minimum duration of the fire watch after work is completed from 30 min. to 1 hr. The duration of the fire watch should be extended if the fire hazards warrant so. Following the completion of the established fire watch time period, fire monitoring should be provided for up to an additional 3 hours as needed as determined by the PAI.

Upon completion of the work and monitoring period, the PAI or a designee should perform a final inspection of the area and complete the permit. The permit should be reviewed for proper completion, enforcement of precautions and follow-up training and retained as a record.

Hot Work permits should not be issued for longer than a single work day, as conditions can change between the time the workers stop hot work operations and restart the following day.

You may also notice that the use of a hot work permit is not needed if you set up a designated area for hot work. This makes conducting hot work more convenient. However, properly setting up a designated hot work area is more involved than just putting welding equipment and a metal table in the corner of a room. These designated areas should be arranged to meet the requirements of the permit. As such, combustibles should be at least 35 ft. away or separated from the work area by a fire barrier.

Risk Logic can help ensure that hot work is properly controlled at your facility. Please contact us for additional information.

Reference Documents:
NFPA Research Report, Structure Fires Started by Hot Work (September 2016)
NFPA Standard 51B (2019), Standard for Fire Prevention during Welding, Cutting and Other Hot Work