Recently, several fires occurring during hot work have been reported to BSEE. Hot work is any job with the potential to create an ignition source, such as an open flame, sparks, or high temperatures. Examples of hot work include welding, using acetylene torches, and grinding and cutting metal.
Incident 1: As a construction crew removed skid pads with a torch on the top deck, slag and sparks fell through the grating onto the manway cover of the water skimmer below, igniting a fire. The fire self-extinguished shortly thereafter as the fire watch was securing a dry chemical fire. The water skimmer had been cleaned a week prior in preparation for vessel entry but had not been deemed inert, and the oil dump lines were later found to be full of flammable condensate. Although gas was not detected in the area around the skimmer before starting work, an 8% lower explosive limit was detected at the manway cover later. Workers used fire retardant tarps earlier in the job, but when the workers moved to a new location above the water skimmer, they did not take the retardant tarps with them.
Incident 2: While cutting grating with an acetylene torch, falling sparks ignited gas leaking from a pinhole on a gas sales riser located 15 feet below the grating. The fire watch noticed and stopped the job. A worker used a 30-pound ABC fire extinguisher to extinguish the flame. Although a gas detector had measured a 0.0% lower explosive limit before the work started, the gas leak occurred in an area not easily accessible for inspection or gas monitoring.
Incident 3: Before a construction crew removed steel bar grating from beneath a building, several inches were elevated to provide a distance barrier between the subfloor and the torch cutting below. Saltwater was used to saturate the subfloor, and water was re-applied periodically. The crew finished their work, and the fire watch remained on location for an additional 30 minutes. A fire was noticed on the lower side of the building 15 minutes later, which was extinguished with the saltwater hose. It was found that the distance barrier may not have been sufficient to prevent a fire and that the combustible surfaces should be saturated with water during the fire watch period and during the job.
Therefore, BSEE recommends that operators and contractors consider:
- Using flameproof tarps or other fire-resistant guards protects equipment from falling sparks and excessive heat. Scaffolding may be required to cover elevated areas. Refer to 30 CFR § 250.113 for procedures to follow prior to, during, and after welding.
- Covering and sealing nearby deck and skid drains before starting hot work prevents flammable gases from entering the area.
- Check skid pans (visually and with a gas detector) for residual flammable liquids and flood them with water if possible.
- Designate a fire watch during jobs involving open flames, sparks, or heat sources. Operators should maintain the fire watch for at least 30 minutes after welding activities end, recognizing that some jobs may require longer periods.
- Ensuring the fire watch is positioned well to view all hazardous areas near the hot work location.
- Locate and inspect the closest fire extinguisher before starting hot work. If an extra fire extinguisher is available, move it near the work area before starting the job.
- Verify that any nearby vessel previously containing hydrocarbons has been properly flushed and deemed inert before starting hot work.
- Complete a hot work permit and Job Safety Analysis and review them immediately before starting the job. All personnel involved with the job should participate in this process.
- Use the facility’s designated safe welding area for hot work when possible and follow your BSEE-approved safe welding and burning permit.
- Use gas detectors to monitor the area continuously and ensure that flammable gases are not present before and during hot work.
- Testing areas where sparks are likely to fall. Remember: gas detectors may be less effective at finding leaks in well-ventilated areas.
- Calibrating gas detectors regularly and bump testing them before each use.