Hot Work includes operations such as electric arc and gas welding, brazing, torch cutting, grinding (large portable grinders on metal), and torch soldering with an open flame. These operations create heat, sparks, and/or hot slag that have the potential to ignite flammable and combustible materials in the work area.
So, “Hot Work” refers to any task that involves burning, welding, or a similar operation capable of initiating fires or explosions, such as cutting, brazing, grinding, and soldering.
The United States Chemical Safety Board (CSB) has identified over 60 fatalities since 1990 due to explosion and fires from hot work activities on tanks.
To find out why these types of accidents occur, the CSB studied 11 incidents, all of which involved hot work on tanks. Although the incidents were unique, all resulted from a flammable vapour coming in contact with an ignition source created by welding or cutting that was performed in, on, or near tanks containing flammables.
In some instances, the presence of a flammable material was unknown to the workers. In all cases, says CSB, the workers had no knowledge that an explosive amount of flammable vapor had accumulated.
Hot Work Safety Recommendations
Here are the 7 recommendations CSB investigators made after studying these hot work incidents:
- Use alternatives. Whenever possible, avoid hot work, and consider alternative methods to accomplish the same results.
- Analyze the hazards. Before starting hot work, perform a hazard identification and risk assessment that considers the scope of the work, potential hazards and methods of controlling those hazards.
- Monitor the atmosphere. Conduct effective gas monitoring in the work area using a properly calibrated combustible gas detector before and during hot work activities, even in areas where a flammable atmosphere is not anticipated.
- Test the area. In work areas where flammables are stored or handled, drain and/or purge all equipment and piping before performing hot work. When welding on or in the vicinity of tanks and containers, properly test and, if necessary, continuously monitor all surrounding tanks or adjacent spaces for the presence of flammables and eliminate potential sources of flammables.
- Use written permits. Ensure that qualified personnel familiar with the specific site hazards review and authorize all hot work and issue permits specifically identifying work to be conducted along with required precautions.
- Train thoroughly. Train personnel on hot work policies and procedures, proper use and calibration of combustible gas detectors, safety equipment, and job-specific hazards and controls. This should be done in a language understood by the workforce.
- Supervise contractors. Provide safety supervision for outside contractors conducting hot work. Inform contractors about site-specific hazards, including the presence of flammable materials.