Hot Work: Controlling Activities that Produces Sparks

By: Vince Plank, CSP

What’s referred to as “hot work activity” is common in many types of workplaces. On construction sites, you’ll find some type of cutting and/or welding during various phases of construction, while in general industry, maintenance shops or fabrication areas are often locations for hot work.

We define hot work activity as tasks involving electric or gas welding, cutting, grinding, brazing, or similar flame or spark-producing operations. Those and other activities can inadvertently place an ignition source into an area with combustible or flammable material. Many of those ignition sources can reach temperatures well over 1,000ºF, providing the potential to ignite flammable and combustible materials.

The hazards associated with improperly managed hot work can be serious, and in some cases, can cause catastrophic events. Activity on or near flammable storage tanks, permit-required confined spaces, and near highly hazardous chemicals are examples of higher-risk situations. According to the U.S. Chemical Safety Board (CSB), more than 60 fatalities have resulted from hot work activity on or near flammable storage tanks since 1990. In this article, we’ll focus primarily on the general industry and construction requirements.

Establishing a safe work environment and minimizing the potential for a fire or explosion requires defined precautions. Hot work permits may be required by insurance companies and general contractors, and some situations involve regulatory requirements. For example, in the process safety management (PSM) of highly hazardous chemicals standard (1910.119), OSHA requires a hot work permit for hot work operations conducted on or near a covered process. The PSM standard includes requirements for preventing or minimizing the consequences of catastrophic releases of toxic, reactive, flammable, or explosive chemicals, particularly releases that may result in toxic, fire or explosion hazards. These include processes which involve a chemical at or above the specified threshold quantities listed in 1910.119 Appendix A and processes which involve a flammable liquid or gas on site in a quantity of 10,000 pounds at one location.

The following guidelines should be implemented for managing hot work safety in the general industry and construction arenas.

First, determine if there are alternatives to hot work that can be used. For example, determine whether materials can be connected through means such as bolting or riveting rather than welding. Can the material be cold cut rather than using a cutting torch? If hot work is required, can the material be relocated to an area free from combustibles and flammables? If there are no practical alternatives, workers should implement the following steps:

  • Complete a comprehensive hazard assessment, with at least:
    • specific steps and details of the hot work,
    • the tools and materials to be used, and
    • the environmental conditions where the hot work is scheduled. This includes combustible or flammable material storage; openings in doors, walls, windows or tanks; as well as ducts or conveyor systems that can transport sparks or hot slag.
  • Monitor for flammable and combustible vapors, especially around tanks or pipes containing flammable or combustible liquids., and areas that could potentially contain flammable vapors resulting from decomposition. It’s imperative to test areas in close proximity and inside the tank(s) before and during hot work. As the day progresses, sunlight can also heat chemicals inside storage tanks.
  • Written permits should be provided by authorizing individual, typically a supervisor or superintendent who has completed hot work safety training and who is responsible for:
    • inspecting the hot work site,
    • assigning a trained fire watch,
    • identifying and communicating fire prevention measures,
    • recording information on the hot work permit, and
    •  providing the permit to the hot work operator.
  • The hot work operator cannot begin hot work until the permit requirements have been satisfied. General requirements for hot work permits include:
    • covering combustible flooring within a 35-foot radius to ensure sparks cannot reach combustible material which could drop to another floor,
    • removing flammable and combustible liquids,
    • covering floor and wall openings to prevent entry of sparks or hot slag,
    • covering combustible materials that cannot be moved,
    • requiring a trained fire watch during the work and for at least 30 minutes after the work is completed,
    • providing an adequate number of portable fire extinguishers, and
    • familiarizing the fire watch with procedures to report a fire and activate the fire alarm.
      The hot work operator must post the permit near the activity, and the permit should only be in effect for a single shift or 8 hours (whichever is less).

• Provide supervision and routine inspection for contractors performing hot work. Since contractors may not be familiar with specific operations and their hazards, they must be informed when performing work onsite. Contractors performing hot work activity on a client’s property must follow the same procedural requirements. When contractors are used to perform hot work, the competency of their hot work program and training should be verified.

• Provide routine training for supervisors/superintendents and employees who perform hot work activity.

Some areas are prohibited from hot work, among them:

    • areas not authorized by management,
    • in buildings or areas where fire suppression or sprinkler systems are impaired,
    • in areas near the storage of large quantities of combustible materials, and
    • in the vicinity of explosive atmospheres and areas that may develop explosive atmospheres due to improper preparation.

Other hazards to consider include thermal/burn protection of employees, adequate ventilation from fume generation and proper securing and storage of compressed gas cylinders.

In conclusion, when hot work activity is required in the workplace, failing to identify, assess and manage all hazards can lead to serious and even catastrophic events.

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