Hot Work: Controlling Spark Producing Activities



Hot work activity is a common task that is necessary in a variety of workplaces. General industry workplaces usually require maintenance shops or fabrication areas while construction jobsites generally require some type of cutting and/or welding during various phases of construction.

Hot work activity is most commonly defined as work involving electric or gas welding, cutting, grinding, brazing, or similar flame or spark-producing operations. These activities can inadvertently place an ignition source into an area with combustible or flammable material. Most ignition sources from these activities can reach temperatures well over 1,000oF which can easily ignite flammable and combustible materials. The hazards associated with hot work can be serious in nature when not properly managed or abated. In certain applications, hot work activity can cause catastrophic events. These include but are not limited to, activity on or near flammable storage tanks, permit-required confined spaces, and near highly hazardous chemicals. According to the US Chemical Safety Board (CSB), since 1990 hot work activity on or near flammable storage tanks has caused over 60 fatalities from fires and explosions.

OSHA has specific requirements for hot work in Confined and Enclosed Spaces and Other Dangerous Atmospheres in Shipyard Employment found in 1915.14; however this article will focus primarily on the general industry and construction requirements.

To minimize the potential for a fire or explosion there are defined precautions to establish a safe work environment. In today’s culture it is common to see a hot work permit procedure required by an insurance company, a general contractor and in certain processes there are 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 contains requirements for preventing or minimizing the consequences of catastrophic releases of toxic, reactive, flammable, or explosive chemicals. These releases 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 one location, in a quantity of 10,000 pounds.

For hot work in the general industry and construction arenas, these guidelines should be implemented for the management hot work safety.

• First, determine if there are alternatives to hot work to complete the task. For example, determine if materials can be connected through alternative means such as bolting or riveting rather than welded. 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 the answer is no, the following steps should be implemented.

• Complete a comprehensive hazard assessment. At a minimum the assessment should include the following:
-Specific steps and details of the hot work;
-The tools and materials to be used;
-The environmental conditions where the hot work is scheduled. This includes combustible or flammable material storage; openings in doors, walls, windows or tanks; ducts or conveyor systems that can transport sparks or hot slag.

• Monitor for flammable and combustible vapors, especially when working around tanks or pipes containing flammable or combustible liquids. This includes areas that could potentially contain flammable vapors due to decomposition. In addition, it is imperative to test areas in close proximity and inside the tank(s) before and during hot work. Keep in mind that as the day progresses, sunlight can also heat chemicals inside storage tanks.

• Written permits should be provided by a permit authorizing individual. A permit authorizing individual is typically a supervisor or superintendent who has completed hot work safety training. The permit authorizing individual is responsible for:
-Inspecting the hot work site;
-Assigning a trained fire watch;
-The identification and communication of fire prevention measures;
-Records information on the hot work permit;
-Provides 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:
-Within a 35 foot radius, cover combustible flooring, ensure sparks cannot reach combustible material which could drop to another floor;
-Remove all flammable and combustible liquids;
-Cover all floor and wall openings to prevent entry of sparks or hot slag;
-Cover combustible materials that cannot be moved;
-Require a trained fire watch during the work and for at least 30 minutes after the work is completed;
-Provide adequate number of portable fire extinguishers;
-Familiarize the fire watch with procedures to report a fire and activating the fire alarm.

The hot work operator must post the permit near the activity. The permit should only be used 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 utilized to perform hot work, their hot work program and training should be verified for competency.

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

Some areas are prohibited from hot work, these include but are not limited to:
-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;
-In the vicinity of explosive atmospheres including areas that may develop explosive atmospheres due to improper preparation.

Other hazards to consider during hot work 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, the hazards must be identified, assessed and managed. Failure to identify and manage all hazards can lead to serious and even catastrophic events.

The information in this article was provided by the US Chemical Safety Board, OSHA, NFPA and ANSI.

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