Hot work permit

Hot work permits and safety procedures are essential for managing the risks associated with hot work, such as welding, cutting, and brazing. A hot work management program is put in place to control or eliminate hot work hazards and their risks. Programs include the development of policies, procedures, and the assignment of responsibilities and accountabilities for all aspects of hot work. [3]

A hot work management program should address:

• Where hot work is permitted
• When hot work is permitted
• Who authorizes, performs, and monitors hot work activities
• What must be assessed before permitting/performing hot work in an area or on a process piece of equipment or area
• What to do to prepare an area for hot work
• What to do if hot work cannot be avoided in a particularly hazardous area
• What hot work tools are required
• How to obtain a hot work permit, when they are required, and who can administer them

[2] [3] Before performing hot work, consider these general good practices:

• Make sure you are following your hot work procedure.
• Make sure that all equipment is in good operating order before work starts.
• Make sure that all appropriate personal protective devices are available at the site and each worker has been trained on how to use, clean, and store them properly.
• Inspect the work area thoroughly before starting. Look for combustible materials in structures (partitions, walls, ceilings).
• Move all flammable and combustible materials away from the work area.
• If combustibles cannot be moved, cover them with fire-resistant blankets or shields. Protect gas lines and equipment from falling sparks, hot materials, and objects.
• Make sure that all available fire suppression systems are in good repair and operable (e.g., sprinklers, hoses, extinguishers, etc.)
• Make sure that appropriate fire extinguishers (e.g., ABC fire extinguishers) are available and easily accessible.
• Sweep clean any combustible materials on floors around the work zone. Combustible floors must be kept wet with water or covered with fire-resistant blankets or damp sand.
• Remove any spilled grease, oil, or other combustible liquid.
• Vacuum away combustible debris from inside ventilation or other service duct openings to prevent ignition. Seal any cracks in ducts. Prevent sparks from entering into the duct work. Cover duct openings with a fire resistant barrier and inspect the ducts after work has concluded.
• Make sure that the first-aid boxes are available and easily accessible.
• Block off cracks between floorboards, along baseboards and walls, and under door openings, with a fire resistant material. Close doors and windows.
• Cover wall or ceiling surfaces with a fire resistant and heat insulating material to prevent ignition and accumulation of heat.
• Secure, isolate, and vent pressurized vessels, piping and equipment as needed before beginning hot work.
• Inspect the area following work to ensure that wall surfaces, studs, wires or dirt have not heated up.
• Post a trained fire watcher within the work area, including lower levels if sparks or slag may fall during welding, including during breaks, and for at least 60 minutes after work has stopped. Depending on the work done, the area may need to be monitored for longer (up to 3 or more hours) after the end of the hot work until fire hazards no longer exist.
• Eliminate explosive atmospheres (e.g., vapours or combustible dust) or do not allow hot work. Shut down any process that produces combustible atmospheres, and continuously monitor the area for accumulation of combustible gases before, during, and after hot work.
• Comply with the required legislation and standards applicable to your workplace.

[4] [5] Basic precautions include:

• Moving the object to be welded away from objects that could explode, combust, or ignite when exposed to the heat of the welding process.
• Moving all objects that are prone to explode, combust, or ignite away from the object being welded.
• Placing devices that are designed to shield potentially explosive, combustible, or ignitable materials from open flames, sparks, or hot slag if they cannot be moved from the immovable object that is being welded.

[6] Special precautions should be taken when welding or cutting operations must take place close to materials that are prone to explode, combust, or ignite in the presence of welding or cutting byproducts. [8]

Additional safety measures include:

• Maintaining suitable fire extinguishing equipment in a state of readiness for instant use.
• Requiring fire watchers whenever welding or cutting is performed in locations where other than a minor fire might develop.
• Inspecting the area before cutting or welding is permitted by the individual responsible for authorizing cutting and welding operations.
• Keeping combustible floors wet, covered with damp sand, or protected by fire-resistant shields.
• Ensuring employees are instructed in the safe means of arc welding and cutting.

[9] [10] Arc welding and cutting operations should be shielded by noncombustible or flameproof screens to protect employees and other persons working in the vicinity from the direct rays of the arc. [7]

Areas where cutting or welding is not permitted:

• In areas not authorized by management.
• In sprinklered buildings while such protection is impaired.
• In the presence of explosive atmospheres or explosive atmospheres that may develop inside uncleaned or improperly prepared tanks or equipment which have previously contained such materials, or that may develop in areas with an accumulation of combustible dusts.
• In areas near the storage of large quantities of exposed, readily ignitable materials such as bulk sulphur, baled paper, or cotton.

[10] A permit certifies that the requirements contained in fire prevention and protection have been implemented prior to beginning the hot work operations, and the permit must be kept on file until completion of the hot work operations. [1]