Hot Work and Fire Prevention: Safety Regulations

This document outlines the safety regulations governing hot work operations and fire prevention practices in various industries. It is based on a compilation of standards and regulations from different jurisdictions to provide a comprehensive overview of the requirements for ensuring workplace safety during hot work.

General Requirements

Hot work operations, including welding, cutting, and heating, are subject to specific fire prevention and protection requirements. These regulations aim to minimize the risk of fire and explosions associated with these activities.

Permit Requirements

Employers are generally required to issue a hot work permit for hot work operations conducted on or near a covered process. The permit must document that fire prevention and protection requirements have been implemented before starting hot work. The permit should also indicate the authorized dates for hot work and identify the object on which work is to be performed. The permit must be kept on file until the completion of the hot work operations. [1] [1]

Fire Prevention Measures

Several fire prevention precautions must be taken before and during hot work operations:

• Combustible materials must be removed or protected from ignition sources. If objects to be welded, cut, or heated cannot be moved, all movable fire hazards in the vicinity must be taken to a safe place or otherwise protected. If all fire hazards cannot be removed, positive means must be taken to confine heat, sparks, and slag and to protect immovable fire hazards.
• Welding, cutting, or heating must not be done where flammable paints, compounds, or heavy dust concentrations create a hazard.
• Suitable fire extinguishing equipment must be immediately available in the work area and maintained in a state of readiness for instant use.
• When normal fire prevention precautions are insufficient, additional personnel must be assigned to guard against fire during and after the operation to ensure no possibility of fire exists. These personnel must be instructed on specific fire hazards and the use of firefighting equipment.
• When welding, cutting, or heating is performed on walls, floors, and ceilings, the same precautions must be taken on the opposite side to address fire hazards in adjacent areas.
• The gas supply to the torch must be positively shut off at a point outside enclosed spaces whenever the torch is not in use or is left unattended. Torches and hoses must be removed from confined spaces overnight or during shift changes. Open-end fuel gas and oxygen hoses must be immediately removed from enclosed spaces when disconnected.
• Drums, pails, and other containers that contain or have contained flammable liquids must be kept closed except when contents are being removed or transferred. Empty containers must be removed to a safe area apart from hot work operations or open flames.

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Specific Industries and Environments

Mining Operations

In mining operations, specific regulations apply to hot work to prevent fires and explosions:

• A written safe work procedure for fire prevention must be established and implemented when using gas or electric welding or cutting equipment, blow torches, or other heat-producing devices underground or in areas where a fire could endanger an entrance to underground workings.
• Combustible material within a 3-meter radius, or where sparks or hot metal could fall, must be wetted with water before hot work begins and again after it is finished.
• The area where hot work is done must be inspected for smoldering fires at regular intervals after the work is finished.
• Fire-fighting equipment must be on hand at all times during the operation and until the completion of the inspection.
• Hot work must not be done within 10 meters of where an explosive is stored or transported.
• Propane or similar fuel that is heavier than air in a gaseous state is generally not permitted underground, except when used for burning or cutting.

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Flammable Substances

Special precautions are necessary when flammable substances are present:

• Hot work should not be performed if a flammable substance is or may be present until suitable tests confirm the work can be safely performed and work procedures are implemented to ensure continuous safe performance.
• Tests must be conducted at intervals appropriate to the work being performed and the results recorded.
• Hot work is prohibited near materials that constitute a fire hazard until suitable steps have been taken to reduce the risk of fire.
• Containers or piping that contain or have contained a flammable substance must be purged using an effective method to remove the flammable substance before any hot work is begun.
• Welding or cutting of metal cleaned with a flammable or combustible liquid is not allowed until the metal has thoroughly dried.

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Containers

Specific rules apply to welding or cutting containers:

• Welding operations must not be performed on drums, barrels, tanks, or other containers until they have been cleaned of all flammable, combustible, or toxic materials or fumes.
• All pipelines or other connections to drums, barrels, or tanks must be disconnected or blanked before performing welding operations.
• Hollow spaces or cavities must be vented and either filled with water or purged with an inert gas before preheating, cutting, or welding.
• An opening must be maintained during welding and cutting to vent gases or vapors.

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Flammable or Explosive Atmospheres

Regulations address working in atmospheres where flammable or explosive substances may be present:

• If a flammable or explosive substance is present in the atmosphere of a work site at a level exceeding 20% of the lower explosive limit (LEL) for that substance, workers are generally prohibited from entering or working at the site.
• This restriction may not apply to firefighters or competent workers acting in emergency situations, provided they are trained, equipped, and work according to an approved standard, and a written record of their training is maintained.

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General Fire Prevention

General fire prevention measures are essential to maintain a safe work environment:

• Garbage that may constitute a fire hazard must be placed in covered receptacles suitable to the nature of the hazard.
• Materials contaminated by flammable liquids must be placed in non-combustible receptacles with close-fitting metal covers, labeled "flammable," and located at least 1 meter away from other flammable liquids.
• Combustible and flammable liquids must be kept in receptacles that meet the requirements set out in the National Fire Code of Canada 1990, including any revisions and errata.
• Portable fire extinguishers must be selected, located, inspected, maintained, and tested to protect worker health and safety. They must be placed within 9 meters of industrial open-flame portable heating devices, tar pots, asphalt kettles in use, and welding or cutting operations in progress.

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Training and Communication

Proper training and communication are crucial for ensuring safety during hot work:

• The employer must thoroughly instruct employees in the safe use of fuel gas.
• Personnel assigned to guard against fire must be instructed as to the specific anticipated fire hazards and how the firefighting equipment provided is to be used.

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Mechanical Integrity

Maintaining the mechanical integrity of process equipment is also vital for preventing fires and ensuring safety:

• Employers must establish and implement written procedures to maintain the ongoing integrity of process equipment.
• Employees involved in maintaining the integrity of process equipment must be trained in an overview of the process and its hazards, as well as in the procedures applicable to their job tasks.
• Inspections and tests must be performed on process equipment following recognized and generally accepted good engineering practices.
• The frequency of inspections and tests must be consistent with manufacturers' recommendations and good engineering practices, and more frequently if necessary based on prior operating experience.
• Each inspection and test performed on process equipment must be documented, including the date, the name of the person who performed the inspection or test, the equipment identifier, a description of the inspection or test, and the results.
• Deficiencies in equipment that are outside acceptable limits must be corrected before further use or in a safe and timely manner.
• Quality assurance measures must be implemented to ensure that equipment is suitable for the process application, installed properly, and that maintenance materials, spare parts, and equipment are suitable for the process application.

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