|Hot Work (Welding, Cutting, Heating, Soldering and Brazing)
|Environmental Health and Safety (EH&S)
|Last Revision Date
The hazards of welding, cutting, soldering and brazing may include fire and explosion, electrical shock, eye injury, burns and noxious fume inhalation. Therefore, safe hot work practices must be observed at all times.
Only qualified personnel who are familiar with required safety practices, will be authorized to perform hot work operations.
Hot Work Permits
- Prior to performing hot work, obtain a hot work permit.
- EH&S will audit/inspect hot work permit upon receipt of completed permit.
- Notify EH&S upon completion of work authorized on permit and return completed permit to EH&S within 24 hours.
Personal Protective Equipment
- Eye Protection: Welding helmets shall be used during all arc welding operations.Welding goggles or other suitable eye protection shall be used during all gas welding or cutting operations and as needed for brazing operations. Eye protection shall be worn when chipping scarf or metal fragments.
- Protective Clothing: All welders should wear flameproof gauntlet gloves. Flameproof aprons may be desirable for protection against radiated heat and sparks. All clothing should be reasonably free from oil or grease.
- Welding Booths and Welding Bays
- Welding Bays: Where arc welding is regularly carried on in a building, the walls of the welding bay should be painted with a finish of low reflectivity.
- Welding Booths: Arc Welding. The worker should be enclosed in an individual booth painted with a finish of low reflectivity, or shall be enclosed with noncombustible screens similarly painted. Booths and screens shall permit circulation of air at floor level.
- Adjacent Work Spaces: Arc Welding. Workers or others adjacent to the welding areas shall be protected from the rays by noncombustible screens or shields or shall be required to wear appropriate goggles.
Ventilation - General
- Mechanical Ventilation and exhaust shall be provided when welding or cutting is done:
- In a space of less than 10,000 cubic feet per welder.
- In a room having a ceiling height of less than 16 feet.
- In confined spaces or where the welding space contains partitions, or other structural barriers that significantly obstruct ventilation.
- On materials or under conditions likely to cause the release of harmful quantities
of toxic airborne contaminants.
Such ventilation shall be at the minimum rate of 2,000 cubic feet per minute per welder, except when local exhaust ventilation or supplied air respirators are provided.
- Local Exhaust Ventilation - may be by means of either:
- Freely movable hoods intended to be placed by the welder as near as practicable to the work being welded and provided with a rate of air flow sufficient to maintain a velocity in the direction of the hood of 100 linear feet per minute in the zone of the welding when the hood is at its most remote distance from the point of welding. (Note: increased rates of ventilation may be required for specific airborne contaminants).
- A fixed enclosure with a top and not less than two sides which surround the welding or cutting operations and with a rate of air flow sufficient to maintain a velocity away from the welder’s breathing zone of not less than 100 linear feet per minute.
Degreasing Operations - Chlorinated Hydrocarbons
Degreasing or other cleaning operations involving chlorinated hydrocarbons shall be so located that no vapors from these operations will reach or be drawn into the atmosphere surrounding any welding operations.
- Prohibited Welding Situations: Cutting or welding shall not be permitted in the following
- In the presence of flammable or explosive atmospheres.
- In areas near the storage of quantities of readily ignitable materials.
- In air handling units and ducts.
- Outside of a regularly assigned welding area without an authorization.
- Precautions Before Welding: Before cutting or welding is permitted outside an assigned
welding area, the area shall be inspected by the individual responsible for authorizing
the cutting and welding operations, generally the welder’s supervisor.
The supervisor shall designate precautions to be followed in granting authorization to proceed after assuring himself of the following:
- Combustible floors shall be kept damp, or protected by fire resistant shields.If combustible materials are on the floor, (paper, wood shavings, etc.) the floor shall be swept clean for a radius of 35 feet. Where floors have been dampened, personnel operating arc welding equipment shall be protected from possible shock.
- If relocation of combustibles to outside the 35 foot radius is impractical, flame retardant covers shall be provided. Edges of covers should be tight to prevent sparks from entering.
- Wall or floor openings or cracks within the welding area shall be tightly covered to prevent the passage of sparks or hot metal to adjacent areas.
- Cutting or welding on pipes or other metal in contact with combustible walls, partitions, or other structures shall not be undertaken if the work is close enough to cause ignition by conduction.
- Containers having held flammable or toxic liquids shall not have any hot work performed on them until they have been cleaned thoroughly. If doubt exists, contact Environmental Health & Safety for additional assistance.
- Portable fire extinguishers appropriate for the type of possible fire shall be available at the work area.
- A fire watch shall be required and provided whenever cutting or welding is performed
in locations where other than a minor fire might develop, or where any of the following
- Overhead welding or cutting is being done.
- Appreciable amount of combustible material in building construction or contents closer than 35 feet to hot operation.
- Observe welding cutting area for at least one half hour after completion of operations and during any lunch or rest period to detect and extinguish possible smoldering fires.
- Storage- Gas cylinders will be stored only in approved spaces where the danger of
being damaged or knocked over is minimized. Cylinders shall be secured from falling.
- Oxygen Cylinders- Shall not be stored in same location with cylinders of flammable gases or combustible materials unless separated by a distance of 20 feet or a fire resistant partition at least 5 feet high with a one hour fire rating.
- Control valves of cylinders not in use shall be covered by protective caps; in use, they shall be unobstructed and immediately accessible to permit quick shut down in an emergency.
- Marking: Compressed gas cylinders shall be legibly marked identifying the gas content on the shoulder of the cylinder.
- Additional safety precautions for the safe handling of compressed gas cylinders can be found in Part III Handbook of Compressed Gases by the Compressed Gas Association.