OSHA's Welding, Cutting and Brazing standards, found in 29 CFR 1910 Subpart Q, set the rules for hot work in general industry. They protect welders, cutters and the people around them from fires and explosions, burns, eye injuries, toxic fumes and electric shock.
Hot work causes fires when sparks and slag travel farther than people expect, sometimes through cracks, floor openings or ducts, and ignite materials out of sight. The Subpart Q rules focus on preventing that, through hot work authorization, fire watches, protective equipment, ventilation and safe handling of gas cylinders and arc welding equipment.
What Are the Welding, Cutting and Brazing Standards?
Subpart Q contains five sections:
- 1910.251, Definitions
- 1910.252, General requirements, covering fire prevention, personnel protection and health and ventilation
- 1910.253, Oxygen-fuel gas welding and cutting
- 1910.254, Arc welding and cutting
- 1910.255, Resistance welding
The fire prevention rules in 29 CFR 1910.252(a) draw on NFPA 51B, the National Fire Protection Association standard for fire prevention during welding and cutting, which OSHA incorporates by reference. Most employers manage these rules through a written hot work permit program.
Key terms
- Hot work: welding, cutting, brazing, soldering, grinding and similar work that produces flames, sparks or heat capable of igniting materials.
- Fire watch: a trained person assigned to watch for and put out fires during and after hot work.
Who Must Comply?
Subpart Q applies to general industry employers whose employees weld, cut or braze, whether in a dedicated shop or during maintenance anywhere in a facility.
Construction work follows 29 CFR 1926 Subpart J (1926.350 to 1926.354), and shipyards and marine terminals have their own hot work rules in Parts 1915 and 1917. OSHA's welding standards page lists them by sector. States with OSHA-approved State Plans may have different or stricter rules, and local fire codes often add hot work permit requirements of their own.
Key Requirements
Basic fire prevention, 1910.252(a)(1)
The standard sets a simple order of precautions. If the object to be welded or cut cannot readily be moved, all movable fire hazards nearby must be taken to a safe place. If neither the object nor the fire hazards can be moved, guards must be used to confine the heat, sparks and slag. If neither step can be taken, welding and cutting must not be performed.
Special precautions
- Combustibles: where practicable, move combustibles at least 35 feet from the work. Otherwise, protect them with flameproof covers, metal guards or curtains.
- Floors: sweep combustible floors clean for a radius of 35 feet, and wet them, cover them with damp sand or protect them with fire-resistant shields.
- Openings: protect combustibles below floor openings, cracks and wall or door openings from falling sparks.
- Extinguishers: keep suitable fire extinguishing equipment, such as water pails, sand buckets, hose or portable extinguishers, ready for instant use.
Fire watch
Under 1910.252(a)(2)(iii), fire watchers are required wherever welding or cutting is done in locations where other than a minor fire might develop, or where any of these conditions exist:
- Appreciable combustible material in building construction or contents closer than 35 feet to the point of operation
- Appreciable combustibles more than 35 feet away but easily ignited by sparks
- Wall or floor openings within a 35-foot radius that expose combustible material in adjacent areas, including concealed spaces
- Combustible materials adjacent to the opposite side of metal partitions, walls, ceilings or roofs that could be ignited by conduction or radiation
Fire watchers must have extinguishing equipment readily available, be trained in its use and know how to sound an alarm. They watch for fires in all exposed areas, try to extinguish them only within the capacity of their equipment, and otherwise sound the alarm. The fire watch must be kept for at least a half hour after welding or cutting is completed.
Authorization and prohibited areas
Before cutting or welding is permitted, the individual responsible for authorizing it must inspect the area and designate the precautions to be followed in granting authorization, preferably in a written permit. Under (a)(2)(vi), cutting or welding is not permitted in areas not authorized by management, in sprinklered buildings while the sprinklers are impaired, in explosive atmospheres, or near large quantities of exposed, readily ignitable materials such as bulk sulfur, baled paper or cotton.
Management must also designate approved areas and establish procedures, designate the individual responsible for authorizing hot work, make sure cutters, welders and supervisors are trained, and advise contractors about flammable materials or hazardous conditions.
Containers
Used drums, barrels and tanks that held flammable or residue-producing substances must be thoroughly cleaned, disconnected or blanked off, and vented before hot work.
Personnel protection and ventilation
- Eye protection: helmets or hand shields for arc welding and arc cutting, and goggles or equivalent protection for gas welding and oxygen cutting, with filter lenses of the right shade (1910.252(b)(2)).
- Protective clothing suited to the hazard, under the general PPE standard.
- Mechanical ventilation is required under (c)(2) when welding in a space of less than 10,000 cubic feet per welder, in a room with a ceiling under 16 feet, or in confined spaces or where structures obstruct cross ventilation. The minimum rate is 2,000 cubic feet per minute per welder.
- Confined spaces need ventilation, an attendant outside with a rescue plan and gas cylinders and welding machines left outside.
- Hazard communication: welding consumables and fumes are covered by the hazard communication program, and specific metals such as cadmium, beryllium and lead carry added requirements.
Oxygen-fuel gas systems, 1910.253
- Acetylene may not be generated, piped (except in approved cylinder manifolds) or used at a pressure above 15 psig.
- Oxygen cylinders in storage must be separated from fuel-gas cylinders or combustible materials, especially oil or grease, by at least 20 feet or by a noncombustible barrier at least 5 feet high with a fire-resistance rating of at least one-half hour.
- Valve protection caps must be in place, hand tight, whenever a cylinder designed for one is not in use or connected for use.
Arc welding, 1910.254
Arc welding equipment must be operated by properly instructed and qualified workers. Machine frames must be grounded, cables with damaged insulation replaced, and cables with splices within 10 feet of the electrode holder not used. Electrode holders must be placed so they cannot contact people, conductive objects, or fuel or compressed gas tanks when not in use.
Training and Documentation
Subpart Q does not set a fixed training frequency or records retention period. It does require that cutters, welders and their supervisors be suitably trained in the safe operation of their equipment and the safe use of the process, that fire watchers be trained in using extinguishing equipment, and that arc welders be properly instructed and qualified. Employees in charge of oxygen or fuel-gas supply equipment must be instructed and judged competent before being left in charge.
A written permit is described as preferable rather than mandatory, but it is the clearest way to show the area was inspected and precautions were set.
Common Compliance Mistakes
- Welding without inspecting the area or getting authorization
- Ending the fire watch as soon as the welder leaves, rather than at least 30 minutes after work stops
- Leaving combustibles within 35 feet without covers or shields
- Hot work while sprinklers are out of service
- Oxygen and fuel-gas cylinders stored together without the 20-foot separation or a fire-rated barrier
OSHA posts current maximum penalties on its penalties page. For penalties assessed after January 15, 2026, the posted maximum is $16,550 per serious violation and $165,514 per willful or repeated violation.
How to Comply: Step by Step
- Designate hot work areas. Set up approved welding areas where possible, so permits are needed only for work elsewhere.
- Name the authorizing person. Assign who inspects areas and approves hot work outside designated areas.
- Use a written permit. Include the 35-foot checks, extinguisher placement, fire watch assignment and sprinkler status.
- Assign and train fire watchers. Keep the watch during work and for at least 30 minutes afterward.
- Check ventilation and PPE. Confirm eye protection, clothing and ventilation fit the process and the space.
- Manage cylinders and equipment. Store oxygen and fuel gas apart, inspect hoses and arc welding cables, and remove damaged equipment.
- Brief contractors. Tell outside welders about hazards and your permit process.
How SMS360 Helps
SMS360's Work Permits module helps you run a consistent hot work permit process. Create digital hot work permits with the checks your procedure requires, route them for approval, and close them out once the fire watch is complete. Mobile access lets supervisors and fire watchers complete permits at the job site.
Completed permits are stored centrally, so you can review open and closed permits, see trends and follow up on issues with assigned corrective actions.
Frequently Asked Questions
How long must a fire watch last after hot work?
Under 1910.252(a)(2)(iii)(B), the fire watch must be maintained for at least a half hour after welding or cutting is completed, to detect and extinguish possible smoldering fires. Your insurer or local fire code may require a longer watch.
Does OSHA require a written hot work permit?
In general industry, 1910.252(a)(2)(iv) requires the responsible individual to inspect the area and designate precautions before authorizing hot work, preferably in a written permit. A written permit is not strictly mandatory under that paragraph, but it is the most practical way to document the inspection and precautions. Local fire codes may require one.
What is the 35-foot rule for welding?
Several Subpart Q precautions use 35 feet. Combustibles should be moved at least 35 feet from the work where practicable, combustible floors swept within a 35-foot radius, and a fire watch posted when appreciable combustibles are within 35 feet or openings within 35 feet expose combustibles.
How far apart must oxygen and acetylene cylinders be stored?
Under 1910.253(b)(4)(iii), oxygen cylinders in storage must be separated from fuel-gas cylinders by at least 20 feet, or by a noncombustible barrier at least 5 feet high with a fire-resistance rating of at least one-half hour.
