OSHA general industry welding, cutting and brazing study guide
Subpart Q of OSHA's general industry rules (29 CFR 1910.251 to 1910.255) covers welding, cutting and brazing. This guide sets out what the rule text states on basic fire precautions, the fire watch and its 35-foot conditions, combustibles and areas where hot work is prohibited, authorization and the duties of management and supervisors, eye protection and screens, ventilation and confined spaces, oxygen-fuel gas cylinder storage and handling, and the basics of arc and resistance welding. Acetylene generators, service piping and the specific-material ventilation rules are not covered in detail. Consensus standards the rule names (such as NFPA 51B and ANSI Z49.1) are only named here, not summarized. Every point links to the regulation and quotes its exact words.
Fire precautions and used containers
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 the object to be welded or cut cannot readily be moved, all movable fire hazards in the vicinity shall be taken to a safe place.”
If the object cannot be moved and not all the fire hazards can be removed, guards must be used to confine the heat, sparks and slag and to protect the fire hazards that cannot be moved.
“If the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed, then guards shall be used to confine the heat, sparks, and slag, and to protect the immovable fire hazards.”
If neither of those two precautions can be followed, welding and cutting must not be performed.
“If the requirements stated in paragraphs (a)(1)(i) and (a)(1)(ii) of this section cannot be followed then welding and cutting shall not be performed.”
The special precautions of paragraph (a)(2), which follow (floor openings, extinguishers, the fire watch, authorization, prohibited areas and more), are introduced as additional precautions that may be necessary when the work falls within the scope of paragraph (a)(1)(ii), the guards case above.
“Special precautions. When the nature of the work to be performed falls within the scope of paragraph (a)(1)(ii) of this section certain additional precautions may be necessary:”
Where floor openings or cracks cannot be closed, precautions must keep sparks from reaching readily combustible materials on the floor below. The same applies to cracks or holes in walls, open doorways and open or broken windows.
“Wherever there are floor openings or cracks in the flooring that cannot be closed, precautions shall be taken so that no readily combustible materials on the floor below will be exposed to sparks which might drop through the floor. The same precautions shall be observed with regard to cracks or holes in walls, open doorways and open or broken windows.”
Suitable fire extinguishing equipment must be kept ready for instant use. Depending on the combustible material exposed, it may be pails of water, buckets of sand, hose or portable extinguishers.
“Suitable fire extinguishing equipment shall be maintained in a state of readiness for instant use. Such equipment may consist of pails of water, buckets of sand, hose or portable extinguishers depending upon the nature and quantity of the combustible material exposed.”
No welding, cutting or other hot work may be done on used drums, barrels, tanks or other containers until they have been cleaned so thoroughly that it is absolutely certain no flammable materials, or substances that might give off flammable or toxic vapors when heated, are present.
“No welding, cutting, or other hot work shall be performed on used drums, barrels, tanks or other containers until they have been cleaned so thoroughly as to make absolutely certain that there are no flammable materials present or any substances such as greases, tars, acids, or other materials which when subjected to heat, might produce flammable or toxic vapors.”
Fire watch
Fire watchers are required whenever welding or cutting is done in locations where other than a minor fire might develop, or when any of the listed conditions exists.
“Fire watchers shall be required whenever welding or cutting is performed in locations where other than a minor fire might develop, or any of the following conditions exist:”
One condition: appreciable combustible material, in building construction or contents, closer than 35 feet (10.7 m) to the point of operation.
“Appreciable combustible material, in building construction or contents, closer than 35 feet (10.7 m) to the point of operation.”
Other conditions: appreciable combustibles are more than 35 feet (10.7 m) away but are easily ignited by sparks; wall or floor openings within a 35-foot (10.7 m) radius expose combustible material in adjacent areas, including concealed spaces in walls or floors; or combustible materials are adjacent to the opposite side of metal partitions, walls, ceilings or roofs and are likely to be ignited by conduction or radiation.
“Appreciable combustibles are more than 35 feet (10.7 m) away but are easily ignited by sparks. (3) Wall or floor openings within a 35-foot (10.7 m) radius expose combustible material in adjacent areas including concealed spaces in walls or floors. (4) Combustible materials are adjacent to the opposite side of metal partitions, walls, ceilings, or roofs and are likely to be ignited by conduction or radiation.”
Fire watchers must have fire extinguishing equipment readily available, be trained in its use, and be familiar with the facilities for sounding an alarm in case of fire. They watch for fires in all exposed areas, try to put them out only when obviously within the capacity of the available equipment, and otherwise sound the alarm.
“Fire watchers shall have fire extinguishing equipment readily available and be trained in its use. They shall be familiar with facilities for sounding an alarm in the event of a fire. They shall watch for fires in all exposed areas, try to extinguish them only when obviously within the capacity of the equipment available, or otherwise sound the alarm.”
When welding on a metal wall, partition, ceiling or roof, precautions must prevent ignition of combustibles on the other side by conduction or radiation, preferably by relocating the combustibles. Where they are not relocated, a fire watch must be provided on the opposite side from the work.
“A fire watch shall be maintained for at least a half hour after completion of welding or cutting operations to detect and extinguish possible smoldering fires.”
When welding on a metal wall, partition, ceiling or roof, precautions must prevent ignition of combustibles on the other side, preferably by relocating them. Where they are not relocated, a fire watch must be provided on the opposite side from the work.
“If welding is to be done on a metal wall, partition, ceiling or roof, precautions shall be taken to prevent ignition of combustibles on the other side, due to conduction or radiation, preferably by relocating combustibles. Where combustibles are not relocated, a fire watch on the opposite side from the work shall be provided.”
Combustibles and prohibited areas
Where combustible materials such as paper clippings, wood shavings or textile fibers are on the floor, the floor must be swept clean for a radius of 35 feet (10.7 m).
“Where combustible materials such as paper clippings, wood shavings, or textile fibers are on the floor, the floor shall be swept clean for a radius of 35 feet (10.7 m).”
Combustible floors must be kept wet, covered with damp sand, or protected by fire-resistant shields. Where floors have been wet down, people operating arc welding or cutting equipment must be protected from possible shock.
“Combustible floors shall be kept wet, covered with damp sand, or protected by fire-resistant shields. Where floors have been wet down, personnel operating arc welding or cutting equipment shall be protected from possible shock.”
Cutting or welding is not permitted in areas not authorized by management, or in sprinklered buildings while that protection is impaired.
“Cutting or welding shall not be permitted in the following situations: (A) In areas not authorized by management. (B) In sprinklered buildings while such protection is impaired.”
It is also not permitted in the presence of explosive atmospheres, including those that may develop inside uncleaned or improperly prepared tanks or equipment that held such materials, or in areas with an accumulation of combustible dusts.
“In the presence of explosive atmospheres (mixtures of flammable gases, vapors, liquids, or dusts with air), 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.”
It is also not permitted near the storage of large quantities of exposed, readily ignitible materials such as bulk sulfur, baled paper or cotton.
“In areas near the storage of large quantities of exposed, readily ignitible materials such as bulk sulfur, baled paper, or cotton.”
Where practicable, all combustibles must be relocated at least 35 feet (10.7 m) from the work site. Where that is impracticable, they must be protected with flameproofed covers or otherwise shielded with metal or asbestos guards or curtains.
“Where practicable, all combustibles shall be relocated at least 35 feet (10.7 m) from the work site. Where relocation is impracticable, combustibles shall be protected with flameproofed covers or otherwise shielded with metal or asbestos guards or curtains.”
Protection of personnel
A welder or helper working on platforms, scaffolds or runways must be protected against falling. Railings, safety belts, life lines or other equally effective safeguards are the options named.
“A welder or helper working on platforms, scaffolds, or runways shall be protected against falling. This may be accomplished by the use of railings, safety belts, life lines, or some other equally effective safeguards.”
Helmets or hand shields must be used during all arc welding or arc cutting, except submerged arc welding. Helpers or attendants must be given proper eye protection.
“Helmets or hand shields shall be used during all arc welding or arc cutting operations, excluding submerged arc welding. Helpers or attendants shall be provided with proper eye protection.”
Goggles or other suitable eye protection must be used during all gas welding or oxygen cutting. Spectacles without side shields, with suitable filter lenses, are permitted for gas welding on light work, for torch brazing or for inspection.
“Goggles or other suitable eye protection shall be used during all gas welding or oxygen cutting operations. Spectacles without side shields, with suitable filter lenses are permitted for use during gas welding operations on light work, for torch brazing or for inspection.”
Helmets and hand shields must be arranged to protect the face, neck and ears from direct radiant energy from the arc.
“Helmets and hand shields shall be arranged to protect the face, neck and ears from direct radiant energy from the arc.”
The shade-number table in the rule is a guide, and its recommendations may be varied to suit the individual's needs.
“The following is a guide for the selection of the proper shade numbers. These recommendations may be varied to suit the individual's needs.”
Where the work permits, the welder should be enclosed in a booth with a low-reflectivity finish, or shall be enclosed with noncombustible screens similarly painted. Booths and screens must allow air to circulate at floor level.
“Where the work permits, the welder should be enclosed in an individual booth painted with a finish of low reflectivity such as zinc oxide (an important factor for absorbing ultraviolet radiations) and lamp black, or shall be enclosed with noncombustible screens similarly painted. Booths and screens shall permit circulation of air at floor level.”
Workers or other persons next to welding areas must be protected from the rays by noncombustible or flameproof screens or shields, or be required to wear appropriate goggles.
“Workers or other persons adjacent to the welding areas shall be protected from the rays by noncombustible or flameproof screens or shields or shall be required to wear appropriate goggles.”
Not covered here
The shade-number values in the 1910.252(b)(2)(ii)(H) table are not reproduced here; read them in the regulation. The consensus standards the rule names for filter lenses are not summarized. We only write what an official source states, so study these parts with your certifying program's materials.
Ventilation and confined spaces
Mechanical ventilation is required for welding or cutting on metals not covered by the specific-material paragraphs when the space is less than 10,000 cubic feet (284 m3) per welder, the ceiling is lower than 16 feet (5 m), or in confined spaces or spaces whose partitions, balconies or other structural barriers significantly obstruct cross ventilation.
“Mechanical ventilation shall be provided when welding or cutting is done on metals not covered in paragraphs (c)(5) through (c)(12) of this section. (For specific materials, see the ventilation requirements of paragraphs (c)(5) through (c)(12) of this section.) (A) In a space of less than 10,000 cubic feet (284 m3) per welder. (B) In a room having a ceiling height of less than 16 feet (5 m). (C) In confined spaces or where the welding space contains partitions, balconies, or other structural barriers to the extent that they significantly obstruct cross ventilation.”
That ventilation must be at least 2,000 cubic feet (57 m3) per minute per welder, except where local exhaust hoods and booths, or approved airline respirators, are provided. Natural ventilation is considered sufficient where those restrictions are not present.
“Such ventilation shall be at the minimum rate of 2,000 cubic feet (57 m3) per minute per welder, except where local exhaust hoods and booths as per paragraph (c)(3) of this section, or airline respirators approved by the Mine Safety and Health Administration and the National Institute for Occupational Safety and Health, pursuant to the provisions of 30 CFR part 11, are provided. Natural ventilation is considered sufficient for welding or cutting operations where the restrictions in paragraph (c)(2)(i) of this section are not present.”
In this paragraph, a confined space means a relatively small or restricted space such as a tank, boiler, pressure vessel or small compartment of a ship.
“As used herein confined space is intended to mean a relatively small or restricted space such as a tank, boiler, pressure vessel, or small compartment of a ship.”
When welding or cutting in any confined space, the gas cylinders and welding machines must be left outside. Heavy portable equipment on wheels must be securely blocked before operations start.
“When welding or cutting is being performed in any confined spaces the gas cylinders and welding machines shall be left on the outside. Before operations are started, heavy portable equipment mounted on wheels shall be securely blocked to prevent accidental movement.”
Where a welder must enter a confined space through a manhole or other small opening, there must be a means of quickly removing him in an emergency, and an attendant with a preplanned rescue procedure must be stationed outside to observe the welder at all times.
“Where a welder must enter a confined space through a manhole or other small opening, means shall be provided for quickly removing him in case of emergency. When safety belts and lifelines are used for this purpose they shall be so attached to the welder's body that his body cannot be jammed in a small exit opening. An attendant with a preplanned rescue procedure shall be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.”
All welding and cutting in confined spaces must be adequately ventilated to prevent toxic buildup or oxygen deficiency, for helpers and others nearby as well as the welder. Replacement air must be clean and respirable.
“All welding and cutting operations carried on in confined spaces shall be adequately ventilated to prevent the accumulation of toxic materials or possible oxygen deficiency. This applies not only to the welder but also to helpers and other personnel in the immediate vicinity. All air replacing that withdrawn shall be clean and respirable.”
Oxygen must never be used for ventilation.
“Oxygen shall never be used for ventilation.”
Not covered here
The specific-material rules in 1910.252(c)(5) through (c)(12) (fluorine compounds, zinc, lead, beryllium, cadmium, mercury, cleaning compounds and stainless steel cutting), the hazard communication labeling rules in (c)(1)(iv) to (vi), and the hood airflow table in (c)(3) are not covered in detail. We only write what an official source states, so study these parts with your certifying program's materials.
Oxygen-fuel gas cylinders
Under no condition may acetylene be generated, piped (except in approved cylinder manifolds) or used at a pressure above 15 psig (103 kPa gauge pressure) or 30 psia (206 kPa absolute).
“Under no condition shall acetylene be generated, piped (except in approved cylinder manifolds) or utilized at a pressure in excess of 15 psig (103 kPa gauge pressure) or 30 psia (206 kPa absolute).”
That requirement is not intended to apply to the storage of acetylene dissolved in a suitable solvent in cylinders made and maintained to U.S. Department of Transportation requirements, or to acetylene for chemical use. The use of liquid acetylene is prohibited.
“This requirement is not intended to apply to storage of acetylene dissolved in a suitable solvent in cylinders manufactured and maintained according to U.S. Department of Transportation requirements, or to acetylene for chemical use. The use of liquid acetylene shall be prohibited.”
Inside buildings, cylinders must be stored in a well-protected, well-ventilated, dry location at least 20 feet (6.1 m) from highly combustible materials such as oil or excelsior.
“Inside of buildings, cylinders shall be stored in a well-protected, well-ventilated, dry location, at least 20 feet (6.1 m) from highly combustible materials such as oil or excelsior.”
Inside a building, fuel-gas cylinders, except those in actual use or attached ready for use, are limited to a total gas capacity of 2,000 cubic feet (56 m3) or 300 pounds (135.9 kg) of liquefied petroleum gas.
“Inside a building, cylinders, except those in actual use or attached ready for use, shall be limited to a total gas capacity of 2,000 cubic feet (56 m3) or 300 pounds (135.9 kg) of liquefied petroleum gas.”
For storage above that amount, a separate room or compartment meeting 1910.253(f)(6)(i)(H) and (I) must be provided, or the cylinders kept outside or in a special building. Special buildings, rooms or compartments must have no open flame for heating or lighting and must be well ventilated.
“For storage in excess of 2,000 cubic feet (56 m3) total gas capacity of cylinders or 300 (135.9 kg) pounds of liquefied petroleum gas, a separate room or compartment conforming to the requirements specified in paragraphs (f)(6)(i)(H) and (f)(6)(i)(I) of this section shall be provided, or cylinders shall be kept outside or in a special building. Special buildings, rooms or compartments shall have no open flame for heating or lighting and shall be well ventilated.”
Acetylene cylinders must be stored valve end up.
“Acetylene cylinders shall be stored valve end up.”
Oxygen cylinders in storage must be separated from fuel-gas cylinders or combustible materials (especially oil or grease) by a minimum distance of 20 feet (6.1 m), or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour. These are the two options.
“Oxygen cylinders in storage shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet (6.1 m) or by a noncombustible barrier at least 5 feet (1.5 m) high having a fire-resistance rating of at least one-half hour.”
Cylinders, valves, couplings, regulators, hose and apparatus must be kept free of oily or greasy substances, and oxygen cylinders or apparatus must not be handled with oily hands or gloves.
“Cylinders, cylinder valves, couplings, regulators, hose, and apparatus shall be kept free from oily or greasy substances. Oxygen cylinders or apparatus shall not be handled with oily hands or gloves.”
An acetylene cylinder valve must not be opened more than one and one-half turns of the spindle, and preferably no more than three-fourths of a turn.
“An acetylene cylinder valve shall not be opened more than one and one-half turns of the spindle, and preferably no more than three-fourths of a turn.”
Not covered here
Manifolds, service piping systems, acetylene generators and calcium carbide storage (1910.253(c), (d), (f) and (g)) are not covered in detail. We only write what an official source states, so study these parts with your certifying program's materials.
Arc and resistance welding
The arc welding voltage limits that must not be exceeded are, for alternating-current machines, 80 volts for manual and 100 volts for automatic (machine or mechanized) arc welding and cutting, and for direct-current machines, 100 volts for both. Where special processes require higher open circuit voltages, means such as adequate insulation must be provided to prevent the operator from accidental contact with the high voltage.
“The following limits shall not be exceeded: (i) Alternating-current machines (A) Manual arc welding and cutting-80 volts. (B) Automatic (machine or mechanized) arc welding and cutting-100 volts. (ii) Direct-current machines (A) Manual arc welding and cutting-100 volts. (B) Automatic (machine or mechanized) arc welding and cutting-100 volts. (iii) When special welding and cutting processes require values of open circuit voltages higher than the above, means shall be provided to prevent the operator from making accidental contact with the high voltage by adequate insulation or other means.”
The frame or case of the welding machine (except engine-driven machines) must be grounded under the conditions and methods in Subpart S.
“The frame or case of the welding machine (except engine-driven machines) shall be grounded under the conditions and according to the methods prescribed in subpart S of this part.”
Cables with splices within 10 feet (3 m) of the holder must not be used.
“Cables with splices within 10 feet (3 m) of the holder shall not be used.”
All resistance welding equipment must be installed by a qualified electrician in conformance with Subpart S.
“All equipment shall be installed by a qualified electrician in conformance with subpart S of this part.”
On nonportable spot and seam welding machines, all external weld initiating control circuits must operate on low voltage, not over 120 volts.
“All external weld initiating control circuits shall operate on low voltage, not over 120 volts, for the safety of the operators.”
On portable welding guns, initiating switch voltage must not exceed 24 volts.
“Initiating switch voltage shall not exceed 24 volts.”
Periodic inspection must be made by qualified maintenance personnel and a certification record kept, with the inspection date, the inspector's signature and the equipment's serial number or other identifier.
“Periodic inspection shall be made by qualified maintenance personnel, and a certification record maintained. The certification record shall include the date of inspection, the signature of the person who performed the inspection and the serial number, or other identifier, for the equipment inspected.”
Not covered here
Arc welding machine design details, supply conductor sizing and flash welding equipment are not covered in detail. We only write what an official source states, so study these parts with your certifying program's materials.
Sources
- eCFR: 29 CFR 1910.252, General requirements (as of Nov 3, 2026)Checked November 5, 2026
- eCFR: 29 CFR 1910.253, Oxygen-fuel gas welding and cutting (as of Nov 3, 2026)Checked November 5, 2026
- eCFR: 29 CFR 1910.254, Arc welding and cutting (as of Nov 3, 2026)Checked November 5, 2026
- eCFR: 29 CFR 1910.255, Resistance welding (as of Nov 3, 2026)Checked November 5, 2026
Other OSHA General Industry study guides: Walking-working surfaces, Exit routes and emergency planning, Fire protection, Electrical safety, Personal protective equipment, Hazardous materials, Permit-required confined spaces, Lockout/tagout, Machine guarding, Electric power generation, transmission and distribution, Powered industrial trucks (forklifts), Materials handling and storage, Bloodborne pathogens, Occupational noise exposure