National
OVERVIEW

This analysis covers the safety requirements for welding, cutting, and brazing operations in general industry and construction workplaces. Such operations are also known as “hot work” jobs. The GENERAL INDUSTRY rules are covered in the first half of this analysis. Scroll down to the CONSTRUCTION WELDING AND CUTTING—OVERVIEW section for the construction workplace requirements.

Welding, cutting, and brazing are hazardous activities that pose a unique combination of both safety and health risks to more than 500,000 workers in a wide variety of industries. The risk from fatal injuries alone is more than four deaths per thousand workers over a working lifetime. For these reasons, OSHA has developed several regulations designed to protect workers from injuries and illnesses related to welding, cutting, and brazing operations.

GENERAL INDUSTRY WELDING, CUTTING, AND BRAZING REQUIREMENTS

OSHA’s welding, cutting, and brazing rules for general industry workplaces cover the following operations:

  • Definitions--29 CFR 1910.251
  • General Requirements--29 CFR 1910.252
  • Oxygen-Fuel Gas Welding and Cutting--29 CFR 1910.253
  • Arc Welding and Cutting--29 CFR 1910.254
  • Resistance Welding--29 CFR 1910.255

Related safety rules. There are additional OSHA regulations that apply to welding, cutting, and brazing operations in general industry:

  • Hexavalent Chromium (Cr(VI))--29 CFR 1910.1026 where chromium-containing materials are heated, burned, or cut and Cr(VI) dusts, fumes, or mists are created
  • Confined Spaces--29 CFR 1910.146 concerning hot work and hot work permits
  • Fire Prevention--29 CFR 1910.39 requires a fire prevention plan
  • Hazard Communication--29 CFR 1910.1200 requires information and training for employees who work with or near any hazardous chemicals
  • Hazardous Materials ­29 CFR 1910.101 to 1910.106 regulate compressed gases and flammable materials
  • Personal Protective Equipment (PPE)--29 CFR 1910.132 to 1910.138 require protective clothing for workers who use hot work equipment
  • PPE--29 CFR 1910, Subpart I, Appendix B provides guidance for hazard assessment and PPE selection
  • Process Safety Management--29 CFR 1910.119 regulates highly hazardous chemicals and hot work operations performed near them

Hazards. Hot work operations generate a variety of hazards: fire, explosion, toxic atmospheres, ultraviolet radiation, and electric shock. Even workers who are not "welders" (i.e., any operator of electric or gas welding and cutting equipment) as such must be aware of the hazards in handling fuel cylinders and inhaling fumes from welding, cutting, and brazing operations.

OSHA has adopted regulations to limit worker exposure to Cr(VI). Occupational exposures to Cr(VI) occur mainly among workers who handle pigments containing dry chromate, spray paints and coatings containing chromate, operate chrome plating baths, and weld or cut stainless steel and other metals that contain chromium.

Hazard control and safe work practices. Safe hot work operations depend on the steps taken to prevent and control exposures to extreme heat, compressed gas, electrical hazards, toxic gases and fumes, noise, and radiated energy. The regulations cover fire prevention and protection, personnel safe work practices and protection, and design specifications for use of equipment. More specifically, they cover:

  • Storage, handling, and conveyance of acetylene and oxygen
  • Safety procedures for arc welding, cutting, and resistance welding equipment
  • Protective clothing for welding operators
  • Ventilation of the work area
  • Respiratory protection in confined spaces
  • Inspection and maintenance of systems and equipment by qualified persons
  • Employee training

Employee training. Employers are responsible for training employees to work safely with fuel gas in welding and cutting operations. The training includes making workers aware of the interactive nature of welding hazards. Employers are also responsible for the proper handling, moving, and storing of fuel cylinders, providing equipment that is compliant with safety rules, and conducting the required testing and inspection of that equipment.

GENERAL PROVISIONS
29 CFR 1910.252

Applicability. The welding, cutting, and brazing rule applies to all workplaces where any type of electric or gas welding and cutting equipment is used.

Industry consensus standards incorporated by reference. The rule incorporates by reference a number of industry consensus standards ( 29 CFR 1910.6), including:

  • National Fire Protection Association (NFPA) Standard 51B-1962, Standard for Fire Prevention in Use of Cutting and Welding Processes
  • American National Standards Institute (ANSI) Z87.1-1968, American National Standard Practice for Occupational and Educational Eye and Face Protection, for all filter lenses and plates that must meet the test for transmission of radiant energy

Note on consensus standards: NFPA, ANSI, and many other industry organizations updated their consensus standards after the federal rules were adopted. OSHA allows employers to follow updated consensus standards without penalty when they provide employee protection that is equal to or greater than the consensus standard referenced in the OSHA rule.

Fire prevention and protection. Employers must ensure that the following basic precautions for fire prevention in welding or cutting work are implemented, or else the welding and cutting operation must not be performed:

  • If the object to be welded or cut cannot readily be moved, then all movable fire hazards in the vicinity must be taken to a safe place.
  • If the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed, then guards must be used to confine the heat, sparks, and slag, and to protect the immovable fire hazards.
  • Combustible material must be protected from exposure to sparks wherever there are floor openings or cracks in the flooring, cracks or holes in walls, open doorways, and open or broken windows that cannot be closed.
  • Fire extinguishers or extinguishing equipment must be ready and available for instant use; such equipment may consist of pails of water, buckets of sand, hose or portable extinguishers, depending on the nature and quantity of the combustible material exposed.
  • Fire watchers are required whenever welding or cutting is performed in locations where other than a minor fire might develop, or any of the following conditions exist:
    • Appreciable combustible material is closer than 35 feet (ft) (10.7 meters (m)) to the point of operation
    • Appreciable combustibles are more than 35 ft (10.7 m) away but can be 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
    • 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 and be trained in its use. They must be familiar with facilities for sounding an alarm in the event of a fire. They must 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. A fire watch must be maintained for at least a half hour after completion of welding or cutting operations to detect and extinguish possible smoldering fires.

Before cutting or welding is permitted, the area must be inspected by the individual responsible for authorizing cutting and welding operations. He or she must designate precautions to be followed in granting authorization to proceed preferably in the form of a written permit.

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 ft (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, personnel operating arc welding or cutting equipment must be protected from possible shock.

Cutting or welding must not be permitted in:

  • Areas not authorized by management
  • Buildings with sprinklers while the sprinklers are not working
  • 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
  • Areas near the storage of large quantities of exposed, readily ignitable materials such as bulk sulfur, baled paper, or cotton

Where practicable, all combustibles must be relocated at least 35 ft (10.7 m) from the worksite. Where relocation is impracticable, combustibles must be protected with flameproofed covers or otherwise shielded with metal or asbestos guards or curtains.

Ducts and conveyor systems that might carry sparks to distant combustibles must be suitably protected or shut down.

Where cutting or welding is done near walls, partitions, ceiling, or roof of combustible construction, fire-resistant shields or guards must be provided to prevent ignition.

If welding is to be done on a metal wall, partition, ceiling, or roof, precautions must 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 must be provided.

Welding must not be attempted on a metal partition, wall, ceiling, or roof having a combustible covering nor on walls or partitions of combustible sandwich-type panel construction. Cutting or welding on pipes or other metal in contact with combustible walls, partitions, ceilings, or roofs must not be undertaken if the work is close enough to cause ignition by conduction.

Management must recognize its responsibility for the safe usage of cutting and welding equipment on its property. Management must:

  • Establish areas for cutting and welding, and establish procedures for cutting and welding, in other areas on the basis of fire potentials of plant facilities.
  • Designate an individual responsible for authorizing cutting and welding operations in areas not specifically designed for such processes.
  • Insist that cutters or welders and their supervisors are suitably trained in the safe operation of their equipment and the safe use of the process.
  • Advise all contractors about flammable materials or hazardous conditions of which they may not be aware.

The Supervisor must:

  • Be responsible for the safe handling of the cutting or welding equipment and the safe use of the cutting or welding process.
  • Determine the combustible materials and hazardous areas present or likely to be present in the work location.
  • Protect combustibles from ignition by the following:
    • Have the work moved to a location free from dangerous combustibles.
    • If the work cannot be moved, have the combustibles moved to a safe distance from the work or have the combustibles properly shielded against ignition.
    • See that cutting and welding are so scheduled that plant operations that might expose combustibles to ignition are not started during cutting or welding.
    • Secure authorization for the cutting or welding operations from the designated management representative.
    • Determine that the cutter or welder secures his approval that conditions are safe before going ahead.
    • Determine that fire protection and extinguishing equipment are properly located at the site.
    • Ensure fire watches are available at the site when required.

Cutting or welding must be permitted only in areas that are or have been made fire safe. When work cannot be moved practicably, as in most construction work, the area must be made safe by removing combustibles or protecting combustibles from ignition sources.

No welding, cutting, or other hot work must 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. Any pipelines or connections to the drum or vessel must be disconnected or blanketed.

All hollow spaces, cavities, or containers must be vented to permit the escape of air or gases before preheating, cutting, or welding. Purging with inert gas is recommended.

Protection from physical hazards. A welder or helper working on platforms, scaffolds, or runways must be protected against falling. This may be accomplished by the use of railings, safety belts, life-lines, or some other equally effective safeguards.

Welders must place welding cable and other equipment so that it is clear of passageways, ladders, and stairways.

Helmets or hand shields must be used during all arc welding or arc cutting operations, excluding submerged arc welding. Helpers or attendants must be provided with proper eye protection, such as:

  • Goggles or other suitable eye protection 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
  • Transparent face shields or goggles for all operators and attendants of resistance welding or resistance brazing equipment, depending on the particular job, to protect their faces or eyes
  • Eye protection in the form of suitable goggles where needed for brazing operations not covered by other provisions of the regulation

Helmets and hand shields must be made of an insulator for heat and electricity. Helmets, shields and goggles must be not readily flammable and must be capable of withstanding sterilization. Helmets and hand shields must protect the face, neck, and ears from direct radiant energy from the arc. Helmets must be provided with filter plates and cover plates designed for easy removal. All parts must be constructed of a material that will not readily corrode or discolor the skin. Goggles must be ventilated to prevent fogging of the lenses as much as practicable. All glass for lenses must be tempered, substantially free from striae, air bubbles, waves, and other flaws. Except when a lens is ground to provide proper optical correction for defective vision, the front and rear surfaces of lenses and windows must be smooth and parallel. Lenses must bear some permanent distinctive marking by which the source and shade may be readily identified.

The following is a guide for the selection of the proper shade numbers. These recommendations may be varied to suit the individual's needs.

Welding operation Shade No.
Shielded metal-arc welding-- 1/16-, 3/32-, 1/8-, 5/32-inch electrodes 10
Gas-shielded arc welding (nonferrous)-- 1/16-, 3/32-, 1/8-, 5/32-inch electrodes 11
Gas-shielded arc welding (ferrous)-- 1/16-, 3/32-, 1/8-, 5/32-inch electrodes 12
Shielded metal-arc welding:
      3/16-, 7/32-, 1/4-inch electrodes 12
      5/16-, 3/8-inch electrodes 14
Atomic hydrogen welding 10­14
Carbon arc welding 14
Soldering 2
Torch brazing 3 or 4
Light cutting, up to 1 inch 3 or 4
Medium cutting, 1 inch to 6 inches 4 or 5
Heavy cutting, 6 inches and over 5 or 6
Gas welding (light) up to 1/8 inch 4 or 5
Gas welding (medium) 1/8 inch to 1/2 inch 5 or 6
Gas welding (heavy) 1/2 inch and over 6 or 8

Note to chart: In gas welding or oxygen cutting where the torch produces a high yellow light, it is desirable to use a filter or lens that absorbs the yellow or sodium line in the visible light of the operation.

Where the work permits, the welder should be enclosed within 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 must be enclosed within noncombustible screens similarly painted. Booths and screens must permit circulation of air at floor level. Workers or other persons adjacent to the welding areas must be protected from the rays by noncombustible or flameproof screens or shields or must be required to wear appropriate goggles.

Protective clothing general requirements. Employees exposed to the hazards created by welding, cutting, or brazing operations must be protected by personal protective equipment (PPE) in accordance with OSHA's PPE standard (29 CFR 1910.132).

Protection and ventilation for health hazards. When welding in a space entirely screened on all sides, the screens must be arranged so they do not restrict ventilation of the area. It is desirable to mount the screens so that they are about 2 ft (0.61 m) above the floor, unless the work is performed at so low a level that the screen must be extended nearer to the floor to protect nearby workers from the glare of welding.

Local exhaust or general ventilating systems must be provided and arranged to keep the amount of toxic fumes, gases, or dusts below the maximum allowable concentration specified in OSHA's hazardous and toxic substances table (29 CFR 1910.1000).

Health hazard notices. A number of potentially hazardous materials are employed in fluxes, coatings, coverings, and filler metals used in welding and cutting or are released to the atmosphere during welding and cutting. The suppliers of welding materials must determine the hazard, if any, associated with the use of their materials in welding and cutting.

Employers must include the following information on health hazard notices:

  • All filler metals and fusible granular materials must carry the following notice, as a minimum, on tags, boxes, or other containers:
    "CAUTION--Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases. Use adequate ventilation.--See ANSI Z49."
  • Filler metals containing cadmium in significant amounts must carry the following notice on tags, boxes, or other containers:
    "WARNING--CONTAINS CADMIUM--POISONOUS FUMES MAY BE FORMED ON HEATING--Do not breathe fumes. Use only with adequate ventilation such as fume collectors, exhaust ventilators, or air-supplied respirators.--See ANSI Z49.1.--If chest pain, cough, or fever develops after use call physician immediately."

Ventilation for general welding and cutting. Mechanical ventilation must be provided when welding or cutting is done on metals and other compounds not covered by this regulation under the following restrictions:

  • In a space of less than 10,000 cubic ft (284 cubic m) per welder
  • In a room having a ceiling height of less than 16 ft (5 m)
  • In confined spaces or where the welding space contains partitions, balconies, or other structural barriers to the extent that they significantly obstruct cross ventilation

Such ventilation must be at the minimum rate of 2,000 cubic ft (57 cubic meters ) per minute per welder, except where local exhaust hoods, booths, or airline respirators are provided. Natural ventilation is considered sufficient for welding or cutting operations where the space restrictions are not present.

Ventilation with hoods or booths. Either a hood or a fixed enclosure (i.e., booth) with airflow will satisfy the requirement for mechanical local exhaust ventilation. Freely movable hoods intended to be placed by the welder as close as possible 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 ft (30 m) per minute in the zone of welding when the hood is at its most remote distance from the point of welding, will satisfy the requirement for a hood, if this ventilation method is chosen.

The rates of ventilation required to accomplish this control velocity using a 3-in. (7.6 cm) wide flanged suction opening are shown as a chart in the regulation at 29 CFR 1910.252(c)(3)(i).

A fixed enclosure (booth) with a top and not less than two sides which surround the welding or cutting operations and with a rate of airflow sufficient to maintain a velocity away from the welder of not less than 100 linear ft (30 m) per minute is an acceptable alternative to a hood.

Welding with fluorine compounds. In confined spaces, welding or cutting involving fluxes, coverings, or other materials which contain fluorine compounds must be done in compliance with the confined space requirements of this regulation. See the Confined Space Operations section of this analysis. A fluorine compound is one that contains fluorine as an element in chemical combination, not as a free gas.

The need for local exhaust ventilation or airline respirators for welding or cutting in other than confined spaces will depend on the individual circumstances. However, experience has shown such protection to be desirable for fixed-location production welding and for all production welding on stainless steels. Where air samples taken at the welding location indicate that the fluorides liberated are below the maximum allowable concentration, such protection is not necessary.

Brazing and gas welding fluxes containing fluorine compounds must have a cautionary wording to indicate that they contain fluorine compounds. One such cautionary wording recommended by the American Welding Society for brazing and gas welding fluxes reads as follows:

CAUTION--CONTAINS FLUORIDES--This flux, when heated, gives off fumes that may irritate eyes, nose, and throat.
1. Avoid fumes--use only in well-ventilated spaces.
2. Avoid contact of flux with eyes or skin.
3. Do not take internally.

 

Welding with zinc. In confined spaces welding or cutting involving zinc-bearing base or filler metals or metals coated with zinc-bearing materials must be done in compliance with the confined space requirements of this regulation. See the Confined Space Operations section of this analysis.

Indoors, welding or cutting involving zinc-bearing base or filler metals coated with zinc-bearing materials must be done in compliance with the hood or booth ventilation requirements of the regulation.

Welding with lead. In confined spaces, welding involving lead-base metals (erroneously called lead-burning) must be done in compliance with the confined space requirements of this regulation. See the Confined Space Operations section of this analysis.

Indoors, welding involving lead-base metals must be done in compliance with the hood or booth ventilation requirements of the regulation.

In confined spaces or indoors, welding or cutting operations involving metals containing lead other than as an impurity or metals coated with lead-bearing materials, including paint, must be done using local exhaust ventilation or airline respirators. Outdoor operations require the use of NIOSH-respirators. In all cases, workers in the immediate vicinity of the cutting operation must be protected by local exhaust ventilation or airline respirators.

Welding with beryllium. Welding or cutting at any location involving beryllium-containing base or filler metals must be done using local exhaust ventilation and airline respirators unless atmospheric tests under the most adverse conditions have established that the workers' exposure is within the permissible exposure limit (PEL) for beryllium ( 29 CFR 1910.1000). In all cases, workers in the immediate vicinity of the welding or cutting operations must be protected as necessary by local exhaust ventilation or airline respirators.

Welding with cadmium. In confined spaces or indoors, welding or cutting operations involving cadmium-bearing or cadmium-coated base metals must be done using local exhaust ventilation or airline respirators unless atmospheric tests under the most adverse conditions show that employee exposure is within the permissible exposure limit (PEL) for cadmium ( 29 CFR 1910.1000). Outdoor operations require NIOSH-approved respirators such as fume respirators.

If the welding (brazing) work involving cadmium-bearing filler metals is to be done in a confined space, it must be done using ventilation as prescribed by the hood or booth ventilation and confined space requirements of this regulation. See the Confined Space Operations section of this analysis for more information.

Welding with mercury. In confined spaces or indoors, welding or cutting operations involving metals coated with mercury-bearing materials, including paint, must be done using local exhaust ventilation or airline respirators unless atmospheric tests under the most adverse conditions show that employee exposure is within the PEL for mercury ( 29 CFR 1910.1000). Such operations, when done outdoors, must be done using NIOSH-approved respirators.

Cleaning compounds. Manufacturer's instructions and other precautions must be followed when cleaning materials are used. Degreasing and other cleaning operations involving chlorinated hydrocarbons must be so located that no vapors from these operations will reach or be drawn into the atmosphere surrounding any welding operation. In addition, trichloroethylene and perchloroethylene should be kept out of atmospheres penetrated by the ultraviolet radiation of gas-shielded welding operations.

Cutting of stainless steels. Oxygen cutting with either a chemical flux or iron powder or gas-shielded arc cutting of stainless steel must be done using mechanical ventilation adequate to remove the fumes generated.

First aid. First-aid equipment must be available at all times. All injuries must be reported as soon as possible for medical attention. First aid must be rendered until medical attention can be provided.

Transmission pipeline applications. The physical and health protection and ventilation requirements of this regulation and arc welding rule (29 CFR 1910.254) must be implemented.

This regulation, the fuel-gas rule, and the arc welding and cutting rules must be implemented where field shop operations are involved for fabrication of fittings, river crossings, road crossings, and pumping and compressor stations.

When arc welding is performed in wet conditions, or under conditions of high humidity, special protection against electric shock must be supplied.

In pressure testing of pipelines, the workers and the public must be protected against injury by the blowing out of closures or other pressure restraining devices. Also, protection must be provided against expulsion of loose dirt that may have become trapped in the pipe.

The welded construction of transmission pipelines must be conducted in compliance with the ANSI/American Petroleum Institute (API) Standard 1104, Standard for Welding Pipe Lines and Related Facilities, API Standard 1104-1968, or updated version.

The connection, by welding, of branches to pipelines carrying flammable substances must be performed in accordance with API Standard PSD 2201--1963, Welding or Hot Tapping on Equipment Containing Flammables, which is incorporated by reference.

The use of Xrays and radioactive isotopes for the inspection of welded pipeline joints must be carried out in conformance with ANSI Z54.1--1963, Non-Medical X-ray and Sealed Gamma-Ray Sources, which is incorporated by reference.

Mechanical piping system applications. The requirements for fire prevention and personnel protection of this rule, and the oxygen-fuel gas and arc welding/cutting rules (29 CFR 1910.253 and 29 CFR 1910.254), must be implemented.

CONFINED SPACE OPERATIONS
29 CFR 1910.252(a)(4) and (b)(4)

For the purposes of identifying a confined space in welding, cutting, and brazing operations, a confined space is a relatively small or restricted space such as a tank, boiler, pressure vessel, or small compartment of a ship.

See the Confined Space analysis section for detailed information about work in a confined space.

Fire prevention in confined spaces. When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, all electrodes must be removed from the holders and the holders carefully located so that accidental contact cannot occur and the machine be disconnected from the power source.

In order to eliminate the possibility of gas escaping through leaks or improperly closed valves, when gas welding or cutting, the torch valves must be closed and the gas supply to the torch positively shut off at some point outside the confined area whenever the torch is not to be used for a substantial period of time, such as during lunch hour or overnight. Where practicable, the torch and hose must also be removed from the confined space.

Work in confined spaces. Ventilation is a prerequisite to work in confined spaces. For ventilation requirements see the General Provisions subsection in this analysis.

Gas cylinders and welding machines must be left outside the confined space when welding or cutting is performed. Before operations are started, heavy portable equipment mounted on wheels must be securely blocked to prevent accidental movement.

Where a welder must enter a confined space through a manhole or other small opening, means must be provided for quickly removing him in case of emergency. When safety belts and lifelines are used for this purpose they must be attached to the welder's body so that his body cannot be jammed in a small exit opening. An attendant with a preplanned rescue procedure must be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect. However, OSHA has stated in an interpretation letter (Emmerich, July 30, 1993) that the agency will accept the use of the tapping procedure on the walls of tanks as a means of communication in lieu of direct observation of the welder by the attendant.

When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, all electrodes must be removed from the holders and the holders carefully located so that accidental contact cannot occur and the machine must be disconnected from the power source.

Whenever the torch is not to be used for a substantial period of time such as during lunch hour or overnight, the torch valves must be closed and the fuel-gas and oxygen supply to the torch positively shut off at some point outside the confined area. Where practicable, the torch and hose must also be removed from the confined space.

After welding operations are completed, the welder must mark the hot metal or provide some other means of warning other workers about the hot metal.

Ventilation in confined spaces. All welding and cutting operations carried on in confined spaces must 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 which was withdrawn must be clean and safe to breathe.

Respirators in confined spaces. In circumstances for which it is impossible to provide such ventilation, airline respirators or hose masks approved for this purpose by NIOSH must be used.

In areas immediately hazardous to life, a full-facepiece, pressure-demand, self-contained breathing apparatus or a combination full-face piece, pressure-demand supplied-air respirator with an auxiliary, self-contained air supply approved by NIOSH must be used.

Where welding operations are carried on in confined spaces and where welders and helpers are provided with hose masks, hose masks with blowers, or self-contained breathing equipment approved by the Mine Safety and Health Administration and the National Institute for Occupational Safety and Health, a worker must be stationed on the outside of such confined spaces to insure the safety of those working within.

Oxygen must never be used for ventilation.

OXYGEN-FUEL GAS WELDING AND CUTTING
29 CFR 1910.253

Employers must adopt procedures to prevent mixtures of fuel gases and air or oxygen that may explode. Mixtures of air or oxygen with flammable gases prior to consumption, except at the burner or in a standard torch, are not allowed unless approved for the purpose.

Portable cylinders. All portable cylinders used for the storage and shipment of compressed gases must be constructed and maintained in accordance with the regulations of the U.S. Department of Transportation, 49 CFR parts 171­179.

Compressed gas cylinders must be legibly marked with either the chemical or the trade name of the gas. Markings must be a stencil, stamp, or label, and must not be readily removable. Whenever practical, the marking must be located on the shoulder of the cylinder.

Acetylene. Under no condition must acetylene be generated, piped (except in approved cylinder manifolds), or utilized at a pressure in excess of 15 pound-force per square inch gauge (103 kiloPascal (kPa) gauge pressure) or 30 pound-force per square inch absolute (206 kPa absolute).

Additional requirements. The regulation contains very detailed additional requirements for:

  • Cylinders
  • Manifolding of cylinders
  • Service piping systems
  • Protective equipment, hose, and cylinders
  • Acetylene generators
  • Calcium carbide storage
ARC WELDING AND CUTTING
29 CFR 1910.254

Arc welding and cutting equipment design requirements. Employers may meet the safety requirements for arc welding and cutting apparatus by complying with either the:

  • National Electrical Manufacturers Association EW­1­1962, Requirements for Electric Arc-Welding Apparatus; or
  • ANSI and Underwriters' Laboratories C33.2--1956, Safety Standard for Transformer-Type Arc-Welding Machines.

Equipment installation. Installation including power supply must be in accordance with the requirements of OSHA's electrical standards (29 CFR 1910, Subpart S). There are detailed requirements for installation described in the regulation. See the Electrical Safety analysis section for more information about electrical safety requirements.

Operation and maintenance. Employers and employees must strictly follow the printed rules and instructions covering operation of equipment supplied by the manufacturers.

Employers must ensure that employees follow the procedures for fire prevention and protection, protection of personnel, and health protection and ventilation in the welding, cutting, and brazing rule (29 CFR 1910.252). There are additional safety requirements in the regulation for machine hook up, grounding, leaks, switches, electrode holders, electric shock, and maintenance.

RESISTANCE WELDING
29 CFR 1910.255

Installation. All equipment must be installed by a qualified electrician in accordance with the requirements of OSHA's electrical standards (29 CFR 1910, Subpart S). See the Electrical Safety analysis section for more information about electrical safety requirements.

There must be a safety-type disconnecting switch or a circuit breaker or circuit interrupter to open each power circuit to the machine, conveniently located at or near the machine, so that the power can be shut off when the machine or its controls are to be serviced.

Ignitron tubes used in resistance welding equipment must be equipped with a thermal protection switch.

Workmen designated to operate resistance welding equipment must have been properly instructed and judged competent to operate such equipment.

Controls of all automatic or air and hydraulic clamps must be arranged or guarded to prevent the operator from accidentally activating them.

Nonportable spot and seam welding machines. There are detailed requirements in the rule for capacitor welding, interlocks, guarding, shields, foot switches, stop buttons, safety pins, and grounding.

Portable welding machines. There are requirements in the rule for counterbalance, safety chains, clevis, switch guards, moving holder, and grounding.

Flash welding equipment. There are requirements in the rule for ventilation, flash guards, and fire curtains.

Maintenance. Periodic inspection must be made by qualified maintenance personnel, and a certification record maintained. The certification record must 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. The operator must be instructed to report any equipment defects to his supervisor and the use of the equipment must be discontinued until safety repairs have been completed.

WELDERS, CUTTERS, AND SUPERVISORS
29 CFR 1910.252(a)(2)(xiii)(C)

Cutters, welders, and their supervisors must be suitably trained in the safe operation of their equipment and the safe use of the process or system when the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed.

FIRE WATCHERS
29 CFR 1910.252(a)(2)

Fire watchers must have fire extinguishing equipment readily available and be trained in its use. They must be familiar with the equipment and procedures for sounding an alarm in the event of a fire. They must 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. A fire watch must be maintained for at least a half hour after completion of welding or cutting operations to detect and extinguish possible smoldering fires.

OXYGEN-FUEL GAS WELDING AND CUTTING PERSONNEL
29 CFR 1910.253(a)(4) and (e)(6)

Workmen in charge of the oxygen or fuel-gas supply equipment, including generators, and oxygen or fuel-gas distribution piping systems must be instructed and judged competent by their employers for this important work before being left in charge.

Skilled mechanics must be properly instructed to repair regulators or parts of regulators, including gages.

ARC WELDING AND CUTTING
29 CFR 1910.254(a)(3) and (d)(1)

Workers who operate arc welding equipment must be instructed and qualified to operate and maintain such equipment, and implement the general provisions of the welding, cutting, and brazing rule (29 CFR 1910.252).

RESISTANCE WELDING
29 CFR 1910.255(a)(3)

Workmen designated to operate resistance welding equipment must be properly instructed and judged competent to operate such equipment.

This section outlines the safety requirements for welding, cutting, and heating operations in construction industry workplaces.

Safety rules. The safety rules for welding, cutting, and heating are:

  • Gas welding and cutting—29 CFR 1926.350
  • Arc welding and cutting—29 CFR 1926.351
  • Fire prevention—29 CFR 1926.352
  • Protective equipment, hose, and cylinders
  • Ventilation and protection in welding, cutting, and heating—29 CFR 1926.353
  • Welding, cutting, and heating preservative coatings—29 CFR 1926.354

Related safety rules. There are additional safety rules that apply to welding, cutting, and heating operations:

  • Hexavalent chromium (Cr(VI))—29 CFR 1926.1126
  • Cadmium—29 CFR 1926.1127
  • Gases, vapors, fumes, dusts, and mists—29 CFR 1926.55
  • Ventilation—29 CFR 1926.57
  • Hazard communication—29 CFR 1926.59
  • Lead—29 CFR 1926.62
  • Process safety management—29 CFR 1926.64
  • Personal protective equipment—29 CFR 1926 Subpart E
  • Fire protection and prevention—29 CFR 1926 Subpart F

Hazards. The safety of welding and cutting operations is dependent on the steps taken to prevent and control exposures to extreme heat, compressed gas, electrical hazards, toxic gases and fumes, noise, and radiated energy. Effects from unsafe practices can range from “sunburn of the eyes” to chronic health effects. The awareness, training, and ability of welders and their supervisors to identify hazards largely determine the safety of these operations.

Safety program elements. A welding, cutting, and heating, or “hot work,” safety program must include the following elements:

  • Restriction of the performance of welding or cutting process to qualified personnel who are trained to perform the specific type of operation (e.g., oxy-acetylene, oxygen-powder, carbon arc, gas tungsten, resistance spot)
  • Recognition by workers of the hazards of the welding, cutting, heating, and brazing operations and the hazardous nature of base material being contacted
  • Description and implementation of a fire prevention and response program, including providing fire extinguishers/sprinklers, appointing fire watchers, restricting activities in flammable/explosive situations, and issuing hot work permits
  • Special procedures for confined space areas
  • Effective industrial hygiene practices
  • Employee protection, mechanical ventilation, personal protective equipment, welding curtains, etc.
  • Safe material handling and storage practices, particularly for gas cylinders

Employee training. Employers must instruct employees in the safe use of fuel gas and in safe welding and cutting operations, including the proper handling, moving, and storing of fuel cylinders. Employers must provide equipment that is in compliance with safety requirements and specifications, and conduct the required testing and inspection of that equipment. Employers must also provide personal protective equipment, ensure adequate ventilation, and make sure that workers are aware of the interactive nature of welding hazards.

GAS WELDING AND CUTTING
29 CFR 1926.350

Transporting, moving, and storing compressed gas cylinders. Valve protection caps must be in place and secured. When cylinders are hoisted, they must be secured on a cradle, sling board, or pallet. They must not be hoisted or transported by means of magnets or choker slings. Cylinders must be moved by tilting and rolling them on their bottom edges. They must not be intentionally dropped, struck, or permitted to strike each other with force.

When cylinders are transported by powered vehicles, they must be secured in a vertical position. Valve protection caps must not be used for lifting cylinders from one vertical position to another. Bars must not be used under valves or valve protection caps to pry cylinders loose when frozen. Warm, not boiling, water must be used to thaw cylinders loose.

Unless cylinders are firmly secured on a special carrier intended for this purpose, regulators must be removed and valve protection caps put in place before cylinders are moved. A suitable cylinder truck, chain, or other steadying device must be used to keep cylinders from being knocked over while in use. When work is finished, when cylinders are empty, or when cylinders are moved at any time, the cylinder valve must be closed. Compressed gas cylinders must be secured in an upright position at all times, if necessary, for short periods of time, while cylinders are actually being hoisted or carried.

Oxygen cylinders in storage must be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 ft (6.1 m) or by a noncombustible barrier at least 5 ft (1.5 m) high having a fire-resistance rating of at least one-half hour.

Inside of buildings, cylinders must be stored in a well-protected, well-ventilated, dry location, at least 20 ft (6.1 m) from highly combustible materials such as oil or excelsior. Cylinders should be stored in definitely assigned places away from elevators, stairs, or gangways. Assigned storage places must be located where cylinders will not be knocked over or damaged by passing or falling objects, or subject to tampering.

The in-plant handling, storage, and utilization of all compressed gases in cylinders, portable tanks, rail tank cars, or motor vehicle cargo tanks must be in accordance with Compressed Gas Association Pamphlet P-1-1965, Safe Handling of Compressed Gases in Containers.

Placing cylinders. Cylinders must be kept far enough away from the actual welding or cutting operation so that sparks, hot slag, or flame will not reach them. When this is impractical, fire resistant shields must be provided.

Cylinders must be placed where they cannot become part of an electrical circuit. Electrodes must not be struck against a cylinder to strike an arc.

Fuel gas cylinders must be placed with valve end up whenever they are in use. They must not be placed in a location where they would not be subject to open flame, hot metal, or other sources of artificial heat.

Cylinders containing oxygen, acetylene, or other fuel gas must not be taken into confined spaces.

Treatment of cylinders. Cylinders, whether full or empty, must not be used as rollers or supports.

No person other than the gas supplier must attempt to mix gases in a cylinder. No one except the owner of the cylinder or person authorized by him, must refill a cylinder. No one must use a cylinder’s contents for purposes other than those intended by the supplier. All cylinders used must meet the Department of Transportation requirements published in 49 CFR Part 178, Subpart C, Specification for Cylinders.

No damaged or defective cylinder must be used.

Use of fuel gas. The employer must thoroughly instruct employees in the safe use of fuel gas, as follows:

Fuel gas must not be used from cylinders through torches or other devices which are equipped with shutoff valves without reducing the pressure through a suitable regulator attached to the cylinder valve or manifold.

Before a regulator to a cylinder valve is connected, the valve must be opened slightly and closed immediately. (This action is generally termed “cracking” and is intended to clear the valve of dust or dirt that might otherwise enter the regulator.) The person cracking the valve must stand to one side of the outlet, not in front of it. The valve of a fuel gas cylinder must not be cracked where the gas would reach welding work, sparks, flame, or other possible sources of ignition.

The cylinder valve must always be opened slowly to prevent damage to the regulator. For quick closing, valves of fuel gas cylinders must not be opened more than 1.5 turns. When a special wrench is required, it must be left in position on the stem of the valve while the cylinder is in use so that the fuel gas flow can be shut off quickly in case of an emergency. In the case of manifolded or coupled cylinders, at least one such wrench must always be available for immediate use. Nothing must be placed on top of a fuel gas cylinder, when in use, which may damage the safety device or interfere with the quick closing of the valve.

Before a regulator is removed from a cylinder valve, the cylinder valve must always be closed and the gas released from the regulator.

If, when the valve on a fuel gas cylinder is opened, there is found to be a leak around the valve stem, the valve must be closed and the gland nut tightened. If this action does not stop the leak, the use of the cylinder must be discontinued, and it must be properly tagged and removed from the work area. In the event that fuel gas should leak from the cylinder valve, rather than from the valve stem, and the gas cannot be shut off, the cylinder must be properly tagged and removed from the work area. If a regulator attached to a cylinder valve will effectively stop a leak through the valve seat, the cylinder need not be removed from the work area.

If a leak should develop at a fuse plug or other safety device, the cylinder must be removed from the work area.

Fuel gas and oxygen manifolds. Fuel gas and oxygen manifolds must bear the name of the substance they contain in letters at least 1-in. high which must be either painted on the manifold or on a sign permanently attached to it. These manifolds must be placed in safe, well-ventilated, and accessible locations and not be located within enclosed spaces.

Manifold hose connections, including both ends of the supply hose that lead to the manifold, must be such that the hose cannot be interchanged between fuel gas and oxygen manifolds and supply header connections. Adapters must not be used to permit the interchange of hoses. Hose connections must be kept free of grease and oil.

When not in use, manifold and header hose connections must be capped. Nothing must be placed on top of a manifold when in use which will damage the manifold or interfere with the quick closing of the valves.

Hoses. Fuel gas and oxygen hoses must be easily distinguishable from each other. The contrast may be made by different colors or by surface characteristics readily distinguishable by the sense of touch. Oxygen and fuel gas hoses must not be interchangeable. (See accompanying figure for example.) A single hose having more than one gas passage must not be used.

When parallel sections of oxygen and fuel gas hoses are taped together, not more than 4 in. out of 12 in. must be covered by tape.

All hoses in use, carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or substance which may ignite or enter into combustion, or be in any way harmful to employees, must be inspected at the beginning of each working shift. Defective hoses must be removed from service.

Hoses which have been subject to flashback, or which show evidence of severe wear or damage, must be tested to twice the normal pressure to which each is subject, but in no case less than 300 p.s.i. Defective hoses, or hoses in doubtful condition, must not be used.

Hose couplings must be of the type that cannot be unlocked or disconnected by means of a straight pull without rotary motion.

Boxes used for the storage of gas hoses must be ventilated.

Hoses, cables, and other equipment must be kept clear of passageways, ladders, and stairs.

Torches. Clogged torch tip openings must be cleaned with suitable cleaning wires, drills, or other devices designed for such purpose. Torches in use must be inspected at the beginning of each working shift for leaking shutoff valves, hose couplings, and tip connections. Defective torches must not be used. Torches must be lighted by friction lighters or other approved devices, and not by matches or from hot work.

Regulators and gauges. Oxygen and fuel gas pressure regulators, including their related gauges, must be in proper working order while in use.

Oil and grease hazards. Oxygen cylinders and fittings must be kept away from oil or grease. Cylinders, cylinder caps and valves, couplings, regulators, hoses, and apparatus must be kept free from oil or greasy substances and must not be handled with oily hands or gloves. Oxygen must not be directed at oily surfaces, greasy clothes, or within a fuel oil or other storage tank or vessel.

Consensus standards. For additional details not covered in the rule, applicable technical portions of ANSI Z49.1-1967, Safety in Welding and Cutting, must apply.

ARC WELDING AND CUTTING
29 CFR 1926.351

Manual electrode holders. Only manual electrode holders which are specifically designed for arc welding and cutting , and are capable of safely handling the maximum rated current required by the electrodes, must be used.

Any current-carrying parts passing through the portion of the holder which the arc welder or cutter grips in his hand, and the outer surfaces of the jaws of the holder, must be fully insulated against the maximum voltage encountered to ground.

Welding cables and connectors. All arc welding and cutting cables must be of the completely insulated, flexible type, capable of handling the maximum current requirements of the work in progress, taking into account the duty cycle under which the arc welder or cutter is working.

Only cable free from repair or splices for a minimum distance of 10 ft from the cable end to which the electrode holder is connected must be used, except that cables with standard insulated connectors or with splices whose insulating quality is equal to that of the cable are permitted.

Cables in need of repair must not be used. When a cable, other than the cable lead referred to above, becomes worn to the extent of exposing bare conductors, the portion that is exposed must be protected by means of rubber and friction tape or other equivalent insulation.

When it becomes necessary to connect or splice lengths of cable one to another, substantial insulated connectors of a capacity at least equivalent to that of the cable must be used. If connections are effected by means of cable lugs, they must be securely fastened together to give good electrical contact, and the exposed metal parts of the lugs must be completely insulated.

Ground returns and machine grounding. A ground return cable must have a safe current-carrying capacity equal to or exceeding the specified maximum output capacity of the arc welding or cutting unit which it services. When a single ground return cable services more than one unit, its safe current-carrying must exceed the total specified maximum output capacities of all the units which it services.

Pipelines containing gases or flammable liquids, or conduits containing electrical circuits, must not be used as a ground return.

When a structure or pipeline is employed as a ground return circuit, it must be determined that the required electrical contact exists at all joints. The generation of an arc, sparks, or heat at any point must cause rejection of the structures as a ground circuit.

When a structure or pipeline is continuously employed as a ground return circuit, all joints must be bonded, and periodic inspections must be conducted to ensure that no condition of electrolysis or fire hazard exists by virtue of such use.

The frames of all arc welding and cutting machines must be grounded either through a third wire in the cable containing the circuit conductor or through a separate wire which is grounded at the source of the current. Grounding circuits, other than by means of the structure, must be checked to ensure that the circuit between the ground and the grounded power conductor has resistance low enough to permit sufficient current to flow to cause the fuse or circuit breaker to interrupt the current.

All ground connections must be inspected to ensure that they are mechanically strong and electrically adequate for the required current.

Operating instructions. Employers must instruct employees in the safe means of arc welding and cutting as follows:

  • When electrode holders are to be left unattended, the electrodes must be removed and the holders must be so placed or protected that they cannot make electrical contact with employees or conducting objects.
  • Hot electrode holders must not be dipped in water. To do so may expose the arc welder or cutter to electric shock.
  • When the arc welder or cutter has occasion to leave his work or to stop work for any appreciable length of time, or when the arc welding or cutting machine is to be moved, the power supply switch to the equipment must be opened.
  • Any faulty or defective equipment must be reported to the supervisor.
  • Any faulty or defective equipment must be reported to the supervisor.
  • A switch or circuit breaker must be provided by which each resistance welder and its control equipment can be isolated from the supply circuit. The ampere rating of this disconnecting means must not be less than the supply conductor ampacity.

Shielding. Whenever practicable, all arc welding and cutting operations must be shielded by a noncombustible or flameproof screen which will protect employees and other persons working in the vicinity from the direct rays of the arc.

FIRE PREVENTION
29 CFR 1926.352

When practical, objects to be welded, cut, or heated must be moved to a designated safe location or, if these objects cannot be readily moved, all movable fire hazards in the vicinity must be taken to a safe place, or otherwise protected. If these objects cannot be moved and if all the fire hazards cannot be removed, positive means must be taken to confine the heat, sparks, and slag, and to protect the immovable fire hazards from them.

No welding, cutting or heating must be done where the application of flammable paints, or the presence of other flammable compounds, or heavy dust concentrations create a hazard.

Fire extinguishing equipment. Suitable fire extinguishing equipment must be immediately available in the work area and must be maintained in a state or readiness for instant use.

Additional precautions where normal fire prevention is insufficient. When the welding, cutting, or heating operation is such that normal fire prevention precautions are not sufficient, additional personnel must be assigned to guard against fire while the actual welding, cutting, or heating operation is being performed, and for a sufficient period of time after completion of the work to ensure that no possibility of fire exists. Such personnel must be instructed as to the specific anticipated fire hazards and how the fire-fighting equipment provided is to be used.

Hot work performed on walls, floors, or ceilings. When welding, cutting, or heating is performed on walls, floors, and ceilings, since direct penetration of sparks or heat transfer may introduce a fire hazard to an adjacent area, the same precautions must be taken on the opposite side as are taken on the side on which the welding, cutting, or heating is being performed.

Enclosed or confined spaces. For the elimination of possible fire in enclosed spaces as a result of gas escaping through leaking or improperly closed torch valves, the gas supply to the torch must be positively shut off at some point outside the enclosed space whenever the torch is not to be used or whenever the torch is left unattended for a substantial period of time, such as during the lunch period. Overnight and at the change of shifts, the torch and hose must be removed from the confined space. Open end fuel gas and oxygen hoses must be immediately removed from enclosed spaces when they are disconnected from the torch or other gas-consuming device.

Except when the contents are being removed or transferred, drums, pails, and other containers which contain or have contained flammable liquids must be kept closed. Empty containers must be removed to a safe area apart from hot work operations or open flames.

Drums, containers, or hollow structures. Drums, containers, or hollow structures which have contained toxic or flammable substances must, before welding, cutting, or heating is undertaken on them, either be filled with water or thoroughly cleaned of such substances, and then ventilated and tested.

Before heat is applied to a drum, container, or hollow structure, a vent or opening must be provided for the release of any built-up pressure during the application of heat.

VENTILATION AND PROTECTION IN WELDING, CUTTING, AND HEATING
29 CFR 1926.353

Mechanical ventilation. Mechanical ventilation must consist of either general mechanical ventilation systems or local exhaust systems.

Ventilation must be deemed adequate if it is of sufficient capacity and so arranged as to remove fumes and smoke at the source and keep their concentration in the breathing zone within safe limits as defined in Subpart D of Part 1926, Occupational Health and Environmental Controls.

Contaminated air exhausted from a working space must be discharged clear of the source of intake air. All air replacing that which was withdrawn must be clean and respirable. Oxygen must not be used for ventilation purposes, comfort cooling, blowing dust from clothing, or for cleaning the work area.

Hot work operations in confined spaces. Except where air line respirators are required or allowed as described below, adequate mechanical ventilation meeting the requirements described above must be provided whenever welding, cutting, or heating is performed in a confined space.

When sufficient ventilation cannot be obtained without blocking the means of access, employees in the confined space must be protected by air line respirators in accordance with the requirements of Subpart E of Part 1926, Personal Protective and Life Saving Equipment. An employee on the outside of the confined space must be assigned to maintain communication with those working within it and to aid them in an emergency.

Where a welder must enter a confined space through a small opening, means must be provided for quickly removing him in case of emergency. When safety belts and lifelines are used for this purpose they must be so attached to the welder’s body that his body cannot be jammed in a small exit opening. An attendant with a pre-planned rescue procedure must be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.

Welding, cutting, or heating of metals of toxic significance. Welding, cutting, or heating in any enclosed spaces involving the following metals must be performed with adequate mechanical ventilation.

  • Zinc-bearing base or filler metals or metals coated with zinc-bearing materials
  • Lead base metals
  • Cadmium-bearing filler materials
  • Chromium-bearing metals or metals coated with chromium-bearing materials

Welding, cutting, or heating in any enclosed spaces involving the following metals must be performed with adequate local exhaust ventilation as described above or employees must be protected by air line respirators in compliance with the respirator rule (29 CFR 1926.103):

  • Metals containing lead, other than as an impurity, or metals coated with lead-bearing materials
  • Cadmium-bearing or cadmium-coated base metals
  • Metal coated with mercury-bearing metals
  • Beryllium-containing base or filler metals

Because of its high toxicity, work involving beryllium must be done with both local exhaust ventilation and air line respirators.

Employees performing such operations in the open air must be protected by filter-type respirators, except that employees performing such operations on beryllium-containing base or filler metals must be protected by air line respirators.

Other employees exposed to the same atmosphere as the welders or burners must be protected in the same manner as the welder or burner.

Inert-gas metal-arc welding. Since the inert-gas metal-arc welding process involves the production of ultra-violet radiation of intensities of 5 to 30 times that produced during shielded metal-arc welding, the decomposition of chlorinated solvents by ultraviolet rays, and the liberation of toxic fumes and gases, employees must not be permitted to engage in, or be exposed to the process until certain special precautions have been taken.

The use of chlorinated solvents must be kept at least 200 ft, unless shielded, from the exposed arc, and surfaces prepared with chlorinated solvents must be thoroughly dry before welding is permitted on such surfaces.

Employees in the area not protected from the arc by screening must be protected by filter lenses. When two or more welders are exposed to each other’s arc, filter lens goggles of a suitable type, must be worn under welding helmets. Hand shields to protect the welder against flashes and radiant energy must be used when either the helmet is lifted or the shield is removed.

Welders and other employees who are exposed to radiation must be suitably protected so that the skin is covered completely to prevent burns and other damage by ultraviolet rays. Welding helmets and hand shields must be free of leaks, openings, and highly reflective surfaces.

When inert-gas metal-arc welding is being performed on stainless steel, adequate local exhaust ventilation as described above or air line respirators must be used to protect against dangerous concentrations of nitrogen dioxide.

General welding, cutting, and heating. Welding, cutting, or heating not involving conditions or toxic materials described above may normally be done without mechanical ventilation or respiratory protective equipment. These protections must be provided, however, where an unsafe accumulation of contaminants exists because of unusual physical or atmospheric conditions.

Employees performing any type of welding, cutting, or heating must be protected by suitable eye protective equipment (see 29 CFR 1926.102).

WELDING, CUTTING, AND HEATING OF PRESERVATIVE COATINGS
29 CFR 1926.354

Before welding, cutting, or heating is commenced on any surface covered by a preservative coating whose flammability is not known, a test must be made by a competent person to determine its flammability. Preservative coatings must be considered to be highly flammable when scrapings burn with extreme rapidity.

When coatings are determined to be highly flammable, they must be stripped from the area to be heated to prevent ignition.

Protection against toxic preservative coatings. In enclosed spaces, all surfaces covered with toxic preservatives must be stripped of all toxic coatings for a distance of at least 4 in. from the area of heat application, or the employees must be protected by air line respirators. In the open air, employees must be protected by a respirator.

Removal of protective coatings. The preservative coatings must be removed a sufficient distance from the area to be heated to ensure that the temperature of the unstripped metal will not be appreciably raised. Artificial cooling of the metal surrounding the heating area may be used to limit the size of the area required to be cleaned.

Thorough operating instructions are required for both gas and arc welding and cutting. Some employers may be required to train special personnel in the fire hazards and firefighting equipment suitable for their operations.

GAS WELDING AND CUTTING
29 CFR 1926.350(d)(1)

The employer must instruct employees in the safe use of fuel gas. See the “Use of Fuel Gas” subsection of this analysis for the specific procedures.

ARC WELDING AND CUTTING
29 CFR 1926.351(d)

Employers must instruct employees in the safe means of arc welding and cutting. See the “Operating Instructions” subsection of this analysis for the specific procedures.

FIRE PREVENTION
29 CFR 1926.352(e)

Personnel assigned to guard against fire while the actual welding, cutting, or heating operation is being performed must be trained to anticipate fire hazards and how to use the available fire-fighting equipment. When normal fire-prevention precautions are not sufficient, additional persons, trained in fire hazards and fire-fighting equipment, must guard against fire.

Related Topics:
National
OVERVIEW

This analysis covers the safety requirements for welding, cutting, and brazing operations in general industry and construction workplaces. Such operations are also known as “hot work” jobs. The GENERAL INDUSTRY rules are covered in the first half of this analysis. Scroll down to the CONSTRUCTION WELDING AND CUTTING—OVERVIEW section for the construction workplace requirements.

Welding, cutting, and brazing are hazardous activities that pose a unique combination of both safety and health risks to more than 500,000 workers in a wide variety of industries. The risk from fatal injuries alone is more than four deaths per thousand workers over a working lifetime. For these reasons, OSHA has developed several regulations designed to protect workers from injuries and illnesses related to welding, cutting, and brazing operations.

GENERAL INDUSTRY WELDING, CUTTING, AND BRAZING REQUIREMENTS

OSHA’s welding, cutting, and brazing rules for general industry workplaces cover the following operations:

  • Definitions--29 CFR 1910.251
  • General Requirements--29 CFR 1910.252
  • Oxygen-Fuel Gas Welding and Cutting--29 CFR 1910.253
  • Arc Welding and Cutting--29 CFR 1910.254
  • Resistance Welding--29 CFR 1910.255

Related safety rules. There are additional OSHA regulations that apply to welding, cutting, and brazing operations in general industry:

  • Hexavalent Chromium (Cr(VI))--29 CFR 1910.1026 where chromium-containing materials are heated, burned, or cut and Cr(VI) dusts, fumes, or mists are created
  • Confined Spaces--29 CFR 1910.146 concerning hot work and hot work permits
  • Fire Prevention--29 CFR 1910.39 requires a fire prevention plan
  • Hazard Communication--29 CFR 1910.1200 requires information and training for employees who work with or near any hazardous chemicals
  • Hazardous Materials ­29 CFR 1910.101 to 1910.106 regulate compressed gases and flammable materials
  • Personal Protective Equipment (PPE)--29 CFR 1910.132 to 1910.138 require protective clothing for workers who use hot work equipment
  • PPE--29 CFR 1910, Subpart I, Appendix B provides guidance for hazard assessment and PPE selection
  • Process Safety Management--29 CFR 1910.119 regulates highly hazardous chemicals and hot work operations performed near them

Hazards. Hot work operations generate a variety of hazards: fire, explosion, toxic atmospheres, ultraviolet radiation, and electric shock. Even workers who are not "welders" (i.e., any operator of electric or gas welding and cutting equipment) as such must be aware of the hazards in handling fuel cylinders and inhaling fumes from welding, cutting, and brazing operations.

OSHA has adopted regulations to limit worker exposure to Cr(VI). Occupational exposures to Cr(VI) occur mainly among workers who handle pigments containing dry chromate, spray paints and coatings containing chromate, operate chrome plating baths, and weld or cut stainless steel and other metals that contain chromium.

Hazard control and safe work practices. Safe hot work operations depend on the steps taken to prevent and control exposures to extreme heat, compressed gas, electrical hazards, toxic gases and fumes, noise, and radiated energy. The regulations cover fire prevention and protection, personnel safe work practices and protection, and design specifications for use of equipment. More specifically, they cover:

  • Storage, handling, and conveyance of acetylene and oxygen
  • Safety procedures for arc welding, cutting, and resistance welding equipment
  • Protective clothing for welding operators
  • Ventilation of the work area
  • Respiratory protection in confined spaces
  • Inspection and maintenance of systems and equipment by qualified persons
  • Employee training

Employee training. Employers are responsible for training employees to work safely with fuel gas in welding and cutting operations. The training includes making workers aware of the interactive nature of welding hazards. Employers are also responsible for the proper handling, moving, and storing of fuel cylinders, providing equipment that is compliant with safety rules, and conducting the required testing and inspection of that equipment.

GENERAL PROVISIONS
29 CFR 1910.252

Applicability. The welding, cutting, and brazing rule applies to all workplaces where any type of electric or gas welding and cutting equipment is used.

Industry consensus standards incorporated by reference. The rule incorporates by reference a number of industry consensus standards ( 29 CFR 1910.6), including:

  • National Fire Protection Association (NFPA) Standard 51B-1962, Standard for Fire Prevention in Use of Cutting and Welding Processes
  • American National Standards Institute (ANSI) Z87.1-1968, American National Standard Practice for Occupational and Educational Eye and Face Protection, for all filter lenses and plates that must meet the test for transmission of radiant energy

Note on consensus standards: NFPA, ANSI, and many other industry organizations updated their consensus standards after the federal rules were adopted. OSHA allows employers to follow updated consensus standards without penalty when they provide employee protection that is equal to or greater than the consensus standard referenced in the OSHA rule.

Fire prevention and protection. Employers must ensure that the following basic precautions for fire prevention in welding or cutting work are implemented, or else the welding and cutting operation must not be performed:

  • If the object to be welded or cut cannot readily be moved, then all movable fire hazards in the vicinity must be taken to a safe place.
  • If the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed, then guards must be used to confine the heat, sparks, and slag, and to protect the immovable fire hazards.
  • Combustible material must be protected from exposure to sparks wherever there are floor openings or cracks in the flooring, cracks or holes in walls, open doorways, and open or broken windows that cannot be closed.
  • Fire extinguishers or extinguishing equipment must be ready and available for instant use; such equipment may consist of pails of water, buckets of sand, hose or portable extinguishers, depending on the nature and quantity of the combustible material exposed.
  • Fire watchers are required whenever welding or cutting is performed in locations where other than a minor fire might develop, or any of the following conditions exist:
    • Appreciable combustible material is closer than 35 feet (ft) (10.7 meters (m)) to the point of operation
    • Appreciable combustibles are more than 35 ft (10.7 m) away but can be 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
    • 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 and be trained in its use. They must be familiar with facilities for sounding an alarm in the event of a fire. They must 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. A fire watch must be maintained for at least a half hour after completion of welding or cutting operations to detect and extinguish possible smoldering fires.

Before cutting or welding is permitted, the area must be inspected by the individual responsible for authorizing cutting and welding operations. He or she must designate precautions to be followed in granting authorization to proceed preferably in the form of a written permit.

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 ft (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, personnel operating arc welding or cutting equipment must be protected from possible shock.

Cutting or welding must not be permitted in:

  • Areas not authorized by management
  • Buildings with sprinklers while the sprinklers are not working
  • 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
  • Areas near the storage of large quantities of exposed, readily ignitable materials such as bulk sulfur, baled paper, or cotton

Where practicable, all combustibles must be relocated at least 35 ft (10.7 m) from the worksite. Where relocation is impracticable, combustibles must be protected with flameproofed covers or otherwise shielded with metal or asbestos guards or curtains.

Ducts and conveyor systems that might carry sparks to distant combustibles must be suitably protected or shut down.

Where cutting or welding is done near walls, partitions, ceiling, or roof of combustible construction, fire-resistant shields or guards must be provided to prevent ignition.

If welding is to be done on a metal wall, partition, ceiling, or roof, precautions must 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 must be provided.

Welding must not be attempted on a metal partition, wall, ceiling, or roof having a combustible covering nor on walls or partitions of combustible sandwich-type panel construction. Cutting or welding on pipes or other metal in contact with combustible walls, partitions, ceilings, or roofs must not be undertaken if the work is close enough to cause ignition by conduction.

Management must recognize its responsibility for the safe usage of cutting and welding equipment on its property. Management must:

  • Establish areas for cutting and welding, and establish procedures for cutting and welding, in other areas on the basis of fire potentials of plant facilities.
  • Designate an individual responsible for authorizing cutting and welding operations in areas not specifically designed for such processes.
  • Insist that cutters or welders and their supervisors are suitably trained in the safe operation of their equipment and the safe use of the process.
  • Advise all contractors about flammable materials or hazardous conditions of which they may not be aware.

The Supervisor must:

  • Be responsible for the safe handling of the cutting or welding equipment and the safe use of the cutting or welding process.
  • Determine the combustible materials and hazardous areas present or likely to be present in the work location.
  • Protect combustibles from ignition by the following:
    • Have the work moved to a location free from dangerous combustibles.
    • If the work cannot be moved, have the combustibles moved to a safe distance from the work or have the combustibles properly shielded against ignition.
    • See that cutting and welding are so scheduled that plant operations that might expose combustibles to ignition are not started during cutting or welding.
    • Secure authorization for the cutting or welding operations from the designated management representative.
    • Determine that the cutter or welder secures his approval that conditions are safe before going ahead.
    • Determine that fire protection and extinguishing equipment are properly located at the site.
    • Ensure fire watches are available at the site when required.

Cutting or welding must be permitted only in areas that are or have been made fire safe. When work cannot be moved practicably, as in most construction work, the area must be made safe by removing combustibles or protecting combustibles from ignition sources.

No welding, cutting, or other hot work must 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. Any pipelines or connections to the drum or vessel must be disconnected or blanketed.

All hollow spaces, cavities, or containers must be vented to permit the escape of air or gases before preheating, cutting, or welding. Purging with inert gas is recommended.

Protection from physical hazards. A welder or helper working on platforms, scaffolds, or runways must be protected against falling. This may be accomplished by the use of railings, safety belts, life-lines, or some other equally effective safeguards.

Welders must place welding cable and other equipment so that it is clear of passageways, ladders, and stairways.

Helmets or hand shields must be used during all arc welding or arc cutting operations, excluding submerged arc welding. Helpers or attendants must be provided with proper eye protection, such as:

  • Goggles or other suitable eye protection 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
  • Transparent face shields or goggles for all operators and attendants of resistance welding or resistance brazing equipment, depending on the particular job, to protect their faces or eyes
  • Eye protection in the form of suitable goggles where needed for brazing operations not covered by other provisions of the regulation

Helmets and hand shields must be made of an insulator for heat and electricity. Helmets, shields and goggles must be not readily flammable and must be capable of withstanding sterilization. Helmets and hand shields must protect the face, neck, and ears from direct radiant energy from the arc. Helmets must be provided with filter plates and cover plates designed for easy removal. All parts must be constructed of a material that will not readily corrode or discolor the skin. Goggles must be ventilated to prevent fogging of the lenses as much as practicable. All glass for lenses must be tempered, substantially free from striae, air bubbles, waves, and other flaws. Except when a lens is ground to provide proper optical correction for defective vision, the front and rear surfaces of lenses and windows must be smooth and parallel. Lenses must bear some permanent distinctive marking by which the source and shade may be readily identified.

The following is a guide for the selection of the proper shade numbers. These recommendations may be varied to suit the individual's needs.

Welding operation Shade No.
Shielded metal-arc welding-- 1/16-, 3/32-, 1/8-, 5/32-inch electrodes 10
Gas-shielded arc welding (nonferrous)-- 1/16-, 3/32-, 1/8-, 5/32-inch electrodes 11
Gas-shielded arc welding (ferrous)-- 1/16-, 3/32-, 1/8-, 5/32-inch electrodes 12
Shielded metal-arc welding:
      3/16-, 7/32-, 1/4-inch electrodes 12
      5/16-, 3/8-inch electrodes 14
Atomic hydrogen welding 10­14
Carbon arc welding 14
Soldering 2
Torch brazing 3 or 4
Light cutting, up to 1 inch 3 or 4
Medium cutting, 1 inch to 6 inches 4 or 5
Heavy cutting, 6 inches and over 5 or 6
Gas welding (light) up to 1/8 inch 4 or 5
Gas welding (medium) 1/8 inch to 1/2 inch 5 or 6
Gas welding (heavy) 1/2 inch and over 6 or 8

Note to chart: In gas welding or oxygen cutting where the torch produces a high yellow light, it is desirable to use a filter or lens that absorbs the yellow or sodium line in the visible light of the operation.

Where the work permits, the welder should be enclosed within 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 must be enclosed within noncombustible screens similarly painted. Booths and screens must permit circulation of air at floor level. Workers or other persons adjacent to the welding areas must be protected from the rays by noncombustible or flameproof screens or shields or must be required to wear appropriate goggles.

Protective clothing general requirements. Employees exposed to the hazards created by welding, cutting, or brazing operations must be protected by personal protective equipment (PPE) in accordance with OSHA's PPE standard (29 CFR 1910.132).

Protection and ventilation for health hazards. When welding in a space entirely screened on all sides, the screens must be arranged so they do not restrict ventilation of the area. It is desirable to mount the screens so that they are about 2 ft (0.61 m) above the floor, unless the work is performed at so low a level that the screen must be extended nearer to the floor to protect nearby workers from the glare of welding.

Local exhaust or general ventilating systems must be provided and arranged to keep the amount of toxic fumes, gases, or dusts below the maximum allowable concentration specified in OSHA's hazardous and toxic substances table (29 CFR 1910.1000).

Health hazard notices. A number of potentially hazardous materials are employed in fluxes, coatings, coverings, and filler metals used in welding and cutting or are released to the atmosphere during welding and cutting. The suppliers of welding materials must determine the hazard, if any, associated with the use of their materials in welding and cutting.

Employers must include the following information on health hazard notices:

  • All filler metals and fusible granular materials must carry the following notice, as a minimum, on tags, boxes, or other containers:
    "CAUTION--Welding may produce fumes and gases hazardous to health. Avoid breathing these fumes and gases. Use adequate ventilation.--See ANSI Z49."
  • Filler metals containing cadmium in significant amounts must carry the following notice on tags, boxes, or other containers:
    "WARNING--CONTAINS CADMIUM--POISONOUS FUMES MAY BE FORMED ON HEATING--Do not breathe fumes. Use only with adequate ventilation such as fume collectors, exhaust ventilators, or air-supplied respirators.--See ANSI Z49.1.--If chest pain, cough, or fever develops after use call physician immediately."

Ventilation for general welding and cutting. Mechanical ventilation must be provided when welding or cutting is done on metals and other compounds not covered by this regulation under the following restrictions:

  • In a space of less than 10,000 cubic ft (284 cubic m) per welder
  • In a room having a ceiling height of less than 16 ft (5 m)
  • In confined spaces or where the welding space contains partitions, balconies, or other structural barriers to the extent that they significantly obstruct cross ventilation

Such ventilation must be at the minimum rate of 2,000 cubic ft (57 cubic meters ) per minute per welder, except where local exhaust hoods, booths, or airline respirators are provided. Natural ventilation is considered sufficient for welding or cutting operations where the space restrictions are not present.

Ventilation with hoods or booths. Either a hood or a fixed enclosure (i.e., booth) with airflow will satisfy the requirement for mechanical local exhaust ventilation. Freely movable hoods intended to be placed by the welder as close as possible 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 ft (30 m) per minute in the zone of welding when the hood is at its most remote distance from the point of welding, will satisfy the requirement for a hood, if this ventilation method is chosen.

The rates of ventilation required to accomplish this control velocity using a 3-in. (7.6 cm) wide flanged suction opening are shown as a chart in the regulation at 29 CFR 1910.252(c)(3)(i).

A fixed enclosure (booth) with a top and not less than two sides which surround the welding or cutting operations and with a rate of airflow sufficient to maintain a velocity away from the welder of not less than 100 linear ft (30 m) per minute is an acceptable alternative to a hood.

Welding with fluorine compounds. In confined spaces, welding or cutting involving fluxes, coverings, or other materials which contain fluorine compounds must be done in compliance with the confined space requirements of this regulation. See the Confined Space Operations section of this analysis. A fluorine compound is one that contains fluorine as an element in chemical combination, not as a free gas.

The need for local exhaust ventilation or airline respirators for welding or cutting in other than confined spaces will depend on the individual circumstances. However, experience has shown such protection to be desirable for fixed-location production welding and for all production welding on stainless steels. Where air samples taken at the welding location indicate that the fluorides liberated are below the maximum allowable concentration, such protection is not necessary.

Brazing and gas welding fluxes containing fluorine compounds must have a cautionary wording to indicate that they contain fluorine compounds. One such cautionary wording recommended by the American Welding Society for brazing and gas welding fluxes reads as follows:

CAUTION--CONTAINS FLUORIDES--This flux, when heated, gives off fumes that may irritate eyes, nose, and throat.
1. Avoid fumes--use only in well-ventilated spaces.
2. Avoid contact of flux with eyes or skin.
3. Do not take internally.

 

Welding with zinc. In confined spaces welding or cutting involving zinc-bearing base or filler metals or metals coated with zinc-bearing materials must be done in compliance with the confined space requirements of this regulation. See the Confined Space Operations section of this analysis.

Indoors, welding or cutting involving zinc-bearing base or filler metals coated with zinc-bearing materials must be done in compliance with the hood or booth ventilation requirements of the regulation.

Welding with lead. In confined spaces, welding involving lead-base metals (erroneously called lead-burning) must be done in compliance with the confined space requirements of this regulation. See the Confined Space Operations section of this analysis.

Indoors, welding involving lead-base metals must be done in compliance with the hood or booth ventilation requirements of the regulation.

In confined spaces or indoors, welding or cutting operations involving metals containing lead other than as an impurity or metals coated with lead-bearing materials, including paint, must be done using local exhaust ventilation or airline respirators. Outdoor operations require the use of NIOSH-respirators. In all cases, workers in the immediate vicinity of the cutting operation must be protected by local exhaust ventilation or airline respirators.

Welding with beryllium. Welding or cutting at any location involving beryllium-containing base or filler metals must be done using local exhaust ventilation and airline respirators unless atmospheric tests under the most adverse conditions have established that the workers' exposure is within the permissible exposure limit (PEL) for beryllium ( 29 CFR 1910.1000). In all cases, workers in the immediate vicinity of the welding or cutting operations must be protected as necessary by local exhaust ventilation or airline respirators.

Welding with cadmium. In confined spaces or indoors, welding or cutting operations involving cadmium-bearing or cadmium-coated base metals must be done using local exhaust ventilation or airline respirators unless atmospheric tests under the most adverse conditions show that employee exposure is within the permissible exposure limit (PEL) for cadmium ( 29 CFR 1910.1000). Outdoor operations require NIOSH-approved respirators such as fume respirators.

If the welding (brazing) work involving cadmium-bearing filler metals is to be done in a confined space, it must be done using ventilation as prescribed by the hood or booth ventilation and confined space requirements of this regulation. See the Confined Space Operations section of this analysis for more information.

Welding with mercury. In confined spaces or indoors, welding or cutting operations involving metals coated with mercury-bearing materials, including paint, must be done using local exhaust ventilation or airline respirators unless atmospheric tests under the most adverse conditions show that employee exposure is within the PEL for mercury ( 29 CFR 1910.1000). Such operations, when done outdoors, must be done using NIOSH-approved respirators.

Cleaning compounds. Manufacturer's instructions and other precautions must be followed when cleaning materials are used. Degreasing and other cleaning operations involving chlorinated hydrocarbons must be so located that no vapors from these operations will reach or be drawn into the atmosphere surrounding any welding operation. In addition, trichloroethylene and perchloroethylene should be kept out of atmospheres penetrated by the ultraviolet radiation of gas-shielded welding operations.

Cutting of stainless steels. Oxygen cutting with either a chemical flux or iron powder or gas-shielded arc cutting of stainless steel must be done using mechanical ventilation adequate to remove the fumes generated.

First aid. First-aid equipment must be available at all times. All injuries must be reported as soon as possible for medical attention. First aid must be rendered until medical attention can be provided.

Transmission pipeline applications. The physical and health protection and ventilation requirements of this regulation and arc welding rule (29 CFR 1910.254) must be implemented.

This regulation, the fuel-gas rule, and the arc welding and cutting rules must be implemented where field shop operations are involved for fabrication of fittings, river crossings, road crossings, and pumping and compressor stations.

When arc welding is performed in wet conditions, or under conditions of high humidity, special protection against electric shock must be supplied.

In pressure testing of pipelines, the workers and the public must be protected against injury by the blowing out of closures or other pressure restraining devices. Also, protection must be provided against expulsion of loose dirt that may have become trapped in the pipe.

The welded construction of transmission pipelines must be conducted in compliance with the ANSI/American Petroleum Institute (API) Standard 1104, Standard for Welding Pipe Lines and Related Facilities, API Standard 1104-1968, or updated version.

The connection, by welding, of branches to pipelines carrying flammable substances must be performed in accordance with API Standard PSD 2201--1963, Welding or Hot Tapping on Equipment Containing Flammables, which is incorporated by reference.

The use of Xrays and radioactive isotopes for the inspection of welded pipeline joints must be carried out in conformance with ANSI Z54.1--1963, Non-Medical X-ray and Sealed Gamma-Ray Sources, which is incorporated by reference.

Mechanical piping system applications. The requirements for fire prevention and personnel protection of this rule, and the oxygen-fuel gas and arc welding/cutting rules (29 CFR 1910.253 and 29 CFR 1910.254), must be implemented.

CONFINED SPACE OPERATIONS
29 CFR 1910.252(a)(4) and (b)(4)

For the purposes of identifying a confined space in welding, cutting, and brazing operations, a confined space is a relatively small or restricted space such as a tank, boiler, pressure vessel, or small compartment of a ship.

See the Confined Space analysis section for detailed information about work in a confined space.

Fire prevention in confined spaces. When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, all electrodes must be removed from the holders and the holders carefully located so that accidental contact cannot occur and the machine be disconnected from the power source.

In order to eliminate the possibility of gas escaping through leaks or improperly closed valves, when gas welding or cutting, the torch valves must be closed and the gas supply to the torch positively shut off at some point outside the confined area whenever the torch is not to be used for a substantial period of time, such as during lunch hour or overnight. Where practicable, the torch and hose must also be removed from the confined space.

Work in confined spaces. Ventilation is a prerequisite to work in confined spaces. For ventilation requirements see the General Provisions subsection in this analysis.

Gas cylinders and welding machines must be left outside the confined space when welding or cutting is performed. Before operations are started, heavy portable equipment mounted on wheels must be securely blocked to prevent accidental movement.

Where a welder must enter a confined space through a manhole or other small opening, means must be provided for quickly removing him in case of emergency. When safety belts and lifelines are used for this purpose they must be attached to the welder's body so that his body cannot be jammed in a small exit opening. An attendant with a preplanned rescue procedure must be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect. However, OSHA has stated in an interpretation letter (Emmerich, July 30, 1993) that the agency will accept the use of the tapping procedure on the walls of tanks as a means of communication in lieu of direct observation of the welder by the attendant.

When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, all electrodes must be removed from the holders and the holders carefully located so that accidental contact cannot occur and the machine must be disconnected from the power source.

Whenever the torch is not to be used for a substantial period of time such as during lunch hour or overnight, the torch valves must be closed and the fuel-gas and oxygen supply to the torch positively shut off at some point outside the confined area. Where practicable, the torch and hose must also be removed from the confined space.

After welding operations are completed, the welder must mark the hot metal or provide some other means of warning other workers about the hot metal.

Ventilation in confined spaces. All welding and cutting operations carried on in confined spaces must 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 which was withdrawn must be clean and safe to breathe.

Respirators in confined spaces. In circumstances for which it is impossible to provide such ventilation, airline respirators or hose masks approved for this purpose by NIOSH must be used.

In areas immediately hazardous to life, a full-facepiece, pressure-demand, self-contained breathing apparatus or a combination full-face piece, pressure-demand supplied-air respirator with an auxiliary, self-contained air supply approved by NIOSH must be used.

Where welding operations are carried on in confined spaces and where welders and helpers are provided with hose masks, hose masks with blowers, or self-contained breathing equipment approved by the Mine Safety and Health Administration and the National Institute for Occupational Safety and Health, a worker must be stationed on the outside of such confined spaces to insure the safety of those working within.

Oxygen must never be used for ventilation.

OXYGEN-FUEL GAS WELDING AND CUTTING
29 CFR 1910.253

Employers must adopt procedures to prevent mixtures of fuel gases and air or oxygen that may explode. Mixtures of air or oxygen with flammable gases prior to consumption, except at the burner or in a standard torch, are not allowed unless approved for the purpose.

Portable cylinders. All portable cylinders used for the storage and shipment of compressed gases must be constructed and maintained in accordance with the regulations of the U.S. Department of Transportation, 49 CFR parts 171­179.

Compressed gas cylinders must be legibly marked with either the chemical or the trade name of the gas. Markings must be a stencil, stamp, or label, and must not be readily removable. Whenever practical, the marking must be located on the shoulder of the cylinder.

Acetylene. Under no condition must acetylene be generated, piped (except in approved cylinder manifolds), or utilized at a pressure in excess of 15 pound-force per square inch gauge (103 kiloPascal (kPa) gauge pressure) or 30 pound-force per square inch absolute (206 kPa absolute).

Additional requirements. The regulation contains very detailed additional requirements for:

  • Cylinders
  • Manifolding of cylinders
  • Service piping systems
  • Protective equipment, hose, and cylinders
  • Acetylene generators
  • Calcium carbide storage
ARC WELDING AND CUTTING
29 CFR 1910.254

Arc welding and cutting equipment design requirements. Employers may meet the safety requirements for arc welding and cutting apparatus by complying with either the:

  • National Electrical Manufacturers Association EW­1­1962, Requirements for Electric Arc-Welding Apparatus; or
  • ANSI and Underwriters' Laboratories C33.2--1956, Safety Standard for Transformer-Type Arc-Welding Machines.

Equipment installation. Installation including power supply must be in accordance with the requirements of OSHA's electrical standards (29 CFR 1910, Subpart S). There are detailed requirements for installation described in the regulation. See the Electrical Safety analysis section for more information about electrical safety requirements.

Operation and maintenance. Employers and employees must strictly follow the printed rules and instructions covering operation of equipment supplied by the manufacturers.

Employers must ensure that employees follow the procedures for fire prevention and protection, protection of personnel, and health protection and ventilation in the welding, cutting, and brazing rule (29 CFR 1910.252). There are additional safety requirements in the regulation for machine hook up, grounding, leaks, switches, electrode holders, electric shock, and maintenance.

RESISTANCE WELDING
29 CFR 1910.255

Installation. All equipment must be installed by a qualified electrician in accordance with the requirements of OSHA's electrical standards (29 CFR 1910, Subpart S). See the Electrical Safety analysis section for more information about electrical safety requirements.

There must be a safety-type disconnecting switch or a circuit breaker or circuit interrupter to open each power circuit to the machine, conveniently located at or near the machine, so that the power can be shut off when the machine or its controls are to be serviced.

Ignitron tubes used in resistance welding equipment must be equipped with a thermal protection switch.

Workmen designated to operate resistance welding equipment must have been properly instructed and judged competent to operate such equipment.

Controls of all automatic or air and hydraulic clamps must be arranged or guarded to prevent the operator from accidentally activating them.

Nonportable spot and seam welding machines. There are detailed requirements in the rule for capacitor welding, interlocks, guarding, shields, foot switches, stop buttons, safety pins, and grounding.

Portable welding machines. There are requirements in the rule for counterbalance, safety chains, clevis, switch guards, moving holder, and grounding.

Flash welding equipment. There are requirements in the rule for ventilation, flash guards, and fire curtains.

Maintenance. Periodic inspection must be made by qualified maintenance personnel, and a certification record maintained. The certification record must 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. The operator must be instructed to report any equipment defects to his supervisor and the use of the equipment must be discontinued until safety repairs have been completed.

WELDERS, CUTTERS, AND SUPERVISORS
29 CFR 1910.252(a)(2)(xiii)(C)

Cutters, welders, and their supervisors must be suitably trained in the safe operation of their equipment and the safe use of the process or system when the object to be welded or cut cannot be moved and if all the fire hazards cannot be removed.

FIRE WATCHERS
29 CFR 1910.252(a)(2)

Fire watchers must have fire extinguishing equipment readily available and be trained in its use. They must be familiar with the equipment and procedures for sounding an alarm in the event of a fire. They must 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. A fire watch must be maintained for at least a half hour after completion of welding or cutting operations to detect and extinguish possible smoldering fires.

OXYGEN-FUEL GAS WELDING AND CUTTING PERSONNEL
29 CFR 1910.253(a)(4) and (e)(6)

Workmen in charge of the oxygen or fuel-gas supply equipment, including generators, and oxygen or fuel-gas distribution piping systems must be instructed and judged competent by their employers for this important work before being left in charge.

Skilled mechanics must be properly instructed to repair regulators or parts of regulators, including gages.

ARC WELDING AND CUTTING
29 CFR 1910.254(a)(3) and (d)(1)

Workers who operate arc welding equipment must be instructed and qualified to operate and maintain such equipment, and implement the general provisions of the welding, cutting, and brazing rule (29 CFR 1910.252).

RESISTANCE WELDING
29 CFR 1910.255(a)(3)

Workmen designated to operate resistance welding equipment must be properly instructed and judged competent to operate such equipment.

This section outlines the safety requirements for welding, cutting, and heating operations in construction industry workplaces.

Safety rules. The safety rules for welding, cutting, and heating are:

  • Gas welding and cutting—29 CFR 1926.350
  • Arc welding and cutting—29 CFR 1926.351
  • Fire prevention—29 CFR 1926.352
  • Protective equipment, hose, and cylinders
  • Ventilation and protection in welding, cutting, and heating—29 CFR 1926.353
  • Welding, cutting, and heating preservative coatings—29 CFR 1926.354

Related safety rules. There are additional safety rules that apply to welding, cutting, and heating operations:

  • Hexavalent chromium (Cr(VI))—29 CFR 1926.1126
  • Cadmium—29 CFR 1926.1127
  • Gases, vapors, fumes, dusts, and mists—29 CFR 1926.55
  • Ventilation—29 CFR 1926.57
  • Hazard communication—29 CFR 1926.59
  • Lead—29 CFR 1926.62
  • Process safety management—29 CFR 1926.64
  • Personal protective equipment—29 CFR 1926 Subpart E
  • Fire protection and prevention—29 CFR 1926 Subpart F

Hazards. The safety of welding and cutting operations is dependent on the steps taken to prevent and control exposures to extreme heat, compressed gas, electrical hazards, toxic gases and fumes, noise, and radiated energy. Effects from unsafe practices can range from “sunburn of the eyes” to chronic health effects. The awareness, training, and ability of welders and their supervisors to identify hazards largely determine the safety of these operations.

Safety program elements. A welding, cutting, and heating, or “hot work,” safety program must include the following elements:

  • Restriction of the performance of welding or cutting process to qualified personnel who are trained to perform the specific type of operation (e.g., oxy-acetylene, oxygen-powder, carbon arc, gas tungsten, resistance spot)
  • Recognition by workers of the hazards of the welding, cutting, heating, and brazing operations and the hazardous nature of base material being contacted
  • Description and implementation of a fire prevention and response program, including providing fire extinguishers/sprinklers, appointing fire watchers, restricting activities in flammable/explosive situations, and issuing hot work permits
  • Special procedures for confined space areas
  • Effective industrial hygiene practices
  • Employee protection, mechanical ventilation, personal protective equipment, welding curtains, etc.
  • Safe material handling and storage practices, particularly for gas cylinders

Employee training. Employers must instruct employees in the safe use of fuel gas and in safe welding and cutting operations, including the proper handling, moving, and storing of fuel cylinders. Employers must provide equipment that is in compliance with safety requirements and specifications, and conduct the required testing and inspection of that equipment. Employers must also provide personal protective equipment, ensure adequate ventilation, and make sure that workers are aware of the interactive nature of welding hazards.

GAS WELDING AND CUTTING
29 CFR 1926.350

Transporting, moving, and storing compressed gas cylinders. Valve protection caps must be in place and secured. When cylinders are hoisted, they must be secured on a cradle, sling board, or pallet. They must not be hoisted or transported by means of magnets or choker slings. Cylinders must be moved by tilting and rolling them on their bottom edges. They must not be intentionally dropped, struck, or permitted to strike each other with force.

When cylinders are transported by powered vehicles, they must be secured in a vertical position. Valve protection caps must not be used for lifting cylinders from one vertical position to another. Bars must not be used under valves or valve protection caps to pry cylinders loose when frozen. Warm, not boiling, water must be used to thaw cylinders loose.

Unless cylinders are firmly secured on a special carrier intended for this purpose, regulators must be removed and valve protection caps put in place before cylinders are moved. A suitable cylinder truck, chain, or other steadying device must be used to keep cylinders from being knocked over while in use. When work is finished, when cylinders are empty, or when cylinders are moved at any time, the cylinder valve must be closed. Compressed gas cylinders must be secured in an upright position at all times, if necessary, for short periods of time, while cylinders are actually being hoisted or carried.

Oxygen cylinders in storage must be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 ft (6.1 m) or by a noncombustible barrier at least 5 ft (1.5 m) high having a fire-resistance rating of at least one-half hour.

Inside of buildings, cylinders must be stored in a well-protected, well-ventilated, dry location, at least 20 ft (6.1 m) from highly combustible materials such as oil or excelsior. Cylinders should be stored in definitely assigned places away from elevators, stairs, or gangways. Assigned storage places must be located where cylinders will not be knocked over or damaged by passing or falling objects, or subject to tampering.

The in-plant handling, storage, and utilization of all compressed gases in cylinders, portable tanks, rail tank cars, or motor vehicle cargo tanks must be in accordance with Compressed Gas Association Pamphlet P-1-1965, Safe Handling of Compressed Gases in Containers.

Placing cylinders. Cylinders must be kept far enough away from the actual welding or cutting operation so that sparks, hot slag, or flame will not reach them. When this is impractical, fire resistant shields must be provided.

Cylinders must be placed where they cannot become part of an electrical circuit. Electrodes must not be struck against a cylinder to strike an arc.

Fuel gas cylinders must be placed with valve end up whenever they are in use. They must not be placed in a location where they would not be subject to open flame, hot metal, or other sources of artificial heat.

Cylinders containing oxygen, acetylene, or other fuel gas must not be taken into confined spaces.

Treatment of cylinders. Cylinders, whether full or empty, must not be used as rollers or supports.

No person other than the gas supplier must attempt to mix gases in a cylinder. No one except the owner of the cylinder or person authorized by him, must refill a cylinder. No one must use a cylinder’s contents for purposes other than those intended by the supplier. All cylinders used must meet the Department of Transportation requirements published in 49 CFR Part 178, Subpart C, Specification for Cylinders.

No damaged or defective cylinder must be used.

Use of fuel gas. The employer must thoroughly instruct employees in the safe use of fuel gas, as follows:

Fuel gas must not be used from cylinders through torches or other devices which are equipped with shutoff valves without reducing the pressure through a suitable regulator attached to the cylinder valve or manifold.

Before a regulator to a cylinder valve is connected, the valve must be opened slightly and closed immediately. (This action is generally termed “cracking” and is intended to clear the valve of dust or dirt that might otherwise enter the regulator.) The person cracking the valve must stand to one side of the outlet, not in front of it. The valve of a fuel gas cylinder must not be cracked where the gas would reach welding work, sparks, flame, or other possible sources of ignition.

The cylinder valve must always be opened slowly to prevent damage to the regulator. For quick closing, valves of fuel gas cylinders must not be opened more than 1.5 turns. When a special wrench is required, it must be left in position on the stem of the valve while the cylinder is in use so that the fuel gas flow can be shut off quickly in case of an emergency. In the case of manifolded or coupled cylinders, at least one such wrench must always be available for immediate use. Nothing must be placed on top of a fuel gas cylinder, when in use, which may damage the safety device or interfere with the quick closing of the valve.

Before a regulator is removed from a cylinder valve, the cylinder valve must always be closed and the gas released from the regulator.

If, when the valve on a fuel gas cylinder is opened, there is found to be a leak around the valve stem, the valve must be closed and the gland nut tightened. If this action does not stop the leak, the use of the cylinder must be discontinued, and it must be properly tagged and removed from the work area. In the event that fuel gas should leak from the cylinder valve, rather than from the valve stem, and the gas cannot be shut off, the cylinder must be properly tagged and removed from the work area. If a regulator attached to a cylinder valve will effectively stop a leak through the valve seat, the cylinder need not be removed from the work area.

If a leak should develop at a fuse plug or other safety device, the cylinder must be removed from the work area.

Fuel gas and oxygen manifolds. Fuel gas and oxygen manifolds must bear the name of the substance they contain in letters at least 1-in. high which must be either painted on the manifold or on a sign permanently attached to it. These manifolds must be placed in safe, well-ventilated, and accessible locations and not be located within enclosed spaces.

Manifold hose connections, including both ends of the supply hose that lead to the manifold, must be such that the hose cannot be interchanged between fuel gas and oxygen manifolds and supply header connections. Adapters must not be used to permit the interchange of hoses. Hose connections must be kept free of grease and oil.

When not in use, manifold and header hose connections must be capped. Nothing must be placed on top of a manifold when in use which will damage the manifold or interfere with the quick closing of the valves.

Hoses. Fuel gas and oxygen hoses must be easily distinguishable from each other. The contrast may be made by different colors or by surface characteristics readily distinguishable by the sense of touch. Oxygen and fuel gas hoses must not be interchangeable. (See accompanying figure for example.) A single hose having more than one gas passage must not be used.

When parallel sections of oxygen and fuel gas hoses are taped together, not more than 4 in. out of 12 in. must be covered by tape.

All hoses in use, carrying acetylene, oxygen, natural or manufactured fuel gas, or any gas or substance which may ignite or enter into combustion, or be in any way harmful to employees, must be inspected at the beginning of each working shift. Defective hoses must be removed from service.

Hoses which have been subject to flashback, or which show evidence of severe wear or damage, must be tested to twice the normal pressure to which each is subject, but in no case less than 300 p.s.i. Defective hoses, or hoses in doubtful condition, must not be used.

Hose couplings must be of the type that cannot be unlocked or disconnected by means of a straight pull without rotary motion.

Boxes used for the storage of gas hoses must be ventilated.

Hoses, cables, and other equipment must be kept clear of passageways, ladders, and stairs.

Torches. Clogged torch tip openings must be cleaned with suitable cleaning wires, drills, or other devices designed for such purpose. Torches in use must be inspected at the beginning of each working shift for leaking shutoff valves, hose couplings, and tip connections. Defective torches must not be used. Torches must be lighted by friction lighters or other approved devices, and not by matches or from hot work.

Regulators and gauges. Oxygen and fuel gas pressure regulators, including their related gauges, must be in proper working order while in use.

Oil and grease hazards. Oxygen cylinders and fittings must be kept away from oil or grease. Cylinders, cylinder caps and valves, couplings, regulators, hoses, and apparatus must be kept free from oil or greasy substances and must not be handled with oily hands or gloves. Oxygen must not be directed at oily surfaces, greasy clothes, or within a fuel oil or other storage tank or vessel.

Consensus standards. For additional details not covered in the rule, applicable technical portions of ANSI Z49.1-1967, Safety in Welding and Cutting, must apply.

ARC WELDING AND CUTTING
29 CFR 1926.351

Manual electrode holders. Only manual electrode holders which are specifically designed for arc welding and cutting , and are capable of safely handling the maximum rated current required by the electrodes, must be used.

Any current-carrying parts passing through the portion of the holder which the arc welder or cutter grips in his hand, and the outer surfaces of the jaws of the holder, must be fully insulated against the maximum voltage encountered to ground.

Welding cables and connectors. All arc welding and cutting cables must be of the completely insulated, flexible type, capable of handling the maximum current requirements of the work in progress, taking into account the duty cycle under which the arc welder or cutter is working.

Only cable free from repair or splices for a minimum distance of 10 ft from the cable end to which the electrode holder is connected must be used, except that cables with standard insulated connectors or with splices whose insulating quality is equal to that of the cable are permitted.

Cables in need of repair must not be used. When a cable, other than the cable lead referred to above, becomes worn to the extent of exposing bare conductors, the portion that is exposed must be protected by means of rubber and friction tape or other equivalent insulation.

When it becomes necessary to connect or splice lengths of cable one to another, substantial insulated connectors of a capacity at least equivalent to that of the cable must be used. If connections are effected by means of cable lugs, they must be securely fastened together to give good electrical contact, and the exposed metal parts of the lugs must be completely insulated.

Ground returns and machine grounding. A ground return cable must have a safe current-carrying capacity equal to or exceeding the specified maximum output capacity of the arc welding or cutting unit which it services. When a single ground return cable services more than one unit, its safe current-carrying must exceed the total specified maximum output capacities of all the units which it services.

Pipelines containing gases or flammable liquids, or conduits containing electrical circuits, must not be used as a ground return.

When a structure or pipeline is employed as a ground return circuit, it must be determined that the required electrical contact exists at all joints. The generation of an arc, sparks, or heat at any point must cause rejection of the structures as a ground circuit.

When a structure or pipeline is continuously employed as a ground return circuit, all joints must be bonded, and periodic inspections must be conducted to ensure that no condition of electrolysis or fire hazard exists by virtue of such use.

The frames of all arc welding and cutting machines must be grounded either through a third wire in the cable containing the circuit conductor or through a separate wire which is grounded at the source of the current. Grounding circuits, other than by means of the structure, must be checked to ensure that the circuit between the ground and the grounded power conductor has resistance low enough to permit sufficient current to flow to cause the fuse or circuit breaker to interrupt the current.

All ground connections must be inspected to ensure that they are mechanically strong and electrically adequate for the required current.

Operating instructions. Employers must instruct employees in the safe means of arc welding and cutting as follows:

  • When electrode holders are to be left unattended, the electrodes must be removed and the holders must be so placed or protected that they cannot make electrical contact with employees or conducting objects.
  • Hot electrode holders must not be dipped in water. To do so may expose the arc welder or cutter to electric shock.
  • When the arc welder or cutter has occasion to leave his work or to stop work for any appreciable length of time, or when the arc welding or cutting machine is to be moved, the power supply switch to the equipment must be opened.
  • Any faulty or defective equipment must be reported to the supervisor.
  • Any faulty or defective equipment must be reported to the supervisor.
  • A switch or circuit breaker must be provided by which each resistance welder and its control equipment can be isolated from the supply circuit. The ampere rating of this disconnecting means must not be less than the supply conductor ampacity.

Shielding. Whenever practicable, all arc welding and cutting operations must be shielded by a noncombustible or flameproof screen which will protect employees and other persons working in the vicinity from the direct rays of the arc.

FIRE PREVENTION
29 CFR 1926.352

When practical, objects to be welded, cut, or heated must be moved to a designated safe location or, if these objects cannot be readily moved, all movable fire hazards in the vicinity must be taken to a safe place, or otherwise protected. If these objects cannot be moved and if all the fire hazards cannot be removed, positive means must be taken to confine the heat, sparks, and slag, and to protect the immovable fire hazards from them.

No welding, cutting or heating must be done where the application of flammable paints, or the presence of other flammable compounds, or heavy dust concentrations create a hazard.

Fire extinguishing equipment. Suitable fire extinguishing equipment must be immediately available in the work area and must be maintained in a state or readiness for instant use.

Additional precautions where normal fire prevention is insufficient. When the welding, cutting, or heating operation is such that normal fire prevention precautions are not sufficient, additional personnel must be assigned to guard against fire while the actual welding, cutting, or heating operation is being performed, and for a sufficient period of time after completion of the work to ensure that no possibility of fire exists. Such personnel must be instructed as to the specific anticipated fire hazards and how the fire-fighting equipment provided is to be used.

Hot work performed on walls, floors, or ceilings. When welding, cutting, or heating is performed on walls, floors, and ceilings, since direct penetration of sparks or heat transfer may introduce a fire hazard to an adjacent area, the same precautions must be taken on the opposite side as are taken on the side on which the welding, cutting, or heating is being performed.

Enclosed or confined spaces. For the elimination of possible fire in enclosed spaces as a result of gas escaping through leaking or improperly closed torch valves, the gas supply to the torch must be positively shut off at some point outside the enclosed space whenever the torch is not to be used or whenever the torch is left unattended for a substantial period of time, such as during the lunch period. Overnight and at the change of shifts, the torch and hose must be removed from the confined space. Open end fuel gas and oxygen hoses must be immediately removed from enclosed spaces when they are disconnected from the torch or other gas-consuming device.

Except when the contents are being removed or transferred, drums, pails, and other containers which contain or have contained flammable liquids must be kept closed. Empty containers must be removed to a safe area apart from hot work operations or open flames.

Drums, containers, or hollow structures. Drums, containers, or hollow structures which have contained toxic or flammable substances must, before welding, cutting, or heating is undertaken on them, either be filled with water or thoroughly cleaned of such substances, and then ventilated and tested.

Before heat is applied to a drum, container, or hollow structure, a vent or opening must be provided for the release of any built-up pressure during the application of heat.

VENTILATION AND PROTECTION IN WELDING, CUTTING, AND HEATING
29 CFR 1926.353

Mechanical ventilation. Mechanical ventilation must consist of either general mechanical ventilation systems or local exhaust systems.

Ventilation must be deemed adequate if it is of sufficient capacity and so arranged as to remove fumes and smoke at the source and keep their concentration in the breathing zone within safe limits as defined in Subpart D of Part 1926, Occupational Health and Environmental Controls.

Contaminated air exhausted from a working space must be discharged clear of the source of intake air. All air replacing that which was withdrawn must be clean and respirable. Oxygen must not be used for ventilation purposes, comfort cooling, blowing dust from clothing, or for cleaning the work area.

Hot work operations in confined spaces. Except where air line respirators are required or allowed as described below, adequate mechanical ventilation meeting the requirements described above must be provided whenever welding, cutting, or heating is performed in a confined space.

When sufficient ventilation cannot be obtained without blocking the means of access, employees in the confined space must be protected by air line respirators in accordance with the requirements of Subpart E of Part 1926, Personal Protective and Life Saving Equipment. An employee on the outside of the confined space must be assigned to maintain communication with those working within it and to aid them in an emergency.

Where a welder must enter a confined space through a small opening, means must be provided for quickly removing him in case of emergency. When safety belts and lifelines are used for this purpose they must be so attached to the welder’s body that his body cannot be jammed in a small exit opening. An attendant with a pre-planned rescue procedure must be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.

Welding, cutting, or heating of metals of toxic significance. Welding, cutting, or heating in any enclosed spaces involving the following metals must be performed with adequate mechanical ventilation.

  • Zinc-bearing base or filler metals or metals coated with zinc-bearing materials
  • Lead base metals
  • Cadmium-bearing filler materials
  • Chromium-bearing metals or metals coated with chromium-bearing materials

Welding, cutting, or heating in any enclosed spaces involving the following metals must be performed with adequate local exhaust ventilation as described above or employees must be protected by air line respirators in compliance with the respirator rule (29 CFR 1926.103):

  • Metals containing lead, other than as an impurity, or metals coated with lead-bearing materials
  • Cadmium-bearing or cadmium-coated base metals
  • Metal coated with mercury-bearing metals
  • Beryllium-containing base or filler metals

Because of its high toxicity, work involving beryllium must be done with both local exhaust ventilation and air line respirators.

Employees performing such operations in the open air must be protected by filter-type respirators, except that employees performing such operations on beryllium-containing base or filler metals must be protected by air line respirators.

Other employees exposed to the same atmosphere as the welders or burners must be protected in the same manner as the welder or burner.

Inert-gas metal-arc welding. Since the inert-gas metal-arc welding process involves the production of ultra-violet radiation of intensities of 5 to 30 times that produced during shielded metal-arc welding, the decomposition of chlorinated solvents by ultraviolet rays, and the liberation of toxic fumes and gases, employees must not be permitted to engage in, or be exposed to the process until certain special precautions have been taken.

The use of chlorinated solvents must be kept at least 200 ft, unless shielded, from the exposed arc, and surfaces prepared with chlorinated solvents must be thoroughly dry before welding is permitted on such surfaces.

Employees in the area not protected from the arc by screening must be protected by filter lenses. When two or more welders are exposed to each other’s arc, filter lens goggles of a suitable type, must be worn under welding helmets. Hand shields to protect the welder against flashes and radiant energy must be used when either the helmet is lifted or the shield is removed.

Welders and other employees who are exposed to radiation must be suitably protected so that the skin is covered completely to prevent burns and other damage by ultraviolet rays. Welding helmets and hand shields must be free of leaks, openings, and highly reflective surfaces.

When inert-gas metal-arc welding is being performed on stainless steel, adequate local exhaust ventilation as described above or air line respirators must be used to protect against dangerous concentrations of nitrogen dioxide.

General welding, cutting, and heating. Welding, cutting, or heating not involving conditions or toxic materials described above may normally be done without mechanical ventilation or respiratory protective equipment. These protections must be provided, however, where an unsafe accumulation of contaminants exists because of unusual physical or atmospheric conditions.

Employees performing any type of welding, cutting, or heating must be protected by suitable eye protective equipment (see 29 CFR 1926.102).

WELDING, CUTTING, AND HEATING OF PRESERVATIVE COATINGS
29 CFR 1926.354

Before welding, cutting, or heating is commenced on any surface covered by a preservative coating whose flammability is not known, a test must be made by a competent person to determine its flammability. Preservative coatings must be considered to be highly flammable when scrapings burn with extreme rapidity.

When coatings are determined to be highly flammable, they must be stripped from the area to be heated to prevent ignition.

Protection against toxic preservative coatings. In enclosed spaces, all surfaces covered with toxic preservatives must be stripped of all toxic coatings for a distance of at least 4 in. from the area of heat application, or the employees must be protected by air line respirators. In the open air, employees must be protected by a respirator.

Removal of protective coatings. The preservative coatings must be removed a sufficient distance from the area to be heated to ensure that the temperature of the unstripped metal will not be appreciably raised. Artificial cooling of the metal surrounding the heating area may be used to limit the size of the area required to be cleaned.

Thorough operating instructions are required for both gas and arc welding and cutting. Some employers may be required to train special personnel in the fire hazards and firefighting equipment suitable for their operations.

GAS WELDING AND CUTTING
29 CFR 1926.350(d)(1)

The employer must instruct employees in the safe use of fuel gas. See the “Use of Fuel Gas” subsection of this analysis for the specific procedures.

ARC WELDING AND CUTTING
29 CFR 1926.351(d)

Employers must instruct employees in the safe means of arc welding and cutting. See the “Operating Instructions” subsection of this analysis for the specific procedures.

FIRE PREVENTION
29 CFR 1926.352(e)

Personnel assigned to guard against fire while the actual welding, cutting, or heating operation is being performed must be trained to anticipate fire hazards and how to use the available fire-fighting equipment. When normal fire-prevention precautions are not sufficient, additional persons, trained in fire hazards and fire-fighting equipment, must guard against fire.

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