Table of Contents

Welding Safety Practices

There are various welding methods available today, all of which have inherent safety and health hazards. Environmental Health and Safety must evaluate all welding processes to protect welders, including staff and students, bystanders, and property. The information below provides a basic overview of welding hazards and some preventive measures that should be taken to weld safely.

  • Only qualified personnel -are authorized to perform welding operations.
  • Employees should be provided with protective equipment, including welding helmets, shields, aprons, gloves, and gauntlets.
  • Arc welders should ensure fireproof screens are placed around the work area to prevent eye flash burns to personnel.
  • Welders should wear eye protection when chipping scarf metal fragments.
  • Forced ventilation should be used in welding operations when natural ventilation is insufficient to prevent the accumulation of gases and fumes. In confined areas, local exhaust ventilation will be required.

Welding Fire Hazards

Welding or cutting near flammable or explosive materials requires close attention to the following safety requirements:

  • A fire extinguisher must be available within 50 feet. Workers must also know how to operate it in the event of a fire.
  • Welders working near combustible materials should be provided with a watch person on standby with suitable fire suppression equipment.
  • Flammable materials should be removed from the immediate area; wooden floors and other combustible surfaces should be protected. When removing flammable materials from the area is impractical, a suitable fire-resistant shield should protect them.
  • After welding operations, the area should be thoroughly inspected for smoldering material.
  • Welding is prohibited where flammable gases or liquids are present until their presence has been eliminated.
  • Welding itself may produce flammable and explosive gases in confined spaces. For more information, refer to the NCSU Confined Space Entry Program.
  • When a fire hazard persists after precautionary measures are taken, the supervisor should decide whether to weld or cut. A fire watch should stand by the welding operation.
  • Compressed gases: The precautions for the handling and storing compressed gases are contained in 29 CFR 1910.101

Welding Containers

Before welding or cutting any tank, cylinder, or other containers, personnel should ensure containers are free from any trace of explosive material. The following procedures will minimize accidents:

  • Containers that contain or have contained explosive, flammable, or combustible substances should be purged or made inert before the welding operation.
  • Containers should be vented during the welding operation. Adequate venting is necessary to prevent containers from exploding or rupturing.

Oxyacetylene Welding/Cutting

Careful handling of the gases and equipment used in oxyacetylene welding is essential. In addition, observe the following:

  • Oil or grease should not be allowed to contact welding equipment.
  • Acetylene should not be used at pressures exceeding 15 psi.
  • Leaking and creeping regulators should be removed from service.
  • Control valves should be opened at most 1-1/2 turns; 1/2 turn is sufficient for most welding operations.
  • The special T-wrench used to open cylinders should be left in place during welding operations to permit quick shutdown in emergencies.
  • Control valves should be unobstructed and immediately accessible to the welder.
  • Protective caps should cover the control valves of cylinders that are not in use.
  • Acetylene cylinders should be stored and used upright to prevent acetone loss and minimize external corrosion.
  • Welding torch hoses should be protected from damage by contact with hot metal, open flames, or other destructive agents.
  • Inspect hoses periodically for leaks.
  • Only standard ferrules or clamps should be used to secure hoses to cylinders and torches. Makeshift tape or wire connections should not be used.
  • The oxygen hoses should always be green in color.
  • Hoses should be released of pressure at the end of each workday.

Gas Welding Flame

The flame should always be kept within the welder’s vision field and not allowed to contact any part of the welding equipment. The following additional procedures should be observed:

  • The torch should be extinguished, and its control valves should be turned off when not in use.
  • The torch should not be pointed at concrete surfaces because a miniature explosion could result in flying concrete fragments.
  • If a flashback occurs, the operator should turn off both torch valves.
  • If a hose bursts or escaping gas ignites at the tank regulator, the control valves should be immediately turned off.
  • On manifold cylinder systems, each fuel-gas cylinder should be provided with a backflow check valve.

Electric Arc Welding

Eye injury can occur while operating arc welders. Use fire-resistant curtains or screens during the welding operation and post warning signs. In addition:

  • Always de-energize electrical circuits before testing or checking.
  • Rotary and polarity switches should not be operated while the equipment is under an electrical load.
  • Motors, generators, and other electrical welding equipment should be grounded.
  • Arc welding equipment should undergo careful inspection before each day’s use.
  • Arc-generating equipment should be repaired by qualified electricians only.

Cadmium Welding Hazards

When cadmium-plated or cadmium-bearing metals are welded, local exhaust ventilation should be provided. In addition:

  • The exhaust hood should be kept as close to the point of generation as possible and should never be more than 8” away.
  • If local ventilation cannot be supplied and welding is done in small, confined spaces, the operator should wear an approved air-line-type respirator. All respirator use must have EH&S approval. Please contact EH&S for more information.
  • Welding should never be performed on a metal or alloy of unknown identity. Cadmium-plated metals can easily be confused with other electroplated metals. When there is any doubt about the composition of a metal to be welded, a sample should be submitted to a metallurgical or chemical laboratory for analysis.
    • Oxides commonly generated in welding processes may originate from the material being welded, the surface coating, or the electrodes of the arc equipment. Cadmium oxide is highly poisonous, particularly in the vapor form. Heavy concentrations cause rawness in the throat, irritation of the mucous membranes, and edema (fluid) in the lungs. Death or permanent lung damage can result from prolonged breathing of cadmium oxide. Unless the welder is familiar with the differences between cadmium-containing metals and others similar in appearance, exposure to toxic concentrations of cadmium oxide can occur when welding cadmium-bearing or plated metals.
    • Adequate ventilation and respiratory protective equipment should be provided to protect against harmful gases, fumes, and dust.

Welding activities outside the permanent shop locations

Hot work permits are required for welding, cutting, torching, brazing, soldering, and other activities unrelated to the permanent shop locations. The permit may be obtained from the University’s Fire and Life Safety Office during regular business hours at https://fls.epsi.ncsu.edu/fire-safety-hot-works/.