Ventilation for Welding and Cutting

Ventilation is used to control overexposures to the fumes and gases during welding and cutting. Adequate ventilation will keep the fumes and gases from the welder’s breathing zone.
NOTE: This does not address ventilation in confined spaces.

Nature of The Hazard - The Fume Plume

The heat or the arc of a welding flame creates fumes and gases, also known as fume plume.
Fumes contain respirable particles.
Gases include the shielding gas and combustion products.
The heat from the arc or flame cause fume plume to rise. These fumes contain hazardous substances and overexposure to them may cause acute or chronic health effects.
Fumes and gases may be produced at toxic levels and they are capable of displacing oxygen in the air resulting in asphyxiation. Overexposure to welding and cutting fumes and gases can cause dizziness, illness, and possible unconsciousness and death.

How to Avoid Welding Hazards - Ventilation

Keep your head out of the fumes. Reposition the work, your head, or both to keep from breathing the fumes.
Ventilation allows control over the fumes and gases that are produced from cutting and welding. Adequate ventilation restricts exposure to dangerous contaminants below acceptable limits.
Have a technically qualified person evaluate exposure to determine if ventilation is adequate. Wear an approved respirator when ventilation is not adequate or practical.
Adequate ventilation is based on:

  • Size and shape of the workplace
  • The number and type of operations
  • Contents of fume plume
  • Position of the workers' and welders' heads
  • Type and effectiveness of ventilation
  • Adequate ventilation can be obtained through natural or mechanical means or both.

    Natural Ventilation – the movement of air through a workplace by natural forces.

  • Roof vents, open doors, and windows provide natural ventilation.
  • The size and layout of the area or building can affect the amount of airflow in the welding area.
  • Natural ventilation can be acceptable for welding operations if the contaminants are kept below the allowable limits.
  • Mechanical Ventilation – is the movement of air through a workplace by a mechanical device such as a fan. Mechanical Ventilation is reliable. It can be more effective than natural ventilation. Local exhaust, local forced air, and general ventilation are examples of mechanical ventilation.
    Local exhaust ventilation systems include a capture device, ducting, and a fan. The capture devices remove fumes and gases at their source. Fixed or moveable capture devices are placed near or around the work. They can keep contaminants below allowable limits.
    One or more of the following capture devices are recommended:

  • Vacuum nozzle at the arc
  • Fume Hoods
  • Gun mounted fume extractor

  • Some systems filter the airflow before exhausting it. Properly filtered airflow may be recirculated.

    Local forced air ventilation is a local air moving system. A fan moves fresh air horizontally across the welder’s face. A wall fan is an example of Local Forced Air Ventilation.
    When using localized ventilation, remember:

  • Locate the hood as close as possible to the work.
  • Position the hood to draw the plume away from the breathing zone.
  • Curtains may be used to direct airflow.
  • Some toxic materials or chemicals may require increased airflows.
  • Velocities above 100 feet per minute at the arc or flame may disturb the process or shielding gas.
  • The capture device can depend on the type of job.
  • To minimize worker overexposure to fumes and gases:

  • Keep your head out of the fumes, and do not breathe the fumes.
  • Reposition the work and your head to avoid the fumes.
  • Choose the correct ventilation method(s) for the specific operation.
  • Use enough ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and the general area.
  • Understand what is in the fumes.
  • Have a technically qualified person sample your breathing air and make recommendations.
  • Keep hazardous air contaminants below allowable limits.
  • Wear the proper respirator when necessary.

  • Resource: AWS Health and Fact Sheet No. 36 - Ventilation for Welding and Cutting