3.7 Air Contaminants
Stephanie Oostman
Welding, cutting, and grinding operations create an array of respiratory hazards for the welder and other people around the shop or jobsite. Fumes, dust, gas, smoke, and vapors are just a few. The first step in preventing breathing hazards is proper ventilation. When welders are outside on a platform 20 stories up welding on a high rise, the ventilation is going to be different than for welders working in a shop or in a confined space such as a ship hull. Each of these situations has a special set of ventilation regulations and parameters.
Confined space welding can be particularly dangerous without adequate training, ventilation, and airflow. For example, TIG welding in a confined space may not seem all that dangerous. But consider that while argon—the purging gas used in GTAW—is inert and not combustible or reactive to other elements in the atmosphere, it is denser than air. If a TIG welder is working in a tight space, their air is slowly being displaced with argon. This will eventually cause a suffocation hazard to the welder and workers nearby without proper ventilation regulations, precautions, and inspections.
There are times when additional respiratory protection needs to be taken other than ventilation. In this section, we will review a few articles of PPE that you may find in a welding environment. All respiratory PPE should be NIOSH-certified to confirm that it adheres to necessary safety protocols. OSHA regulation 1910.134 discusses respiratory safety in great detail.
Dust Masks
While this section discusses respirators, it’s worth mentioning that there are instances when a simple dust mask may suffice for the job.
Dust masks do not provide full respiratory protection because they do not create a full seal around the nose and mouth: they only provide a partial seal around the face. A dust mask is also called a filtering facepiece and is intended for filtering out larger material particles like dust, fiberglass, metal chips, and debris. They do not filter out toxic airborne chemicals, gasses, or hazardous dust particles like chromium.
Respirators
Respirators come in all shapes and sizes. There are some things to consider when selecting a respirator for welding. Arguably the two most important questions are: does it fit, and will it fit under your welding helmet? If the respirator does not create a tight seal around your nose and mouth or does not fit under the welding helmet, the rest does not matter because you wouldn’t be fully protected.
N95 class respirators are a minimum filter for welding when it comes to filtering out larger particulates and oil and non-oil lubricants in the air. The filters on an N95 respirator have a service life, meaning there is a limited time for which the filters provide safe and adequate function. It is possible to run through filters prior to that time if you are working in a particularly dusty or dirty environment. Adequate N95 filtering requires a clean-shaven face, fit testing by an authorized person, and record keeping. If an employer requires N95 mask filters, they must pay for them.
PAPRs
Recall that PAPR is short for powered air-purifying respirator. These are battery-powered full or partial-face respirators that filter air through a canister or cartridge. The unit uses a blower to pass air through a HEPA-grade filter, which is then passed to a mouthpiece or sealed face mask. PAPRs do not require fit testing for a proper seal and may be a choice of respiratory PPE for those with facial hair that otherwise may not allow them to pass a fit test with other respirators. When outfitted appropriately, PAPRs provide protection to the wearer from vapors, dust, debris, smoke, and gasses.
Supplied Air
A supplied-air respirator (SAR) provides a user a fresh air source via a hose connected to compressed air. These respirators don’t just filter incoming air, they also supply a whole fresh air source. This is ideal for individuals working in a hazardous or toxic air environment for long periods of time. The air source on these products is stationary whereas in other PPE products the air supply is from a canister the user carries with them or is simply a filter attached to the face mask. An example scenario when a welder would use an SAR would be a diver that has a fresh air feed to the surface vs an air tank on their back.
Attributions
- Figure 3.15: Face mask or dust mask or filtering facepiece respirator – breathing protection against air pollution or flu or virus outbreak by Jernej Furman is released under CC BY 2.0
- Figure 3.16: image released under the Pexels License
- Figure 3.17: Underwater oxy-arc cutting by Israeli Navy is released under CC BY-SA 3.0
provide a user a fresh air source via a hose connected to compressed air. These respirators don't just filter air coming in, they supply a whole fresh air source.