Protect Welder Health with Control Banding: A Practical Approach
September 13, 2023
Control banding has a 20-year history, starting with pharmaceuticals and chemicals and then into nanotechnology and ergonomics. It highlights the hierarchy of controls by providing a decision-making framework to assess chemical substances and develop exposure control guidance, particularly for chemicals without authoritative Occupational Exposure Limits (OEL).
This blog presents a practical demonstration of how control banding can be applied to welding tasks. Welding and thermal cutting are often thought of as an activity or task that occurs across many different industries like painting or abrasive blasting tasks. Tasks where the source of the health hazard is within arm’s length of the worker. With over 30 different welding processes (according to the American Welding Society) for construction, fabrication and repair, welding is an industry itself.
Control Banding and Welding Fumes
Welding fumes were classified as a Human Carcinogen by IARC (International Agency for Research on Cancer) in 2017; however, there is no occupational exposure limit for aggregate welding fumes making it subject to the ALARA (as low as reasonably achievable) principle in most jurisdictions. While control banding does not replace traditional Industrial Hygiene (IH) assessment methods for welding, it is a practical method to protect worker health today. Not many small or medium-sized businesses with welding activities have the resources to employ a professional industrial hygienist or mount an extensive sampling campaign. Additionally, traditional assessment methods can incur delays in waiting for sampling results and recommendations while workers continue to be overexposed.
Control banding simplifies exposure controls and offers a pragmatic approach to assess risks and recommend controls, particularly when occupational exposure limits for aggregate welding fumes are unavailable.
Follow the Hierarchy of Controls When Reviewing Your Welding Operations
Using a consistent, objective system to quickly identify engineering and administrative controls is valuable. For example, a work site with welding operations needs a control approach for each task. Control banding simplifies the number of control approaches based on the type of task. These control approaches can include natural ventilation, engineering controls, containment, and expert advice. The number of approaches is also then reduced to three because the carcinogenic nature of welding or thermal cutting fume rejects any control approaches based on natural or dilution ventilation.
Engineering controls such as local exhaust ventilation (LEV) can reduce fume exposures if used correctly (that is, positioned 1 to 1.5 hood diameters from the arc) and routinely measured for effectiveness. LEV should be part of the solution but not the basis of a control approach. Even if LEV does not eliminate welding fumes at the source, it can enhance natural ventilation to reduce fume exposure to coworkers in the shop or in the immediate vicinity outdoors.
Control approaches for welding need to start with containment. Containment of the process is where emissions are captured at the source. The containment needs to create pressure around the isolated source so that clean air moves into the contaminated zone. This scenario is ideal but may not be practical or available outside of dedicated, state-of-the-art manufacturing facilities. Containment of the worker is another way of protecting welders. In this type of containment, the worker is surrounded by clean air under positive pressure, similar to an isolation room. Most welding necessitates the worker being within arm’s length of the work, which makes an isolation room unrealistic; however, isolating the worker’s breathing zone is not.
The use of a powered, air-purifying respirator (PAPR) is intended to create a containment level of protection for the welder during welding and thermal cutting processes. Because utilizing a PAPR is not a true containment of the contaminant, the control scheme must include protection for other workers, contractors, or visitors. Increased ventilation or LEV, restricted work areas, decontamination practices, and PPE are also part of this control approach.
Control Banding Welding Processes
Another aspect of welding work that lends itself to control banding is the classification of welding processes into two categories: low-fume emitters and high-fume emitters.
High-Fume Emission Processes
In high-fume emission processes, there is no physical barrier between the arc and the welder, and the welding process uses the consumable as the electrode. Thermal cutting processes are high fume by default. Examples of thermal cutting processes are:
- Shielded metal arc welding (SMAW, also called manual metal arc welding or MMA)
- Flux-cored arc welding (FCAW)
- Gas metal arc welding (GMAW)
- Arc cutting
- Arc gouging
Low-Fume Emission Processes
In contrast, low-fume emission processes include gas tungsten arc welding (GTAW or “TIG”), which does not use a consumable electrode; and submerged arc welding (SAW) and resistance welding (RW, also known as “spot welding”), in which a physical barrier (a mound of flux or parts being welded) is placed between the arc and welder.
Four Approaches to Welding Fume Exposure Control
By separating the exposed population into two groups and the exposure profile into two categories, control banding simplifies exposure control into four approaches:
- High-fume emitting process: the welder and helper require a PAPR with cape and HEPA filter.
- High-fume emitting process: coworkers or bystanders in the shop or in the immediate vicinity outdoors require a half-face, air-purifying respirator (HFAPR) with a P100 filter.
- Low-fume emitting process: the welder and helper require an HFAPR with a P100 filter.
- Low-fume emitting process: coworkers or bystanders in the shop or in the immediate vicinity outdoors require an N95 respirator.
While control banding does not replace traditional IH assessment methods for welding, it provides a clear path toward protecting workers’ health until an OEL is designated.
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