Page 52 - OHS, May 2022

PPE: RESPIRATORY PROTECTION
Respiratory Health 101: What You Need to Know about Welding PPE When welders utilize the correct respirators work can be done safely and effifficiently.
elding, joining together metal parts by heating the and the substance’s applicable airborne exposure limits. It also surfaces to the point of melting, inherently comes takes PELs in the workspace into account.
with some occupational hazards. They vary by A respirator’s maximum protection is calculated by the application; however, sparks, spatter, particulate following formula:
fumes and arc rays are some of the hazards that may be present. To APF x PEL (or applicable limit) = MUC.
protect from these hazards, personal protective equipment (PPE) is needed. The common or foundational types of PPE for welding are safety glasses, welding helmets, FR welding jackets, and leather welding gloves.
For some welding applications, additional PPE, including respiratory protection, may be required if exposure to welding fume constituents exceeds defined limits, such as OHSA’s Permissible Exposure Limits (PELs), which we will expand on later. Ultimately, welding PPE can be thought of as a system or circuit in which multiple items may be used together to provide adequate protection from the hazards the operator may be exposed to.
Welding Fume & Potential Respiratory Hazards
Fume is created when metal or other solids vaporize and molecules condense in cool air. Fumes created during mild steel welding include complex metallic oxides of iron and manganese. Welding on galvanized steel may produce a condition known as “metal fume fever,” which presents with flu-like symptoms such as headaches, chest pain, nausea, joint pain, fever and chills.
Weld and filler metal coatings can contain such substances as lead, chromium or zinc. It’s best to remove coatings before welding whenever possible. Welding with stainless steel and hard-facing consumables may require additional ventilation and other protective measures to eliminate or minimize exposures.
Welding in confined spaces can exacerbate any of these potential hazards. When possible, welding should be done in open, well-ventilated areas. Respiratory protection is essential when exposure levels can or do exceed applicable exposure limits.
Understanding Respiratory PPE
As mentioned above, welders must use respiratory protection if exposures to various constituents of welding fume exceed the limits set forth by OSHA PEL or the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLV). Following the OHSA PEL is required by law within the US but Lincoln Electric recommends welders comply with whichever threshold is lower.
OSHA and the National Institute of Occupational Safety and Health (NIOSH) recognize two concepts for the proper selection of respiratory protection: assigned protection factors (APF) and maximum use concentration (MUC).
APFs are the workplace level of respiratory protection provided by a respirator when an employee implements a “continuing, effective respiratory protection program.” Maximum use concentrations (MCUs) represent a hazardous substance’s “maximum atmospheric concentration” from which respirators can protect employees. It’s determined by the respirator’s APF
The proper level of protection is critical when it comes to choosing the right type of respiratory protection. Two popular types that might be selected when they meet the necessary selection criteria include Powered Air Purifying Respirators (PAPR) and Reusable Half-Mask Welding Respirators.
PoweredAirPurifyingRespirators(PAPR)
Loose-fitting, positive-pressure powered air-purifying respirators deliver filtered ambient shop air to the operator. These NIOSH 42 CFR Part 84-approved respirators are a comprehensive system that can include an air-purifying blower, high efficiency particulate arrestance (HEPA) filters, custom welding helmet and more.1
These systems feature a HEPA filter that provides rated protection against respirable dust and metal fume particles, including hexavalent chromium, oxides of manganese andiron, zinc oxide, aluminum, nickel, beryllium, cadmium, and lead fumes. They filter out 99.97 percent of this particulate at 0.3 microns. Most PAPRs also feature a spark screen that protects the filter from fire while filtering large particulate, and a pre-filter that traps medium sized particulate while increasing HEPA filter life. PAPRs for welding commonly have an APF of 25.
Reusable Half Mask Respirators
One of the most common, low cost and readily available types of personal respiratory equipment is half mask respirators, which historically were not widely used within the welding industry. Why? Simply put, most half mask respirators weren’t compatible with other welding PPE and/or were uncomfortable. Luckily, modern R&D advances in this respiratory PPE category have improved both compatibility and comfort, making these respirators more widely used for metal fabrication.
Reusable half-mask respirators may feature various classifications of filters, including N99, P99, N100 or P100 NIOSH-rated filters. The most common filter in half-mask respirators used for welding is a P100 rated filter, which delivers 99.97 percent efficiency in filtering non-oil and oil-based particulates and aerosols on the shop floor. Half-mask respirators with these filters offer an APF of 10.
Selection Guidance
When selecting personal respiratory equipment, first and foremost, you must select equipment that provides the proper level of protection (including APF and MUC) for your specific application. After safety needs are met, then other product specific criteria should be evaluated. These product specific elements include but aren’t limited to product cost, filter life, comfort, fit testing requirements and welding-specific features.
48 Occupational Health & Safety | MAY 2022
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