Page 82 - OHS, July/August 2022

PPE: RESPIRATORY PROTECTION
The Last Line of Defense
OSHA keeps workers safe from silica with dust management and extraction, but sometimes PPE is needed to ensure healthy employees.
BY KYLE ANDERSON
Respirators are the last line of defense for dust mitigation and filtration through silica and sanding to protect users from respirable crystalline silica. According to OSHA, this fine particle is at least 100 times smaller
than ordinary sand granules found at the beach. These particles are formed when cutting, sawing, grinding, drilling and crushing stone, rock, concrete, brick, block and mortar.
About 2.3 million people in the U.S. are exposed to silica at work. When this form of silica is inhaled, it increases the risk of developing silica-related diseases such as silicosis. Silicosis is an incurable lung disease that can be fatal and typically occurs within 15 to 20 years of working while exposed to respirable crystalline silica. Other respirable crystalline silica diseases include lung cancer, chronic obstructive pulmonary disease (COPD) and kidney disease.
For respirators, safety standards are put in place to help protect workers from these diseases, which can sometimes be fatal. OSHA requires all respirators on jobsites to be approved and rated by the National Institute for Occupational Safety and Health (NIOSH), the federal agency responsible for testing and approving respirators used in U.S. workplace settings. Each respirator goes through standard tests to qualify the respirator as an air-purifying respirator (APR) and receives a classification.
What Do the NIOSH Ratings Mean?
Particulate respirators are classified by the filter material (N, R, P) and the protective properties (95, 99, 100). Below are the filter’s Classification when exposed to oils:
■ N Class: respirators/cartridges are not resistant to oils
■ R Class: respirators/cartridges are somewhat resistant to oils
■ P Class: respirators/cartridges are strongly resistant to oil/ oil proof
In this case, we will use the following definition for oil, “Mineral, vegetable, synthetic substance, animal, or vegetable fast that slippery, combustible, viscous, liquid, liquefiable at room temperatures soluble in various organic solvents as ether, but not in water.”
As mentioned above, particulate respirators are also classified by their protective properties. Here’s a breakdown of 95, 99 and 100. ■ 95 percent: filters at least 95 percent of the most-penetrating
particle sizes
■ 99 percent: filters at least 99 percent of the most-penetrating
particle sizes
■ 100 percent: filters at least 99.97 percent of the most-
penetrating particles (HEPA Filters)
The Most Common Protection
N95 filters are the most common, and N95 respirators that are NIOSH-approved have a testing and certification (TC) approval
number printed on the respirator for easy identification. N95- rated respirators filter at least 95 percent of airborne particles but are not resistant to oil-based particles.
Not every N95 mask on the market is NIOSH approved and complies with OSHA jobsite requirements. N95 masks can be identified as NIOSH approved by searching for it on the Certified Equipment List. This list is supplied and regulated by the CDC and gives the user the option to search by TC number. If there are no results found, it is not a valid NIOSH approval number, and it does not meet testing standards to be approved. Depending on the manufacturer, disposable respirators typically have a five-year shelf life, and the date of manufacture and expiration are required on the packaging.
Additionally, N95 NIOSH-approved respirators will have required specific labeling printed on the facepiece. The most common replica of an N95 respirator is the KN95. The two look very similar, but the KN95 mask is the Chinese standard for air filtrating devices and does not meet the U.S. standard for effectiveness. Both masks filter out 95 percent of the most- penetrating particles, however, the KN95 mask is not regulated by NIOSH.
Standards and Testing
Per OSHA, to protect workers exposed to respirable crystalline silica, there are two respirable crystalline silica standards: one for construction, and the other for general industry and maritime. These regulations require contractors to always have approved respiratory protection readily available for their employees. On top of that, every user must undergo medical evaluations and fit testing conducted annually.
When an employee accepts a job where respiratory protection is needed, or if the user is consistently encountering work
78 Occupational Health & Safety | JULY/AUGUST 2022
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