Page 40 - OHS, July/August 2021

PPE: RESPIRATORY PROTECTION
Does My Face Covering Work? Ask ASTM F3502
Each industry has its own hazards, making the search for a face covering difficult.
BY HUGH HOAGLAND, MICHAEL MCDONALD, RUWAN WIJESUNDERA, ROB TAYLOR, BRIAN SHIELS
Thecoronavirusmadepopularthe face coverings in public spaces all over the world as a means to stop transmission of the virus. This means that face masks, or cloth face coverings (CFCs) were also commonly found in workplaces of all kinds.
ASTM’s new F3502 Barrier Face Covering Specification, issued February 15, 2021, comes in time to improve the fit, function and other characteristics of face masks.1 This standard was issued unusually fast in ASTM consensus and addresses everything about how to test cloth/barrier face coverings.
Function
ASTM F3502 points to several test methods or specifications to assist test labs, certification bodies, manufacturers and end users to assess and properly
market CFCs for worker protection when additional respiratory protection is not needed in the work environment. These include, but are not limited to, filtration, breathability and fit or leakage assessments. Let’s take a look at each one.
Filtration. The ASTM F3502 standard addresses filtration by testing 20 samples of cloth face coverings—ten in new condition and ten after a maximum number of cleaning cycles (as specified by manufacturer). These face coverings are tested for both sub-micron particulate filtration efficiency (PFE) and airflow resistance using a method similar to N95 respirator testing with modified acceptance criteria. Testing is performed on full products or, for certain products, the area of the product that fully covers the person’s nose and mouth.
Since CFCs are normally made of
launderable fabrics, the standard also requires the testing of PFE’s impact from routine laundering or cleaning. This is most commonly accomplished by normal machine laundering to a standard test method like AATCC TM 135 (North American home laundry). But otherlaundry preconditioning methods are available, including ISO 6330 (European home laundry), NFPA 2112 (industrial laundry) or hand washing.
Breathability. Airflow resistance is tested by a method described in the standard but is similar to inhalation/ exhalation resistance testing for N-series respirators: Method for Determination of Inhalation and Exhalation Resistance for Air-Purifying Respirators as per NIOSH Procedures TEB-APR-STP-0003 and TEB-APR-STP-0007.2
ASTM F3502 again uses a two-level
36 Occupational Health & Safety | JULY/AUGUST 2021
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