Page 42 - OHS, July/August 2021

PPE: RESPIRATORY PROTECTION
classification system for airflow resistance/breathability, with Level 1 (good performance) for cloth face coverings with airflow resistance being between 5 mmH2O to 15 mmH2O, and Level 2 (better performance) having airflow resistance less than 5 mmH2O. Any cloth face covering with resistance higher than 15 mmH2O would be non-compliant with ASTM F3502.
Fit or Leakage Assessment. The F3502 Specification requires the manufacturer to self-report a leakage assessment that can be as simple as a product design analysis. For manufacturers wishing to provide a quantitative analysis, they can supplement (but not replace) that leakage assessment with F3407 Test Method for Respirator Fit Capability for Negative-Pressure Half-Facepiece Particulate Respirators to determine the leakage ratio.
Other acceptable “examples of means to accomplish a leakage assessment could include dimensional analysis, computer modeling, placement of barrier face coverings on standardized head or head/torso forms and judging their respective areas of coverage and conformity to the head or head-torso form face showing conformance to the fit and sizing characterizations of AATCC M14-2020 or performing a quantitative analysis.”
Four Function Classifications
Based on the above-noted performance levels for PFE and airflow resistance, there are four possibilities for overall performance. These are based on the lowest efficiency and highest resistance measured for the 20 tested samples (inclusive of samples subjected to cleaning/laundering):
■ Level 1 for both PFE and Airflow Resistance
■ Level 1 for PFE and Level 2 for Airflow Resistance
■ Level 2 for PFE and Level 1 for Airflow Resistance
■ Level 2 for both PFE and Airflow Resistance
It should be understood that Level 2 for both parameters
represents the best performance of the cloth face covering but fit is also an important consideration. It should also be noted that some individuals with specific medical conditions (adults or children) could perceive difficulty breathing while wearing a barrier face covering with Level 2 airflow resistance.
Flame Resistance vs. Flame Spread
Flame spread and flame resistance are important in some work settings, so ASTM F3502 addresses them by pointing to applicable standards. Standards ASTM F1506 and NFPA 2112 addressed providing some level of protection and assured flame resistance to the CFCs. Neither standard addressed function from a particulate filtration, airflow resistance or fit perspective. Now ASTM guides flame resistance (by pointing to proper standards) and addresses the proper function. (For Fire Fighting see NFPA 1971 and our article on the true arc flash and flame protection afforded by SCBA devices.)3,4
Flame spread is tested on all clothing sold in the U.S. by regulation 16 CFR Part 1610, however, this standard does not address flame resistance as often assumed.5 Garments can burn in this test method and most do, it is a control of “how fast” they burn. Cloth face coverings are considered wearing apparel and are subject to 16 CFR Part 1610 at a minimum, and the application to F3502 is that the material flammability/flame spread be Class 1, but for true AR/FR/FFR or other flame rated standards, the CFCs must meet the following, more stringent, standards.
ASTM F1506 for arc rated clothing and the NFPA 2112 for flash fire rated clothing committees moved very quickly to add CFCs to their scope and tone down labeling requirements and certification requirements to help workers exposed to flash fire and arc flash get the PPE they needed early in the crisis but neither of these standards addressed the fit of the CFC, function of breathability or particulate filtration. ASTM F3502 does just that.
■ NFPA 2112-2018 issued their changes in August 11, 2020 in TIA 18-1, Reference: various sections in Chapter 1, 2, 3, 4, 5, 6, 7, 8, Annex A and C.6 This was a change in labeling requirements and third-party certification. The CFCs were not defined as a product so only the components required certification to speed production.
■ ASTM F1506-20a updated the standard in Nov. 3, 2020 to include CFC’s with only a change in labeling requirements.
Other Requirements
Reuse must be specified by the manufacturer and if allowed, must be tested. The face coverings may not have exhalation valves. If the device requires replaceable filters, they have to be designed so they cannot be inserted improperly. Transparent parts are allowed if the design allows enough filtration to provide the source control function.
Labeling requirements include manufacturer’s name, model or style number and a citation of meeting the ASTM F3502 standard. An additional product use document/packaging statement about the limits of the CFC shall also be included if the device is not also dual certified as a medical mask or a respirator, and several other requirements to meet traceability, sizing, care and use, and legislative requirements for garments.
Hugh Hoagland is Kinectrics Arc and Flame PPE Testing Technical Specialist
Michael McDonald, MASc. is a scientist at Kinectrics focusing on mask and respirator testing
Ruwan Wijesundera, MASc. is a scientist at Kinectrics focusing on mask and respirator testing
Rob Taylor, B.S. is a Service Line Leader in Analytical Chemistry at Kinectrics focusing on Nuclear Chemistry
Brian Shiels, M.S. is Quality Manager at Kinectrics ArcWear Division, an organic chemist and textile engineer
REFERENCES
1. https://www.astm.org/Standards/F3502.htm
2. https://www.cdc.gov/niosh/npptl/stps/apresp.html
3. https://www.fireengineering.com/firefighting/electrical-arc-flash-hazards- and-personal-protective-equipment/#gref
4. https://e-hazard.com/can-i-wear-an-n95-or-other-respirator-in-an-arc- flash-exposure/
5. https://www.govinfo.gov/content/pkg/CFR-2015-title16-vol2/pdf/CFR- 2015-title16-vol2-part1610.pdf
6. https://www.nfpa.org/assets/files/AboutTheCodes/2112/ TIA_2112_18_1.pdf
38 Occupational Health & Safety | JULY/AUGUST 2021
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