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Viral Penetration Resistance
As stated in National Fire Protection Association (NFPA) 1971 Standard on Protective
Ensemble for Structural Fire Fighting, the ability of the test materials to
resist viral penetration will be determined in accordance with the method outlined
in American Society Testing and Materials (ASTM) F 1671, Standard Test Method
for Resistance of Materials Used in Protective Clothing to Penetration by Blood-Borne
Pathogens Using Phi-X-174 Bacteriophage as a Test System.
The testing device used is the ASTM F 903 Chemical Penetration Cell (Figure
1). Both sides of individual test specimens, prepared prior to submission,
were sealed with Gore-Tex® joint sealant to ensure no leakage
occurred from the side of the penetration test cell. Then specimens are clamped
into the cell forming a closed chamber for the external side of the material.
Approximately 60 ml of synthetic blood, the test vehicle or bacteriophage suspension,
is introduced into the test chamber contacting the external material surface.
After the initial 5 minutes observation period, the air pressure applied to
the viral suspension is raised from 0 psig to 2 psig over 30 seconds and is
held for a 1 minute interval. The surface of the test specimen is observed
closely to determine whether visual penetration occurs. After the 1 minute
of applied pressure, the pressure is released (0 psig) and the specimen is
allowed to sit for an additional 54 minutes at atmospheric pressure. At the
end of the test period, the surface of the specimen is observed for penetration
on the normal inside surface of the material.
To evaluate the occurrence of viral penetration, the surface of
the test specimen is then rinsed with a sterile assay broth that
is then collected. This assay fluid is plated using standard plaque
assay techniques. The assay plates are then incubated for 18-24
hours and counted. Results are based on visual detection and reported
as pass or fail. Specimens showing no plaques on any of the assay
plates are scored as pass. If plaques show on the surface of the
plates the results are scored as fail.
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