Revised Breakthrough Levels for Gas Masks
NOTE: This page is archived for historical purposes and is no longer being maintained or updated.
Letter to All Respirator Manufacturers
Issue Date: April 16, 2010
From: Heinz Ahlers, Chief, Technology Evaluation Branch, National Personal Protective Technology Laboratory
Subject: Revised Breakthrough Levels for Gas Masks
The National Institute for the Occupational Safety and Health (NIOSH) approves gas masks with carbon monoxide (CO) protection for escape purposes under subpart I of Title 42, Code of Federal Regulations, Part 84 (42 CFR 84) and Statement of Standard for Chemical, Biological, Radiological, and Nuclear (CBRN) Air-Purifying Escape Respirators (APER). A policy statement, dated November 20, 1996, was written describing an additional test to be imposed for devices in which the temperature of the effluent gas reaches 100o C during required, constant-flow testing. The policy statement established a maximum allowable breakthrough concentration of 10 ppm carbon monoxide during the additional test.
NIOSH has revisited this policy and believes that the breakthrough concentration of 10 ppm incorrectly accounted for the fit factor of the respirator and was therefore too conservative. The breakthrough concentration is now established at the current NIOSH REL of 35 ppm. This change does not affect previously certified carbon monoxide respirators.
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