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Determination of known exhalation valve leakage using an irritant smoke test kit.

Snyder E; McKay R
American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California. Fairfax, VA: American Industrial Hygiene Association, 2002 Jun; :48
This study evaluated the ability of a qualitative fit test method (irritant smoke) to detect known exhalation valve leakage. The OSHA protocol for the irritant smoke test mandates the use of a low flow air pump at 200 Ml/minute or aspirator squeeze bulb. Many commercial test kits include an aspirator bulb, which is subject to variation from depth and frequency of squeeze. Previous studies on irritant smoke used a hand held squeeze bulb. This study evaluated the effectiveness of a constant low flow pump to detect exhalation valve leakage using an irritant smoke fit test kit. Twenty subjects wearing North 7600 series full-face respirators equipped with P100 filters were fit tested with a Portacount Plus to ensure adequate fit. After successful fit was demonstrated, the exhalation valve was replaced with a damaged valve and/or rotated approximately 90 degrees to produce a fit factor below 100. Having induced an exhalation valve leak, the irritant smoke test was performed using the OSHA irritant smoke protocol. To avoid introducing additional unknown leakage, all head movement exercises were replaced with the head straight, normal breathing maneuver. Irritant smoke did not detect 40% of respirators with leaking exhalation valves. Sixty percent of the subjects were able to detect the irritant smoke. Test sensitivity was 60%, well below the ANSI Z88.l 0 recommended 95% criterion. Of the 12 subjects that detected irritant smoke, none detected the smoke in less than a minute; the average detection time was 3:05 minutes. Other findings to be presented include suppression of the irritant response. These findings suggest that qualitative fit testing using an irritant smoke fit test with a 200 mL/minute continuous flow pump does not have adequate sensitivity to detect fit factors less than 100.
Irritants; Qualitative-analysis; Breathing; Breathing-atmospheres; Sensitivity-testing; Respirators; Respiratory-protection; Respiratory-protective-equipment
Publication Date
Document Type
Fiscal Year
NIOSH Division
Priority Area
Research Tools and Approaches; Respirator Research
Source Name
American Industrial Hygiene Conference and Exposition, June 1-6, 2002, San Diego, California
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division