Short answer: It isn’t.
We get this question a lot and it’s understandable how it can be misinterpreted. The quantitative fit testing method requires eight dynamic exercises. Seven are performed and measured for one minute each. One is performed for 15 seconds and is not measured. Want to guess which one?
When the employee grimaces the expectation is that the step “fails” the seal, and the Portacount doesn’t count those particles in the measurement. The only thing being “excluded,” is the measurement of particles during that exercise. It should be noted that the the grimace step doesn’t get performed with a qualitative test, because the subject would then taste the challenge agent in the subsequent test steps. This may add to the confusion if you are using both forms of fit testing.
What is a grimace?
I usually describe the exercise as an exaggerated facial expression like grinning or smelling something really awful. This will likely break the seal slightly. The Portacount will measure the re-seal during the bending over exercise.
Learn more about respirator fit testing
- Read the OSHA 1910.134 specification
- TSI PortaCount Pro series quantitative respirator fit test systems
- Other posts about respirator fit testing
RAECO-LIC LLC is the authorized TSI representative in the Midwest United States.