OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

January 4, 1999

Ms. Janice C. Bradley
Industrial Safety Equipment Association
1901 N. Moore St, Suite 808
Arlington, VA 22209

Dear Ms. Bradley:

This is in response to your letter dated August 20, addressed to the Occupational Safety and Health Administration's (OSHA's), Office of Health Compliance Assistance (OHCA). In regard to a problem with the grimace step during Quantitative Fit Testing while using the Portacount, you have suggested that the step be eliminated or moved in the exercises to be performed first, before the Portacount is turned on. Unfortunately, neither suggestion would comply with the standard.

The grimace exercise, as you mentioned in your letter, is intended to test the respirator's ability to reseal to the wearer's face. A fit test modified to incorporate either of your suggestions would not allow the respirator to demonstrate this.

Even though each exercise in the protocol lasts one minute, the employee should be instructed to grimace for only the first 15 seconds of the minute set aside for the grimace exercise and revert to normal breathing for the remainder of the period. If this precaution is followed, most employees can usually be successfully fit tested using the protocol as written in Appendix A. If an employee repeatedly fails the fit test in a particular respirator, the employer should try to fit test the employee in a different respirator.

The Portacount is designed to calculate the overall fit factor from the fit factors of the individual exercises. The older Portacount included the grimace exercise in the calculations. If an employer has an employee who appears to be failing the fit test due to just the grimace exercise, the overall fit test can be calculated using the formula in Appendix A using only the results from the other seven exercises. This would normally only have to be done for a small percentage of test subjects. Obviously, if this doesn't work, then another respirator should be tried. I hope these suggestions are helpful. You should also contact the manufacturer for further suggestions.

I hope this answers your questions about fit testing with the Portacount. If you have any other questions, you may contact OSHA's Office of Health Compliance Assistance at (202) 693-2190.


Richard E. Fairfax
Directorate of Compliance Programs