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 http://www.osha.gov.


July 23, 2007

Mr. Thomas K. Reinhard
Allsafe Environmental, Inc
375 Criswell Dr.
Boiling Springs, PA 17007

Dear Mr. Reinhard:

This is in response to your letter dated June 14, 2007 to our Directorate of Enforcement Programs about the fit-testing requirements in the respiratory protection standard, 29 CFR 1910.134. In your letter you specifically ask for clarification on whether quantitative or qualitative fit-testing must be used when fit-testing a full-facepiece powered air-purifying respirator (PAPR). This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence.

Either Qualitative Fit-Testing (QLFT) or Quantitative Fit-Testing (QNFT) may be used to fit-test positive-pressure, atmosphere-supplying respirators (SARs) and PAPRs. This is allowed by paragraph 1910.134(f)(8) of the standard, even though it is recognized that neither test will directly show that these respirators can actually achieve the fit factor of 10,000, which would correspond to their Assigned Protection Factor of 1000. As explained in the preamble, fit-testing these respirators seeks to measure the tightness of the facepiece seal. These types of respirators must be fit-tested in the negative-pressure mode, even though they will be used as positive-pressure respirators in the workplace. Either method will detect most leakage and identify poorly fitting respirators. Any minor leaks are expected to be overcome by the positive-pressure present under normal use. Therefore, the positive-pressure SARs and PAPRs that pass either the qualitative or quantitative fit-test may be used at the higher protection factor assigned these respirators (i.e., 1000).

Quantitative fit-testing may be used for any tight-fitting facepiece respirator. It must be used when fit-testing a full-facepiece negative-pressure respirator to obtain its assigned protection factor of 50 and allow it to be used in environments up to 50 times the PEL. This includes both the negative-pressure air-purifying respirators and the supplied-air respirators used in the demand mode. When quantitative fit-testing is used, all full-facepiece respirators must meet or exceed a fit factor of 500, while quarter- and half-mask respirators must meet or exceed 100.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. 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. 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 http://www.osha.gov. If you have any further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,



Richard E. Fairfax
Directorate of Enforcement Programs