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.

December 14, 1984

Robert W. Patterson, M.D.
Family Medical Center
Post Office Box 1860
Sanford, North Carolina 27330

Dear Dr. Patterson:

This is in response to your letter dated November 5 regarding the Occupational Safety and Health Administration's (OSHA) regulations on the regular calibration of equipment, particularly spirometers and audiometers.

The best reference to answer your questions is OSHA's General Industry standards (enclosed).

Specifically, with regard to spirometers, minimum standards can be found in Appendix D of section 1910.1043 -- Cotton Dust standard (copy enclosed). There is no reference to regular calibration but rather the outlined standards must be met each time spirometry is done. Appendix C of this standard contains the predicted values for the FEV-1 and the FVC for males and females. A correction factor of 0.85 is used for blacks to adjust for physiological differences.

Calibration requirements for audiometers can be found in paragraph (h)(5) of section 1910.95 -- Noise standard (copy enclosed). Specifically, the functional operation of the audiometer shall be checked before each day's use, an acoustical calibration shall be done at least annually in accordance with Appendix E of the standard, and finally an exhaustive calibration should be done every two years in accordance with the American National Standard Specifications for Audiometers, S3.6-1969. Specifications for Audiometers can be obtained by writing the American National Standards Institute, Inc., 1430 Broadway, New York, New York 10018.

We hope this information answers your questions. Please let us know if we can be of further assistance.


Edward J. Baier
Directorate of Technical Support


November 5, 1984

Occupational Safety & Health
200 Constitution Avenue, NW
Washington, D.C. 20201


Dear Sir:

I am very interested in obtaining information as to the OSHA regulations for regular calibrations of equipment particularly spirometers and audiometers. We are interested in doing industrial medicine work, however, wanted to get the guidelines prior to beginning this. I look forward to your response.

Yours truly,

Robert W. Patterson, M.D.