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.

April 14, 1993

MEMORANDUM FOR:     JAMES W. LAKE, REGIONAL ADMINISTRATOR
                   REGION X

FROM:               ROGER A. CLARK, DIRECTOR 
                   DIRECTORATE OF COMPLIANCE PROGRAMS

SUBJECT:            Interpretation of 1910.212

This is in response to your letter of February 25, regarding a request by Linda Tycz of Teton Microbiology Laboratory for an interpretation of 29 CFR 1910.212 with respect to interlock requirements for centrifuges.

Although centrifuges are not specifically mentioned in the machine-guarding regulations and are not covered by the particular provision at 1910.212(a)(4), the general provision at 1910.212(a)(1) does cover hazards created by rotating parts or the point of operation. Accordingly, centrifuges that present such hazards must comply with the provisions of .212(a)(1), (a)(2), and (a)(3).

An interlock would seem to be the most effective type of guard for this situation, although under the general provision other types of guarding may be used provided they meet the requirement of being "designed and constructed [so] as to prevent the operator from having any part of his body in the danger zone during the operating cycle".

Manufacturers of centrifuges generally install interlocks as safety features to meet the listing requirements of nationally recognized testing laboratories, such as the Underwriters Laboratories standard (UL) 1262, Standard for Safety Laboratory Equipment, and the Canadian Standards Association standard (CSA) C22.2, No. 151-M1886, Laboratory Equipment (copies enclosed). While training in the safe operation of equipment is important, it alone is not a sufficient substitute for guarding.

If you have additional questions, please let us know.