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 18, 1980

Lloyd C. Pillsbury, Vice President
Data Instruments Inc.
4 Hartwell Place
Lexington, Massachusetts 02173

Dear Mr. Pillsbury:

This is in response to your correspondence regarding the application of presence sensing devices to general purpose press brakes, interpretation of OSHA purpose power brakes, interpretation of OSHA requirements, and confirms telephone conversations with Mr. Bode, a member of my staff.

Replies to your questions are provided as follows:

1. Power press brakes are regulated under the requirements of 29 CFR 1910.212. The guidance set forth by ANSI B11.3-1973, and the B11.3 draft revision of November 1978, are applicable to the safeguarding of the machines. Procedures similar to those required under 29 CFR 1910.217 are desirable and in some instances are required under the stipulations of the ANSI B11.3-1973, which is enforced by reference under 29 CFR 1910.212 as an applicable standard.

2. Power press brakes are primarily regulated under 29 CFR 1910.212.

3. OSHA considers the safety distance formula applicable to power press breaks. Where the means for safeguarding the press break point of operation incorporates valid application of the safety distance formula, it is acceptable to OSHA.

4. OSHA compliance officers evaluate power press brake safety guarding in relation to hazardous employee exposure and the requirements of 29 CFR 1910.212. Guidance provided by ANSI B11.3-1973, an the B11.3 committee recommendations for minimum acceptable safeguarding criteria are used during their evaluation.

5. Brake monitors are not required to be installed on power press breaks.

6. & 7. Whether or not muting is provided for on any machine, such as a press break, is the express responsibility of the employer. Should an employee by exposed to a hazard as the result of an employer's actions, then OSHA would invoke a violation of the Act. A muted safeguard which permits employee exposure would be a violation of 29 CFR 1910.212(a)(1). Potential employee exposure to hazards is addressed by the OSHA Field Operations Manual, a portion of which is enclosed for further clarification.

8. The incorporation of control reliability similar to that defined by 29 CFR 1910.217 is advisable to the extent that fail safe operation is assured. The requirement for fail safe operation can be established.

9. The Office of Federal Compliance Programming is responsible for issuing clarification and interpretations regarding OSHA regulations which have national impact. Any questions may be directed to this office, as you have done in this case.


John K. Barto
Chief, Division of
Occupational Safety Programming