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 13, 1981

Mr. M. F. Einecker
Manager Control Engineering
Danly Machine Corporation
2100 South Laramie Avenue
Chicago, Illinois 60650

Dear Mr. Einecker:

This is in response to your inquiry for a clarification of the requirement of 29 CFR 1910.217(b)(7)(xiv).

Your concern as to the appropriate location for the air pressure sensor is very pertinent. The OSHA standard and the ANSI B11.1 standard, from which the OSHA standard was derived, offer little guidance as to the specific location within the system that air pressure should be monitored. It is therefore prudent to explore the intent of the device as it relates to the safety of power press operations.

The OSHA standard requires that in the event of a failure of the counterbalance air supply that the clutch/brake control shall be automatically deactivated. Loss of a functional counterbalance system significantly alters the power press stopping mechanism effectiveness, and thereby subjects operators to possible injury. The manner in which the air supply is monitored and the specific location at which it is monitored should, to the extent possible provide for fail-safe operation of the press. Since it is the operation of the counterbalance air cylinders which are of concern, it would be logical to monitor the available air supply adjacent to the pneumatic cylinders. Whether one or more sensors are required to effectively monitor the air supply needs to be determined by the press manufacturer and would vary with the configuration of the press and its components.

The specific manner and location for monitoring the air supply to the clutch/brake control should also be thoroughly evaluated by the press manufacturer to determine the most effective way in which to assure operator safety.

OSHA compliance personnel examine specific power press installations relative to the requirements of the standard, and to the installation requirements which are specified in the manufacturers' manuals and directives.

If we may be of further assistance, please call or write


John K. Barto
Chief, Division of Occupational
Safety Programming