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.

July 27, 1979

Mr. Garry H. Barnett
Manager-Safety Environmental
Health Nabisco, Inc.
East Hanover, New Jersey 07936

Dear Mr. Barnett:

This letter confirms a recent telephone conversation with Mr. Wasko of my staff regarding the reduction of air pressure below 30 psi for cleaning purposes.

As discussed, it has been determined that the OSHA Instruction STD 1-13.1, formerly OSHA Program Directive 100-1, need not be revised for your cleaning purposes since this instruction puts no limit on the orifice diameter or on the velocity pressure and air volume exiting the gun, cleaning lance, etc. The only restriction on air pressure is that, on dead-ending the exit orifice, the static pressure shall be less than 30 psi. The "less than 30 psi" is not to be interpreted as the velocity pressure downstream of the orifice's exit.

It should be possible, therefore, to eliminate any difficulty that you may have in the cleaning procedures in your bakery operations with the properly designed gun, cleaning lance, etc.

If we may be of any further assistance, please feel free to write or call [the Office of General Industry Compliance Assistance at (202) 693-1850].


Grover C. Wrenn Director,
Federal Compliance
and State Programs