October 11, 1996

Robirda Phillips
SAIF Corporation
400 High St SE
Salem OR 97312-1000

Dear Ms. Phillips:

This is in response to your September 10, 1996 letter in which you ask for a rule interpretation on the following questions:

1. When employees are using four foot pipe extension air nozzles, does the pressure still have to be decreased to 30 psi or have a relief valve, since the wand prevents the employee from using the air on himself for cleaning, but does allow for clean-up inside a veneer dryer?
   
   
2. If a relief valve is required for the above, where must it be located? At the end of the pipe or at the nozzle trigger end?
   
   
3. Based on the Federal letter of interpretation dated 12/ 6/ 85 to George Reilly, Water Thur Museum, it is our understanding that compressed air may be used for cleaning purposes at or above 30 psi if the source has a relief device that will drops the pressure to 30 psi or below if the flow is dead-ended?
   
   
4. What is OSHA’S definition of dead-ended? The OSHA instructions STD 1-13.1 Program Directive #100-1 is part of the response to Mr. Reilly. It mentions an enclosure showing two acceptable methods of meeting this requirement. Can we obtain a copy of this?
   
   
5. Give examples of what types of work practices could be done using compressed air at higher than 30 psi.
   
   
6. If compressed air is reduced to less than 30 psi, is there any time that employers can permit employees to clean their clothing with the compressed air?

In answer to your questions compressed air may be used for cleaning purposes in any process at pressures greater than 29 psi provided there is a relief device or air-ports within the system that will drop the pressure to 29 psi or below if the air system is dead ended. When an air gauge is placed on the end of the air nozzle restricting air flow, the relief ports must discharge sufficient air so as to reduce the air pressure, as registered on the gauge, to 29 psi or below. Having relief ports at the nozzle or having at least two 1/16 inch holes anywhere along the extension pipe, in most cases, will reduce the air pressure to 29 psi or below.

Under no circumstances may employees use compressed air to clean off their clothing while they are wearing them.

Dead ended means the airflow is restricted at the discharge end of the pipe or nozzle by contacting another surface forcing the air pressure to build up or to be discharged through the relief ports.

If we can be of further assistance to you please contact Jerry Hoard at 378-3272 or through E-mail at: tech.web@state.or.us.

Please visit our Internet web site for information about OR-OSHA. We are located at: http://www.cbs.state.or.us/external/osha/index.html

Sincerely,

Marilyn K. Schuster, Manager
Standards & Technical Resources Section
Oregon Occupational Safety & Health Division

S:\SHARE\TEC_TEMP\LTRSINTE\PHILLIP.WPD