Interpretation ID: aiam1371

Mr. Donald T. Fischer, Project Director, Coupling Section, Industrial Division, Aeroquip Corporation, 1225 West Main Street, Van Wert, OH 45891; Mr. Donald T. Fischer
Project Director
Coupling Section
Industrial Division
Aeroquip Corporation
1225 West Main Street
Van Wert
OH 45891;

Dear Mr. Fischer: This responds to your request of January 8, 1974, made to Mr. Herlih of this office for an interpretation of S5.1.2.3 of Standard No. 121, *Air brake systems*, as it applies to a check valve which is designed to bleed back no more than 5 psi pressure from the service reservoir toward the source of air pressure.; The check valve described in the specification you enclosed woul satisfy the requirements of S5.1.2.3 as long as there is no air loss in excess of the designed bleed off, and that total air loss never lowers the pressure at any time below the air compressor 'cut in' pressure.; Yours truly, Richard B. Dyson, Assistant Chief Counsel