Interpretation ID: aiam2018
Dana Corporation
Tech. Center
8000 Yankee Road
Ottawa Lake
MI 49267;
Dear Mr. Ostrander: This responds to Dana Corporation's July 11, 1975, question whether system which controls a truck engine throttle from a remote location by means of compressed air from the truck's brake system would violate the requirements of Standard No. 121, *Air brake systems*.; The answer to your question is no. Standard No. 121 does not contain prohibition on the use of air pressure from the air brake system for powering auxiliary devices. The vehicle must of course conform to Standard No. 121 following installation of the device, if the installation occurs prior to the first purchase in good faith for purposes other than resale. For example, the compressor build-up pressure would still be required to meet S5.1 of the standard.; Although not a requirement of the standard, the NHTSA does consider i appropriate that a pressure protective valve be placed in the line to the auxiliary device so that a rupture of an auxiliary line does not cause depletion of air pressure in the brake system.; Sincerely, Frank Berndt, Acting Chief Counsel