Interpretation ID: aiam2672
Project Engineer
AM General Corporation
32500 Van Born Road
Wayne
MI 48184;
Dear Mr. Shillinger: This responds to AM General Corporation's July 18, 1977, request fo confirmation that certain aspects of the M.A.N. articulated transit bus conform to the requirements of Standard No. 121, *Air Brake Systems*, and Standard No. 124, *Accelerator Control Systems*. In an October 3, 1977, telephone call with Mr. Herlihy of this office, it was determined that the request for interpretation is now limited to confirmation that the four-way pressure protection valve described in M.A.N.'s June 22, 1977, letter would meet the location and functional requirements of S5.1.2.3 of Standard No. 121. Section S5.1.2.3 specifies--; >>>S5.1.2.3 Each service reservoir shall be protected against loss o air pressure due to failure or leakage in the system between the service reservoir and its source of air pressure by check valves or equivalent devices.<<<; I am enclosing prior interpretations of the location requirement o S5.1.2.3. While the agency cannot 'approve' systems based on schematic drawings, it appears that the location of the four-way protection valve in the M.A.N. drawings does not violate the provisions contained in S5.1.2.3.; As we understand the description and capabilities of the four-wa valve, it appears to be a pressure protection device that is 'equivalent' to the check valve otherwise required by S5.1.2.3.; Sincerely, Joseph J. Levin, Jr., Chief Counsel