Interpretation ID: 1984-2.46
TYPE: INTERPRETATION-NHTSA
DATE: 08/03/84
FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA
TO: Terry E. Teeter -- Transmission Division, Eaton Corp.
TITLE: FMVSS INTERPRETATION
TEXT:
Terry E. Teeter, P.E. Engineering Supervisor Transmission Division Eaton Corporation P.O. Box 4013 Kalamazoo, Michigan 49003
This responds to your May 14, 1984, letter to the National Highway Traffic Safety Administration regarding the transmissions that you manufacture for air brake equipped trucks. You stated that your transmissions use vehicle air pressure to accomplish gear changing and other transmission control functions. You stated your understanding that the transmission air system is an accessory similar to air powered wipers or air horns and therefore air lines connected to the system are exempt from Federal Motor Vehicle Safety Standard No. 106, Brake Hoses. As explained below, not all accessory lines are excluded from the standard, and the issue of whether your transmission lines are covered by the standard depends on whether a failure of the line would result in a loss of pressure in the brake system.
Federal Motor Vehicle Safety Standard No. 106, Brake Hoses, defines brake hose as:
a flexible conduit, other than a vacuum tubing connector, manufactured for use in a brake system to transmit or contain the fluid pressure or vacuum used to apply force to a vehicle's brakes.
As you pointed out in your letter, the agency has previously determined that hoses connected to accessories such as air powered wipers or air horns need not comply with Standard No. 106. However, these hoses are only excepted from the standard if they do not transmit or contain the brake air pressure used to apply force to a vehicle's brakes. To determine whether the hoses of your transmission air system are excluded from Standard No. 106, you must determine whether a failure of such a hose would result in a loss of air pressure in the brake system. If this would be the case, the hoses transmit or contain the pressure used to apply force to the vehicle's brakes and therefore would have to comply with the standard. If you use a check valve or some other device to prevent loss of pressure, then the hose would not contain or transmit the air pressure and would not be required to comply with Standard No. 106.
Sincerely, Frank Berndt Chief Counsel
May 14, 1984
National Highway Traffic Safety Administration Office of Chief Counsel 400 7th Street, S.W. Washington, D.C. 20590
Attention: Frank Berndt
Gentlemen:
We manufacture heavy duty truck transmissions that are used in Class 7 and Class 8 highway trucks. These trucks typically use air braking systems that utilize air brake hoses subject to FMVSS-106. Various models of our transmissions use vehicle air pressure to accomplish gear changing and other transmission control functions (see attached typical transmission drawing). This basic system has been in use for over thirty years.
It is our understanding that the transmission air system is an accessory such as the air powered wipers or the air horn (previously clarified in "Preamble to Amendment to Motor Vehicle Safety Standard No. 106-74", Docket No. 1-5; Notice 10, Part 571; S106-74-Pre 6: copy attached), and therefore exempt from FMVSS-106. Please confirm that our understanding is correct.
If you wish to discuss this in more detail, or if you desire more information, please feel free to contact me at (616) 342-3400.
Sincerely,
Terry E. Teeter, P.E. Engineering Supervisor Preamble omitted.