Interpretation ID: nht78-1.14
DATE: 03/20/78
FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA
TO: Alfred Teves GMBH
TITLE: FMVSS INTERPRETATION
TEXT: In your letter of June 23, 1977, to Mr. W. M. Radler, you asked if Federal Motor Vehicle Safety Standard (FMVSS) No. 106-74, Brake Hoses, would apply to a special hose assembly intended for use with your Hydrobooster system. The diagram you enclosed showed the hose assembly interconnecting the charging valve with the brake booster unit. Power steering fluid is fed through it under pressure.
Your representative, Mr. Paul Utans, has presented two rubber hose assemblies in the recent past. On October 5, 1977, he submitted what we assume to be the design to be used with your Hydrobooster. It is stamped with the date 10/8/77.
In the preamble to Notice 11, Docket 1-5, published June 24, 1974, (39 FR 24012) all power steering type hoses that connected power steering pumps with accumulators were exempted from the standard. Hoses connecting accumulators with boosters were also exempted if redundant boosters were provided. The National Highway Traffic Safety Administration (NHTSA) has reviewed this latter interpretation and determined that all power steering type hose should be exempt from FMVSS 106-74, whether or not redundant boosters are present.
Brake power booster systems must meet the applicable performance requirements of FMVSS 105-76, "Hydraulic Brake Systems" which does not require a redundant booster. Further, the requirements in FMVSS 106-74 are not appropriate for power steering hoses. The interpretation in Notice 11 is therefore modified to permit the exemption of all power steering type hoses and tubing assemblies used with hydraulically operated brake power boosters until performance requirements for them are established.
After consideration of the sample and the information you have supplied, we have concluded that the subject hose assembly must be classified as power steering hose. Consequently, your Hydrobooster hose assembly is considered exempt from coverage by FMVSS 106-74 until appropriate requirements for such hose assemblies can be included in the standard. A plastic tube assembly used in the same system would also be exempt.
Sincerely,
ATTACH.
Welfred M. Redler, P.E. -- Office of Crash Avoidance, NHTSA
June 23, 1977
Subj.: Request Dear Mr. Redler,
for one of our customers, a central hydraulic system is being installed since the beginning of production of the 78 model range; the wiring diagram of this system is attached. The tube which is presently mounted between accumulator and hydrobooster is to be replaced before long by a plastic hose for reasons of noise transmissions. Mr. Utans has already informed you that we cannot use a rubber hose with the required dimensions (internal dia. 10 mm) for this specific purpose. Since, however, we are not sure about the requirements the hose will have to meet in the U.S.A., we kindly ask you to inform us about them.
The following hose characteristics should be taken into consideration:
a) When installed in the system, the hose must withstand a permanent pressure of 36 - 52 bar (522 - 754 psi).
b) In the case of a failure of this hose, the system will still meet the requirements as per FMVSS 105-75, S 7.10.
c) Since it is a plastic hose, the requirements as per FMVSS 106-74, S 6.3, Whip Test, cannot be met. However, we hold the view that this is not necessary since the hose is used as a connection for two units attached to the same vehicle part (frame) where no important vibrations will occur. As has been mentioned before, this hose will be exclusively used as a noise deadening hose.
d) If, contrary to our expectations, you decide that our plastic hose is a hydraulic brake hose as defined by FMVSS 106-74, we should like to ask you to release us from the obligation to meet the requirements of sections 5.2 Identification and 6.3. Whip Test.
When taking a decision, please bear in mind that similar hoses are presently installed in production vehicles in the U.S.A.
Thanking you in advance for your kind assistance we remain,
Yours sincerely, Alfred Teves GmbH
P.P.9
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