Interpretation ID: 20869NichirinDF

Mr. Frank Johnson
Executive Vice President
Nichirin Inc.
139 Copernicus Blvd.
Brantford, Ontario
N3P 1N4

Dear Mr. Johnson:

This responds to your letter concerning Federal Motor Vehicle Safety Standard No. 106, "Brake Hoses," and its application to automotive vacuum brake tubing. I regret the delay in responding. You ask us to clarify the meaning of S9.2 of the standard and several requirements set forth for vacuum brake tubing.

S9.2 of Standard 106 states:

Each vacuum brake hose assembly or appropriate part thereof shall be capable of meeting any of the requirements set forth under this heading, when tested under the conditions of S11. and the applicable procedures of S10. However, a particular hose assembly or appropriate part thereof need not meet further requirements after having met the construction [sic] requirement (S9.2.1) and then having been subjected to any one of the requirements specified in S9.2.2 through S9.2.11.

You first ask whether S9.2.1 is a "construction" requirement, as referenced in S9.2, or a "constriction" requirement. The answer is the latter. S9.2 should refer to S9.2.1 as a "constriction" requirement.

You next ask whether S9.2 requires a vacuum brake hose assembly or appropriate part thereof to meet only one of the requirements specified in S9.2.2 through S9.2.11, or all of the requirements. The answer is generally, all of the requirements. Under the second sentence of S9.2, a particular hose assembly must be subjected to the constriction requirement of S9.2.1, followed by any one of the tests in S9.2.2 through S9.2.11, considering the appropriateness of the test for the assembly. Manufacturers must ensure that their brake hose assemblies or parts thereof will pass all of these tests. NHTSA explains, in 49 CFR 571.4 (copy enclosed), the use of the word "any" in our safety standards and regulations. That section states, in part, that: "The word any, used in connection with a range of values or set of items in the requirements, conditions, and procedures of the standards or regulations in this chapter, means generally the totality of the items or values, any one of which may be selected by the Administration for testing, except where clearly specified otherwise." (See 571.4 for several examples and further explanation.)

You question the applicability of the adhesion test (S9.2.9) and the deformation test (S9.2.10) to vacuum brake tubing. You believe that these tests were written for rubber hose and are inappropriate for brake tubing.

Automotive vacuum brake tubing is "brake hose" under Standard 106. The standard defines "brake hose" as (S4): "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...." Automotive vacuum brake tubing must meet all applicable requirements of Standard 106.

NHTSA has stated in past interpretations that brake hose (tubing) will not be tested to requirements that are obviously inapplicable. The adhesion test (S9.2.9) of Standard 106 is conducted on brake hose (tubing) that has more than one layer, such as an inner tube and outer cover. We have also stated that the adhesion test is not applicable if there are no layers in the hose's construction which could fail to adhere. (See enclosed copy of September 13, 1984, letter to R.S. Anson.)

You state that the deformation test (S9.2.10) of Standard 106 should not apply to brake tubing because "plastic under 'light duty' applications would not meet the first application of 50 lbs. force." In previous letters on this subject, NHTSA indicated that brake tubing is subject to the deformation requirement of the standard. (See enclosed copies of a July 8, 1974, letter to Bendix and June 19, 1981 and November 2, 1981, letters to Meiji Rubber and Chemical Company.) If you believe that the deformation test is inappropriate for plastic vacuum tubing, you may petition the agency to change the standard in this regard. However, such a petition must be accompanied with data and information to support your views. We will consider your information in deciding whether to initiate a rulemaking to amend the standard.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosures
ref:106
d.4/21/2000