Mr. Mark Swallen
1660 Indian Wood Circle
Dear Mr. Swallen:
This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard (FMVSS) No. 106, Brake Hoses (49 CFR 571.106). You asked about which set of measurements to use from Table 1 for the expansion test for hydraulic brake hoses when the inside diameter of the brake hose falls between the listings. The answer is provided below.
In responding to your letter, I note that the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements.
FMVSS No. 106 at S5.3.2 Expansion and burst strength states:
The maximum expansion of a hydraulic brake hose assembly at 1,000 psi and 1,500 psi shall not exceed the values specified in Table I (S6.1). The hydraulic brake hose assembly shall then withstand water pressure of 4,000 psi for 2 minutes without rupture, and shall not rupture at less than 5,000 psi (S6.2).
In Table 1, the descriptions of the hydraulic brake hose, inside diameter, are: "1/8 inch or 3 mm or less," "3/16 inch or 4 to 5 mm," and "1/4 inch or 6 mm or more". You indicated that the inside diameter of your hydraulic brake hose falls in between the first and second of these sets, and asked which set of measurements should be used.
Reading this provision as a whole, it is our opinion that the second set of hydraulic brake hose (3/16 inch or 4 to 5 mm) covers all hydraulic brake hose with inside diameter greater than that specified for the first set and less than that specified for the third set. In other words, the set covers brake hose with inside diameter greater than "1/8 inch or 3 mm" and less than "1/4 inch or 6 mm". Thus, the inside diameter of your hydraulic brake hose falls into the category described in Table 1 as "3/16 inch or 4 to 5 mm".
I note that on December 20, 2004 (69 FR 76298), NHTSA issued in the Federal Register, a final rule updating FMVSS No. 106, including the requirements for air brake hose, brake hose assemblies, and brake hose end fittings. The final rule takes effect on December 20, 2006. However manufacturers that wish to do so may begin complying with this new rule beginning on February 18, 2005.
I hope this information is helpful. If you have any questions, please contact Dorothy Nakama at (202) 366-2992.