Interpretation ID: aiam3410
British Standards Institution
Maylands Avenue
Hemel Hempstead
Herts HP2 4SQ
England;
Dear Mr. Bingham: This responds to your letters concerning section 4.2(d) of Standard No 209, *Seat Belt Assemblies*. Section 4.2(d) provides that after seat belt webbing has been subjected to an abrasion test, it must have not less than 75 percent of the strength of the unabraded webbing set in section 4.2(b) of the standard. You pointed out that section 5.2(d) is inconsistent with section 4.2(d). As explained below, section 4.2(d) correctly states the requirement intended by the agency and section 5.2(d) needs to be corrected.; The abraded webbing strength test procedure set forth in section 5.2(d of the standard is incorrect. It specifies that the median value of the breaking strengths of the abraded and unabraded webbing are used to determine the percentage of breaking strength retained. Such a test procedure unfairly penalizes a manufacturer that produces webbing with an unabraded breaking strength far in excess of the requirements specified in section 4.2(b).; For example, section 4.2(b) specifies that Type I webbing is to have breaking strength of 6,000 pounds. Assume that the unabraded webbing has a median breaking strength of 8,000 pounds and the abraded webbing has a median breaking strength of 5,600 pounds. The median breaking strength of the abraded webbing is substantially more than 75 percent of the 6,000 pound breaking strength specified in section 4.2(b). However, the median abraded breaking strength is only 70 percent of the median unabraded breaking strength.; The agency intends to modify the standard so that the abraded webbin strength test procedure specifies that the median breaking strength of the abraded webbing is compared to the breaking strength specified in section 4.2(b) to determine the percentage of breaking strength retained.; Sincerely, Frank Berndt, Chief Counsel