Interpretation ID: aiam2608
Vice President - Sales Engineering
American Seating Company
901 Broadway Avenue
N. W.
Grand Rapids
MI 49504;
Dear Mr. Barecki: This responds to your March 24, 1977, letter asking for a interpretation of the requirements for knee contact area in Standard No. 222, *School Bus Passenger Seating and Crash Protection*, which state that, when impacted, 'the resisting force of the impacted material shall not exceed 600 pounds and the contact area on the knee form surface shall not be less than 3 square inches.' You ask whether this requirement can be interpreted as meaning that, when impacted, the resisting force of the impacted material shall not exceed 200 pounds per square inch rather than 600 pounds over 3 square inches.; The 600 pound maximum force and the 3 square inch minimum contact are are two distinct requirements. The first specifies an upper bound on the load that will be applied to the upper leg while the latter specifies a lower bound on the knee area over which an impact load must be distributed. To combine the two requirements, as you suggest, tends to relax the contact area requirement for a load which is less than 600 pounds. Such an interpretation would not ensure the level of safety the agency demands for knee contact area. The suggested combination of the two requirements may not provide an adequate distribution of forces over the knee. Accordingly, the agency declines to accept the suggested interpretation of the standard.; Sincerely, Joseph J. Levin, Jr., Chief Counsel