Interpretation ID: 17433.drn

L. W. Camp, Director, Automotive Safety Office
Environmental and Safety Engineering
Ford Motor Company
330 Town Center Drive
Dearborn, MI 48126

Dear Mr. Camp:

This responds to your February 27, 1998, request for an interpretation of requirements specified in Standard No. 221, School bus body joint strength. In that letter, you ask that we reconsider our November 28, 1997, interpretation letter to Ford of which joints "fall within the definitions of 'body panel joint' and 'bus body' as defined in Paragraph S4." You also ask for further guidance on how to "objectively test curved, compound, and reinforced body joints in accordance with paragraph S6."

As you are aware, the National Highway Traffic Safety Administration ( NHTSA) has not yet issued a rulemaking document making a final decision about the notice of proposed rulemaking (NPRM) issued March 15, 1991 (56 FR 11142) on Standard No. 221. As previously stated in our November 1997 letter, until and unless Standard No. 221 is amended, the applicable requirements are those that are currently in Standard No. 221. Our earlier letter to you reiterated a longstanding agency position about which joints are subject to the standard.

As for testing curved and compound body joints, we have reconsidered the views in our earlier letter to you about testing these joints. There are two relevant provisions in Standard No. 221, S6.1.1 and S6.1.2. S6.1.1 specifies that if a body panel joint is 8 inches or longer:

cut a test specimen that consists of any randomly selected 8-inch segment of the joint, together with a portion of the bus body whose dimensions, to the extent permitted by the size of the joined parts, are those specified Figure 1, so that the specimen's centerline is perpendicular to the joint at the midpoint of the joint segment.

S6.1.2 provides: "If a joint is less than 8 inches long, cut a test specimen with enough of the adjacent material to permit it to be held in the tension testing machine specified in S6.3."

Our current view on testing curved and complex joints is that if NHTSA cannot cut a test specimen as described in S6.1.1 or in S6.1.2 (with adjacent material), the tension testing machine can not be used to test the joint. In these circumstances, if the test device specified in Standard No. 221 cannot be used to test the joint, NHTSA will not test that joint. Again, bear in mind that this and other issues relating to the performance and testing of curved and complex joints will be addressed in the pending rulemaking document on Standard No. 221.

I am very sorry for the delay in responding to your concerns. If you have any further questions at this time, please contact Dorothy Nakama of my staff at (202) 366-2992.

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosure
d.7/17/98
ref:221