Interpretation ID: nht94-5.17

TYPE: INTERPRETATION-NHTSA

DATE: December 23, 1994

FROM: Philip R. Recht -- Chief Counsel, NHTSA

TO: Paul N. Wagner, President, Bornemann Products, Inc.

TITLE: None

ATTACHMT: ATTACHED TO LETTER DATED 8-26-88 FROM ERIKA Z. JONES TO GLENN J. DUNCAN; ALSO ATTACHED TO LETTER DATED 9-28-94 FROM PAUL N. WAGNER TO MARY VERSAILLES (OCC 10392)

TEXT: This responds to your letter of September 28, 1994, requesting an interpretation of how the requirements of S4.2.1 in Standard No. 207, Seating Systems, would apply to an integrated seat. Section S4.2.1 states

Except for vertical movement of nonlocking suspension type occupant seats in trucks or buses, the seat shall remain in its adjusted position during the application of each force specified in S4.2.

Your questions and our response to each follow.

1) Can the agency respond specifically to what the seat adjustment refers to? Does this mean only that once a seat recliner (used only for comfort), or a seat slide track, is positioned at its normal driving position, or appropriate testing position, it may not be moved until the completion of the test?

Or, does it mean that while the static test is conducted a recliner mechanism, for example, can not change position during the test, due to bending or twisting, or release of internal parts, even though the frame did not break during the test? In oth er words, the recliner may bend or twist, but the seating structure remained intact, despite deformation of the recliner mechanism.

Section S4.2.1 requires a seat, with one exception, to remain in the position to which it was adjusted while the force specified in S4.2 is applied. The exception is that vertical movement of nonlocking suspension type occupant seats may occur while the load is applied. Section S4.2 requires a seat to withstand certain specified forces. NHTSA has previously stated that S4.2 "allows some deformation of the seats during the force test, provided that structural integrity of the seats is maintained." (Se e August 26, 1988 letter to Mr. Glenn L. Duncan, Esq.) NHTSA would not consider any deformation allowed by S4.2 (for example, bending or twisting) by itself to be a change in adjustment position. However, if bending or twisting resulted in the seat movin g from one adjustment position to another (for example, a change in detent position within the adjustment mechanism), there would be a change in adjustment position.

In the example provided in your letter, the adjustment position of the seat back recliner mechanism is caused by the gear mechanism being "destroyed," even though the recliner mechanism itself does not separate from the seat. It appears that this scenar io involves more than deformation as the seat back is free to move to a variety of adjustment positions. Therefore, the seat would not comply with S4.2.1.

2) An integrated seat has several angle adjustments on its recliner, which are only for the purpose of comfort. In reference to the static testing, does the integrated seat need to be tested in its designed riding position, or need it be tested in ev ery possible reclined position?

Both S4.2(a) and S4.2(b) require the seat to withstand the specified load "(i)n any position to which it can be adjusted." The usage of the term "any," when "used in connection with a range of values or set of items," is specifically defined at 49 CFR 57 1.4 as meaning "the totality of the items or values, any one of which may be selected by the Administration for testing." Thus, NHTSA may chose to test a seat in any of the range of possible reclined positions. Section S4.2(c) incorporates the requiremen ts of S4.2(a) and S4.2(b); therefore, NHTSA may also chose to test an integrated seat in any of the range of possible reclined positions.

I hope this information has been helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992.