Interpretation ID: nht78-1.33

DATE: 03/22/78

FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your January 11, 1978, letter asking whether several joints in your school bus must comply with Standard No. 221, School Bus Body Joint Strength.

The terms which establish the applicability of the requirements of the standard to a particular section of a school bus body are defined in S4 of the standard. Read together they establish the following test. If the edge of a surface component (made of homogeneous material) that encloses occupant space in a bus comes into contact or close proximity with any other body component, the requirements of S5 apply, unless the area in question is designed for ventilation or another functional purpose, or is a door, window, or maintenance access panel. Applying this test to the several joints to which you refer, it appears that they do not need to comply with the requirements since they connect panels which are considered to be maintenance access panels.

The National Highway Traffic Safety Administration (NHTSA) notes that maintenance access panels are granted this exception from the requirements because of their need for removal for routine service to underlying components. The NHTSA will not consider all bus walls as maintenance access panels simply because wiring may be present behind them since routine maintenance would not be required on such wiring. Further, should any of the panels to which you refer in your letter not have wiring or other serviceable components requiring routine maintenance behind them, they will not be treated as maintenance access panels.

SINCERELY,

January 11, 1978

Joseph J, Levin, Jr. Chief Counsel National Highway Traffic Safety Administration

Dear Mr. Levin:

SUBJECT: 571.221 Standard Number 221, School Bus Body Joint Strength

Section S4 defines a body panel joint as follows:

""Body panel joint" means the area of contact or close proximity between the edges of a body panel and another body component, excluding spaces designed for ventilation or another functional purpose, and excluding doors, windows, and maintenance access panels." Blue Bird has initially set up the following panels to meet 60% joint strength per S5.

Front Upper Inner Panel

Rear Upper Inner Panel

Rear Vision Panel Inside Right Hand

Rear Vision Panel Inside Left Hand

Rear Inner Panel Right Hand

Rear Inner Panel Left Hand

Post Cap Rear Emergency Door Access Right Hand

Post Cap Rear Emergency Door Access Left Hand

We have had field and production line complaints regarding wiring access with the many rivets in these panels and propose to designate these panels as maintenance access panels per section S4 and install them with screws as shown in the enclosed pictures. Sheets 1 through 5 show the lamp wiring which is serviced by the appropriate inside panels.

We understand that competitive make buses are already using similar designs and we are being pressured by the marketplace from both the cost and serviceability points of view to adopt the proposals which appear in this letter.

We look forward to receiving your confirmation that these proposals fully comply with the requirements of FMVSS 221.

W. G. Milby Manager, Engineering Services

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