Interpretation ID: aiam3181
Manager
Engineering Services
Blue Bird Body Company
P. O. Box 937
Fort Valley
GA 31030;
Dear Mr. Milby: This responds to your October 8, 1979, letter and follow-up meeting i which you ask several questions about the compliance of your school buses with Standard No. 221, *School Bus Body Joint Strength*. In your letter, you ask about four separate joints and ask whether they would be required to comply with the standard.; As you know, the standard applies to any joint of a body panel tha encloses bus body space and a body structure member. An exception from the standard exists for those joints that connect maintenance access panels. In our meeting with you, we stated the agency's objection to the existing industry practice involving maintenance access panels, and further stated that the agency was contemplating rulemaking to restrict the maintenance access panel exception.; Responding directly to the four joints that you reference in you letter, you first ask whether the contact point between the headlining panel and the spring clip is a joint subject to the standard. A spring clip is entirely enclosed within a bus wall. Its function is to aid in holding the body panel in place while the rivets or adhesives are being applied. It serves no function beyond that. The agency does not believe that a spring clip is either a body structure member or a body panel enclosing occupant space. Accordingly, the joint of this clip and any other body member is not a joint subject to the standard.; In your second question, you ask whether the joint between th headlining panel and the headlining panel positioning tab is a joint subject to the standard. The positioning tab is a device that is approximately two inches long and contacts the headlining panel in two places between the bus body bows. The purpose of this tab, is to prevent buckling of the headlining panel between the two bows. The agency concludes that positioning tabs are body structure members. Therefore, if they contact a body panel at its edge, the intersection of these two components creates a joint subject to the standard.; Your third question asks whether an extruded aluminum sash assembl must comply with the standard. You state in your letter that this assembly is part of the window and, therefore, exempt from the requirements. The aluminum sash assembly to which you refer is an add-on device above the window found in your larger buses to provide more headroom. The agency concludes that this device has no function as a part of the window but merely is a trim panel that serves to cover part of the bus sidewall. Accordingly, the joint connecting this panel to the remainder of the bus structure would be required to comply with the standard.; Finally, you ask whether the joint between a positioning angle and headlining panel must comply with the joint strength requirements. A positioning angle is a body structure member that runs from bow to bow and supports the edge of the headlining panel to prevent buckling. The agency concludes that this positioning angle is a body structure member and its connection with a body panel is a joint subject to the standard's requirements.; Sincerely, Frank Berndt, Chief Counsel