Interpretation ID: aiam0951
Marketing Specialist
DION FR Polyester Resins
Diamond Shamrock Chemical Company
P. O. Box 829
Redwood City
CA
94064;
Dear Mr. Trampenau: This is in reply to your letters of October 9 and December 4, 1972 concerning the application of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials', to motor homes and other multipurpose passenger vehicles.; You ask whether 'molded plastic exterior shells' of motor homes an other vehicles must meet the burn rate requirement of the standard, even when they are completely though variously covered in the vehicle interior. The answer to this question in both respects is no. Whether a material is subject to the requirement depends on whether it is used for producing any of the components listed under Paragraph S4.1 of the standard, either as a surface material, an underlying material, or a padding and cushioning material. Motor vehicle shells are not listed under Paragraph S4.1 and, therefore, they are not subject to the requirements of the standard.; You also ask whether 'molded plastic engine covers, separating th engine compartment from the passenger compartment,' must meet the burn rate requirement of the standard, even when they are completely though variously covered in the vehicle interior. Engine compartment covers are listed under Paragraph S4.1 of the standard, but they are subject to the requirements, as are all the listed components, only to the extent that they are part of the occupant compartment. Any material in the vehicle occupant compartment which covers that part of the engine compartment in juxtaposition with the occupant compartment would be considered an engine compartment cover. Under Paragraph S4.2 the portion of the engine compartment cover that must meet the requirements, as for any of the listed components, depends on whether the surface material is bonded, sewed, or mechanically attached to underlying material and thereby achieves an intimate joining of materials which are normally separate. The important question, then, is not so much how the covering for the molded plastic is attached, but how closely spaced are the attachment points. If the covering is not bonded, sewed, or mechanically attached to the underlying molded plastic so that an intimate joining is not achieved, then the covering would be considered the engine compartment cover and, under Paragraph S5.2.1, the thickness of the portion to be tested 'is that of the material as used in the vehicle, except that where the material's thickness exceeds 1/2 inch the specimen is cut down to that thickness.' On the other hand, if the covering and the molded plastic are attached so that an intimate joining is achieved, then the covering and the molded plastic would together be considered the engine compartment cover and, again under Paragraph S5.2.1, the thickness of the portion to be tested 'is that of the (composite) material as used in the vehicle, except that where the (composite) material's thickness exceeds 1/2 inch the specimen is cut down to that thickness.'; The manner of attachment, if any, of the molded plastic to its coverin does not affect the burn rate requirement. Where structural equipment such as shelves and bunks completely cover the molded plastic which separates the engine compartment from the passenger compartment, the engine compartment cover would not be subject to the requirements of the standard. However, should the structural equipment not completely cover the molded plastic engine cover, then it must meet the requirements.; Yours truly, Richard B. Dyson, Assistant Chief Counsel