Q: What does FMVSS 302 require for automotive zippers?
FMVSS 302 is the US federal flammability standard for interior materials in motor vehicles. A specimen is clamped horizontally in a metal frame and exposed to a small flame for 15 seconds; the standard measures how far and how fast the flame travels along the specimen. The usual acceptance is that the burn rate does not exceed 102 millimetres per minute.
For a zipper used on a seat cover or a trim panel, the test is normally run on the assembly as used: tape with its coating, plus the foam or backing it is laminated to, because the combination burns differently from the tape alone. Condition the specimen, record the thickness, and note the direction of the weave and the orientation of the chain. The flame exposure time and the specimen size are fixed by the regulation, so refer to the standard text.
A pass requires the measured burn rate to be within the limit for every specimen in the set; a single specimen that burns faster fails the set. Keep the report with the material specification and retest after any change of backing, coating or adhesive.