Q: How is GB/T 5455 vertical flame testing done on zippers?
GB/T 5455 is a vertical flame test for textiles. The specimen is mounted vertically in a frame, a burner flame is applied to the lower edge for a set time, and the operator records the after-flame time, the after-glow time and the damaged length. The result is used to classify the material's burning behaviour rather than to give a single pass or fail.
For zipper tape the specimen should be prepared as used: flat tape, and separately the tape with coating or film. Conditioning, flame application time, burner position and the method of measuring the damaged length are all specified in the standard, so quote them in the report and refer to the standard text for the exact figures.
Acceptance depends on the application and on the classification the customer requires; protective clothing and vehicle interiors usually demand a higher class than general apparel. Record all three measured values, not just a class, because a short after-flame with a long after-glow tells a different story. Retest after a change of fibre, dye class or flame-retardant finish.