GB/T 40717-2021 in English

Interpretation of the core content of the standard

GB/T40717-2021 is my country's first national standard specifically formulated for flame-retardant tires, which stipulates a complete technical system from special markings to performance testing. The standard applies to two types of products, truck tires and passenger car tires, focusing on controlling the two key indicators of self-extinguishing when leaving the fire and oxygen index ≥ 24%.

Comparison of key technical requirements

Detailed explanation of test method

1. Tire flame retardancy test

A butane torch is used to conduct a 10-second combustion test on the crown, sidewall and heel of the tire. Requirements:

• The tire must be parked in an environment of 18-36℃ for ≥24h before the test
• The test point must be located with a "+" mark
• The outer flame temperature is controlled at 1250-1350℃

2. Rubber compound oxygen index test

Implementation suggestions

Precautions for manufacturers

• Flame retardants such as chlorinated paraffin and aluminum hydroxide should be used preferentially during formula design
• Separate production batch records of flame-retardant tires should be established during the production process
• Finished product testing should include oxygen index pre-inspection of tread/sidewall rubber

Testing agency operating specifications

• Temperature calibration of the flamethrower is required every quarter
• The oxygen index tester should meet the accuracy requirements of GB/T10707
• The test report should clearly mark the sampling position diagram

Standard Evolution Analysis

This standard fills the technical gap in my country's flame-retardant tires. Its technical indicators refer to international standards such as ISO834-1:1999 "Fire Resistance Test", but innovatively proposes the following test methods:

• Three-position sampling method (crown/sidewall/heel)
• Dynamic combustion test replaces static test
• Introduction of size exemption clause