A test assembly using the fabric to be tested is made. The burner is placed along the joint of the seat and back of the test chair. A flame is applied to it 3 times for a certain time, first 20 seconds, then 80 seconds and finally 140 seconds. Combustion, flaming and glowing are observed.
The tested material is categorized class 1 to 3:
- positive result after 20 seconds results in class 3;
- positive result after 80 seconds results in class 2;
- positive result after 140 seconds results in class 1.