A test specimen is oriented vertically on a specimen holder. The burner is either placed horizontally at the height of the specimen (surface ignition) or at an angle of 30° below the specimen (bottom edge ignition). If ignition occurs, the ignition time is recorded. ISO 6940: The flame is applied to the test material for a maximum 2of 0 seconds or until ignition time occurs. The ignition time is recorded. When 5 instances of ignition are obtained, the ignition time of the test material is calculated. ISO 6941: The flame is applied to the test material for 10 seconds or during the ignition time calculated following ISO 6940. The time needed to reach three marker threads.
The test material is judged by the ignition time and the flame spread properties.