Fire behaviour according to UL94

Flammability behaviour according to UL94 is a standard used worldwide to assess the fire safety of plastics. It distinguishes between different classes:

• HB (Horizontal Burn): The test specimen is ignited horizontally, the burning rate is limited.
• V-2 to V-0 (Vertical Burn): The test specimen is ignited vertically and divided into three classes:
• V-2: Self-extinguishing within 30 seconds, burning drips permitted.
• V-1: Self-extinguishing within 30 seconds, no burning drips, limited afterglow.
• V-0: Self-extinguishing within 10 seconds, no burning drips, no afterglow.
• 5V: A more stringent fire test in which the test specimen is exposed to multiple flames.
• 5VB and 5VA: Variants of 5V with specific requirements for burn-through holes.