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Flammability

Flammability according to UL
Data of the incendiary class according to the UL ‘94 specification.

  UL Underwriters Laboratories, Inc., USA

This test for technical plastic is widespread. The 4 incendiary classes are classified according to their burning behavior:

UL 94 HB         Testing of the incendiary behavior of a horizontally held test piece.

UL 94 V-2
UL 94 V-1        Testing of the incendiary behavior of a vertically suspended test piece.
UL 94 V-0

Incendiary class V
The following criteria must be fulfilled for the respective classification:

Classification criteria V-0  V-1 V-2
Maximum burning duration £ 10 s  £ 30 s £ 30 s
Total burning duration of 5 samples after 10 x flamings £ 50 s  £ 250 s  £ 250 s
Ignition of cotton wool laid underneath by burning drips no no yes
Maximum duration of incandescence after the 2nd flaming  30 s 60 s 50 s

Incendiary class HB
The requirements in this case are:
  • Incendiary speed <38.1 mm per min at sample thicknesses of 3.05 to 12.7 mm
    or
  • Incendiary speed <76.2 mm per min at sample thicknesses under 3.5 mm
    or
  • maximum sp read of flames < 102 mm