UL 94, “The Standard for Flammability of Plastic Materials
for Parts in Devices and Appliances”, is one
of the most widely accepted flammability performance
standards for plastic materials. This standard
determines a materials ability to propagate or
extinguish a flame once ignited. According to UL,
this standard has been harmonized with IEC 60707, 60695-11-
10 and 60695-11-20 and ISO 9772 and 9773.
There are 12 flame classifications specified in UL 94. The classifications
are used to describe materials burning characteristics
after test specimens have been exposed to a specified test
flame under controlled laboratory conditions. The classifications
relate to rate of burning, time to extinguish, ability to resist dripping,
and whether or not the drips are burning.