UL-94 Vertical & Horizontal Flame Test

UL-94 Vertical & Horizontal Flame Test is a plastics flammability standard released by Underwriters Laboratories of the USA. The UL-94 standard classifies plastics according to how they burn in various orientations and thicknesses.

From lowest to highest, the grades are:

Horizontal Flame Tests
94HB	slow burning on a horizontal specimen; burning rate < 76 mm/min for thickness < 3 mm and burning stops before 100 mm
94HBF 94HF-1 94HF-2	as above but specifically for foam materials. Equivalent to ISO 9772
Vertical Flame Tests
94V-2	burning stops within 30 seconds on a vertical specimen; drips of flaming particles are allowed.
94V-1	burning stops within 30 seconds on a vertical specimen; drips of particles allowed as long as they are not inflamed.
94V-0	burning stops within 10 seconds on a vertical specimen; drips of particles not allowed.
94-5VB	the sample is exposed to a 5″ flame 5 times. A burn-through hole is allowed.
94-5VA	the sample is exposed to a 5″ flame 5 times. A burn-through hole is not allowed.

Tests are generally conducted on a 5″ x 1/2″ (127 mm x 12.7 mm) specimen of the minimum approved thickness (0.8mm, 1.6mm, 3.2mm, 6.4mm, 12.7mm.)

For 5VA and 5VB ratings, tests are performed on both bar and plaque specimens, and the flame ignition source is approximately five times as severe as that used for testing the other materials.

There are other classifications that apply to thin films (VTM-0, VTM-1, VTM-2). Here the sample is a 8″ x 2″ sheet rolled around a 0.5″ former and tested as a vertical tube.

ITA Labs’ UK laboratory is extremely experienced at providing UL-94 results, with a fast turnaround, at very competitive rates.

To discuss your potential requirements, call Alastair on 01727 871301.

To discuss how we could help you please contact Alastair Monk