UL94 5VA & 5VB Flammability Standard

Specimens

  • Bars: Length 125 mm (5 in) x Width 13 mm (0.5 in) x Thickness [typically 3.0 mm (1/8 in)].
  • Plaques: Length 150 mm (6 in) x 150 mm (6 in) x Thickness [typically 3.0 mm (1/8 in)].

Procedure for Bars

  1. A total of 10 specimens (2 sets) are tested per thickness.
  2. Five specimens of each thickness are tested after conditioning for 48 hours at 23 degrees C and 50% RH.
  3. Five specimens of each thickness are tested after conditioning for 7 days at 70 degrees C.
  4. For bar specimens, the specimens are mounted with the long axis vertical.
  5. A 125 mm overall high Bunsen burner flame with a 40 mm blue inner cone is applied to the lower corner of each specimen at an angle of 20 degrees from vertical such that the tip of the blue inner cone touches the specimen. The flame is applied for 5 seconds and removed for 5 seconds. The operation is to be repeated until each specimen has been subjected to 5 applications of the test flame.

Procedure for Plaques

  • Same as for bars except that the plaques are to be mounted on the horizontal plane with the flame applied to the center of the bottom surface of the plaque.

Requirements for 5VA

  1. The specimens may not burn with flaming or glowing combustion for more than 60 seconds after the fifth application of the test flame.
  2. The specimens may not drip flaming particles that ignite the dry absorbent surgical cotton located 300 mm below the test specimen.
  3. Plaque specimens may not exhibit burnthrough.

Requirements for 5VB

  1. The specimens may not burn with flaming or glowing combustion for more than 60 seconds after the fifth application of the test flame.
  2. The specimens may not drip flaming particles that ignite the dry absorbent surgical cotton located 300 mm below the test specimen.
  3. Plaque specimens can exhibit burnthrough.