Av. Lázaro Cárdenas 3801 Col. Valle de Las Brisas CP 64790 Monterrey, México +52 (8) 357 77 79 mailto:mail@matel.com.mx

UL VW-1 Vertical Wire Flame Test

The purpose of the UL VW-1 Vertical Wire Flame Test is to screen out flammable wires. Since the
ignition source is small (under 1 K W), and is applied for only 75 seconds.

In the UL VW-1 Flame Test, a tirrill burner (similar to a Bunsen burner) is used as the ignition source.
The wire sample is mounted and the flame is applied for 15 seconds and then removed. The flame is
then reapplied, either after 15 seconds or when the sample ceases to flame (whichever is longer), for a
total of five 15-second applications. After the above procedure is completed, a wire sample that passes
this test must not burn for more than one minute and must not burn more than 25% of the Kraft indicator
flag. In addition, the surgical cotton at the base of the burner must not be ignited.