VW-1 is a vertical flame test for wire and cable, a standard established by Underwriters Laboratories, formerly known as FR-1.
VW-1 is a vertical flame test for wire and cable and the rating that marks cable as having passed it, a flammability standard established by Underwriters Laboratories. In the test, a sample is held vertically and exposed to a flame for specified intervals, and to pass, the cable must self-extinguish within set limits without flame spreading too far, without burning through an indicator flag above, and without dripping flaming particles. A VW-1 rating indicates the cable meets this recognized flame-resistance requirement. The rating was formerly known as FR-1.
Because the vertical orientation is a demanding way to assess flame propagation, the VW-1 rating is a widely recognized mark of flame resistance for individual wires and cables. It helps identify cable suited to applications where flame performance matters.
In commercial and industrial systems, the VW-1 rating supports the selection of flame-resistant cable for installations with fire-safety requirements. Recognizing the designation helps in understanding a cable's flame performance.
At Windy City Wire, an understanding of flammability ratings, including VW-1, reflects a focus on cable that meets recognized safety standards. Recognizing how the VW-1 vertical flame test verifies flame resistance helps customers select cable suited to the fire-safety requirements of commercial and industrial installations.
VW-1 (formerly FR-1)
UL (Underwriters Laboratories), which established the VW-1 flame test
Formerly known as FR-1.