4 Scope

4.1 The UL flame exposure is a vertical-tray fire test for determining values of cable damage height and smoke release from electrical and optical-fiber cables when the cables are subjected to a flaming ignition source. For a cable to be acceptable under the UL test procedure, each of the following is to be exhibited (see 1 and 2):

1. a) The cable char height is to be less than 8 feet, 0 inch (244 cm) when measured from the bottom of the cable tray in accordance with Section 8.

2. b) The total smoke released is to be 95 m² or less.

3. c) The peak smoke release rate is to be 0.25 m²/s or less.

Summary of Topics

This new Fifth Edition of ANSI/UL 1685 dated July 28, 2025 incorporates editorial changes including renumbering and reformatting to align with current style, as well as including a change to the Clarification of the Criteria for the FT4 Flame Test, Revised in 12.1(a).