scope:

This standard provides a detailed test procedure for determining the ampacity or derating factor in the following cable installation configurations:

- Block-out or sleeve type cable penetration fire stops

- Conduits covered with a protective material

- Tray covered with a protective material

- Cable directly covered or coated with a fire-retardant material

- Free-air drops enclosed with a protective material

The standard is applicable to cables installed and sized to IEEE Std 835-1994 for conduits and free-air drops, and NEMA WC51-1991/ICEA P-54-440 for cable tray. ¹ IEEE Std 835-1994 does provide ampacities for cables in a tray with a fixed spacing and may be used for cable penetration fire stop configurations only.

This standard does not endorse the use of or provide application guidance for the installation of cable penetration fire stops and fire-protective materials. Cable designs are available that can withstand and remain functional during direct exposure to a fire. The user should refer to IEEE Std 634-1978 for the qualification requirements of cable penetration fire stops.

Purpose

The purpose of this standard is to provide a test procedure for use in establishing the ampacity or ampacity derating factor for cables installed in fire-protected conduits, trays, or free-air drops, cable penetration fire stops, or electrical separation wrap systems.

¹ Information on references can be found in clause 2.