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Description / Abstract:
This standard provides a test procedure for determining the
ampacity derating factor in the following cable installation
configurations:
— Block-out or sleeve-type cable penetration fire
stops
— Conduits covered with a protective material
— Trays 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™ for conduits and free-air drops, and NEMA WC51/ICEA
P-54-440 for cable tray.1 IEEE Std 135™ 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™ 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 derating factor for cables
installed in fire-protected conduits, trays, free-air drops, cable
penetration fire stops, or electrical separation wrap systems.
1 Information on references can be found in Clause
2.