本标准提供了确定下列电缆载流量降额系数的试验程序 安装配置:阻挡式或套筒式电缆贯穿防火挡；覆盖有保护材料的导管；覆盖有保护材料的托盘；直接覆盖或涂有阻燃材料的电缆；用保护材料封闭的自由空气滴。 本标准适用于按照IEEE标准835（TM）和NEMA WC51/ICEA P-54-440对导管和自由空气滴进行安装和尺寸调整的电缆。IEEE Std 135（TM）确实为固定间距的电缆槽中的电缆提供载流量，并且只能用于电缆贯穿件防火配置。 本标准不认可电缆贯穿件阻火器和防火材料的使用，也不提供安装应用指南。电缆设计可以承受直接暴露在火灾中并保持功能。用户应参考IEEE Std 634（TM）了解电缆贯穿件防火带的资格要求。

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(TM) for conduits and free-air drops, and NEMA WC51/ICEA P-54-440 for cable tray. IEEE Std 135(TM) 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(TM) for the qualification requirements of cable penetration fire stops.