Clearance Distances

Wildland fire management teams can be faced with the potential for fires to damage power transmission or telecommunication lines. The damage can be severe enough to cause failure of the system which can have critical implications to public safety. One method to minimize the potential for fire to damage this equipment is to clear vegetation away from the lines, poles and towers. However, clearing distance guidelines have been developed from the standpoint of “what is required to prevent ignition of fires due to arcing from the line to the ground?” The question of what is required to prevent fire caused damage is different. Unfortunately, no studies have been found that address the question of how to minimize the risk of fire-induced thermal damage to the transmission or telecom system. This study attempts to address that question.

This effort is being conducted jointly between the Fire Sciences Laboratory (USFS) and Region 2 of the US Forest Service. Xcel Energy Corporation is also a partner in this effort. The primary objective is to define the vegetation clearing distances required to minimize thermal damage. The study is accomplished through three methods: 1) collection of anecdotal information about damage to power and telecommunication infrastructure; 2) computer simulations of thermal impact on support towers and poles, overhead conductors, and ground based enclosure; and 3) correlation of data from simulations with literature and observations.


Image of power transmission line in natural setting.