Evaluation of suppression methods for electrical cable fires

The electrical cable fire suppression tests conducted at Sandia National Laboratories were performed to provide confirmatory research for the US Nuclear Regulatory Commission (NRC) on suppression systems effectiveness. This report describes full-scale tests on both horizontally and vertically oriented cable trays, filled with either IEEE-383 qualified cables or unqualified cables, to determine the effectiveness of Halon 1301, water sprinklers, directed water spray, and carbon dioxide fire suppression systems. These four methods of fire suppression were evaluated to determine their effectiveness in suppressing both exposure type and fully developed type cable tray fires. The results show that although all methods of suppression were effective, given sufficient suppressant concentrations, spray durations, and soak times, the water suppression methods were the most effective. Despite their effectiveness in suppressing cable fires, it was observed that both gaseous and water suppressants may cause or permit damage to nonburning cables and equipment. The adverse environments associated with the fire and suppression related activities (e.g., high temperatures, humidity, corrosiveness) could damage cables and equipment and result in immediate or latent damage. Occurrence or likelihood of these failures was not investigated in this test series.