The potential increase in cable loads in building void spaces to support the increased use of computers and the re-cabling of local area networks (LANs) has raised concerns in the regulatory community regarding the potential impact on life safety. Specific concerns regarding exposed LAN cables installed in above-ceiling return air plenums resulted in ASHRAE initiating a research project with the National Research Council Canada to investigate the issue. The project on cable fires in plenums (RP-1108) includes surveys in North American buildings to determine the type and quantities of cable in return air plenums and fire scenarios that could potentially ignite the cables. It also includes fire tests performed at three scales: small, medium, and full. This paper provides preliminary results from the project including the building surveys. The results of bench and medium-scale tests are also discussed. The bench-scale tests, which were conducted using a cone calorimeter combined with FTIR gas analysis equipment to measure combustion by-products, are discussed. The medium-scale tests were conducted using a modified standard room fire test facility. These tests were used to investigate the effect of both thermal and flame exposure on communication cables.

Units: SI