Evaluation of SF6 as a Tracer Gas for Determining Smoke Movement in Shipboard Fires.

This test program evaluated the application of using Sulfur HexafluorideSF6 as a tracer gas for determining smoke movement in ships. The testing was carried out on board the U.S. Coast Guard research vessel ALBERT E. WATTS. The test area consisted of a pressurized test Citadel containing three deck levels with compartments and passageways. The movement of SF6 was recorded and evaluated in three test phases. These included 1 a passive or natural release of SF6 into the test compartment, 2 a dynamic or fan forced release of SF6 into the test compartment, and 3 SF6 being released into a fire in test compartment. Two technical methods, a continuous reading analyzer and a chromatographic analysis of grab samples, were used to monitor for the presence of SF6. The test results indicate that SF6 can be used to provide a qualitative picture of smoke movement sufficient to evaluate ventilation systems and shipboard smoke control procedures. The SF6 behavior simulated smoke movement qualitatively, but no quantitative correlation was evident between the SF6 concentration and smoke intensity. Qualitative correlations were also found between the presence of SF6 and optical density, and SF6 concentrations and temperature. The test data showed that the passive release mode, the dynamic release mode, and the fire tests ranked four different ventilation scenarios in the same order of effectiveness for the removal of smoke and SF6.