Smoke Emissions from Aircraft Interior Materials at Elevated Heat Flux Levels Using Modified NBS Smoke Chamber

The National Bureau of Standards (NBS) smoke chamber is a widely used instrument for measuring smoke emitted from materials when exposed to radiant heat and flame sources. The standard NBS chamber, however, lacks the capability of spanning the range of realistic heat flux levels experienced from a jet fuel fire. In order to provide this flexibility, a variable radiat heat flux Mellen furnace capable of reaching 10 British thermal units per square foot second (Btu/feet 2 s) was installed in the chamber. Also, a radiometer was mounted in the chamber for calibration of the furnace and a load cell was installed beneath the sample holder to monitor weight loss of test specimens. Finally, a laser transmissometer was mounted to allow comparisons with the standard photometric system supplied with the chamber. These modifications resulted in a more versatile laboratory test for characterizing material smoke emissions when exposed to radiant heat or flame, and for correlating laboratory and full-scale fire test results. Fifteen aircraft cabin materials were tested at .2., 5.0, 7.5, and 10 Btu/feet 2 s for piloted and nonpiloted exposure. For most jof the materials tested, smoke production increased with increasing heat flux provided the sample did not ignite. Polycarbon and polysulfone sheeting, wool carpet and PVC/ABS flooring produced considerably more smoke at heat flux levels above the 'standard' 2.2 Btu/feet 2 s value. It was concluded that the 'standard' 2.2 Btu/feet 2 s heat flux is insufficient for evaluating the smoke characteristics of cabin materials in a postcrash cabin fire situation where a higher and wider range of heat flux levles exists. (Author)