The Initiation of Smolderin Combustion in Cellulosic Fabrics

The time and heat flux required for the initiation of smoldering com bustion in cellulosic fabrics depends on the properties of both the environment and the fabric. In the environment, there must be sufficient oxygen to support smolder ing combustion and there must be sufficient heat to raise the temperature of the fabric to the point where combustion becomes self supporting. The critical factors for the cellulosic fabrics are the potassium and/or sodium ion content and the ther mal characteristics of the fabric. A series of simple weave, raw cotton fabrics, com monly referred to as cotton ducks, and an upholstery fabric were examined. The requirements for the initiation of smoldering combustion were similar for both the ducks and the upholstery fabric. However, the situation for the upholstery fabric was complicated by the non-homogeneous distribution of ions in the material and spatial variations in fabric thickness and basis weight. Also, for fabrics with potas sium and sodium ion contents in the range of approximately 1500 to 2500 ppm, there was an increased sensitivity to the environmental factors.