The fire hazard potential of thermally thin cellulose nonwovens with different overlap configurations

Abstract

The fire hazard potential of nonwovens with different overlap configurations and various thicknesses between 0.5 and 5 mm were investigated to clarify the possible worsening situation induced by the difference in overlapping configurations. The fire hazard of thermally thin nonwovens is characterized by flame spread, flame height, temperature distribution, and mass loss. The flame spread rate and FDI (fire development index) increase and then decrease as the thickness of the nonwovens increases. The fire hazard potential of samples with OL configuration (overlapping layer by layer configuration) is higher than that with AO configuration (accordion-style overlap configuration), which is reflected in the high FDI, average fire spread rate, and flame height, and low ignition time. The difference between the fire risk of the two overlapping configurations was confirmed by analyzing the heat transfer mechanism. Due to the different packaging methods, the AO and OL configurations of nonwovens show different degrees of shrinkage and curling effects during combustion. The large air gap between the layers and the weight of the sample edge are the reasons for the weak contraction of the sample with an AO configuration. The sample shrinkage with OL configuration strengthens the flame spread to a certain extent by increasing the convective heat transfer in the preheat zone.