Evaluating turnout composite layering strategies for reducing thermal burden in structural firefighter protective clothing systems

Abstract

A modular approach for arranging the component layers used in the construction of structural firefighter turnout garments is explored as a strategy for reducing the thermal burden contributed by these protective garments to firefighter heat stress. An instrumented sweating manikin was used to measure the insulation, evaporative resistance and total heat loss through turnout systems configured to represent different layering strategies. The outer shell, moisture barrier and thermal liner layers of the structural turnout base composite were tested individually to determine each layer's thermal insulation and evaporative resistance. Multiple two- and three-layer combinations were analyzed for their application in specific working conditions. This study demonstrates that the moisture barrier layer contributes the most resistance to evaporative heat loss through the turnout system, while dry heat loss is most restricted by the thermal liner component. Removal of a single inner liner layer was equally beneficial for heat loss, regardless of material properties. It shows the potential benefit of turnout design strategy that utilizes a modular or adaptive layering approach to reduce turnout-related heat strain in conditions consistent with fire protection.