Investigation of cooling methods and efficiency of firefighters wearing protective clothing after heat exposure.

Abstract

Objectives. This study aimed to evaluate four cooling methods (natural cooling method [NCM], stripping cooling method [SCM], fan cooling method [FCM] and water-spray cooling method [WSCM]) for their effectiveness in reducing heat stress and skin burns in firefighters after heat exposure. Methods. Skin heat flow and fabric temperature were measured on a stored energy test device during the exposure and cooling stages. The study assessed thermal protective performance by comparing the cooling methods, noting the time to second-degree burns and the energy released to the skin. Results. The SCM showed the best thermal protective performance, followed by the FCM, NCM and WSCM. No skin burns were observed with the SCM. Compared to the NCM, the FCM extended the time to second-degree burns by 3.2% (F1 fabric system) and 10.7% (F2 fabric system). The SCM had the lowest accumulated energy released to the skin and the highest cooling efficiency. The accumulated stored energy and released energy of the FCM decreased with increasing wind speed, whereas the values for the WSCM increased with longer water spray durations. These results can guide the development of optimal cooling methods to enhance firefighter safety and protection.