Temperature Analysis for the Prediction of Steam Formation and Transfer in Multilayer Thermal Protective Clothing at Low Level Thermal Radiation

Abstract

It is important to understand the process of evaporation and steam transfer through firefighter protective clothing in order to be able to prevent steam burns. As humidity sensors are too slow to measure fast changes of humidity inside the clothing layers, temperature changes were used to analyze the evaporation of moisture. Temperature measurements turned out to be useful to predict the evaporation speed within the clothing layers, as temperatures remain constant during the evaporation. The measurements showed that the temperatures within the clothing layers containing a wet layer never rose higher than the temperatures within dry clothing. As soon as all moisture had evaporated, temperature increase followed exactly the curves of the measurements of dry samples.

Analysis of Steam Formation and Migration in Firefighters’ Protective Clothing Using X-Ray Radiography

“…The results of the X-ray radiography measurements agreed well with the findings of the temperature measurements of our previous study [8]. The duration of evaporation was very similar with both measurement methods.…”

“…Evaporation in wet TB started earlier than in wet UW, which can be explained by the temperature gradient with obviously higher temperatures in TB than in UW [8]. Therefore, evaporation started at a high rate right from the beginning with wet TB while a delay of the start of evaporation could be seen with wet UW.…”

“…They correspond to materials used in state-of-the-art firefighter jackets in combination with aramid underwear and are identical to those used in Keiser and Rossi [8]. The jacket consisted of five layers; a heat resistant outer shell, a water vapour permeable membrane, two layers of a thermal barrier (1 and 2) and a liner.…”

“…Therefore, they contained moisture according to their regain of ~5%. Figure 1 shows the setup, which is described in more details in Keiser and Rossi [8]. It consisted of an upright standing polyether ether ketone (PEEK) tube positioned below an infrared radiation source.…”

“…In a previous study, we analysed the temperature distribution within protective clothing layers including a wet layer [8]. By analysing the temperature courses we found correlations with the evaporation process.…”