Session: DFMLC-02-01-Modeling and Optimization for Sustainable Design and Manufacturing

Paper Number: 95105

95105 - Thermal Modeling of Novel Firefighting Gloves With Phase Change Material 

Background

Firefighters are at risk of severe burns to their hands and wrists. Therefore, it is vital to enhance the thermal protective performance of firefighters’ gloves to ensure adequate protection from burn injuries. To comply with NFPA 1971 (Standard on Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting), current structural firefighting gloves must meet the minimum requirement of a thermal protective performance (TPP) rating of 35, equating to 17.5 seconds until second-degree burns occur in a flashover situation [1]. Although the minimum requirement of TPP is 17.5 seconds, it is possible that firefighters need longer times to complete all the rescue tasks in fire scene. Hence, research is needed to explore the novel and advances materials that are capable of remarkable delaying the time to reach the second-degree burn injury when integrated into gloves. Novel phase change materials (PCM) absorb large amounts of heat while maintaining constant temperature when melting. Hence, a PCM-integrated glove may be capable of achieving more efficient thermal protection The aim of this study is to optimize PCM properties and placement location in structural firefighting gloves under different hazard conditions (i.e., explosive/flashover and hazardous conditions) to improve the thermal protective performance of firefighting gloves.

Method

One Dimensional heat transfer simulations were performed through COMSOL Multiphysics (COMSOL, Inc., Burlington, MA 01803, USA) to investigate the improvement of TPP when integrating a PCM layer in a structural firefighting glove at explosive/flashover condition (heat flux at 83 kW/m²) [2] and hazardous condition (heat flux at 8.3 kW/m²). Parametric studies were conducted to explore the effects of PCM thermal properties, and location in the glove to determine the optimum properties, and configuration of PCM in a glove for the best hand protection. The extremely fine mesh size was selected for the modeling. Around 105 mesh elements were established in the finite volume domain. The melting point, latent heat of fusion, specific heat, and density were optimized in this model.

Results

PCMs with higher density and specific and latent heat of fusion had larger heat capacities and thermal inertias, resulting in better TPP than required by the current minimum TPP industry standard. The optimum melting point of PCM was found to be in the range of 80^°C-140^°C for the best hand protection. Results show that the location of the PCM layer should be close to the inner glove at explosive/flashover condition. However, under typical hazardous condition, it is better to locate the PCM closer to the outer environment.

Conclusions

PCM-integrated firefighters’ gloves can (theoretically) mitigate firefighters’ wrist and hand burn injuries during routine duties when responding to a fire scene (under flashover or hazardous conditions). After additional experimental testing, the modelling results will be used to develop a next-generation glove prototype, where 3D hand model testing can be conducted and the effects on dexterity can also be explored. The novel PCM could also be used by manufacturers for other types of personal protective equipment where temperature regulation is important (e.g., firefighter turnout gear, firefighter rescue jackets and trousers).

Reference

[1] NFPA 1971, Standard on Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting, 2018.

[2] Coletta, G.C., Arons, I.J., Ashley, L.E., Drennan, A.P., 1976. The Development of Criteria for Firefighters’ Gloves. Volume II: Glove Criteria and Test Methods. DHHS (NIOSH) Publication Number 77-134-B.

Presenting Author: Susan Xu NIOSH

Presenting Author Biography: Dr. Xu is a General Engineer in Research Branch at NIOSH NPPTL. She has a Ph.D. degree in mechanical engineering and a graduate level of statistics. She has been working in mechanical engineering and public health research area over 15 years at university, industry and government as a mechanical engineer and analyst and authored or coauthored 20+ publications. Her research areas are biomechanical engineering, occupational safety for prevention of work-related illness and injury, and personal protective equipment research for Gloves, Powered air-purifying respirator (PAPR), Self-Contained Breathing Apparatus (SCBA) and Elastomeric Half Mask Respirators (EHMRs).

Authors:

Susan Xu NIOSH
Jonisha Pollard NIOSH
Weihuan Zhao University of North Texas