Session: DED Design Tool Showcase

Paper Number: 148205

148205 - Thermal Protection Enhancement of Firefighters’ Glove by Phase Change Material - a 3d Gloved Hand Experimental Study 

Background

Firefighters can be exposed to a wide range of thermal conditions. In a recent report from NFPA, more than 10% of injuries occurred in fire fields were caused by thermal stress and burns [1]. Unlike clothes, a glove is small in volume, and it is the thinnest/weakest component of firefighter turnout gear due to the need for hand dexterity to complete tasks. Hence, new research is needed to explore novel materials that can better protect firefighters’ hands from burn injuries and thermal stress at a fire scene. Novel phase change materials (PCM) can absorb large amounts of heat while maintaining a constant melting temperature. We use this phenomenon of PCM to significantly enhance the thermal protection of current commercial firefighters' gloves. A 3D gloved hand model is vital to explore the feasibility to integrate PCM in a glove structure and actual thermal protection improvement of glove by PCM. Therefore, this work will be the first 3D gloved hand study to experimentally explore (1) the effects of PCM on the thermal insulation performance of entire firefighters’ glove, (2) the heat and moisture (mimicking hand sweating and water hose spray) transport behavior in the whole glove on hand under extreme heat conditions, and (3) the thermal behavior of PCM-integrated firefighters’ glove at post-heat exposure.

Methods

A bio-based PCM from PureTemp LLC with a 68^°C melting point was used in glove. The PCM was sealed into small packets and inserted at the palm and dorsal sides of a commercial structural firefighters’ glove. Two different thicknesses of PCM packets were studied: 0.5-mm versus 1.0-mm variants. The entire PCM-integrated glove was worn on a 3D hand model for testing. A muffle furnace was used to mimic radiant/convective heat sources encountered at a fire scene. The furnace temperature was set at 200°C and 300°C to simulate hazardous and flashover conditions, respectively [2]. In addition, the effect of moisture contents in the glove on temperature control performance was also explored. Various moisture content levels in firefighters’ glove fabrics (i.e., 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt% and 70wt%) were investigated to evaluate their effects on the entire glove thermal protection performance.

Results

The results of experiments showed that the 1.0-mm PCM packets increased the time it took for the hand surface to reach a harmful temperature level by more than 85% (up to 2-minute extension), but also took a longer time cooling down when removed from the heat source compared to the baseline glove (no PCM). The 0.5-mm PCM packets could also improve the thermal protection performance compared to the baseline glove, and cooled down much faster than the 1.0-mm PCM at post-heat exposure. The moisture contents in firefighters’ glove affected the thermal protection times on hand.

Conclusion

The 0.5- and 1-mm PCM integrated firefighter’s gloves can increase the time to reach the burn injury compared to the baseline glove without PCM. However, considering the cool-down time at post-heat exposure, the 0.5-mm PCM is a better choice for firefighters’ gloves for efficient hand protection.

Disclaimer

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention (CDC).

Reference

[1] Campbell, R., Evarts, B. United States firefighter injuries in 2020, NFPA Res.

[2] Coletta, G.C., Arons, I.J., Ashley, L.E., Drennan, A.P. The Development of Criteria for Firefighters' Gloves Volume II: Glove Criteria and Test Methods, Contract No. CDC-99-74-59, February 1976.

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

Presenting Author: Susan Xu National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory

Presenting Author Biography: Dr. Susan Xu has served as a general engineer at the NIOSH National Personal Protective Technology Laboratory （NPPTL） research branch. Dr. Xu has a Ph.D. degree in mechanical engineering and a graduate level certificate of applied statistics. She has worked as a mechanical engineer and analyst conducting public health research for over 20 years at university, industry, and government level and authored or coauthored 27 publications. Her research areas are biomechanical engineering, occupational safety for the prevention of work-related illness and injury, and personal protective technology research for gloves, powered air-purifying respirators, self-contained breathing apparatus, and elastomeric half mask respirators.

Authors:

Susan Xu National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory
Jonisha Pollard National Institute for Occupational Safety and Health, National Personal Protective Technology Laboratory
Weihuan Zhao Northeastern State University