Original article The impact of air gap on thermal performance of protective clothing against hot water spray Yehu Lu 1 , Guowen Song 2,4 , Jun Li 3 and Faming Wang 1 Abstract The air gap size and distribution developed between clothing and a human body play a critical role in clothing perform- ance, specifically for thermal protective clothing. Hot liquid is considered as one of the common hazards in industrial working environments. In this study, the clothing air layer entrapped between protective clothing and a manikin body was determined using three-dimensional body scanning, and the protective performance provide by the clothing was pre- dicted using an instrumented hot water spray manikin evaluation system. The relationship between the average air gap size and overall protective performance was analyzed. The impact of clothing air gap developed along the human body on predicted burn injury was considered. In addition, the air gap distribution and its relation to skin burn injury were compared for the selected garments. In general, the results indicated that the average air gap size showed positive effects on the overall protective performance. For all body parts except the pelvis, the air gap size presented a significant relationship with the percentage of burn injury. For an individual garment, there was no significant correlation found between the air gap distribution and skin burn injury. The garment with a larger air gap size and minimal air gap changes during hot water spray provided better protective performance. The research findings could provide the technical basis for further development of high performance protective clothing. Keywords hot water spray, thermal protective clothing, air gap, skin burn Hot liquid splashes were considered as one of the main hazards encountered from industrial to home scales. 1,2 Protective clothing was required to protect the wearer’s occupational health and life safety. The protection from hazards of hot liquid was different from the heat and flame. However, the typical clothing mainly designed for flame-resistant was worn by oil and gas industrial workers. 1 In recent years, several studies have been conducted to understand the heat and mass transfer through protective materials to human skin under exposure to hot liquid splashes. 2–5 The results demonstrated that the protective performance of fab- rics was affected by the permeability, surface properties, structure, thickness and fabric combination. Minimizing the mode of mass transfer during the liquid exposure was proved to be an effective way to improve the protective performance. 2 Protective cloth- ing required a stringent conformity to wearer’s body dimensions, providing higher protective performance and lower thermal stress and physical burden. 6 Improper fitting garments might impair work efficiency or even cause an accident during working. 7–9 For exam- ple, too long crotch might constrain worker’s mobility and flexibility or might make wearer vulnerable to haz- ardous environment in emergency conditions. 10 Comparing with the development of new materials, the design of garment construction and fit was rela- tively convenient to improve the overall performance. 11 1 National Engineering Laboratories for Modern Silk, Soochow University, Suzhou, China 2 Iowa State University, Ames, IA, USA 3 Fashion Institute, Donghua University, Shanghai, China 4 Tianjin Polytechnic University, Tianjin, China Corresponding author: Guowen Song, Iowa State University, 1064 LeBaron Hall, Ames, IA 50011, USA. Email: gwsong@iastate.edu Textile Research Journal 2015, Vol. 85(7) 709–721 ! The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0040517514553875 trj.sagepub.com at UNIVERSITY OF ALBERTA LIBRARY on May 21, 2015 trj.sagepub.com Downloaded from