Investigation of air gaps entrapped in protective clothing systems

Abstract

Air gaps entrapped in protective clothing are known as one of the major factors affecting heat transfer through multiple layers of flexible clothing fabrics. The identification and quantification of the air gaps are two aspects of a multidisciplinary research effort directed toward improving the flame/thermal protective performance of the clothing. Today's three-dimensional (3-D) whole body digitizers, which provide accurate representations of the surface of the human body, can be a novel means for visualizing and quantifying the air gaps between the wearer and his clothing. In this paper we discuss how images from a 3-D whole body digitizer are used to determine local and global distributions of air gaps and the quantification of air gap sizes in single and multilayer clothing systems dressed on a thermal manikin. Examples are given that show concordance between air gap distributions and burn patterns obtained from full-scale manikin fire tests. We finish with a discussion of the application of air gap information to bench-scale testing to improve the protective performance of current flame/thermal protective clothing.

Advanced modelling of the transport phenomena across horizontal clothing microclimates with natural convection

“…These factors influence the way clothing and body interact, thus dictating the characteristics of the different microclimates existing inside clothing. Several works in the literature show that the features of these microclimates play a central role in the transport processes across clothing (Torvi et al 1999;Song 2007;Ding et al 2010;Kim et al 2002;Barker et al 2004;Min et al 2007;Psikuta et al 2012;Morrissey and Rossi 2013;Mayor et al 2014a). In these regions, heat is transported by radiation and conduction or natural convection, depending on the distance and temperature difference between their boundaries.…”

“…Some researchers report the use of three-dimensional scanning techniques together with data from thermal manikins, in an attempt to relate the features of the clothing microclimates (e.g. thickness, volume) and the heat transfer measured across protective clothing (Song 2007;Kim et al 2002). Others used different types of heated-guarded hotplates to study the transport rates across microclimates, in a variety of conditions mimicking clothing use (Torvi et al 1999;Ding et al 2010;Morozumi et al 2012).…”

Variability in body size and shape of UK offshore workers: A cluster analysis approach

“…In addition to informing these, the use of clustering in medical diagnoses based on phenotype for a range of disorders including asthma (Moore et al, 2010) and spinal deformity (Stokes et al, 2009), cluster analysis has been already become established as an effective design tool in a number of contexts -for instance for firefighters' clothing (Laing et al, 1999) or gloves (Hsiao et al, 2015). While the use of clustering in examining shape for survival suit design is unprecedented, it has been used in textile research for quantifying air gaps in thermal protection using mannequins (Kim et al, 2002;Mah & Song, 2010). Traditional methods which calculated linear dimensions of individuals and the garments may have informed fitting issues, but are inadequate for elucidating the full complexity of the relationship between a body and the clothing worn (Lu et al, 2014).…”

“…Furthermore, the volumetric increase when donning the survival suit is proportionally smallest for the largest and heaviest individuals , suggesting that suit tightness of fit increases with body size. Whereas larger air gaps have been shown to decrease the severity of burns in flame retardant clothing (Kim et al, 2002), a smaller air gap would be advantageous in a survival suit, especially if water ingresses into this space, and subsequent flushing is amplified by wave action (Power et al, 2015). While the inherent buoyancy of a survival suit is affected by the amount of material, a better fitting suit will reduce the extent of trapped air built up which has the potential to be constrained by external pressure (e.g.…”

A Fabric Burn Hazard Protection Evaluation System

“…The burn hazard is a direct function of the radiative and convective heat flux history to the skin. The heat flux to the skin is dependent not only on the heat flux components to the clothing and the heat transfer characteristics of the clothing material, but also on the draping of the clothing over the skin [2], e.g., gap dimension, air flow, contact, etc. A number of test apparatuses and procedures to test the flame/thermal protective performance of fabrics have been developed through the years and have been adopted as standards.…”