Single-layered garments

Song, G., 2007. Clothing air gap layers and thermal protective performance in single layer garment. J. Ind. Text. 36 (3), 193-205. 

Hooper, R. and Jones, G. (2005). The effect of single- or multiple-layered garments on interface pressure measured at the backpack-shoulder interface. Applied Ergonomics 36(1) 79-83. 

The single layer model is extended to describe multiple layers of fabric which would be the case in practical situations where a body would be clothed in more than one garment. Roberts et al. [24] propose a simple approach which assumes that the pressure and flow conditions in the first layer are not strongly affected by the presence of the second layer (resistance to flow though the second fabric is much greater than Poiseuille flow resistance through the outer clothing gap). 

With a layered clothing system, two plus two often equals five when it comes to thermal protection. Thanks to the additional insulation provided by the air trapped between layers, two lighter-weight or lower-rated garments can often provide the same or even better protection when worn together than a single, heavier primary protection layer. 

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