Optimising the number of layers in firefighters' hoods

The objective was to adapt Standard test methods for determining properties of apparel fabrics so these properties are a better reflection of fabrics when used in end-products, while retaining a controlled environment and thus allowing fabric comparisons2. Test methods in which properties are compared when fabrics are dry and damp, and/ or in which they are in multiple-layered assemblies have been developed and applied to a range of fabrics.

Section: Resultssupporting

confidence: 67%

“…an effect of air spaces under the fabric layer). And further, improved protection against burn injury accrues from increasing the number of layers of fabric from one to four, the greatest percentage change evident with addition of one layer [32].…”

mentioning

confidence: 99%

Standard Test Methods Adapted to Better Simulate Fabrics in Use

Laing

Gore

Wilson

et al. 2010

“…Studies investigating the interaction of layers of fabrics typically used in military body armour are also rare. Even in the general textile science literature, the effect of the interaction of layers of fabric on their properties are not commonly discussed, exceptions include House et al, 29 Ren and Ruckman 30 and Laing et al 31 The aim of the work summarised in this article was to identify the fragment protective performance and failure mechanisms of one-and two-layer fabric packs of two commercially available para-aramid fabrics suitable for use in military body armour.…”

mentioning

confidence: 99%

Protecting the extremities of military personnel: fragment protective performance of one- and two-layer ensembles

Sakaguchi¹,

Carr

Horsfall

et al. 2012

In order to provide protection from fragmenting ballistic threats, combat body armour contains multiple layers of fabric. The garment covers the torso, but may provide (removable) protection to the upper arms, neck and groin. Such garments are thick, stiff, impede movement and increase the thermophysiological loading of the dismounted soldier. Examination of wound locations from recent conflicts has suggested it would be advantageous to provide protection to the extremities. Current modular systems can be expanded with strap-on coverings to the arms and legs, but this further exacerbates the mass, mobility and thermal problems already observed. Soldiers already wear coverings on their arms and legs in the form of a combat uniform, and the provision of a hierarchical protection system incorporated in the existing uniform has been discussed. Not all areas of the body would be protected to the same level. In the current work, the fragment protective capabilities of one or two layers of commercially available para-aramid woven fabric. Specifically, 1.1 g chisel-nosed fragment simulating projectile V50 data were obtained. The aim was to establish whether the incorporation of such one or two layers of para-aramid woven fabric into current combat clothing could provide a level of fragment protection with only a minimal associated increase in stiffness, mass and thermal resistance. Post-failure analysis was conducted to investigate inter-layer interaction and failure mechanisms. This work suggests that the use of one- and two-layer para-aramid woven fabric layers incorporated into clothing could offer some protection against wounding to the extremities from fragments.

“…10 Layering also affects thermal resistance, resistance typically increasing with more layers (e.g. improved protection against burn injury is evident with one to four layers, with the addition of one layer changing the resistance by the greatest percentage 11 ). However, results are sometimes the reverse of those expected; a smaller air space contributing to a 'warmer' assembly as in human and manikin trials.…”

mentioning

confidence: 99%

Layering of fabrics in laboratory tests to reflect combinations as outdoor apparel

Laing

MacRae

Wilson

et al. 2011

The objective was to examine the effects of layering fabrics on selected properties known to be critical in the outdoor recreational activity market (permeability to air and to water vapor, and thermal-related measures including ’dry’ and ’wet’ thermal resistance). With laboratory-based testing used by manufacturers to aid fabric selection, information on the way in which fabrics behave as layered arrangements is pertinent.Comparisons of effects on fabric properties were based on fibers (merino wool, polyester), knit structures (single jersey, interlock, eyelet), and whether differences were apparent with multiple-layer arrangements typical of end use, including outer layers. Standard methods and modifications to these were applied. Some properties differed according to the spacing (distance) between layers and/or between a first layer and a hypothetical ’skin’ surface. Differences among the different fabrics/fibers were more apparent with one layer than with multiple layers. Layering of fabrics which are likely to be used as garments worn together has major effects on properties such as permeability to air and water vapor, thermal resistance, and nominal thermal conductance. Effects of adding a second layer typically exceeded those of adding a third.