The Development of a Moisture Vapour and Air Permeable Laminate for use by the Royal Air Force of the UK
Annemarie Nicholson, W L Gore & Associates, Livingston, UK
The UK RAF has a requirement for a new generation of aircrew clothing. As part of this requirement they plan to replace the Mark 10 Immersion Protection Garment (IPG) that has been in use for many years. The RAF issued a specification for the IPG which provided a number of challenges to the designer and manufacturer of such a garment. Primary in the list of requirements was the need for the garment to be air permeable so that, in the event of loss of canopy or rapid descent from high to low altitude, there would be no problems caused by differential pressures affecting the wearer of the garment. This needs to be achieved without the aid of a mechanical device.
Additionally, there is the requirement, that, in the event of an ejection over water, the suit should withstand the potential exposure to flame as part of the ejection and still be completely waterproof when the wearer is immersed in water.
At the SAFE (Europe) 2001 Symposium in Helsinki, a solution to these requirements was proposed utilising a variation on the current fabric construction. This paper presents a Gore-Tex® alternative.
A brief summary of the work that has been undertaken to date at Gore to develop a suitable fabric will be presented. Firstly, the lamination trials, to select suitable fabric candidates, including extensive internal laboratory tests, followed by decompression tests at RAF Henlow and Thermo-Man tests at Du Pont in Geneva to indicate the likelihood that the fabric would meet the requirements of the RAF specification when made into a garment.
After completing this initial work and taking input from interested parties, a programme of tests to evaluate the fitness of the fabric for use was carried out to determine whether it would withstand wear and tear that it could expect to be subjected to in its lifetime. These tests included exposing the fabric to typical contaminating substances e.g. Aviation fuel, diesel & hydraulic oils.
The contaminated fabrics were tested for waterproofness and a contaminated suit was burnt on the Thermo-Man tester. Finally, physiological tests that were performed at the Institute of Naval Medicine in Gosport will be discussed and the benefits of the Gore-Tex immersion protection garment highlighted. These include significantly reduced weight and bulk, enhanced waterproofness, fire protection and greatly improved contamination protection.
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