Fire safety of composites in the US Navy

Composite materials for marine applications offer the benefit of weight sav ings, corrosion resistance, and reduced life-cycle costs. The composite str uctures used in marine applications tend to be large, complex, and thick. A s such, the use of low-temperature non-autoclave cure resins is desirable. The US Navy is presently using fire-retardant (brominated) vinyl-eater resi n for some topside composite structures. These composites are produced by t he vacuum-assisted resin transfer method. Brominated vinyl-ester resin gene rates dense heavy smoke with high yields of carbon monoxide. Acid gases suc h as hydrogen bromide are also produced. Several alternative resins with an d without non-halogenated fire retardants have recently been evaluated by t he Naval Surface Warfare Center, Carderock Division in small-scale fire tes t methods. These included cone calorimeter testing at three different fluxe s of 25, 50, and 75 kW m(-2). The summary of results, including smoke produ ction rate and carbon monoxide yield, is presented for various vinyl-ester resins with and without additives. Brominated epoxy vinyl eater marked #116 8 exhibited lower heat release rates but significantly higher smoke generat ion and CO yield than non-brominated vinyl esters. Of the additives studied , aluminum trihydrate (15 phr, #1196) shows a 20 and 25% decrease in peak h eat release rates, 24 and 13% decrease in average heat release rates, and 2 7 and 24% decrease in average mass loss rates at radiant heat fluxes of 50 and 75 kW m(-2) respectively. (C) 1999 Published by Elsevier Science Ltd. A ll rights reserved.