Fire safety of composites in the US Navy: Fid-Bau Portal

Fire safety of composites in the US Navy

Sorathia, U. / Ness, J. / Blum, M.

Composite materials for marine applications offer the benefit of weight savings, corrosion resistance, and reduced life-cycle costs. The composite structures used in marine applications tend to be large, complex, and thick. As such, the use of low-temperature non-autoclave cure resins is desirable. The US Navy is presently using fire-retardant (brominated) vinyl-ester resin for some topside composite structures. These composites are produced by the vacuum-assisted resin transfer method. Brominated vinyl-ester resin generates dense heavy smoke with high yields of carbon monoxide. Acid gases such as hydrogen bromide are also produced. Several alternative resins with and without non-halogenated fire retardants have recently been evaluated by the Naval Surface Warfare Center, Carderock Division in small-scale fire test methods. These included cone calorimeter testing at three different fluxes of 25, 50, and 75 kW m^-2. The summary of results, including smoke production rate and carbon monoxide yield, is presented for various vinyl-ester resins with and without additives. Brominated epoxy vinyl ester marked no.1158 exhibited lower heat release rates but significantly higher smoke generation and CO yield than non-brominated vinyl esters. Of the additives studied, aluminum trihydrate (15 phr, no.1196) shows a 20 and 25 % decrease in peak heat release rates, 24 and 13 % decrease in average heat release rates, and 27 and 24 % decrease in average mass loss rates at radiant heat fluxes of 50 and 75 kW m^-2 respectively.