Combustibility of polyurethane foam is an important industry issue. Many test methods are in place to characterize foam combustion, and legislation exists to ensure that the foam complies with specified standards. This paper provides a basic understanding of foam combustibility based on the British Standard BS5852 test method. Dynamic weight loss of foams made with two types of liquid flame retardants with and without melamine is used to provide this understanding. Thermogravimetric analysis and cone calorimeter have been used to support the discussions. In melamine free foams, our study has shown that the decomposition temperature of the liquid flame retardant is a key parameter, which governs the foam combustion. In the melamine containing foams, the overall combustion behavior is independent of the type of liquid flame retardant used. However, intrinsic differences do exist, and synergy is seen between melamine and liquid flame retardant under specific conditions. Applying this basic understanding and the actual combustion standards, foam producers can attain flexibility in designing cost effective foam formulations.
