a b s t r a c tA quantitative understanding of the processes that take place in the condensed phase of a burning material is critical for prediction of ignition and growth of fires. In the current study, a model of burning of two widely-used charring and intumescing polymers, bisphenol A polycarbonate and poly(vinyl chloride), was developed and validated. The modeling was performed using a flexible computational framework called ThermaKin, which had been developed in our laboratory. ThermaKin solves time-resolved energy and mass conservation equations describing a one-dimensional material object subjected to external heat. Most of the model parameters were obtained from direct property measurements. The model was validated against the results of cone calorimetry experiments performed under a broad range of conditions. Potential sources of uncertainties in the model parameterization were analyzed.
Conventional thermally durable materials such as metals are being replaced with heat resistant engineering polymers and their composites in applications where burn-through resistance and structural integrity after exposure to fire are required. Poly aryl ether ether ketone (PEEK) is one such engineering polymer. Little work has been published with regards to the flammability of PEEK and its filled composites. The current study aims to assess the flammability and fire behaviour of PEEK and its composites using thermogravimetric analysis, pyrolysis combustion flow calorimetry, limiting oxygen index, a vertical flame resistance test, and fire (cone) calorimetry.
Five material properties commonly used to describe the fire behavior of solids were evaluated as sole explanatory variables for four small‐scale fire tests with pass/fail outcomes by using a physically based probabilistic (phlogistic) burning model. The phlogistic model describes the likelihood of passing vertical Bunsen burner tests and a regulatory heat release rate test reasonably well over a wide range of material properties, as deduced from the correlation coefficient and mean deviation of the predicted and measured values. Of the thermal, combustion, and fire properties examined, the best predictors of the likelihood of passing the fire tests of this study were the heat of combustion of the sample, the heat release capacity, and the heat release parameter. The relative merits and drawbacks of qualitative (threshold) and quantitative (probabilistic) approaches to predicting fire test results using thermal and combustion properties are discussed. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
SUMMARYThe molecular design of semi-inorganic polymers has produced polysilphenylene-siloxane and polyphosphazene elastomers having comparable fire safety to heat resistant engineering plastics. In flaming combustion a polyphosphazene rubber had a four times lower peak heat release rate than the polyurethane elastomer currently used in fire-blocked aircraft seat cushions. Figure 1. In 1987 the Federal Aviation Administration (FAA) imposed federal airworthiness regulation (FAR) 25.853c on the flammability of aircraft seat cushions to delay their involvement in cabin fires [4,5]. This test for flammability of seat cushions involves subjecting a fully constructed seat cushion (e.g. Figure 2) to an oil burner flame for 2 min (Figure 3) and recording the mass loss of the cushion and the burn length. The FAA requirements are that the burn length of the cushion should not exceed 43 cm ð17 inÞ and the mass loss should not exceed 10% of the original weight. Manufacturers responded to these regulations by wrapping the polyurethane seat cushion in a fire resistant barrier fabric [3,5] (Figure 2). Seat fire blocking allowed manufacturers to pass the 2 min FAA certification test but the polyurethane foam burns vigorously when the fire blocking layer has been consumed (Figure 1). More recently, combustion-modified polyurethane foam rubbers have been developed [6], some of which pass the FAA seat cushion flammability test without the need for a fire blocking layer [7,8]. These second-generation aircraft seat cushions
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