Small scale fire testing on composites

Abstract

A small-scale propane burner test was developed to enable rapid characterization of composite systems under reproducible conditions for either hot face temperature or heat flux. The burner rig is a low cost device which enables a 100mm square specimen to be subjected to a near uniform heat flux over its surface. The small-scale tests were conducted to measure the thermal conductivities of woven roven (WR) glass fiber mats with a weight of 0.13kg and 11.8mm thickness at high temperatures up to 800°C. An empirical equation was derived for calculating the variation in thermal conductivity of the dry glass fiber mats. A series of fire resistance tests on composite laminates was carried out using a small scale furnace. During the tests the samples were that prepared and laminated using hand-lay-up techniques were exposed to fire conditions defined by a furnace temperature versus time curve. Excellent fire resistance under hydrocarbon curve test conditions was demonstrated for several matrix materials (i. e. isophthalic polyester, orthophthalic polyester, vinyl ester). This information was important for the marine sector and companies such as Devonport group (DML) and Vosper Thorneycroft (VT) to determine if materials could perform to the A60 requirements. The A60 requirements for fire resisting structural are refer to the subject the material to 60 minutes fire testing under the SOLAS temperature/time regime. This then press the material for CFRP pipe repair and metal vessels in petroleum and transportation industries. The experimental results from tests using the small scale furnace were compared with predictions of thermal responses of composite panels in fires using an existing theoretical model. The ID FD model is capable of modelling the thermal response behaviour of polyester/WR and vinyl ester/WR laminates subject to fire for small scale heat sources. Substantial savings in the cost of implementation of new applications may be achieved by modelling thermal responses. A thermal model based on a finite difference technique takes into accountt he decompositionp rocessesin the laminate. The thermal model used was an extension of a model already developed by the Composites Group at the University of Newcastle. This model can also be developed to incorporate the responses of composite structures under load.