Polyester resins are made up of carbon, hydrogen and oxygen atoms and, like all organic compounds, they will burn. However, by altering their structure and/or the use of additives, it is possible to modify their burning behaviour so that laminates made from such resins present a lower hazard under fire conditions.
In most applications the use of GRP presents no greater fire hazard than the use of a very hard wood. Unfortunately a ‘standard fire’ does not exist and behaviour of GRP in a fire depends on a number of factors amongst which are:The following are brief summaries of some tests used. The appropriate specification should be consulted for full details.
Simple horizontal burning tests
Many tests for fire behaviour exist and almost every country has its own particular methods, often requiring large specimens and special equipment. The following are brief summaries of some tests used. The appropriate specification should be consulted for full details.
Usually a strip of material 150mm x 12.5mm is clamped horizontally and a test flame is applied to one end.
The material under test may be a cast specimen or a laminate; the test flame can be from a gas or alcohol burner; and the results can be expressed as a burning time, a burning rate or the distance burnt. Tests of this type include:
BS 2782: 1974 Method 508A.
BS 3532: 1962 Appendix B.
British Rail Specification 602. Appendix 9.
Ministry of Technology OTO 5537 & 5549.