What is meant by ‘field of application’ of test results for fire resisting ductwork?
ANSWER – The answer comes in two parts. DIAP and EXAP rules are an output from European harmonization of fire testing methods and classifications. At a national level, experienced persons or fire test organisations have previously provided assessments of expected performance based on expert judgement. [a] The direct field of application (DIAP) DIAP rules are provided in BS EN 1366 test standards. They are derived from information obtained from tests carried out in accordance with relevant EN 1366 tests at recognised laboratories in Europe. The test results achieved by a particular design may be directly applied to a limited number of variations (e.g. a reduction in duct size) without recourse to expert advice, providing the design remains substantially as tested. The scope of the current BS 476 test method does not consider the effect, detrimental or not, that variations in the test construction may have on the achieved performance of the duct. The test result only applies to the teste
