This document specifies a method for evaluating materials and products that produce low levels of heat release when exposed to high irradiance levels typical of fully developed fires. It differs from ISO 5660-1 by prescribing items such as specific specimen size, specimen holder, specimen orientation, volumetric flow rate for O2 analyses and irradiance levels at which testing is conducted.The test method described in this document is intended for use on products and materials that contain only small amounts of combustible elements, e.g. test specimens that yield a total heat release of 0,75 MJ/m2 to 15 MJ/m2.NOTE 1 The test method for specimens that yield moderate to high total heat release is described in ISO 5660-1. The information obtained from this test method in this document can also be used for fire safety engineering purposes.NOTE 2 As in ISO 5660-1, the heat release rates are not measured directly and absolute but are theoretically calculated using the empirically derived constant of proportionality that links heat released and measured oxygen consumed.