This International Standard specifies a method suitable for the production control or productdevelopment purposes for assessing the heat release rate of essentially flat products exposed in thehorizontal orientation to controlled levels of radiant heating with an external igniter. The heat releaserate is determined by the use of a thermopile instead of the more accurate oxygen consumptiontechniques. The time to ignition (sustained flaming) is also measured in this test. Test specimen massloss can also be measured optionally.