This part of ISO 9239 specifies a method for assessing the burning behaviour of horizontally mounted flooring systems exposed to a heat flux gradient in a test chamber, when ignited with pilot flames. The radiant heat gradient is higher than the one described in ISO 9239-1 in order to simulate conditions in a corridor adjacent to a room containing a fully developed fire (post-flashover). This method is applicable to all types of flooring such as textile carpets, cork, wood, rubber and plastic coverings as well as coatings. Results obtained by this method reflect the performance of the flooring, including any substrate if used. Modifications of the backing, bonding to a substrate, underlay, or other changes of the flooring may affect test results. This part of ISO 9239 is applicable to the measurement and description of the properties of floorings in response to heat and flame under controlled laboratory conditions. It should not be used alone to describe or appraise the fire hazard or fire risk of floorings under actual fire conditions.