Wildfire – Ignition Potential of Decks Subjected to an Ember Exposure

Attached decks can be a vulnerable component of a building if they ignite and the resulting fire spreads to and into the occupied space. The objectives of this study were to evaluate the ability of an ember exposure to directly ignite combustible wood and plastic composite decking without the contribution of accumulated debris at ember accumulation points, and evaluate the effectiveness of the standard underdeck flame-impingement exposure test to predict the performance of decking to an ember exposure. Whereas a flame-impingement exposure for an attached deck is possible during a wildfire, an ember exposure is almost certain when a building is threatened by a wildfire. A key question in this study is whether the current SFM (and ASTM) standard test methods are adequate and sufficient to predict performance under an ember exposure, or whether a separate standard test method is needed to predict performance under an ember exposure.