Review of large-scale fire tests on cross-laminated timber

Concerns about the environmental impact of building construction is leading to timber being more commonly used. However, it often faces scepticism regarding its safety in the event of fire. This article provides a point of reference on the fire performance of cross-laminated timber through a review of large-scale tests. Although adequately protecting CLT can make its contribution to fire insignificant, some of the internal surface of an enclosure can be exposed whilst still achieving adequate fire performance. Natural fire tests show that the charring rate and zero-strength layer thickness are higher than commonly used in guidance documents. The type of adhesive used to bond lamellae influences performance where delamination can lead to secondary flashovers, particularly in smaller enclosures. Structural elements can potentially collapse without self-extinction and/or suppression intervention. Tests to date have focussed on a residential context and knowledge gaps remain regarding larger enclosures, such as office-type buildings.