Temperature distribution within Cross Laminated Timber panels exposed to different fire scenarios

Abstract

With a significant momentum towards sustainability in the construction industry, cross laminated timber (CLT) has emerged as a prominent material. However, a key challenge lies in its distinct behaviour during fire events limiting its broader adoption. This study investigates the temperature distribution within CLT panels under both standard and parametric fire conditions, with a particular focus on the decay and cooling phases that are not captured by standard fire tests. First, a systematic literature review was conducted to identify research gaps and the limitations in the current design guidelines and standard in designing CLT exposed to fire. This was followed by an experimental analysis involving multiple tests conducted under standard and parametric fires, using both loaded and unloaded specimens. The results revealed that under parametric fires, CLT exhibits ongoing heat penetration within the panel even when the charring progress has stopped and the char front line has stabilized to a constant depth. This ongoing heat penetration raises temperatures in uncharred layers and potentially comprises the structural integrity of the CLT element even after visible charring has ceased. Additionally, mechanical loading was found to have no significant impact on temperature development which simplifies future experimental studies. This study mainly provides valuable perspective into the temperature distribution within CLT panels, highlights the limitations of current design guidelines and underscores the importance of considering parametric fire scenarios in performance-based fire design for CLT structures.