The fire performance of engineered timber products and systems

Timber is an inherently sustainable material which is important for future construction in the UK. In recent years many developments have been made in relation to timber technology and construction products. As the industry continues to look to construct more efficient, cost effective and sustainable buildings a number of new engineered timber products have emerged which are principally manufactured off-site. In terms of light timber frame, products such as structural insulated panels (SIPs) and engineered floor joists have emerged. For heavy timber construction, systems such as glulam and cross laminated timber (CLT) are now increasingly common. Despite many of the obvious benefits of using wood as a construction material a number of concerns still exist relating to behaviour in fire. Current fire design procedures are still reliant upon fire resistance testing and ‘deemed to satisfy’ rules of thumb. Understanding of ‘true’ fire performance and thus rational design for fire resistance requires experience of real fires. Such experience, either gathered from real fire events or large fire tests, is increasingly used to provide the knowledge required to undertake ‘performance based designs’ which consider both fire behaviour and holistic structural response. At present performance based structural fire design is largely limited to steel structures and less frequently concrete buildings. Many of the designs undertaken are in accordance with relevant Eurocodes which give guidance on the structural fire design for different materials. For the same approaches to be adopted for timber buildings a number of barriers need to be overcome. Engineered timber products, such as SIPs and engineered joists, are innovative technologies. However, their uptake in the UK construction market is increasing year on year. Little is known about how such systems behave in real fires. As a result the development of design rules for fire is a difficult task as failure modes are not well understood. To overcome this...