White Paper on Fire Resistance of Timber Structures
Andrew Buchanan, Birgit SP Wood Technology, Sweden �tman, Andrea Frangi
Fire resistance of timber structures is a very large field. In order to keep this document relatively small, the scope of is limited as follows: This report attempts to define a Performance-Based framework for the fire safety design of multi-story timber buildings. The report concentrates on medium-rise multi-story timber buildings from 3 stories to 10 stories tall, which are likely to be most popular and technical feasible. Taller buildings are discussed briefly. The report concentrates on mass timber buildings, constructed from large timber posts and beams (from LVL or glulam) and large wood panel construction using cross-laminated timber (CLT) or other heavy timber panels. Light wood frame buildings protected with gypsum plasterboard (2 by 4 construction) have been covered elsewhere and are not considered to be feasible for building above about 6 stories. The report concentrates on the fire resistance of structural elements and assemblies, and does not include early fire safety issues such as ignition and flame-spread on wood surfaces. It does not address broader fire safety issues such as fire safety systems, fire fighting, or evacuation. External fire spread via building facades and windows is partly included, since wooden façade claddings are considered by many architects to be an essential feature of timber buildings, at least up to 8-10 stories. Automatic fire sprinkler systems are discussed briefly, since the combination of active and passive fire protection is considered to be an important way to provide fire safety for tall timber buildings. Fire resistance of timber connections is included briefly, including both mechanical fasteners and glued connections. The influence of adhesives on the fire behaviour of bonded structural timber elements is discussed briefly.