Abstract:  Currently raw timber frame buildings are still widely used and face the need for fire resistance assessment and upgrading. This paper provides a brief overview of the current methods and status of research into the fire resistance of wood components, and designs and implements ambient temperature tests as well as fire resistance tests based on hydrocarbon (HC) and standard heating curves for small-section (200 mm×100 mm) log beam components of Douglas-fir. It was found that: the beam members were brittle at ambient temperature and failed in overall bending at both temperature rising conditions, with fire resistance limits of 17 min and 20 min respectively; the cross-sectional temperature characteristics and the measured charring results showed that the charring rate was greater near the mid-span section. It is recommended that the charring characteristics be obtained by inversion of the overall fire resistance test to cover random effects such as non-uniformity of the component material, and that a charring assessment method based on the whole process of fire temperature rise and fall also be developed.

Key words: Key words: Douglas fir timber, charring rate, fire resistance rating, timber beam elements