Fire performance of hardwood finger joints

This paper investigates the performance of Malaysian hardwood, dark red meranti finger joints in fire. Finger joints were prepared using two load-bearing type adhesives and tested in tension by means of a bench-scale fire test. They were tested in tension to replicate the failure of finger joints in tension layers of a glulam beam, which commonly occurs in a standard fire resistance test. Finger joints from softwood were also prepared and tested for comparison purposes. In addition, tensile tests at ambient temperature were conducted for both the hardwood and softwood finger joints in order to determine the approximate load level applied during the bench-scale fire tests. The time to failure, residual cross section and charring rate were determined and analysed. Results showed that the type of adhesive significantly influenced the time to failure. Furthermore, a lower residual cross-section was found in the finger joints bonded with phenol resorcinol formaldehyde (PRF) compared to the finger-jointed polyurethane (PUR) specimens. Therefore, PRF is better able to resist fire tests, has a higher residual strength and a longer time to failure compared to PUR.