Evaluation of fire-retardant properties of edge-jointed lumber from tropical fast-growing woods using cone calorimetry and a standard fire test

Abstract

Some tropical fast-growing woods were converted to edge-jointed lumber, and their fire-retardant properties due to chemical coating were evaluated using cone calorimetry and a standard fire test. The woods used were Indonesian and Malaysian albizia and gmelina plantation trees, with Japanese hinoki as a reference. The lumber was coated with 100 g/m2 of trimethylol melamine phosphoric acid in a 25% aqueous solution. The treated and untreated lumber was tested in a laboratory-scale exposure furnace in accordance with JIS A 1304 and the cone calorimeter test with heat flux of 40kW/m2 following the ISO 5660. Results showed that fire endurance of all lumber was enhanced by the treatment. The fire-retardant properties were improved with increasing surface density. Though a similar trend was seen, the fire-retardant properties of the lumber revealed by the cone calorimeter test were inferior to those seen with standard fire test. Addition of thermocouples to the cone calorimeter allowed us to obtain information on the critical temperature (260°C) and charring temperature (300°C) of the lumber.