Abstract
Various types of carbon materials are being used as overlays in the manufacture of fire resistive particleboards. The fire endurance of carbon materials overlaid particleboards was evaluated by three different methods, and the results were compared with those of boards without any overlay and of non-combustible commercial boards. The mechanical and dimensional properties of these overlaid particleboards were also examined. The results obtained were as follows:
1) The fire endurance of overlaid boards was improved both in the time delay in temperature rise at unexposed surface (JIS A 1304) and in burn through when exposed in high velocity flame due to low combustibility of carbon. The creep under fire of overlaid boards showed better performance than those of conventional particleboards and non-combustible commercial structural boards due to high heat-resisting property of carbon. Graphite and charcoal from softwoods saw dust and bark were found to be highly effective as the overlay materials in increasing fire resistance of particleboards.
2) The mechanical properties of overlaid boards were lower than those of the control particleboard. However, they could be improved by reinforcing overlaid boards with glass or carbon fiber clothes, or by veneering.
3) Overlaid boards showed great dimensional stability because of high water resisting property of carbon and low compaction of particles.
