Birgit Östman

Charring of protected wood studs

The charring of wood studs has been studied in the cone calorimeter at constant heat flax 50 kW/m(2) and compared to data from full-scale furnace wall tests. The wood studs were unprotected or protected by gypsum plasterboards on the exposed side. Similar charring depths were found and the data analysed mainly in terms of fire exposure. A simple small-scale technique was developed to measure the heat transfer through protective boards and tbe charring depth of wood studs. These properties are essential for the load bearing capacity of wood frame structures.

Smoke production in the cone calorimeter and the room fire test

The smoke production rates for 13 different surface lining materials have been determined in the cone calorimeter at three irradiance levels: 25, 50 and 75 kW/m2. Two light systems have been used simultaneously, a helium-neon laser and a white light source, showing equal results. Different smoke parameters obtained in the cone calorimeter have been compared with those obtained in a full-scale room fire test. There seems to be a reasonable agreement which must be further studied.

Durability of the reaction to fire performance of fire-retardant-treated wood products in exterior applications – a 10-year report

ABSTRACT Fire retardants may considerably improve the reaction to fire properties of wood products, but the long term durability needs to be addressed. Several long term studies of fire retardant treated (FRT) wood products over time are presented. They are performed according to a European system based on earlier Nordic and North American systems and include accelerated aging according to different procedures and natural weathering up to 10 years. Main conclusions are: •u2003products studied and used commercially •u2003The reaction to fire properties of FRT wood may be maintained after accelerated and natural aging if the The hygroscopic properties are unchanged compared to untreated wood for most FRT wood retention levels are high enough, but several products lose most of their improved reaction to fire properties during weathering •u2003Paint systems contribute considerably to weather protection and are usually needed to maintain the reaction to fire performance at exterior applications