Concepts and considerations
As timber burns at a predictable speed, it is possible to anticipate and plan for its behaviour in a fire. High thermal conductivity materials, such as steel, heat up readily and uniformly giving rise to problems of expansion and loss of strength over a whole section. In contrast, the thermal insulation properties of timber ensure that the timber just a few millimetres inside the burning zone remains only warm and therefore more structurally stable over a longer time period.
As timber burns at a predictable speed, it is possible to anticipate and plan for its behaviour in a fire.
“Reaction to fire” refers to a material’s behaviour when exposed to fire; “fire resistance”
describes the ability of a building, or an element of a building, to provide its “structural” or “compartmentation” function in the event of a fire.
Active fire fighting strategies are activated only in the event of a fire, whereas passive fire fighting techniques are built into the fabric of the building.