A simple theoretical description of the behaviour of intumescent paints

A simple theoretical description is given of the behaviour of a layer of intumescent paint under the action of a constant heat input at one surface. The physical model of Buckmaster, Anderson and Nachman is used and several new results are derived. In particular a relationship is derived between the tune it takes for the temperature at the inner surface of the layer to rise to a given value and the parameters characterising the layer of paint. Other results depend upon the assumption that the front at which intumenscence takes place moves through the layer slowly compared with decay tunes of thermal transients within the layer