Where Does The Fire Risk Come From?
In many cases, fires in thatched properties are often chimney related and associated with the use of multi-fuel appliances such as wood burning stoves, or open fires. Multi-fuel appliances can generate temperatures in excess of 300ºC, which in turn can cause the chimney brickwork to reach a temperature of over 200ºC - enough to begin the charring process.
Due to the design of thatched properties this charring could go unnoticed for some time until it reaches the surface and the thatch ignites - at which point any detection is too late as the fire will spread rapidly.
Heat can transfer through chimney brickwork to produce a "hot spot", capable of causing smolder in the thatch. The figures shows the temperature profiles within the thatch resulting from an average flue gas temperature of 300ºC and a thatch depth of 1m.
Key to the colour temperature profiles shown on the diagram are:-
| Red | 250ºC |
| Yellow | 200ºC |
| Green | 150ºC |
| Pale Blue | 100ºC |
| Mid Blue | 50ºC |
Dark Blue, thatch at ambient temperature.
