Fire Safety Science Digital Archive

A study has been made of the effect of an incident airflow upon the smouldering of several specimens of fibre insulation board. The board was cut into small strips and placed in a wind tunnel; smouldering was then initiated and the time of travel over unit distance (smouldering time) was determined. In general the smouldering time was inversely proportional a fractional power of the air velocity; in some cases this relation was probably affected by cooling due to the airflow. It was aIso shown that smouldering could be initiated by glowing cigarette be ends under an air draught of 2 m.p.h.; this draught was also sufficient to cause flaming in the combustible ash formed by smouldering under still air conditions. As the flame subsequently spread rapidly across the board it was concluded that smouldering in fibreboard, under conditions of slight draught may easily lead to a large scale fire.