In fire situations water supplies, being limited, have to be carefully allocated to the various demand points. In a petroleum depot, the situation making greatest demands on the available water supply is commonly that of a tank fire, when adjacent tanks must be protected by supplies of drencher water. Considers how the radiation intensity of the plume of fire and smoke over a burning tank may be mathematically simulated and then turns to the problem of calculating the resultant incident radiation on neighbouring points. The pattern of incident radiation on a neighbouring tank may thus be derived and the total heat flow falling on the tank estimated. Given the heat flow, the need for cooling water flow over the roof and shell of the threatened tank is evaluated. Based on the earlier calculations, a simplified formula is derived for calculating the needed drencher flow on threatened tanks. Outside the specialised field of petroleum tank fires, the treatment in the paper of the questions of emitted and incident radiation will be of use in studying problems arising in other fires.

KEYWORDS: fire, fire protection, water supply, oil tanks, heat flow, calculating, drenchers, water flow.