Fire Safety Science Digital Archive

The amount of venting to relieve the pressure and of water to cool tanks of flammable liquids exposed to fires are examined. The rise in pressure and temperature have been assessed from estimates of the heat such a tank would receive from a fire in its own or another bund. From the values to which the pressure and temperature rise should be limited the amount of pressure relief and water cooling have then been calculated. The pressure relief is close to the values recommended by the National Fire Protection Association though the provision of water cooling gives some grounds for reducing the sizes of vent area. Theoretically about 1/6th of the rate recommended by the National Fire Protection Association is capable of extracting all the heat to which the tank is exposed but this requires all the water to be vaporized and none lost by splashing. This would require impractically small nozzles distributed closely over the whole of the circumferential area of the tank and in view of this it is doubtful that any worthwhile reduction in the recommended rates could be effected without further experimental study.