Fire Safety Science Digital Archive

The rapid horizontal spread of fire in a building compartment is largely the result of the deflection of flames by the ceiling and the flow over large distances of hot gases under it. Opening enough holes in the ceiling should therefore reduce this rate of spread though the areas of venting required will be much larger than required to reduce smoke logging, but no amount of venting can necessarily stop the fire if it can spread unaided by the ceiling. Such spread could be controlled, where necessary, by water. Water curtains or sprinklers - without vents - control fires before they become too large. In principle the combined use of vents and water could prevent the spread of very large fires. This report describes some experiments in a building 15.5 m (51.5 ft) long and 4.5 m (15 ft) wide which demonstrate that the combined use of roof vents and water curtains can effectively limit fire spread; further studies are desirable to assess their economic value vis-a-vis, say a sprinkler system or a higher level of compartmentation.