Fire Safety Science Digital Archive

This note reports studies of the action of sprinklers on fires in an experimental building 3.8m x 7.7m x 2.85 high, representing a shop, giving on to a corridor 6m wide and 17m long, representing a covered pedestrian mall. The water pressure at the sprinkler heads was about 1.2 bar (18 Ib/in^2). The fires were always either extinguished or reduced in intensity by the sprinklers. Substantial quantities of smoke were generated by the sprinklered fires, and smoke extraction would be essential to prevent extensive travel of smoke along the mall. The smoke passed into the mall as a layer of hot or warm gases flowing under the ceiling and the great bulk of this remained in a well defined layer as it flowed down the mall so that extraction of gases at the ceiling could have prevented the travel of smoke along the mall. Although the sprinklers reduced the temperature of the gases and their buoyancy to a level at which the flow through a natural vent would be reduced, they also lessened the amount of gases to be vented. Subsidiary experiments enabled estimates to be made of the reductions in the burning rate and the rate of flow and sensible heat of the smoky gas passing along the mall.