Fire Safety Science Digital Archive

A series of large-scale fire tests were conducted on the extinguishment of corrugated cartons stored on metal racks. Three different storage heights (3.0 m, 4.5 m, and 6.0 m) were investigated. A specially designed water applicator, supported at a close distance from the top of the test array, was used to deliver a uniform water application density directly onto the array. The applicator could be actuated at any stage of the fire development process to simulate sprinkler response under different fire scenarios. Products of combustion from the fire were collected by a large-capacity calorimeter for the determination of heat release rate for the entire test duration. The effects of water application rate, fire size at the time of water application, and storage height were examined. A single empirical correlation of the extinguishment data was established between the fuel consumed during extinguishment normalized by the fire consumable mass left at the time of water application, Mext/M0,,, and the water application rate normalized by the mass burning rate at water application, Mw/Mb w. A power law relationship exists between Mext /Mo ,, and Mw/Mb,w with the power being -1.55. The same kind of correlation was also obtained in a laboratory scale extinguishment study on wood cribs and wood pallets of different heights. Based on the correlation, a critical water application rate (per unit exposed surface area) for rack storage array of corrugated cartons was determined to be 3.0 g/m²s which is very close to the values reported for wood arranged in other geometries such as crib, slab, and pallet.