Fire Safety Science Digital Archive

During the past few years, laboratory experiments have been made to examine and compare the extinguishing properties of water sprays and water jets when applied to fully-developed fires in model rooms. This work and a review of certain full-scale tests, is described in the report. While these model experiments have provided useful information on the amount of water required to extinguish such fires, and on the minimum rate of application at which extinction is possible, they have suffered from the disadvantage that no suitable full-scale tests have been made by which their findings may be systematically compared with those of practical fire-fighting. Experiments of the National Board of Fire Underwriters, for example, consisted of twelve tests, each with different conditions of application of water; nine tests were with sprays and three were with jets, and five different pressures were employed, ranging from 50 to 500 lb/in.^2 Comparisons of particular smll-scale tests with their full-scale counterparts, where these existed, showed the results to be reasonably consistent, however, and gave promise of the general extension of information to full-scale. In these circumstances, an offer by the home Office to arrange for facilities for the performance of full-scale tests was most welcome , and the ready agreement of the City of Birmingham Fire Service to co-operate in performing a trial sequence of twelve tests permitted the work to proceed. Reports of members of the Service appended to this paper, show, among other things that the joint experiment was appreciated by them also, and their advice and observations, based on their long experience, were invaluable to the Joint Fire Research Organization. This report describes the sequence of twelve tests, the objects of which were to obtain an estimate of the repeatability of full-scale tests, to measure the amount of water required to control a fully-developed fire in a full-scale room, and to compare control by a spray and a jet at one chosen condition.