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300 F I R E RESEARCH Jessop, C. M. and Chambers, E . D. (Joint Fire Research Organization, Boreham Wood, England) "Auto Diallers in the United Kmgdom," Joint Fire Research Orgamzaiion Fire Research Note No 888 (September 1971) Section: L Subjects: Alarm, automatic; Statistics Reviewed by G. Fristrom A survey was made of the number of operable auto diallers in the United King- dom Auto diallers normally pass a recorded message via a manned telephone exchange to a fire brigade control room. From a random samplmg, the total number of such systems in the Umted Kingdom was calculated. O. Miscellaneous EQnkley, P. L . (Joint Fire Research Organization, Boreham Wood, England) "Some Notes on the Control of Smoke m Enclosed Shopping Centres," Joint Fire Research Orgamzaiion Fire Research Note No. 876 (May 1971) Section: O Subjects: Smoke; Ventilation Author's Summary This note considers ways in which the spread of hot gases and smoke from a fire in an enclosed shoppmg centre may be hmited. I f the shop fronts are fire re- sistmg the hot smoky gases may be confined to the shops of origin Otherwise the size of the fire and hence the rate of 'production' of hot smoky gases must be limited (preferably by sprinklers) and i t is then possible to confine the hot smoky gases to a stratified layer beneath the ceiling while the air beneath them is rela- tively cool and clear. The extent of the layer should be hmited by dividmg the space beneath the ceihng mto smoke reservoirs by screens extendmg part of the way towards the floor. Screens by themselves are ineffective; hot gases must be extracted from a smoke reservoir at at least the same rate as they flow into i t while fresh air must be mtroduced or allowed to flow into the building to replace the extracted hot gases. Theoretically the principle can be used to confine hot smoky gases to the space beneath the ceilmg of the shop of origin but the rates of extract required can seldom be achieved on practice in the confines of a small shop and i t is generally necessary to allow the smoky gases to flow into smoke reservoirs beneath the ceilmg of the mall. The requirements of both natural and powered systems for extractmg smoke from the smoke reservoirs are considered.
