Patent GB-1397612-A (GB)
Title: Fire safety systems
IPC: A62C99/00
Filed: 1972-03-28
Abstract: 1397612 Fire safety system K G SMOKE DISPERSAL Ltd 26 March 1973 [28 March 1972] 46933/74 Divided out of 1397611 Heading A5A A fire safety system for use in a building in which there are a plurality of accommodation units and a plurality of communal access units comprises a plurality of smoke detectors associated with the communal units, a pressurised shaft having a plurality of apertureclosing panels communicating with respective ones of said communal units, a plurality of smoke vents in an exterior wall or walls of the building serving when open to permit egress of smoke from respective ones of said communal units, a plurality of self-closing fire doors each serving when closed to restrict the passage of smoke from one of said communal units to another communal unit, and a plurality of electro-magnetic locks controlled by said smoke detectors, a first number of said locks serving when energised to maintain closed respective ones of said aperture-closing panels, a second number of said locks serving when energised to maintain closed respective ones of said smoke vents, and a third number of said locks serving when energised to maintain open respective ones of said self-closing fire doors. Each detector may control at least one of the first locks, at least one of the second locks and at least one of the third locks, and or each lock may be controlled by a plurality of detectors. The electromagnetically-controlled apertureclosing panels may be of the type mounted to pivot about a horizontal axis below the centre of gravity of the panel, spring means being provided to urge the part of the panel above the pivot axis outwardly into the shaft, and the panel normally being held closed by the electromagnetic lock. A similar device may be employed as smoke vent, preferably the vent described and claimed in Specification 1326113. The system is preferably battery-operated. The building shown in plan in Fig. 1 consists of accommodation units 1 surrounding a central service area comprising staircases 2, lifts 3 and vertical shafts 4, 5, 6, 7, and having access thereto via main corridors 8, 9, 10, 11 provided with self-closing fire doors 14 - 20 normally held open by electromagnetic locks. Each shaft 4-7 is pressurised by a fan in the basement, is closed at the top of the building, includes vents opening into the staircases, and has a closable opening on each floor for the passage of air into one of 8-11. Smoke detectors, e.g. dependent on the interruption of a beam of light or gamma radiation, or on light scatter produced by smoke particles, are provided in corridors 8-11 and also in subsidiary corridors 12, 13, which have smoke vents 21, 22 in their external walls. When smoke is detected in 12 or 13, for example, the fans in shafts 4-7 speed up to increase air pressure on staircase 2; a vent from shaft 7 to floor level in corridor 9 opens; self-closing fire doors 14, 15 close; and vents 21, 22 open. Thus fresh air from 7 drives the smoke along corridors 12, 13 to vents 21, 22, and escapees can reach and use staircase 2 via doors 23, 24. Figs. 2 and 3 illustrate modifications of the Fig. 1 plan, in Fig. 2 corridors 12 being omitted and smoke vents being provided at each outer wall of corridors 13, and in Fig. 3 corridors 13 also being omitted, and trunking being provided to supply pressurised air to the accommodation units and to clear smoke from the main corridors. Fig. 4 shows a building of elongate rectangular plan, accommodation units being provided on either side of a single central corridor. Reference is made to parent Specification 1397611.