GB2191090A

GB2191090A - Improvements in or relating to fire safety systems

Info

Publication number: GB2191090A
Application number: GB08613412A
Authority: GB
Inventors: Cyril Herbert Moss
Original assignee: WEST LEIGH GROUP Ltd
Current assignee: WEST LEIGH GROUP Ltd
Priority date: 1986-06-03
Filing date: 1986-06-03
Publication date: 1987-12-09
Also published as: GB8613412D0

Abstract

A fire safety system for a multi-storey building having a plurality of separate accommodation units leading off a communal access unit on each floor and at least one enclosed staircase providing access to said communal access units, has a least one smoke detector positioned in each communal access unit and a vent means in each communal access unit controlled by the smoke detector to open when smoke is detected, the system further comprising means to increase the air pressure in the enclosed staircase above the pressure in the communal access units when smoke is detected in any of them.

Description

SPECIFICATION Improvements in or relating to fire safety systems This invention relates to fire safety systems and is particularly concerned with systems for clearing smoke from multi-storey buildings when a fire occurs therein. More specifically the invention is concerned with a fire safety system in a multi-storey building which comprises a plurality of accommodation units on each floor of the building, at least one communal unit on each floor providing means of access to the accommodation units on that floor, and enclosed stairs or staircases providing means of access to each of said communal units through a respective door.

The multi-storey building may be, for example, a block of flats or an office block, and the communal units hereinbefore referred to will normally be enclosed corridors leading from one or more enclosed lobbies to the entrance to the flats or offices. The lobby on each floorwill normally provide access to one or more lifts and also to an enclosed emergency staircase. Normally the emergency staircase will be isolated from the lobby buy a closed door.

It is known that, when a fire occurs in an accommodation unit of a large multi-storey building, the most likely time for casualties to occur is shortly after the outbreak of the fire when the occupants of the neighbouring accommodation units are attempting to leavethebuilding.Atthistimesmoke from the fire may enter the adjacent communal unit, and this smoke may prevent the occupants ofthe adjacent accommodation units from reaching the nearest door leading to the emergency staircase.

Accordingly various proposals have been made for clearing the smoke from the communal units, particularly during this initial period. For example various fire safety systems are disclosed in United Kingdom PatentSpecifications Nos. 1 326112,1 326 113,1397611,1397612,1438001,1438002,1441 930 and 1479793.

Most of the systems disclosed in the above-mentioned Patent Specifications inciude one or more smoke detectors installed in the building and arranged, when smoke is detected, to activate apparatus for causing the ingress offresh airtothe communal units and egress of smokefrom the communal units. This may be done, for example, by providing a smoke vent of the kind shown in Specification No. 1 326 112 which provides separate openingsforthe ingress ofairandthe egress of smoke. Alternatively, or in addition, the smoke detector, or detectors, may activate means for increasing the air pressure in the communal unitsto drive the smoke out of the unit and replace it with fresh air.

In accordance with the present invention at least one smoke detector is associated with each communal unitand means controlled bythe,ora, respective smoke detector are provided to allow air from outsidethe building to enterthe communal unit and to allowsmokefrom thesaid communal unitto leave the building when smoke is detected in that communal unit. In addition further means are provided to increasethe pressure in the staircase abovethe pressure in anyofthe communal units in the building when smoke is detected in any of the communal units.

The first means referred to in the preceding paragraph may be, for example, a smoke vent ofthe kind described in Patent Specification No.1326112.

Such a vent may be located, for example, atthe end of each corridor of the building and will open as soon as smoke is detected in the respective corridor. This will allow fresh air to enterthe corridor and also allowsmoketo leave the corridor. Thusthe occupants ofthe accommodation units opening on to the corridor in which smoke has been detected will normally be able to reach the nearest door leading to the, or an, emergency staircase. Furthermore, when the door communicating with the emergency staircase is opened by the escaping occupants, the increased pressure in the staircase, in accordance with the present invention, will cause airto pass through the doorway into the corridor and thus to assist in clearing smoke from the corridorthrough thesmokeventattheend of the corridor.

In accordance with a subsidiary feature ofthe invention, manually operable means are provided to control the extent to which the pressure in the staircase is increased above the pressure in the rest ofthe building. Normally, for example, when the smoke is detected, the increase in pressure will be such that, when one ofthe doors from the staircase to a communal unit is open, there is a volume of air of at least 2 cubic metres per second through the fully opened staircase door into the communal unit.

This flow of air will normally be satisfactory to keep the corridor clear enough for the occupants of the building to escape. However under certain adverse wind conditions it may be insufficientforthis purpose, and under such conditions the pressure in the staircase can be increased manually above the normal amount in order to increase the flow of air into the corridor. Alternatively, when fire fighting personnel arrive, and particularly ifthey are equipped with breathing apparatus, they may determinethattheflow of air is unnecessary forthe clearance of smoke and that it could assist in feeding the fire. Underthese circumstances the pressure in the staircase may be reduced so that it is only slightly above the pressure in the rest of the building, or even so that it is equal to that pressure.

Thus the present invention provides a system which enables the occupants ofthe building to escape in safety, but which at the same time can be prevented from increasing the possibility of damage to the building as a result of air being fed to thefire.

1. Afire safety system for multi-storey buildings having a plurality of separate accommodation units leading off a communal access U jlit on each floor and at least one enclosed staircase providing access to said communal access units, wherein at least one smoke detector is provided in each communal access unit, and vent means are provided in each

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to fire safety systems This invention relates to fire safety systems and is particularly concerned with systems for clearing smoke from multi-storey buildings when a fire occurs therein. More specifically the invention is concerned with a fire safety system in a multi-storey building which comprises a plurality of accommodation units on each floor of the building, at least one communal unit on each floor providing means of access to the accommodation units on that floor, and enclosed stairs or staircases providing means of access to each of said communal units through a respective door. The multi-storey building may be, for example, a block of flats or an office block, and the communal units hereinbefore referred to will normally be enclosed corridors leading from one or more enclosed lobbies to the entrance to the flats or offices. The lobby on each floorwill normally provide access to one or more lifts and also to an enclosed emergency staircase. Normally the emergency staircase will be isolated from the lobby buy a closed door. It is known that, when a fire occurs in an accommodation unit of a large multi-storey building, the most likely time for casualties to occur is shortly after the outbreak of the fire when the occupants of the neighbouring accommodation units are attempting to leavethebuilding.Atthistimesmoke from the fire may enter the adjacent communal unit, and this smoke may prevent the occupants ofthe adjacent accommodation units from reaching the nearest door leading to the emergency staircase. Accordingly various proposals have been made for clearing the smoke from the communal units, particularly during this initial period. For example various fire safety systems are disclosed in United Kingdom PatentSpecifications Nos. 1 326112,1 326 113,1397611,1397612,1438001,1438002,1441 930 and 1479793. Most of the systems disclosed in the above-mentioned Patent Specifications inciude one or more smoke detectors installed in the building and arranged, when smoke is detected, to activate apparatus for causing the ingress offresh airtothe communal units and egress of smokefrom the communal units. This may be done, for example, by providing a smoke vent of the kind shown in Specification No. 1 326 112 which provides separate openingsforthe ingress ofairandthe egress of smoke. Alternatively, or in addition, the smoke detector, or detectors, may activate means for increasing the air pressure in the communal unitsto drive the smoke out of the unit and replace it with fresh air. In accordance with the present invention at least one smoke detector is associated with each communal unitand means controlled bythe,ora, respective smoke detector are provided to allow air from outsidethe building to enterthe communal unit and to allowsmokefrom thesaid communal unitto leave the building when smoke is detected in that communal unit. In addition further means are provided to increasethe pressure in the staircase abovethe pressure in anyofthe communal units in the building when smoke is detected in any of the communal units. The first means referred to in the preceding paragraph may be, for example, a smoke vent ofthe kind described in Patent Specification No.1326112. Such a vent may be located, for example, atthe end of each corridor of the building and will open as soon as smoke is detected in the respective corridor. This will allow fresh air to enterthe corridor and also allowsmoketo leave the corridor. Thusthe occupants ofthe accommodation units opening on to the corridor in which smoke has been detected will normally be able to reach the nearest door leading to the, or an, emergency staircase. Furthermore, when the door communicating with the emergency staircase is opened by the escaping occupants, the increased pressure in the staircase, in accordance with the present invention, will cause airto pass through the doorway into the corridor and thus to assist in clearing smoke from the corridorthrough thesmokeventattheend of the corridor. In accordance with a subsidiary feature ofthe invention, manually operable means are provided to control the extent to which the pressure in the staircase is increased above the pressure in the rest ofthe building. Normally, for example, when the smoke is detected, the increase in pressure will be such that, when one ofthe doors from the staircase to a communal unit is open, there is a volume of air of at least 2 cubic metres per second through the fully opened staircase door into the communal unit. This flow of air will normally be satisfactory to keep the corridor clear enough for the occupants of the building to escape. However under certain adverse wind conditions it may be insufficientforthis purpose, and under such conditions the pressure in the staircase can be increased manually above the normal amount in order to increase the flow of air into the corridor. Alternatively, when fire fighting personnel arrive, and particularly ifthey are equipped with breathing apparatus, they may determinethattheflow of air is unnecessary forthe clearance of smoke and that it could assist in feeding the fire. Underthese circumstances the pressure in the staircase may be reduced so that it is only slightly above the pressure in the rest of the building, or even so that it is equal to that pressure. Thus the present invention provides a system which enables the occupants ofthe building to escape in safety, but which at the same time can be prevented from increasing the possibility of damage to the building as a result of air being fed to thefire. CLAIMS

1. Afire safety system for multi-storey buildings having a plurality of separate accommodation units leading off a communal access U jlit on each floor and at least one enclosed staircase providing access to said communal access units, wherein at least one smoke detector is provided in each communal access unit, and vent means are provided in each communal access unitcontrolled bysaidsmoke detectorto provide communication between the interior ofthe access unit and the exterior ofthe building when smoke is detected in that communal access unit and further means are provided to increase the air pressure in the enclosed staircase or staircases above the pressure in the communal access units when smoke is detected in any communal access unit.

2. Afiresafetysystem according to claim 1, wherein the vent means for providing communication between the communal access unit and the exterior ofthe building is a smokevent which,when open, provides separate openings for the egress of smoke and the ingress of air.

3. Afire safety system according to claim 1 or claim 2, wherein the communal access unit is an elongate corridor and the staircase and the vent means are spaced along the length of the corridor.

4. A fire safety system according to claim 3, wherein either a staircase or a vent means is positioned at an intermediate point in the corridor, and vent means or staircases, respectively, are positioned atthe ends of the corridor.

5. Afire safety system according to any preceding claim,whereinthe means to increasethe air pressure in the enclosed staircase or staircases may be controlled by means otherthan the smoke detectors.