GB2225661A - Emergency evacuation system - Google Patents

Abstract

The system comprises one or more hazard detectors, e.g. fire/smoke detectors A-J, and a plurality of audio emitters 1-26 to be distributed about a site. These are connected to a central control unit (60, Fig. 5, not shown) which, on the basis of stored information about the distribution of detectors and emitters, can respond to a hazard signal from any detector by causing an audio signal to 'travel' from one emitter to another along a route leading to safety relative to the position of the detected hazard. Persons are to follow the characteristic 'travelling' signal from one emitter to the next. <IMAGE>

Description

SAFETY SYSTEM This invention relates to safety systems for facilitating escape from and avoidance of hazards, and particularly fires, in enclosed structures such as buildings, underground stations etc.

For many years there has been increasing concern about the systems and procedures available for evacuating people from enclosed spaces when hazards such as fires occur.

Conventional systems typically have a system of detectors for e.g. smoke or heat, which when set off actuate an alarm.

The alarm may be e.g. a bell, and/or a recorded voice saying "please leave the building immediately" or the like. In some cases a remote monitor may be able to locate the fire by identifying the detector(s) which has/have been set off.

However there is not generally any immediate and effective help given to those near the hazard. In particular, people commonly do not know the shortest way out, are unaware of whether they are going towards or away from safety, and in the case of a fire may be blinded by smoke so that visual signals e.g. "EXIT" signs are of no help to them.

It is an object of the present invention to provide a system that can give effective direct assistance to those trying to escape from or to avoid such hazards. More preferably, it is sought to provide a system adapted for use in locations having a network of corridors and/or multiple exits etc.

The invention therefore takes a radically different approach by using an audio system with "moving" sound to identify safety routes directionally. The system has a control unit comprising an automatic data processor and means for storing information regarding available routes at the site of installation. The processor unit has inputs for the respective outputs of plural hazard detectors. These may be for example smoke and/or heat detectors, to be distributed about the site in which the system is to be used. Detectors may be provided along with other components of the system, or a pre-existing or separate set of detectors may be used, e.g. a set already installed as part of an alarm system. The control unit also has means for storing information regarding the location of the detectors on site in relation to the stored routes information.

An essential element of the complete installed system is having a plurality of sound emitters, e.g. loudspeakers, for distribution along on-site routes. Again, the control unit is arranged to store information regarding their location in relation to the routes and detectors. The route information as stored may of course consist entirely of information regarding the sequences of specified detectors and speakers.

The control unit is programmed to monitor the inputs for the detectors so as to identify any incoming signal identifying a hazard and, on receiving such a signal, to cause the audio signal mentioned above to be generated and to sound from respective emitters, at least in the vicinity of a detector that has been set off, sequentially along a safe route, predetermined with respect to that detector on the basis of the information stored in the control system.

Commonly there will be plural emitters for spacing along the or each programmed route, and the audio signal is preferably short, and/or changing in sound with time, so that its "travel" from one speaker to the next, in the direction of safety, is easily detected and followed. The signal may "cycle", i.e. sound from a speaker near to the actuated detector, then from the next one, and so on e.g.

until an exit is reached whereupon the signal sounds again from the first speaker etc. In e.g. long corridors the sound may need to "cycle" more frequently. It has been found that the directional sense conveyed to subjects, even when blindfolded, by such a signal "travelling" from emitter to emitter is excellent.

It is preferred that the system be set up to associate one or more "sets" of emitters with each detector, to define at least one route away from the location of that detector.

Of course, the routes associated with one detector may overlap with one or more routes associated with another detector. Also, a set of "local" emitters identified as being nearest to an actuated detector may give out a predetermined alarm or warning message e.g. "keep away" or "do not enter" rather than the "directional" signal. This may be combined with means for assigning an "at risk" status to emitters assigned to exits, when these are particularly near an actuated detector. The "at risk" speaker gives the sequential "directional" signal, but the system monitors the status of the warning message loudspeaker adjacent the detector in the direction of the exit.If a check indicates that that emitter has failed, e.g. through a short or open circuit perhaps caused by fire, the system will cause the "at risk" exit loudspeaker to give out a warning message instead of the directional message, as a precaution against use of that exit. Where a given detector input has more than one programmed route (i.e. set of emitters) associated with it, these may all be activated or only some. In particular, the control unit may be programmed to check the safety of routes by monitoring whether additional detectors lying along those routes have been set off, and selecting alternatives accordingly. Thus, the system may identify shortest routes to exits from any particular detector location, plus additional routes from that location to a different exit, or to the closest, primary, exit by a different route.

Preferably, the system also comprises an emitter surveillance facility for checking whether, and detecting when any emitter ceases to function. This provides a means for checking the extent of spread of e.g. a fire in progress, as well as serving as an important system status monitor when the system is "on standby", and the system can be designed to select safe routes taking account of this emitter status as checked.

The system of the present invention may also function as a normal public address/paging system when not in the "emergency mode" initiated by activation of one or more detectors. Thus, audio inputs to the sound generation means of the system may include microphones etc. as well as the means for generating the special directional emergency tones and predetermined warning messages.

Also, the control unit may be able to choose between either a "local" or a "total" evacuation e.g. at the discretion of an operative. That is, means may be provided for sounding only certain selected alarms and directional signals in response to a detector activation, in a given "zone", rather than for the full range of "safe routes" assigned for that detector. This would be useful e.g. for evacuating only one floor of a building at a time where the risk of guiding an excessive number of people down a restricted stairway all at once might on some floors be greater than the fire risk.

By way of example, embodiments of the invention are now described. Reference is made to the accompanying drawings, in which: Fig. 1 is a schematic corridor layout in a building; Fig. 2 indicates a plurality of pre-programmed routes on the plan of Fig. 1; Fig. 3 shows a selection of these routes in the case of a particular detector being activated; Fig. 4 shows a more comprehensive selection of routes for a "total evacuation"; Fig. 5 is a block diagram of the components of a system embodying the present invention; and Fig. 6 is a flowchart of control steps.

Fig. 1 shows a network of two parallel longitudinal corridors 40,41 linked by four transverse corridors 42-45, with six peripheral exits 46-51. Fire/smoke detectors A to J are distributed around the network, three in each longitudinal corridor and one in each transverse corridor.

These can be completely conventional detectors, and may be part of an already-installed fire detection system. However in the system of the present invention they are connected not merely to an alarm but to respective inputs of a control microprocessor 60, as shown schematically in Fig. 5. Still referring to Fig. 5, the microprocessor 60 has plural control outputs 61 to a unit 62 for signal routing and amplification. This unit 62 also has inputs from a number of audio sources 63 via line drivers, the function of which will be described further below. The plural outputs 65 from the amplifier/routing unit 62 pass through a number of respective low-power amplifiers 64 to respective loudspeakers.

A disposition of loudspeakers (numbered 1 to 26) is shown schematically in Fig. 1. It will be noted that a pair of speakers is closely associated with each detector, while further speakers are associated with respective exits. With more widely-spaced detectors, there might well be more than two speakers between adjacent detectors.

It is particularly preferred that each speaker location should be provided with a single bi-directional speaker unit capable of selectively directing audio output in either direction, or both directions, along the corridor, the unit being wall-mounted, while providing a minimum sound intensity laterally i.e. in its own immediate vicinity.

The control microprocessor 60 is programmed with necessary information regarding the routes along which the various identified speakers lie and the relation of those routes to the location of each detector. More particularly, when the system is installed, each detector A-J is labelled for the system and each loudspeaker 1-26 likewise so that routes from each detector to exits 46-51 can be defined in terms of the identification numbers of the series of loudspeakers which lie along them. Referring to Fig. 2, for example, relevant routes are shown for detectors A, B and C.

For detector A there is route Al, past speaker 1; route A2 past speakers 29, 19 and 18; route A3 past speakers 21, 22, 15 and 26 and route A4 past speakers 4 and 25. Each of these routes leads away from detector A, more or less directly, to an exit and hence safety in the event of a hazard at detector A. On installation of the present system the microprocessor 60 is loaded with this route/loudspeaker information for each detector A-J.

Furthermore, for each detector the system assigns "local" loudspeakers. For detector A, these will be speakers 2 and 3. In the event of a hazard being indicated by detector A, these speakers are caused to deliver a predetermined repeated verbal message such as "do not enter", i.e. they serve in particular to keep people away from the site of danger when they are near to it.

Fig. 2 also shows routes for detectors B and C. It should be noted that for e.g. route B1, loudspeakers 2 and 3 become speakers defining the route to safety rather than "local" speakers giving a verbal "keep away" warning. The assignment of a particular function to a particular speaker is done automatically by the control processor on the basis of information it receives concerning the status of each detector.

The directional safety signal is produced as follows.

Certain of the audio inputs 63 shown in Fig. 5 are designed to produce a predetermined characteristic tone, which changes with time. On the basis of information received regarding detector status, the central processor 60 identifies one of the routes pre-loaded into its memory which represents a safe route away from hazard. For example, if a fire is detected by detector A only, routes Al to A4 would represent safe routes away from the fire. The central processor is programmed to instruct the signal routing unit 62 to supply the amplified characteristic tone into speakers lying along each of those routes, in a controlled timed sequence beginning with speakers near the detector and passing from speaker to speaker along each route to the relevant exit.Preferably these speakers are spaced at intervals of about 10 metres, and on the basis of the known speaker spacing the control system sequences the characteristic tone to "travel" from speaker to speaker at somewhat faster than walking speed. Where the bidirectional speakers mentioned above are used, the signal can be directed back towards the hazard so as to be easy to follow by someone moving away from it. The "dead" space laterally adjacent each speaker helps to direct attention immediately to the next one, which rapidly becomes audible as soon as the first speaker is reached. Such a characteristic tone, directed back towards the detector but with its source effectively receding away from it, is found to be a very effective means of guiding people towards safety.One tone that has been found particularly useful is a click followed by a fading gong-like tone: association in this way of two signal parts with different resonance characteristics makes for more certain identification of the signal proceeding from the next nearest loudspeaker in preference to one which might by chance be audible from a more distant speaker through some acoustic peculiarity.

The system may provide an option between "local" and "total" evacuation of the site. For example, the routes Al to A4 referred to above are effective to evacuate the area immediately around detector A, i.e. for local evacuation.

Where for some reason it may be desirable to evacuate the entire site even when the hazard has been detected only at A, a route schedule as shown in Fig. 4 can be stored and put into effect if desired.

Choice between local and total evacuation may be at the discretion of a person responsible for operating the system in an emergency.

Another feature of the system is that routes assigned from a particular detector will not have the directional signal scheduled to them if the system notes that there is evidence that a particular route is not safe, e.g. if another detector lying along that route has been set off or destroyed, or if speakers along that route are detected as being out of action for any reason. To this end the system includes a loudspeaker surveillance unit 70 (shown in Fig.

5) which sends an appropriate signal to the control processor whenever it detects an anomalous function of any loudspeaker, e.g. a short circuit or open circuit which might be due to fire damage. This can give more precise information about the spread of a fire than detector status alone. Of course, it also has application to the day-to-day running of the system to ensure that any parts which for any reason may malfunction are noticed and can be repaired or replaced.

Another function performed by the programmed processor 60 is the assignment of "at risk" status to certain loudspeakers. In particular this may apply to speakers positioned at exits. In the event of a fire, speakers at exit(s) which is/are close to an active "do not enter" zone i.e. a detected hazard are assigned "at risk" status by the system. Where loudspeaker surveillance indicates subsequently that a speaker between the detected hazard and the "at risk" exit has been damaged, the control automatically switches the "at risk" speaker to send out the "do not enter" message rather than the "directional" tone. For example, if detector A were activated (see Fig.

3) speaker 1 would be assigned "at risk" status and would take over broadcast of the "do not enter" message from loudspeaker 2 should the latter be detected as being faulty.

Fig. 6 shows the logical sequence involved in outputting the exit signal which is sequenced from speaker to speaker away from the hazard.

An example of programming "blocks" making up a preferred system, from which a programmer could put together a suitable system, is as follows: Software Features: User is to be able to program detector and loudspeaker assignment on installation of the system.

Control program to read detector inputs, serial or parallel interfaces.

Decide on exit routes.

Control exit routes. Provide message controls and tone sequence.

Monitor amplifier/speaker operation for faults. Faults detected will be assumed as fire spread and re-route exits.

Synchronisation of exit routes including sequence padding so tones from 2 or more paths arrive at mutual locations together.

PA mode (every day use) 16 + control lines.

User programmable zone selection - (speaker to zone).

User programmable signal selection to zone.

User programmable input selection set up.

8 zone paging selection (real time) from paging microphones.

Digital voice message selection and zoning.

The present system may be integrated with a standard public address system; the capacity of the control processor 60 for assigning signals to particular sets or "zones" of speakers is very useful in this respect. For example, certain of the audio inputs shown in Fig. 5 could be microphones e.g. for making platform announcements if the system is implemented at a station.

Fig. 5 also shows a standard visual display unit and keyboard for use in initial programming of the control unit as well as for the day-to-day control and switching of the system between its various non-emergency modes.

Claims (21)

CLAIMS:

1. A safety system, for installation at a site to help people escape from a hazard occurring at the site, comprising a control unit which has: (i) hazard signal receiving means, for connection to one or more hazard detectors; (ii) signalling means for causing predetermined audio signals to sound from a plurality of sound emitters; (iii) means for storing information about (a) relation of sound emitters to hazard detector(s), and (b) at least one route defined by a series of sound emitters; (iv) means for responding to the receiving of a hazard signal from a hazard detector by causing the signalling means to make a predetermined audio signal sound successively from the sound emitters of the at least one route; thereby providing for a directional audible signal leading away from the detected hazard.

2. A system according to claim 1, further comprising a plurality of sound emitters for connection to the signalling means.

3. A system according to claim 2 in which the sound emitters are loudspeakers.

4. A system according to claim 2 or claim 3 in which the sound emitters are selectively bi-directional.

5. A system according to any one of the preceding claims, further comprising one or more hazard detectors for connection to the hazard signal receiving means.

6. A system according to claim 5 in which the hazard detectors are fire or smoke detectors.

7. A system according to any one of the preceding claims wherein the information stored includes assignment of one or more route-defining sets of emitters to each hazard detector.

8. A system according to claim 7 wherein the control unit selects a safe route from plural possible routes on the basis of the location or locations of detected hazard, and causes the directional audio signal to be sent for that route.

9. A system according to any one of the preceding claims, wherein the control unit assigns an "at risk" status to one or more emitters most closely associated with a detector that indicates a hazard, and the signal sending means send a different, "at risk" audio signal to these emitters.

10. A system according to claim 9 in which the "at risk" audio signal is a recorded verbal warning.

11. A system according to any one of the preceding claims, further comprising means for monitoring the operational status of the emitters.

12. A system according to claim 11 in which the control unit uses the emitter status information in choosing a safe route or routes.

13. A system according to any one of the preceding claims, further comprising an operator console.

14. A system according to claim 13 which has means allowing an operator to choose the mode of route selection.

15. A system according to claim 14 in which modes of route selection include total evacuation and partial evacuation of the site at which the system is to be installed.

16. A system according to any one of the preceding claims in which the successively-sounding audio signal is a tone changing with time.

17. A safety system installed at a site, for helping people to escape from a hazard occurring at the site, comprising: (i) one or more hazard detectors; (ii) a plurality of sound emitters distributed along routes of the site; (iii) a control unit having input for signals from the one or more hazard detectors, and means for storing information relating to the distribution of the emitters and hazard detector(s).

the control unit further being adapted to respond to a hazard signal from a said hazard detector by causing a predetermined audio signal to sound successively from sound emitters distributed along a safety route determined on the basis of the stored information, leading to safety away from the detected hazard.

18. A safety system according to claim 17 in which the signal is caused to sequence from emitter to emitter at a speed faster than walking pace along said route.

19. A safety system according to claim 17 or claim 18 wherein the emitters caused to sound are directional, and are caused to project their signal in a direction generally towards the detected hazard.

20. A safety system according to any of claims 17 to 19, the site of installation having a network or branched pattern of corridors.

21. A safety system substantially as described herein with reference to the accompanying drawings.