GB2286474A - Hazard warning system - Google Patents

Abstract

The comprises sensors 22 - 29 placed round the building or vessel to detect the hazard and indicate its position to a central processor. The processor calculates safe escape routes and switches on hazard indicators 10 - 17 such as emergency exit signs to indicate accordingly. Thus the buildings users may be directed away from the hazard. <IMAGE>

Description

Hazard Detection and Indication System This invention relates to hazard detection and indication systems and more particulary but not exclusively to hazard detection and indication systems for use in buildings, vessels or like structures.

Hazard detection systems are widely found, and often legally required, in buildings and vessels such as ships and aircraft. The hazards concerned include fires, chemical leakage, radioactive leakage, flooding and in the case of air or spacecraft, loss of pressure.

Such alarm systems generally have hazard detection means which may include manually operated alarm buttons, smoke detectors, infrared detectors and chemical and pressure detectors. Often, in smaller buildings, each detector will be a stand-alone device, having its own built-in audible alarm. In larger buildings, however, a series of sensors, which may be a mixture of different types of sensors, may be connected up to a single processor. The single processor uses information received from the sensors to determine the presence of the hazard and sets off a central alarm that may be heard throughout the building or vessel.

In some cases there may be built in a means of automatically alerting the emergency services. In many cases the setting off of an audible alarm is accompanied by the switching on of an emergency lighting system which includes the lighting up of visual signs indicating possible escape routes.

A disadvantage with systems such as the one described above is that no attempt is made to distinguish between safe and unsafe escape routes. In the known art generally all escape routes are lit up.

Thus it is unfortunately all too common that, as a result of the alarm being raised in the case of a hazard such as a fire, people attempting to escape from a building are led towards, rather than away from, the danger.

In accordance with the invention there is thus provided a device for warning of a hazard in a building, vessel or like structure, the device comprising: a plurality of hazard detection means, computing means and a plurality of hazard indication means, wherein the computing means are operable to use data from the detection means to ascertain the presence and location of the hazard and to calculate safe escape routes from the building, vessel or like structure and wherein the hazard indication means are operable to indicate, either visually or acoustically, the safe escape routes.

According to a second aspect of the present invention there is provided a method of warning of a hazard in a building, vessel or like structure comprising the steps of detecting indications of the hazard at a plurality of locations in the building, vessel or like structure, ascertaining from the detected indications the presence and whereabouts of the hazard, computing from the ascertained whereabouts of the hazard any safe escape routes from the building, vessel or like structure, and indicating the safe routes either visually or acoustically.

An indication may be provided that there are no safe escape routes.

The computing means may continually collect data from the detecting means and update its output. Thus the indication means keeps up with changes in the situation.

The hazards involved include fires, chemical leakage, radioactive leakage, flooding or loss of pressure. This list of possible hazards is not exhaustive and any hazard which may be detected by passive or active detection means and wherein the location of the hazard is required to be known, either for escaping from the hazard or to approach the hazard to deal therewith, would be suitable for the system of the present invention.

The hazard detection means, by which indications of the hazard are detected, may include manually operated alarm buttons, smoke alarms, pressure detectors, chemical detectors, infrared detectors, radiation detectors, flood detectors or even in some cases cameras. Again, this list is not exhaustive and any detector appropriate to the specific hazard being considered may be incorporated into the device of the present invention.

The detection means at any given location may indicate the nearest escape route.

The indication means, for indicating the safe escape routes, may be the standard visual signs for indicating the location of an emergency exit. In general these signs are set to light up automatically when the alarm is triggered. When used with the present invention, however, they would only be lit up when the system determines that the relevant escape route is safe. In one embodiment the sign may be lit up in a different way when the route is unsafe. For example the indication means may be set to remain alight constantly to indicate that the route is safe and to flash to indicate danger. In an alternative embodiment the indication means may additionally incorporate a danger sign that is lit up when the system decides that the relevant escape route is unsafe.In a further embodiment indication means may be provided for indicating alternative escape routes that may be reached from its location. When an emergency occurs the indication means will indicate which of the alternatives is safe. In a further embodiment the indication means may comprise an acoustic indication of the hazard. Alternative recorded messages may be included to tell approaching people that the escape route being entered is either safe or dangerous as appropriate.

Reference herein to a building includes an underground structure. Reference to a vessel includes a land, sea, submarine, air or space vessel and reference to a like structure means any other structure in which hazards may occur which must be dealt with or from which escape is required.

The computing means may be programmable or hard wired. The system may have built-in testing means.

The computing means may comprise EPROM chips.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, purely by way of example, to the accompanying drawings in which: Fig. 1 is a plan of a building to which the present invention may be applied, Fig. 2 is a truth table showing the possible hazard location permutations for the building of Fig.

1.

Fig. 3 shows how computing means may be programmed to deal with the building shown in Fig. 1.

Fig. 4 shows a computing means according to the present invention.

Fig. 5 shows an alarm means in accordance with the invention.

Fig. 6 shows a block diagram of the present invention.

The present invention may be applied to a building such as the one shown in plan in Fig. 1. A series of spaces 1 to 8 having emergency exit signs 10 to 17 are linked by a corridor 9. Emergency exits 18 to 21 are located as indicated. Smoke detectors 22 to 29 or like detecting means are located in each of the rooms 1 to 8. Each of the emergency signs 10 to 17 is as shown in Fig. 5, having arrows pointing in opposite directions.

In the event of a hazard any arrow indicating a safe direction is lit up. Any other arrow, that is an arrow pointing to an emergency exit reached by a space in which the hazard has been detected may either be left unlit or set to flash.

Fig. 6 is a block diagram of the system according to the invention. Hazard detectors 50/0 to 50/N are connected to computing means 51. The computing means 51 is connected in turn to indication means 52/0 to 52/N. Inputs derived from the hazard detectors 50/0 to 50/N are processed in accordance with the truth table shown in Fig. 2. The truth table is set up for the case of the 8 space building shown in Fig. 1.

A number of ways of incorporating the truth table into the computing means 51 will suggest themselves to the skilled man. One such method is to incorporate the table into a program and incorporate the program into an EPROM chip and such a program is shown in the listing given in Fig. 3. This program is written in assembler code and specifies the appropriate output for each received input combination. Instead of EPROM, a totally software implementation using a microcomputer is just as possible. An alternative means is to employ Karnaugh-mapping techniques to reduce the truth table to minimalist form and use that to customise a programmable logic array (PLA). Thus, appropriate outputs are sent to the emergency signs.

For the case where all the detectors, 50/0 to 50/N indicate danger an embodiment may AND together all the inputs or outputs, to produce a ninth output sent to all the indicators 52/0 to 52/N to highlight a separate message not shown, saying that there are no safe exits.

Fig. 4 shows a possible circuit arrangement for a device according to the invention to serve the building shown in Fig. 1. Inputs from the detectors 50/0 to 50/8 are shown as A to G in the Figure. These inputs are buffered and sent to an EPROM chip 60. The outputs of the chip 60 are produced in accordance with the truth table shown in Fig. 2. These outputs control the right and left hand illuminated sign arrays respectively designated by numerals 61 and 62 in the diagram. The signs themselves are represented by LED devices as shown.

Devices supplied as detection means are normally equipped to produce a test signal and testing means may be built into the computing circuit, or the outputs may be monitored by attaching a bank of LEDs thereto or by observing the indicators 52/0 to 52/N under test conditions.

In applying the invention to different formats of building etc a suitable plan for locating detection devices and indication signs would be prepared as appropriate for the building layout and the location of likely escape routes. A truth table, defining available escape routes for given combinations of activated sensors would be drawn-up and a logic chip etc programmed accordingly. With current technology it is feasible to translate a logic table into programmed circuitry relatively quickly on site.

In drawing up the truth table it is possible to arrange the system to indicate the nearest safe escape route for any given location of the hazard.

As an alternative to building a discrete system, the invention may be incorporated into an integrated computerised building management system (BMS) as is widely used in large buildings.

Claims (13)

CLAIMS:

1. A device for warning of a hazard in a building, vessel or like structure, the device comprising: a plurality of hazard detection means, computing means and a plurality of hazard indication means, wherein the computing means are operable to use data from the detection means to ascertain the presence and location of a hazard and to calculate safe escape routes from the building, vessel or like structure and, wherein the hazard indication means are operable to indicate the safe escape routes.

2. A method of warning of a hazard in a building, vessel or like structure comprising the steps of monitoring for indications of the hazard at a plurality of locations in the building, vessel or like structure, ascertaining from any indications detected the presence and location of the hazard, computing from the ascertained location of the hazard any safe escape routes from the building, vessel or like structure, and indicating visually or acoustically the safe escape routes.

3. A device according to claim 1 wherein the hazard indication means are further operable to indicate that there are no safe escape routes.

4. A device according to claim 1 or claim 3 wherein the hazard detection means include at least one of manually operated alarm buttons, smoke alarms, pressure detectors, infrared detectors, radiation detectors, flood detectors and cameras.

5. A device according to claims 1, 3 or 4 wherein the hazard detection means are strategically located around the building, vessel or like structure in such a way that data received from them is indicative of the safety or otherwise of an escape route.

6. A device according to any one of claims 1, 3, 4 or 5 wherein an individual indication means is lit up when the presence of a hazard is ascertained and only if the escape route associated with the individual indication means is deemed to be safe.

7. A device according to claims 1, 3, 4 or 5 S wherein an individual indication means is lit up when the presence of a hazard is ascertained.

8. A device according to claim 7 wherein the individual indication means is lit up in one way if the associated escape route is safe and is lit up in another way if the associated escape route is unsafe.

9. A device according to claim 7 or claim 8 wherein the individual indication means is lit up if more than one escape route is associated with it to indicate which, if any, escape route is safe.

10. A device according to any one of claims 1 or 3 to 9 wherein the hazard indication means are operable to indicate the safe escape routes if any by means of the selection and playing of an appropriate audible message.

11. A method according to claim 2 wherein all of the steps are carried out substantially continuously.

12. An integrated Building Management System including the device of any one of claims 1 or 3 to 10.

13. A method or device substantially as hereinbefore described with reference to the accompanying drawings.