WO2015075454A1

WO2015075454A1 - A fire detection system and associated components thereof

Info

Publication number: WO2015075454A1
Application number: PCT/GB2014/053434
Authority: WO
Inventors: Bernard Cain
Original assignee: Aaa Molar Engineers Limited
Priority date: 2013-11-20
Filing date: 2014-11-20
Publication date: 2015-05-28
Also published as: EP3072119A1; GB2520499A; GB2520499B; EP3072119B1; GB201320517D0

Abstract

A fire detection system comprising: an expansion member which is configured to expand from a normal condition by predetermined amounts when exposed to temperatures associated with a fire; a sensor mechanism which is configured to issue a first signal on sensing a first predetermined expansion of the expansion member from the normal condition, and to issue a second signal on sensing a second predetermined expansion of the expansion member from the normal condition, the second predetermined expansion from the normal condition being greater than the first predetermined expansion from the normal condition; and an alert module configured to transmit an alert signal after both the first and second signals have been received.

Description

Title: A fire detection system and associated components thereof Description of Invention

Embodiments of the invention relate to fire detection systems. Other embodiments include rooms, and buildings which include such fire detection systems. More specifically, embodiments of the present invention include "double knock" fire detection systems.

Emergency services, such as the fire and rescue services, are called out to many fires and potential fires. These services are reluctant to permit fire detection systems to trigger an automatic alert to be sent to the emergency services because of the large number of false alarms which occur. However, the automatic transmission of an alert in the event of actual fire would decrease the overall response time and ensure that the emergency services are alerted even if no one is present to transmit an alert manually (e.g. through use of a telephone).

In some countries, legislation is in place (or is being brought into place) which promotes or requires the installation of sprinkler systems (or other fire suppression systems), even in domestic properties. However, there is a perception that sprinkler systems can cause significant water damage. This perception has caused resistance to the installation of sprinkler systems. Other systems to reduce the risks associated with fires and yet avoid potential damage from fire suppression systems are, therefore, needed.

There is a desire to provide a system which automatically alerts the emergency services to a fire to allow fast responses from the emergency services.

H13468WO Embodiments of the present invention, therefore, seek to ameliorate one or more problems associated with the prior art.

Accordingly, an aspect of the present invention provides a fire detection system comprising: an expansion member which is configured to expand from a normal condition by predetermined amounts when exposed to temperatures associated with a fire; a sensor mechanism which is configured to issue a first signal on sensing a first predetermined expansion of the expansion member from the normal condition, and to issue a second signal on sensing a second predetermined expansion of the expansion member from the normal condition, the second predetermined expansion from the normal condition being greater than the first predetermined expansion from the normal condition; and an alert module configured to transmit an alert signal after both the first and second signals have been received.

The expansion member may be a linear elongate expansion member which is configured to increase in length when heated.

The linear elongate expansion member may be tethered by an anchor member to a carrier at a first end of the linear elongate expansion member and the sensor mechanism is positioned towards a second end of the linear expansion member.

The sensor mechanism may be mounted on the carrier.

The carrier may include a plurality of mounting guides which are configured to support the linear elongate expansion member between the first and second ends thereof. The system may be configured to issue the first signal upon the expansion member expanding a distance from the normal condition, which distance corresponds to a temperature increase of between about 10 and about 15 degrees Celsius.

The system may be configured to issue the second signal upon the expansion member expanding a distance from the normal condition, which distance corresponds to a temperature increase of between about 20 and about 35 degrees Celsius.

The alert module may be coupled to a communications link and may be configured to transmit the alert signal via the communications link.

The communications link may be between the fire detection system and a system of the emergency services such that the transmission of the alert signal automatically alerts the emergency services to the fire.

The expansion member may be formed from chlorinated polyvinyl chloride (CPVC).

The expansion member and sensor mechanism may be configured to be located within a void at least partially defined by coving.

Another aspect of the present invention provides a room including a fire detection system. Another aspect of the present invention provides a building including a fire detection system.

Another aspect of the present invention provides a carrier for use in a fire detection system, the carrier including: a mounting arrangement configured to receive the sensor mechanism; and an anchor member configured to tether at least part of the expansion member with respect to the carrier. The carrier may further include the expansion member.

Another aspect of the present invention provides an expansion member for use with a carrier.

Embodiments of the present invention are described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a schematic view of a fire detection system of an embodiment;

Figure 2 shows a carrier of an embodiment;

Figure 3 shows a sensor mechanism of an embodiment;

Figure 4 shows coving for use with embodiments;

Figure 5 shows coving fitted to a room (in cross-section); Figure 6 shows a plan view of a building including a room of an embodiment; and

Figure 7 shows coving fitted to a room (in cross-section) of an embodiment.

With reference to figure 1 , embodiments of the present invention include a fire detection system 1 .

The fire detection system 1 includes an expansion member 2 which is associated with a sensor mechanism 3. The sensor mechanism 3 is coupled to an alert module 4. The expansion member 2 is configured to expand different predetermined amounts when exposed to different temperatures. In particular, the expansion member 2 is configured to expand a first predetermined amount when exposed to a first temperature and to expand a second predetermined amount when exposed to a second temperature. The first temperature is lower than the second temperature and the first predetermined expansion (from a normal condition such as room temperature) is less than the second predetermined expansion (from the normal condition). For the avoidance of doubt, the expansion of the expansion member 2, as discussed herein, is the expansion of the expansion member 2 relative to is normal condition (e.g. at room temperature). The sensor mechanism 3 is configured to detect or otherwise sense the expansion of the expansion member 2 and to issue a first signal on sensing the first predetermined expansion and a second signal on sensing the second predetermined expansion. Accordingly, in embodiments, the sensor mechanism 3 senses exposure of the expansion member 2 to the first predetermined temperature and the second predetermined temperature.

The first and second signals issued by the sensor mechanism 3 are received by the alert module 4. The alert module 4 is configured to receive the first and second signals from the sensor mechanism 3. The alert module 4 is, in turn, configured to transmit an alert signal once the alert module 4 has received both the first and second signals. With reference to figure 2, the expansion member 2 may comprise a linear elongate expansion member which is configured to expand such that the length of the linear elongate expansion member increases. Accordingly, the first predetermined expansion comprises an increase in the length of the expansion member 2 relative to its length in the normal condition (e.g. at room temperature). Similarly, the second predetermined expansion comprises an increase in the length of the expansion member 2 relative to its length in the normal condition (e.g. at room temperature).

The linear elongate expansion member forming the expansion member 2 of some embodiments may comprise a length of material between about 1 .5m and 6m in length. Linear elongate expansion members may be provided of various lengths, in 0.5m increments (e.g. 1 .5m, 2m, 2.5m, etc).

In embodiments, the linear elongate expansion member is formed from a material for which a 4 m length thereof will expand by approximately 10mm to 15mm (preferably 12-13mm) on exposure to the temperatures associated with a fire (or with a fire starting).

The expansion member 2 may be mounted on a carrier 6. The carrier 6 may comprise a mounting member 61 which is configured to be mounted to a wall or ceiling, for example. The mounting member 61 may, therefore, comprise a main body 62 defining one or more apertures for receipt of a fixing arrangement (such as a screw or nail). In some embodiments, the mounting member 61 is configured to be adhered to a wall or ceiling or coving (see below) and may include an adhesive material.

In some embodiments, the main body 62 of the mounting member 61 of the carrier 6 comprises an elongate plate. A first planar side of the elongate plate of the main body 62 is configured to be positioned adjacent a support surface and secured thereto (the support surface may be a wall or ceiling). A second planar side of the elongate plate of the main body 62 opposes the first planar side across a depth of the plate. The main body 62 includes one or more mounting guides 63 which extend from the second planar side of the elongate plate, in some embodiments. The mounting guides 63 are configured to support at least part of the expansion member 2 and to guide the movement of part of the expansion member 2 during expansion of the expansion member 2. The main body 62 may also include an anchor member 64. The anchor member 64 also extends, in some embodiments, from the second planar side of the elongate plate. The anchor member 64 is also configured to support at least part of the expansion member 2.

The anchor member 64 and mounting guides 63 may be similar in form. However, the mounting guides 63 are configured to permit movement of the at least part of the expansion member 2 with respect thereto such that the mounting guides 63 then support a different part of the expansion member 2. This may occur, for example, during expansion of the expansion member 2. Accordingly, the mounting guides 63 may comprise support blocks (configured to receive a part of the expansion member 2 therebetween) or rings (configured to receive a part of the expansion member 2 therethrough).

The anchor member 64, on the other hand, secures (or otherwise tethers) a part of the expansion member 2 such that at least part of the expansion member 2 cannot move with respect to the anchor member 64. The anchor member 64 and the mounting guides 63 may form a channel (which may be an elongate linear channel) to receive the expansion member 2.

Thus, in the case of an elongate linear expansion member, the expansion member 2 may be secured to the carrier 6 at a first end of the expansion member 2 by the anchor member 64. The length of the expansion member 2 may then be supported by the mounting guides 63 such that the expansion member 2 and carrier 6 maintain a desired position with respect to each other. In such embodiments, expansion of the expansion member 2 causes movement of parts of the expansion member 2 away from the anchor member 64 (which ensures that the movement as a result of expansion of the length of the expansion member 2 substantially occurs in a single direction).

Parts of the expansion member 2 may, therefore, move with respect to the carrier 6 and this movement may be through the mounting guides 63.

The expansion member 2 may be formed from CPVC or some other plastic. The expansion member 2 may be formed from a metal. The expansion member 2 does, however, expand in a predictable manner when exposed to the temperatures associated with a fire. The expansion member 2 may be a solid expansion member 2 or may include one or more cavities therein.

The sensor mechanism 3 may take many different forms. In the example of figure 3 (and other examples), the sensor mechanism 3 includes a pair of micro-switches 31 . Each of the pair of micro-switches 31 is spaced apart from the other of the pair along a length of the expansion member 2. Each micro- switch 31 is associated with an actuation element 21 of the expansion member 2. The actuation elements 21 may comprise a protrusion which extends from the expansion member 2 towards the pair of micro-switches 31 . The protrusions may be formed from respective studs which are attached to the expansion member (e.g. using an adhesive or by penetrating the expansion member 2). The actuation elements 21 are configured such that they each actuate a respective one of the micro-switches 31 as that actuation element 21 moves with respect to that micro-switch 31 .

The actuation elements 21 may have a curved surface which faces their respective micro-switches 31 . Each of the micro-switches 31 may include a curved or round element as part of an actuator of the micro-switch 31 , the actuator of the micro-switch 31 being configured to abut against the associated actuation element 21 and to be moved by the actuation element 21 as a result of expansion of the expansion member 2. Accordingly, a first of the actuation elements 21 is positioned on the expansion member 2 a first distance from a first of the micro-switches 31. A second of the actuation elements 21 is positioned on the expansion member 2 a second distance from a second of the micro-switches. An expansion of the expansion member 2 will cause movement of a part of the expansion member 2 such that the first actuation element 21 approaches the first micro-switch 31 . If expansion is sufficient, then the first actuation element 21 will cause actuation of the first micro-switch 31 and this will cause the issuance of the first signal. The expansion will also cause movement of a part of the expansion member 2 such that the second actuation element 21 approaches the second micro- switch 31 . If expansion is sufficient, then the second actuation element 21 will cause actuation of the second micro-switch 31 and this will cause the issuance of the second signal. The distance between the first actuation element 21 and the first micro-switch 31 is less, in this example, than the distance between the second actuation element 21 and the second micro-switch 31 . As such, the first micro-switch 31 is actuated to cause issuance of the first signal following a first expansion of the expansion member 2 and the second micro-switch 31 is actuated to cause issuance of the second signal following a second expansion of the expansion member 2 - the first expansion being less (relative to the original length of the expansion member 2) than the second expansion. As the expansion member 2 is configured to expand predetermined amounts when exposed to predetermined temperatures (a greater expansion being representative of a higher temperature), the first and second expansions represent first and second temperatures to which the expansion member 2 has been exposed.

With reference to figure 6, the expansion member 2 and sensor mechanism 3 (and carrier 6 if provided) are configured to be fitted in a room 91 of a building 9 - which may be a domestic residence or a commercial establishment). In embodiments, the expansion member 2 and sensor mechanism 3 (and carrier 6 if provided) are configured to be fitted behind coving 7 which is often found in rooms 91 and which covers the junction between the ceiling 92 and wall 93 (see figure 5). An example of such coving 7 is shown in figure 4.

The coving 7, therefore, at least partially defines a void 71 - the void 71 also being defined by the wall 93 and ceiling 92. This is shown in figure 5. The expansion member 2 and sensor mechanism 3 (and carrier 6 if provided) may be located within the void 71 when fitted. The expansion member 2 and sensor mechanism 3 may be mounted to the coving 7 (e.g. by the mounting member 61 being secured to the coving 7). In embodiments, the carrier 6 is the coving 7. In embodiments, the carrier 6 is mounted to the wall 93 and ceiling 92 (and maybe also the coving 7) in the void 71 .

In embodiments, the coving 7 defines one or more apertures 72a, 72b which improve the transmission of heat from the room (in which the coving 7 is fitted) into the void 71. In particular, the one or more apertures 72a, 72b may allow hot gasses to pass from the room into the void 71 in order to increase the temperature of the expansion member 2 to cause the expansion thereof. Allowing hot gasses into the void 71 in this manner means that an expansion member 2 will expand to a predetermined expansion quicker than it would expand had there been no void 71 . Hot gasses may pass from the room into the void via aperture 72b before cooling upon contact with the ceiling 92, following which a continued source of hot gasses will force the cooler gasses back into the room via aperture 72a. Advantageously, this circulation of hot gasses around the expansion member 2 leads to a very sensitive system for sensing changes in temperature. As will be appreciated, two apertures 72a, 72b are provided in the illustrated embodiment. In some embodiments, more or less apertures may be provided.

In Figure 7 an alternative arrangement is shown which is similar to the arrangement shown in Figure 5 with the exception of the presence of mounts 73. In this arrangement the mounts 73 may be permeable - for example, the mounts 73 may include the apertures 72a, 72b - to permit flow of gasses between the room and the void 71 . Advantageously, this means that the coving 7 need not include the apertures and this provides for an improved aesthetic appeal. Moreover, since the coving 7 need not include the apertures it is possible to utilise generic coving with the present innovation without the need for producing custom-made coving having apertures defined therein.

The mounts 73 may be fixed to the respective ceiling 92 and wall 93 using conventional techniques (such as by using adhesive or fixing screws). The coving 7 may also be fitted in the usual manner, for instance by using adhesive to secure the coving 7 to the mounts 73.

The alert module 4 may include a processor 42 which may comprise one or more logic gates. The alert module 4 may comprise one or more electronic switches and/or analog devices. The alert module 4 is configured to receive the first and second signals issued by the sensor mechanism 3. As such, the alert module 4 may be coupled to the sensor mechanism 3 by a wired communication link. In some embodiments, the communication link is wireless and the alert module 4 is remote from the sensor mechanism 3. If the communication link is a wired communication link, then the alert module 4 may be proximal to the sensor mechanism 3 but may be remote therefrom. A remote alert module 4 may be configured to receive first and second signals from a plurality of sensor mechanisms which are associated with a plurality of expansion members 2 such that the remote alert module 4 forms a central controller.

The alert module 4 is configured - as discussed above - to transmit an alert signal in the event that both the first and second signals are received from the sensor mechanism 3 (or from one and the same sensor mechanism 3 in the event that the alert module 4 is associated with more than one sensor mechanism 3). In some embodiments, the first signal is received from a first sensor mechanism 3 and the second signal is received from a second sensor mechanism 3 (each sensor mechanism being associated with a different expansion member 2). The receipt of both first and second signals need not be contemporaneous. In embodiments, the first signal is received by the alert module 4 which is configured to record that the first signal has been received in a memory 41 of the alert module 4. Receipt of the first signal by the alert module 4 may cease and the alert module 4 may later receive the second signal (the receipt of which may or may not be recorded in the memory 41 ). The alert module 4 determines from the recorded receipt of the first signal in the memory 41 and receipt of the second signal (or its recorded receipt in the memory, if applicable) that both signals have been received and the alert signal is transmitted.

In some embodiments, the sensor mechanism 3 is configured to issue the first signal substantially continuously (perhaps for a predetermined period of time) after its issuance is triggered by the sensed expansion of the expansion member 2. Accordingly, the alert module 4 is configured such that it can receive the first and second signals contemporaneously and is configured to transmit the alert signal on receipt of the first and second signals contemporaneously.

In embodiments, the alert module 4 is communicatively coupled to a system 5 of the emergency services such that the alert module 4 is configured to transmit the alert signal to the system 5 of the emergency services. Thus, an automatic fire detection and emergency services alert system is provided.

The communication link between the alert module 4 and the system 5 of the emergency services may be a telephone link, an internet link, a radio link, or a microwave link - or any other wired or wireless link. The alert signal may, in some embodiments, include an identifier of the location of the fire detection system 1 , and/or the sensor mechanism(s) 3 which issued the first and second signals which triggered the transmission of the alert signal, and/or the expansion member 2 associated with the sensor mechanism(s) 3, and/or the alert module 4 which transmitted the alert signal. The identifier may comprise, for example, an street address or other geographical location. As such, the alert signal may be used to identify the location of the suspected fire. This location may be a generalised location (such as a street) or a more specific location (such as a specific building and/or floor and/or room). The alert signal may also include information such as the length of time between the issuance of the first signal and the second signal by the sensor mechanism(s) 3 and/or the first and second temperatures which would have caused the issuance of the first and second signals. The alert signal, therefore, may comprise one or more data packets.

The system 5 of the emergency services is configured to receive the alert signal and to bring the issuance (and, in some embodiments, the content) of the alert signal to the attention of the emergency services. The emergency services may, therefore, send a fire truck (of other emergency services vehicle and/or personnel) to the suspected location of the fire based on the information provided by the alert signal.

Thus, in operation, one or more expansion members 2 and associated sensor mechanism(s) 2 may be installed in a room of a building. In some embodiments, one or more expansion members 2 are installed such that they extend around a substantial part of the periphery of the room (or the substantially the entire periphery of the room) - for example, in a void 71 which is at least partially defined by coving 7. The sensor mechanism(s) 3 are coupled to one or more alert modules 4 by a communication link as described above. There may be an alert module 4 for each sensor mechanism 3; there may be an alert module 4 for a plurality of sensor mechanisms 3; there may be an alert module 4 for all of the sensor mechanisms 3 associated with a particular room or with a particular floor of a building or with a particular building.

If a fire occurs in a room in which an expansion member 2 and sensor mechanism 3 has been installed, then this will cause an increase in the temperature in at least part of that room. This increase in temperature will cause the temperature of the expansion member 2 to increase which will, in turn, cause expansion of the expansion member 2. If the expansion member 2 expands sufficiently, then the first signal is issued by the sensor mechanism 3 indicating to the alert module 4 that a first predetermined temperature has been reached. If the expansion member 2 expands still further then the second signal is issued by the sensor mechanism 3 indicating that a second predetermined temperature has been reached (the second predetermined temperature being higher than the first predetermined temperature). The sensor mechanism 3 and expansion member 2 are configured such that the first signal is issued in the event of the temperature of the expansion member 2 being representative of a fire having started in the room and the second signal is issued in the event of the temperature of the expansion member 2 being representative of a fire having spread in the room (i.e. the fire has not be extinguished and additional material is burning).

In some embodiments, the alert module 4 may be configured to transmit a warning signal to the system 5 of the emergency services on receipt of the first signal before the second signal has been received by the alert module 4. In embodiments, the alert module 4 includes a user interface 43 (or panel) which provides an indication (e.g. a visual or audible indication) of whether a first and/or second signal has been issued by any of the sensor mechanisms 3 associated therewith. The user interface 43 may also provide an indication (e.g. a visual or audible indication) that a warning or alert signal has been transmitted by the alert module 4. In some embodiments, the alert module 4 and system 5 of the emergency services can perform two-way communication such that the system 5 of the emergency services is configured to transmit an confirmation to the alert module 4 of receipt of the warning and/or alert signal, and/or confirmation that the emergency services have been dispatched, and/or a request for a user at the site of the alert module 4 to contact the emergency services (e.g. by telephone).

It will be appreciated that other arrangements of sensor mechanism 3 could be implemented in accordance with embodiments of the invention. For example, a single micro-switch 31 may be provided which is configured to be actuated by two different actuation elements 21 which are spaced apart from each other along a length of the expansion member 2. In other embodiments, the actuation elements 21 may comprise magnets and the pair of micro-switches 31 (or a single micro-switch 31 ) may, instead, be respective Reed switches. In some embodiments, the pair of micro-switches 31 (or a single micro-switch 31 ) may, instead, be another type of mechanical switch, such as a ball-switch, a PCB-switch, a plunger switch and so forth. Indeed, in some embodiments a mechanical switch need not be utilised at all. For instance, a non-contact switch may be used instead. Examples of non-contact switches may include ultrasonic sensors, light sensors, capacitive sensors, inductive sensors, photoelectric sensors and so forth.

The carrier 6, if provided, may have mounted thereto both the anchor member 64 and the sensor mechanism 3. An expansion of the carrier 6 would, therefore, impact on the temperatures at which the first and second signals are issued. This would need to be taken into account in the configuration of the sensor mechanism 3 and expansion member 2 with respect to the carrier 6. In embodiments, however, the carrier 6 is formed from a material which does not substantially expand when exposed to the temperatures normally associated with a house fire (or, at least, the temperatures normally associated with the start of a house fire).

In some embodiments, the expansion member 2 is replaceable such that the coupling between the anchor member 64 and the expansion member 2 can be decoupled and a different expansion member 2 can be coupled thereto. The carrier 6 may be configured to allow repeated replacement of the expansion member 2. In other embodiments, the replacement of the expansion member 2 is prohibited and the expansion member 2 cannot be de-coupled from the anchor member 64 without damaging the anchor member 64.

As will be appreciated, a power supply 8 is provided and coupled to the sensor mechanism 3 and to the alert module 4. In some embodiments, a plurality of sensor mechanisms 3 are coupled to the same power supply 8 which may be a different power supply 8 to the power supply 8 which is coupled to the alert module 4. In some embodiments, each sensor mechanism 3 has its own power supply 8. In embodiments, the power supply 8 or supplies 8 comprise one or more batteries and/or a mains electricity connection.

Aspects of the invention include coving 7 defining one or more apertures 71 . Other aspects of the invention include a room to which the fire detection system 1 has been fitted and a building to which the fire detection system 1 has been fitted.

Another aspect of the invention includes an expansion member 2 for removable coupling to the anchor member 64. Another aspect of the invention includes a carrier 6 suitable to receive an expansion member 2 or including such an expansion member 2 (the carrier 6 may include the sensor mechanism 3 or a mounting arrangement 65 to receive a sensor mechanism 3). In the described embodiments, the expansion member 2 and sensor mechanism 3 (and carrier 6 if provided) are located in a void 71 defined by the ceiling 92, wall 93 and coving 7 (and mounts 73 if provided). However, it is to be understood that in some embodiments the expansion member 2 and sensor mechanism 3 (and carrier 6 if provided) may be located in a void defined by alternative components. For instance, the coving 7 may be replaced by a different form of covering such as a panel or tiling or the like. Indeed, whilst it is preferred to locate the expansion member 2 and sensor mechanism 3 (and carrier 6 if provided) in a void between the ceiling 92 and wall 93 of a room, in some embodiments the components may be located between the floor and wall of a room, such as in a void located behind a skirting board.

In the above described embodiments, first and second signals are issued by the sensor mechanism 3. In some embodiments, it is envisaged that a third signal may also be issued on the sensing, by the sensor mechanism 3, of a third predetermined expansion of the expansion member 2 (the third predetermined expansion being an expansion with respect to the normal condition which is greater than the second predetermined expansion and which, therefore, represents a third temperature). Yet further signals may also be issued in a similar manner by the sensor mechanism 3. The sensor mechanism 3 may, therefore, include a third - or more - micro-switches 31 for example (and there may be a third - or more - actuation elements 21 too). The alert module 4 may be configured to issue the alert signal only after a predetermined number of the signals from the sensor mechanism 3 have been received. The alert module 4 may be configured to issue a warning signal once a lower predetermined number of such signals have been received (which may include one such signal). The alert module 4 may be further configured to transmit one or more progress signals (e.g. to the system 5 of the emergency services) once one or more further signals are received from the sensor mechanism 3 after the alert signal has already been transmitted (in order to give the emergency services further information about the intensity and/or spread of the fire).

In embodiments, the warning signal transmitted by the alert module 4 may trigger the activation of an evacuation alarm (visual and/or audible) by the fire detection system 1 . In embodiments, the evacuation alarm is triggered by transmission of the alert signal by the alert module 4. In embodiments, an aspect of the evacuation alarm (e.g. frequency) may increase if an alert signal and/or progress signal is transmitted after the evacuation alarm is activated. The fire detection system 1 may be configured to control the operation of the evacuation alarm in the aforementioned embodiments.

When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1 . A fire detection system comprising:

an expansion member which is configured to expand from a normal condition by predetermined amounts when exposed to temperatures associated with a fire;

a sensor mechanism which is configured to issue a first signal on sensing a first predetermined expansion of the expansion member from the normal condition, and to issue a second signal on sensing a second predetermined expansion of the expansion member from the normal condition, the second predetermined expansion from the normal condition being greater than the first predetermined expansion from the normal condition; and

an alert module configured to transmit an alert signal after both the first and second signals have been received.

2. A fire detection system according to claim 1 , wherein the expansion member is a linear elongate expansion member which is configured to increase in length when heated.

3. A fire detection system according to claim 2, wherein the linear elongate expansion member is tethered by an anchor member to a carrier at a first end of the linear elongate expansion member and the sensor mechanism is positioned towards a second end of the linear expansion member.

4. A fire detection system according to claim 3, wherein the sensor mechanism is mounted on the carrier.

5. A fire detection system according to claim 2 or 3, wherein the carrier includes a plurality of mounting guides which are configured to support the linear elongate expansion member between the first and second ends thereof.

6. A fire detection system according to any preceding claim, configured to issue the first signal upon the expansion member expanding a distance from the normal condition, which distance corresponds to a temperature increase of between about 10 and about 15 degrees Celsius.

7. A fire detection system according to any preceding claim, configured to issue the second signal upon the expansion member expanding a distance from the normal condition, which distance corresponds to a temperature increase of between about 20 and about 35 degrees Celsius.

8. A fire detection system according to any preceding claim, wherein the alert module is coupled to a communications link and is configured to transmit the alert signal via the communications link.

9. A fire detection system according to claim 8, wherein the communications link is between the fire detection system and a system of the emergency services such that the transmission of the alert signal automatically alerts the emergency services to the fire.

10. A fire detection system according to any preceding claim, wherein the expansion member is formed from chlorinated polyvinyl chloride (CPVC).

1 1 . A fire detection system according to any preceding claims, wherein the expansion member and sensor mechanism are configured to be located within a void at least partially defined by coving.

12. A fire detection system according to claim 1 1 , wherein the coving defines one or more apertures to provide one or more passageways through the coving from a first side of the coving to a second side of the coving opposite to the first side.

13. A fire detection system according to claim 1 1 , further including one or more mounts eatable between the coving and a ceiling / wall, for mounting the coving to the ceiling / wall, wherein the or each mount defines an aperture to provide a passageway through the mount from a first side of the mount to a second side opposite to the first side.

14. A fire detection system according to any preceding claim, wherein the sensor mechanism is configured to issue a third signal on sensing a third predetermined expansion of the expansion member from the normal condition, and, the third predetermined expansion from the normal condition being greater than the second predetermined expansion from the normal condition.

15. A fire detection system according to claim 14, wherein the alert module is configured to transmit an alert signal after the third signal has been received.

16. A fire detection system according to claim 14 or claim 15, configured to issue the third signal upon the expansion member expanding a distance from the normal condition, which distance corresponds to a temperature increase of between about 30 and about 55 degrees Celsius.

17. A room including a fire detection system according to any preceding claim.

18. A building including a fire detection system according to any of claims 1 to 15.

19. A carrier for use in a fire detection system according to any of claims 1 to 16, the carrier including:

a mounting arrangement configured to receive the sensor mechanism; and an anchor member configured to tether at least part of the expansion member with respect to the carrier.

20. A carrier according to claim 19, further including the expansion member.

21 . An expansion member for use with a carrier according to claim 19 or 20.

22. A fire detection system substantially as herein described with reference to the accompanying drawings.

23. A room substantially as herein described with reference to the accompanying drawings.

24. A building substantially as herein described with reference to the accompanying drawings.

25. A carrier substantially as herein described with reference to the accompanying drawings.

26. An expansion member substantially as herein described with reference to the accompanying drawings.

27. Any novel feature or novel combination of features disclosed herein.