GB2591586A

GB2591586A - A Detector for a Fire Alarm System

Info

Publication number: GB2591586A
Application number: GB2018915.5A
Authority: GB
Inventors: Cain Stuart
Original assignee: Project Fire Global Holdings Ltd
Current assignee: Project Fire Global Holdings Ltd
Priority date: 2019-12-06
Filing date: 2020-12-01
Publication date: 2021-08-04
Anticipated expiration: 2040-12-01
Also published as: GB201917883D0; EP4070296A1; WO2021111119A1; GB2591586B; GB202018915D0

Abstract

A detector 10 for a fire alarm system 100 is provided comprising a housing 12 including a first and second sensing element 14A,14B. The first and second sensing element 14A,14B comprise one or more different operating characteristics. Upon detection of a fire by the first 14A or second 14B sensing element, a first alarm response is generated. Upon detection of a fire by both the first and second sensing elements 14A,14B a second alarm response is generated. The different operating characteristics may be an orientation of the first and second sensing elements 14A,14B within the housing 12. The first and second sensing elements 14A,14B may have opposing or orthogonal configurations. The first alarm response may be a local warning. The second alarm response may be a remote warning to an external party. The first and second sensing elements 14A,14B may comprise the same sensor type and may be a temperature sensor, a sprinkler bulb, or an optical sensor. The use of more than one sensing element reduces the likelihood of a false alarm.

Description

A Detector for a Fire Alarm System

Technical Field of the Invention

The present invention relates to a detector for a fire alarm system, and in particular, to a detector comprising multiple sensing elements.

Background to the Invention

It is known to provide fire alarm systems having multiple detectors Each detector typically includes a single sensor, which might be a temperature sensor or an optical sensor, for example. Upon triggering of such a sensor, the fire alarm system may perform a given action which typically includes sounding of an audible alarm, illumination of a warning light, activation of an associated sprinkler system and/or activation of an external alarm, e.g. to a nominated contact and/or an emergency service provider.

For fire alarm systems it is essential that each and every true incident causes a response from the fire alarm system. However, as the same time, it is desirable to reduce the number of false alarms provided to prevent such responses being performed when unnecessary. Where the response consists of a visual or audible alert this may cause annoyance for the user. Where the response causes false activation of a sprinkler system and/or contact of an emergency service provider the consequences can be more serious.

More recently, systems have been developed where a failsafe has been built into fire alarm systems requiring the triggering of multiple detectors before certain responses are performed. This has been shown to reduce the occurrence of false alarms, however, it would be advantageous to provide a detector (and an associated fire alarm system) configured such that the likelihood of false alarms is prevented further.

It is therefore an aim of an embodiment or embodiments of the invention to overcome or at least partially mitigate one or more problems associated with the prior art.

Summary of the Invention

According to an aspect of the invention there is provided a detector for a fire alarm system, the detector comprising a housing; and a first sensing element and a second sensing element provided within the housing, the first and second sensing elements being configured to detect a fire by monitoring one or more parameters indicative of a fire within a monitored environment; wherein the first and second sensing elements comprise one or more different operating characteristics; and wherein the detector is configured, in use, to cause performance of a first alarm response of the fire alarm system upon detection of a fire by the first or second sensing element, and to cause performance of a second alarm response of the of the fire alarm system upon detection of a fire by both the first and second sensing elements.

Advantageously, utilising two (or more) sensing elements reduces the likelihood of false triggering of the second alarm response as it requires both the first and second sensing elements to detect the fire before that response is performed. Having the first and second sensing elements having different operating characteristics reduces the likelihood of both sensing elements malfunctioning at the same time or for the same reason (which may cause a false alarm). Furthermore, providing both first and second sensing elements within a single detector housing provides for reduced false alarms whilst at the same time not relying on detection of a fire by two spatially separated detectors, potentially reducing the size or extent of a fire required to trigger the second alarm response.

The one or more different operating characteristics may comprise an orientation of the first and second sensing elements within the housing. For example, the first and second sensing elements may be positioned with different orientations within the housing. The first and second sensing elements may be positioned within the housing with opposing orientations. In some embodiments the first and second sensing elements may be positioned with orthogonal orientations. The first sensing element may be provided substantially vertical, in use, within the housing with the second sensing element provided substantially horizontal, in use, within the housing, or vice versa. Advantageously, two differently orientated sensing elements may have a different impact response for any given external impact on the detector, thereby reducing the likelihood of a single impact breaking or potentially triggering both sensing elements causing a false alarm.

The one or more different operating characteristics may comprise a configuration of control circuitry associated with the first or second sensing elements. In embodiments, the detector comprises a first control circuit associated with the first sensing element and a second control circuit associated with the second sensing element. The first and second control circuits may comprise one or more electrical contacts. The one or more electrical contacts may be biased -e.g. they may be biased to an open or closed position. The one or more electrical contacts may be spring biased. The one or more electrical contacts may move against said bias upon detection of a fire by the respective sensing element. In embodiments, one or more electrical contacts of the first control circuit are biased to a closed position, in use, and one or more electrical contacts of the second control circuit are biased to an open position, in use, or vice versa.

The first alarm response may comprise a local response. When used here and throughout the specification the term "local response" may mean a response which is provided within the monitored environment. For example, the first alarm response may be an audible or visual warning provided within the environment, or within a sub-region within the monitored environment -e.g. a sub-region associated with the detector which does not necessarily include the whole of the environment monitored by the fire alarm system.

The second alarm response may comprise an external response. When used here and throughout the specification the term "external response" may mean a response with involves some form of communication with one or more parties external to the monitored environment -e.g. providing a notification or alert to a nominated party and/or an emergency service provider. In embodiments, the second alarm response may comprise activation of an associated sprinkler system, for example.

The first and/or second alarm response may comprise outputting a signal to a building control unit. The building control unit may be accessible, in use, by an emergency service provider, for example. The building control unit may subsequently be used to control movement of building occupants, e.g. an evacuation from the building in dependence on the signals received from the detector.

In embodiments the first and second sensing elements comprise the same sensor type.

The first and/or second sensing element may comprise a temperature sensor. In such embodiments, the or each temperature sensor may be configured to monitor a temperature associated with the monitored environment. For example, the or each temperature sensor may be operable to monitor the temperature of gases entering the housing. The detector may be configured such that the presence of a fire may be detected in dependence on the monitored temperature. For example, the monitored temperature may be compared with a threshold temperature value, with a fire being detected in dependence on the monitored temperature exceeding that threshold temperature value.

In embodiments where both the first and second sensing elements comprise a temperature sensor, the first and second sensing elements may be operable to compare the monitored temperature against the same threshold temperature value In other embodiments, the first sensing element may be operable to compare a monitored temperature with a first threshold temperature value, whereas the second sensing element may be operable to compare a monitored temperature with a second threshold temperature value The first and/or second sensing elements may comprise a bulb, such as a glass bulb conventionally used as part of a sprinkler head. For example, the bulb may comprise a liquid therein which may expand (or contract) with temperature. At higher temperatures (e.g. temperatures significantly above a standard temperature for the monitored environment) the liquid inside the bulb may expand to such an extent that the bulb breaks. In some embodiments, the first and/or second sensing element may be /5 configured such that breaking of the bulb causes opening or closing of a corresponding control circuit -e.g. opening or closing of corresponding electrical contacts. In this way, the temperature of the monitored environment may be used to detect the presence of a fire. Advantageously, a bulb of this type may provide a relatively quick response time to a temperature rise in the monitored environment.

The first and/or second sensing element may comprise an optical sensor. In embodiments the or each optical sensor may be configured to monitored an optical parameter associated with the monitored environment. The or each optical sensor may comprise an optical sensor of the type typically used in smoke alarms for detecting the presence of smoke, and hence a fire in the monitored environment. In embodiments, the or each optical sensor may comprise an infrared sensor, or a thermal sensor for

example.

The first and/or second sensing element may comprise an electrical sensor. For example, the or each electrical sensor may comprise an ionisation-type sensor configured to detect the presence of smoke or the like in a monitored environment The housing may comprise a protective housing for the first and second sensing elements. The protective housing may be configured to prevent or reduce the likelihood of damage to the first and/or second sensing elements, e.g. through accidental impact or the like. In embodiments, the housing may enclose the first and second sensing elements. The housing may be provided with one or more vents therein allowing for gas from the monitored environment to enter the housing. For example, and as discussed herein, the first and/or second sensing elements may comprise a temperature or optical sensor. As such, the housing may be configured to provide both a protective enclosure for the sensing elements whilst still allowing the sensing elements to monitor the one or more parameters.

The housing may be formed of a plastics material. In presently preferred embodiments, the housing is formed of metal.

The housing may comprise one or more fixing means. The one or more fixing means may correspond to fixing means used in existing detector fittings. Advantageously, the housing may be configured such that the detector may be retrofit in existing buildings and may possibly be integrated with existing fire alarm systems of such buildings The detector may be operable to output a control signal for performing the first alarm response and/or the second alarm response. The detector may be operable to output the control signal via a wired or wireless connection. The detector may comprise a control unit for generating and outputting the control signal. The control unit may be operable to generate and output the control signal in dependence on one or more status signals received from the first and/or second sensing elements corresponding to a detection status of the sensing element. Here, the first and/or second sensing elements are operable to output a status signal indicative of its detection state. The first and/or second sensing element (e.g. a control circuit associated therewith) may be configured such that the status signal is output upon detection of a fire by the sensing element or unless a fire is detected by the sensing element. The control unit may be operable to infer detection of a fire by a respective sensing element in dependence on receipt (or ceasing to receive) the status signal.

In alternative embodiments control of the associated fire alarm system is I 0 performed, in use, via an external control unit, and in such embodiments the detector may be configured such that the control unit of the detector is operable to output the control signal to the external control unit, or the first and/or second sensing elements are operable to output a status signal(s) to the external control unit.

According to a further aspect of the invention there is provided a fire alarm system comprising a detector of any aspect described herein The fire alarm system may comprise one or a plurality of detectors of any aspect described herein. In embodiments the fire alarm system may comprise one or more other detector types -e.g. conventional, single sensor detectors. In such embodiments, the fire alarm system may be configured such that performance of the first and/or second alarm response is controlled in dependence on a detection status of at least one detector of the present invention and at least one other detector -e.g. at least one conventional, single sensor detector. In embodiments, the fire alarm system comprises three separate detector types, at least one of which comprises a detector of the present invention. Advantageously, the fire alarm system may use both conventional detectors and detectors of the present invention in combination therewith, each requiring different triggers to activate respective sensing elements, to improve performance and reduce false alarms. For instance, the use of different detector types having different triggers may reduce or eliminate the possibility of a single even falsely activating a detector.

The fire alarm system may comprise a central control unit. The central control unit may be operable to receive one or more signals from the or each detector of the fire alarm system. The central control unit may be operable to receive signal(s) from a local control unit associated with the (or each) detector, or directly from first and/or second sensing elements of the (or each) detector.

The central control unit may be operable to output one or more control signals for controlling operation of one or more components of the fire alarm system to perform the first and/or second alarm response. The central control unit may be operable to generate and output the control signal in dependence on one or more status signals received from the first and/or second sensing elements corresponding to a detection status of the sensing element. Here, the first and/or second sensing elements are operable to output a status signal indicative of its detection state. The first and/or second sensing element (e.g. a control circuit associated therewith) may be configured such that the status signal is output upon detection of a fire by the sensing element or unless a fire is detected by the sensing element. The central control unit may be operable to infer detection of a fire by a respective sensing element in dependence on receipt (or ceasing to receive) the status signal.

The central control unit may be operable to control operation of the fire alarm system as a whole, e.g. to temporarily disable the fire alarm system. Advantageously, the central control unit may be operable to allow for one or more detectors of the system to be removed, repaired and/or replaced.

In embodiments, the first alarm response may comprise a local response. For example, in some embodiments the first alarm response may be an audible or visual warning provided within the environment, or within a sub-region within the monitored environment -e.g. a sub-region associated with the detector which does not necessarily include the whole of the environment monitored by the fire alarm system. In such embodiments the fire alarm system may include one or more visual or audio output means e.g. one or more lights or speakers/alarms positioned within the environment.

In embodiments, the second alarm response may comprise an external response, which may include providing a notification or alert to a nominated party and/or an emergency service provider. In such embodiments the fire alarm system may include the central control unit, wherein the central control unit is configured to communicate with an external party (e.g. over a wireless telecommunication network) in performing the second alarm response. In embodiments, the fire alarm system may comprise a sprinkler system, and the second alarm response may comprise activation of the sprinkler system, for example.

The fire alarm system may comprise a building control unit. The building control unit may be accessible, in use, by an emergency service provider, for example.

The building control unit may subsequently be used to control movement of building occupants, e.g. an evacuation from the building in dependence on the signals received from the detector.

According to another aspect of the invention there is provided a control system for a fire alarm system of any aspect described herein, the control system comprising one or more controllers, and being configured to: receive a first input signal from the first sensing element, the first input signal comprising information indicative of the one or more parameters monitored by the first sensing element; receive a second input signal from the second sensing element, the second input signal comprising information indicative of the one or more parameters monitored by the second sensing element; determine whether the first and/or second sensing element has detected a fire in dependence on the received first and/or second input signals; and generate an output signal for causing performance of a first alarm response of the fire alarm system upon detection of a fire by the first or second sensing element, and/or for causing performance of a second alarm response of the of the fire alarm system upon detection of a fire by both the first and second sensing elements.

In embodiments, the one or more controllers collectively comprise: at least one electronic processor having an electrical input for receiving the first and/or second input signals. The one or more controllers may collectively comprise at least one electronic memory device electrically coupled to the at least one electronic processor and having instructions stored therein. The at least one electronic processor may be configured to access the at least one memory device and execute the instructions thereon so as to generate the control signal for causing performance of the first and/or second alarm response.

The control system may be configured to receive first and/or second input signals from a plurality of detectors, e.g. a plurality of detectors according to an aspect described herein, and/or optionally one or more conventional, single sensor detectors.

The control system may be operable to receive the first and/or second input signals directly from the first and second sensing elements. In embodiments, the (or each) detector may comprise a local control unit and the control system may be operable to receive the first and/or second input signals indirectly via the local control unit(s).

The control system may comprise an output (e.g. an electrical output) to output the control signal for controlling operation of one or more components of the fire alarm system to perform the first and/or second alarm response.

In embodiments, the control system may be configured to generate and optionally output the control signal in dependence on first and/or second input signals in the form of one or more status signals received from the first and/or second sensing elements corresponding to a detection status of the sensing element. Here, the first and/or second sensing elements are operable to output a status signal indicative of its detection state. The first and/or second sensing element (e.g. a control circuit associated therewith) may be configured such that the status signal is output upon detection of a fire by the sensing element or unless a fire is detected by the sensing element. The central control unit may be operable to infer detection of a fire by a respective sensing element in dependence on receipt (or ceasing to receive) the status signal.

In embodiments, the first alarm response may comprise a local response. For example, in some embodiments the first alarm response may be an audible or visual warning provided within the environment, or within a sub-region within the monitored environment -e.g. a sub-region associated with the detector which does not necessarily include the whole of the environment monitored by the fire alarm system. In such embodiments the control system may be operable to generate and output a control signal for controlling operation of one or more visual or audio output means e.g. one or more lights or speakers/alarms positioned within the environment.

In embodiments, the second alarm response may comprise an external response, which may include providing a notification or alert to a nominated party and/or an emergency service provider. For example, the control system may be operable to generate and output a control signal for a communications module of the control system or the fire alarm system as a whole. In such embodiments the control system may be operable to communicate with an external party (e.g. over a wireless telecommunication network using the communication module) in performing the second alarm response. In embodiments, the fire alarm system may comprise a sprinkler system, and the control system may be operable to generate and output a control signal for controlling activation of the sprinkler system, for example.

The fire alarm system may comprise a building control unit. The building control unit may be accessible, in use, by an emergency service provider, for example. The building control unit may subsequently be used to control movement of building occupants, e.g. an evacuation from the building in dependence on the signals received from the detector. In such embodiments, the control system may be operable to generate and output a control signal for controlling operation of, or communicating with the building control unit.

According to an aspect of the invention there is provided a method for monitoring an environment using a fire alarm system of any aspect described herein, the method comprising: using the first and second sensing elements of the detector to monitor one or more parameters indicative of a fire within the environment; and performing a first alarm response of the fire alarm system upon detection of a fire by the first or second sensing element, and performing of a second alarm response of the of the fire alarm system upon detection of a fire by both the first and second sensing elements.

The method may comprise utilising a plurality of detectors to monitor the environment. The plurality of detectors may comprise a plurality of detectors according to an aspect described herein, and/or optionally one or more conventional, single sensor detectors.

In embodiments, the first alarm response may comprise a local response. For example, in some embodiments the first alarm response may be an audible or visual warning provided within the environment, or within a sub-region within the monitored environment -e.g. a sub-region associated with the detector which does not necessarily include the whole of the environment monitored by the fire alarm system. In such embodiments the method may comprise controlling operation of one or more visual or audio output means e.g. one or more lights or speakers/alarms positioned within the environment. Ii

In embodiments, the second alarm response may comprise an external response, which may include providing a notification or alert to a nominated party and/or an emergency service provider. For example, the method may comprise communicating with an external party in performing the second alarm response. In embodiments, the fire alarm system may comprise a sprinkler system, and the method may comprise controlling activation of the sprinkler system, for example.

The fire alarm system may comprise a building control unit. The building control unit may be accessible, in use, by an emergency service provider, for example. The method may comprise using the building control unit to control movement of building occupants, e.g. an evacuation from the building. In such embodiments, the method may comprise controlling operation of, or communicating with the building control unit.

Detailed Description of the Invention

In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a schematic representation of an embodiment of a detector of the invention, Figure 2 is a schematic representation of an embodiment of a control system of the invention; Figure 3 is a schematic representation of an embodiment of a fire alarm system of the invention; and Figure 4 is a flowchart illustrating an embodiment of a method of the invention.

In general, the invention relates to a detector 10 for a fire alarm system 100. The detector 10 includes first and second sensing elements 14a, 14b for detecting the occurrence of a fire in a monitored environment. Depending on whether neither, one or both sensing elements 14a, 14b detects a fire, the fire alarm system 100 is controlled in a different manner to perform different alarm responses.

Figure 1 is a schematic representation of a detector 10 of the invention. The detector 10 includes a housing 12 within which are positioned first and second sensing elements in the form of a first sprinkler bulb 14a and a second sprinkler bulb 14b.

The housing 12 is formed of metal and forms a protective enclosure for the first and second sprinkler bulbs 14a, 14b. Advantageously, the housing 12 may significantly reduce the likelihood of the sprinkler bulbs 14a, 14b breaking through (accidental) contact with an external object. Vents 15 are provided in a lower surface of the housing 12 to allow gases to enter the interior of the housing 12 for monitoring by the sprinkler bulbs 14a, 14b.

The sprinkler bulbs 14a, 14b in the illustrated embodiment are configured similarly to conventional glass sprinkler-head bulbs having a volume of liquid contained therein which may expand (or contract) with temperature as will be appreciated. Upon reaching a given temperature the expansion of the liquid within the bulbs 14a, 14b is such that the bulb 14a, 14b breaks under the resultant pressure. The breaking (or "popping") of the bulb 14a, 14b can therefore be used as an indicator of the temperature of the monitored environment. Here, breaking of the sprinkler bulbs 14a, 14b is detected via respective first and second control circuits (not shown). The control circuits include electrical contacts which can open or close in dependence on whether the respective sprinkler bulb 14a, 14b has broken. Information indicative of the operational state of the electrical contacts (and hence the state of the bulbs 14a, 14b) is output as signal 20 and is used to control performance of a first and/or second alarm response depending on whether neither, one or both of the sprinkler bulbs 14a, 14b has detected a fire.

As shown, sprinkler bulb 14a is positioned within the housing 12 in a first orientation, here being a substantially vertical orientation which respect to the detector's orientation, in use. Sprinkler bulb 14b is positioned within the housing 12 in a second orientation, perpendicular to the first, as shown. Advantageously, having the first and second sensing elements having different operating characteristics, specifically having the bulbs 14a, 14b positioned orthogonal to one another, reduces the likelihood of both bulbs malfunctioning at the same time or for the same reason -e.g. accidental impact (which may otherwise cause a false alarm).

In a variant, the different operating characteristics of the bulbs 14a, 14b may alternatively (or additionally) comprise the configuration of respective control circuits of the first and second sprinkler bulbs 14a, 14b. For instance, a first control circuit associated with the first sprinkler bulb 14a and a second control circuit associated with the second sprinkler bulb 14b can be provided, each including one or more electrical contacts. In some instances, the one or more electrical contacts may be biased -e.g. they may be biased (e.g. spring biased) to an open or closed position, and may move against said bias upon detection of a fire by the respective sprinkler bulb 14a, 14b. The electrical contact(s) of the first control circuit may be biased to a closed position, in use, and electrical contact(s) of the second control circuit may be biased to an open position, in use, or vice versa. Such an arrangement is shown in Figure 5.

Specifically, Figure 5 shows a detector 300 of the invention. The detector 300 includes a housing 312 within which are positioned first and second sensing elements in the form of a first sprinkler bulb 314a and a second sprinkler bulb 314b. As with the housing 12 of Figure 1, the housing 312 is formed of metal and forms a protective enclosure for the first and second sprinkler bulbs 314a, 314b. Similarly, vents 315 are provided in a lower surface of the housing 12 to allow gases to enter the interior of the housing 312.

The sprinkler bulbs 314a, 314b are configured similarly to conventional glass sprinkler-head bulbs having a volume of liquid contained therein which may expand (or contract) with temperature as will be appreciated. As shown, the sprinkler bulbs 314a, 314b are positioned between respective spring-loaded contacts 313a, 315a; 313b, 315b, retaining the contacts in an open position in normal use. Upon reaching a given temperature the expansion of the liquid within the bulbs 314a, 314b is such that the bulb 314a, 314b breaks under the resultant pressure. In this variant, breaking of the sprinkler bulbs 314a, 314b allows respective first and second contacts 313a, 315a; 313b, 315b to close under the bias provided thereto. Closure of the contacts 313a, 315a; 313b, 315b causes output signal 320 to be output to a fire alarm system 100 and is used to control performance of a first and/or second alarm response depending on whether neither, one or both of the sprinkler bulbs 314a, 314b has detected a fire.

As with sprinkler bulbs 14a, 14b of the detector 10, the sprinkler bulbs 314a, 314b are positioned within the housing 12 in opposing orientations, specifically a substantially horizontal orientation and a substantially vertical orientation which respect to the detector's orientation, in use.

Advantageously, having the sensing elements having different operating characteristics, specifically having the bulbs 14a, 14b or associated control circuits biased in opposite senses reduces the likelihood of both bulbs 14a, 14b or control circuits malfunctioning at the same time or for the same reason (which may otherwise cause a false alarm).

In the illustrated embodiment, the signal 20 is output from the detector 10 directly or indirectly to a fire alarm system, e.g. fire alarm system 100 or via a control system 50 as described herein. As discussed herein, the signal 20 is indicative of the operational state (e.g. a detection state) of the sprinkler bulbs 14a, 14b and is used to control performance of a first and/or second alarm response depending on whether neither, one or both of the sprinkler bulbs 14a, 14b has detected a fire.

Figure 2 illustrates an embodiment of a control system 50 in accordance with the invention The control system 50 includes a controller 52 having a processor 54. The processor 54 is operably coupled to an electrical input 56 for receiving an input signal which, in the illustrated embodiment comprises signal 20 from the detector 10. In use, the input signal 20 comprises data indicative of an operational state of the first and/or second sprinkler bulb 14a, 14b. The input signal 20 is received directly or indirectly (e.g. via a separate controller) from control circuits associated with the sprinkler bulbs 14a, 14b.

The controller 52 includes a memory device 60 electrically coupled to the processor 54 and includes instructions 62 stored therein. The instructions 62 relate to operating instructions for controlling performance of the first and/or second alarm response (Figure 4) In use, the processor 54 is configured to access the memory device 60 and execute the instructions 62 in order to generate a control signal 22 for controlling

IS

performance of the alarm response(s). The control signal 22 is output via electrical output 58.

As discussed, the controller 52 is configured to receive the input signal 20 from detector 10, and in particular from each of the control circuits associated with the first and second sprinkler bulbs 14a, 14b. The processor 54 is configured to analyse the input signal 20 to determine whether one or both of the sprinkler bulbs Na, 14b has broken, and hence detected the presence of a fire in the monitored environment. The processor 54 then generates and outputs the control signal 22 based on this determination to control performance of the first and/or second alarm response (Figure 4).

Figure 3 illustrates an embodiment of a fire alarm system 100 in accordance with the invention. The fire alarm system 100 includes a plurality of detectors 10a, 10b, 10c, the control system 50, an alert system 102, a sprinkler system 104 and a communication module 106.

Detectors 10a, 10b, 10c are each equivalent to detector 10 shown in the preceding Figures and are, in use, positioned at different locations within a monitored environment. Each of the detectors 10a, 10b, 10c is operable to output a signal 20a, 20b, 20c. Each of the signals 20a, 206, 20c are indicative of the operational state (e.g. a detection state) of the respective sprinkler bulbs 14a, 14b of each of the detectors 10a, 10b, 10c and is used to control performance of a first and/or second alarm response as discussed herein. Signals 20a, 20b, 20c are received at input 56 of control system 50 as input signal 20.

The alert system 102 is provided within (or otherwise associated with) the monitored environment and includes one or more visual and/or audible alert means -e.g. lights, alarms and the like which may be activated as part of an alarm response, specifically, and as discussed herein, as part of a first alarm response. Likewise, the sprinkler system 104 is provided within the monitored environment and is activated as part of an alarm response. Here, the sprinkler system is activated as part of a second alarm response -i.e, to prevent inadvertent activation of the sprinkler system. Communication module 106 need not be provided within the monitored environment but is communicably coupled to the control system 50. The purpose of the communication module 106 is to communicate with an external party as part of an alarm response, and specifically as part of a second alarm response as discussed herein.

The apparatus 100 is controllable via control system 50.

Specifically, electrical input 56 of the controller 52 is operatively coupled to the plurality of detectors 10a, 10b, 10c. As discussed herein, the input signal 20 received from the plurality of detectors 10a, 10b, 10c comprises data indicative of the operational state (e.g. a detection state) of respective sprinkler bulbs 14a, 14b of the detectors 10a, 10b, 10c and is used to control performance of a first and/or second alarm response depending on whether neither, one or both of the sprinkler bulbs 14a, 14b has detected a fire. The processor 54 is configured to analyse the input signal 20 to determine which (if any) detector 10a, 10b, 10c has detected a fire and whether the first and/or second sprinkler bulb 14a, 14b of the relevant detector 10a, 10b, 10c has broken. From this, a determination is made as to whether a first alarm response or second alarm response is required, and in dependence on this determination the processor 54 is configured to generate and output the control signal 22 to one or more of the alert system 102, sprinkler system 104 and/or communication module 106 to control operation thereof in accordance with one or more predetermined actions.

Figure 4 illustrates an embodiment of a method 200 of the invention for monitoring an environment using the fire alarm system 100 shown in Figure 3 At step 202, the method comprises monitoring one or more parameters indicative of a fire within the environment. In this embodiment, the one or more parameters comprise temperature monitored using detectors 10a, 10b, 10c, and specifically sprinkler bulbs 14a, 14b of those detectors 10a, 10b, 10c as discussed herein.

At step 204, the method 200 comprises determining whether the first sensing element, here the first sprinkler bulb 14a, has detected the presence of a fire within the environment. Specifically, step 204 comprises determining whether the first sprinkler bulb 14a of any of the detectors 10a, 10b, 10c has broken At step 206, the method 200 comprises determining whether the second sensing element, here the second sprinkler bulb 14b, has detected the presence of a fire within the environment. Specifically, step 206 comprises determining whether the second sprinkler bulb 14b of any of the detectors 10a, 106, 10c has broken.

If neither the first sprinkler bulb 14a nor the second sprinkler bulb 14b has broken the method proceeds to step 208 where it is determined that there is no fire and therefore no action is taken.

If either the first sprinkler bulb 14a or the second sprinkler bulb 14b, but not the other sprinkler bulb 14a/14b is determined to have broken, the method moves on to step 210. Here, it is determined that there may be a possible false alarm given only one of the two co-located sprinkler bulbs 14a, 14b has triggered. In this case, a first alarm response is initiated.

As discussed herein, the first alarm response preferably consists of a local response. In the illustrated embodiments, the local response includes controlling the alert system 102 to provide an audible or visual warning within the environment. In this way, an alert may be provided to encourage or instruct occupants of the monitored environment to investigate the cause of the alarm further. Preferably, the first alarm response does not include control of the sprinkler system 104 and/or the communication module 106 given that a first alarm response corresponds to a situation wherein the fire alarm system 100 has detected the possibility of a false triggering of a given detector 10a, 10b, 10c.

If both the first sprinkler bulb 14a and the second sprinkler bulb 14b of a given detector 10a, 10b, 10c is determined to have broken, the method moves on to step 212. Here it is determined (with greater confidence than in prior art systems) that there is a fire given both bulbs 14a, 14b have triggered. In this case, a second alarm response is initiated As discussed herein, the second alarm response preferably consists of an external response. In the illustrated embodiments, the external response includes controlling the communication module 106 to issue an alert to a nominated external party, such as an emergency service provider. Additionally, the sprinkler system 104 may be triggered and in some instances one or more actions forming part of the first alarm response may also be performed as appropriate.

The one or more embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

CLAIMSA detector for a fire alarm system, the detector comprising: a housing; and a first sensing element and a second sensing element provided within the housing, the first and second sensing elements being configured to detect a fire by monitoring one or more parameters indicative of a fire within a monitored environment; wherein the first and second sensing elements comprise one or more different operating characteristics; and wherein the detector is configured, in use, to cause performance of a first alarm response of the fire alarm system upon detection of a fire by the first or second sensing element, and to cause performance of a second alarm response of the of the fire alarm system upon detection of a fire by both the first and second sensing elements 2. A detector as claimed in claim 1, wherein the one or more different operating characteristics comprise an orientation of the first and second sensing elements within the housing 3. A detector as claimed in claim 2, wherein the first and second sensing elements are positioned within the housing with opposing or orthogonal orientations 4. A detector as claimed in claim 3, wherein the first sensing element is provided substantially vertical, in use, within the housing with the second sensing element provided substantially horizontal, in use, within the housing, or vice versa.5. A detector as claimed in any preceding claim, wherein the one or more different operating characteristics comprise a configuration of control circuitry associated with the first or second sensing elements.A detector as claimed in claim 5, comprising a first control circuit associated with the first sensing element and a second control circuit associated with the second sensing element, the first and second control circuits comprising one or more electrical contacts A detector as claimed in claim 6, wherein the one or more electrical contacts are biased, preferably spring biased, to an open or closed position A detector as claimed in claim 7, wherein the one or more electrical contacts may be spring biased are operable to move against said bias upon detection of a fire by the respective sensing element.A detector as claimed in claim 7 or claim 8, wherein one or more electrical contacts of the first control circuit are biased to a closed position, in use, and one or more electrical contacts of the second control circuit are biased to an open position, in use, or vice versa.10. A detector as claimed in any preceding claim, wherein the first alarm response comprises a local response.11. A detector as claimed in any preceding claim, wherein the second alarm response comprises an external response.12. A detector as claimed in any preceding claim, wherein the first and/or second IS alarm response comprises outputting a signal to a building control unit.13. A detector as claimed in any preceding claim, wherein the first and second sensing elements comprise the same sensor type 14. A detector as claimed in any preceding claim, wherein the first and/or second sensing element comprise a temperature sensor.15. A detector as claimed in claim 14, wherein the first and/or second sensing elements comprise a sprinkler bulb 16. A detector as claimed in claim 15, wherein the sprinkler bulb is configured to break upon reaching a given temperature, and wherein the first and/or second sensing element is configured such that breaking of the bulb causes opening or closing of a corresponding control circuit.17. A detector as claimed in any preceding claim, wherein the first and/or second sensing element comprise an optical sensor.18. A detector as claimed in any preceding claim, wherein the housing comprises a protective housing for the first and second sensing elements.19. A detector as claimed in any preceding claim wherein the housing is provided with one or more vents therein allowing for gas from the monitored environment to enter the housing 20. A detector as claimed in any preceding claim wherein the housing is formed of metal.21. A fire alarm system comprising a detector of any of claims 1 to 20.22. A control system for a fire alarm system of claim 21, the control system comprising one or more controllers, and being configured to: receive a first input signal from the first sensing element, the first input signal comprising information indicative of the one or more parameters monitored by the first sensing element; receive a second input signal from the second sensing element, the second input signal comprising information indicative of the one or more parameters monitored by the second sensing element, determine whether the first and/or second sensing element has detected a fire in dependence on the received first and/or second input signals; and generate an output signal for causing performance of a first alarm response of the fire alarm system upon detection of a fire by the first or second sensing element, and/or for causing performance of a second alarm response of the of the fire alarm system upon detection of a fire by both the first and second sensing elements.23. A method for monitoring an environment using a fire alarm system of claim 21, the method comprising: using the first and second sensing elements of the detector to monitor one or more parameters indicative of a fire within the environment; and performing a first alarm response of the fire alarm system upon detection of a fire by the first or second sensing element, and performing of a second alarm response of the of the fire alarm system upon detection of a fire by both the first and second sensing elements.