FIRE DETECTION SYSTEM TESTING

Abstract

A detector unit for use in a fire detection system is provided, comprising: a sensor for monitoring an environmental condition; an indicator for generating a visible indication; and a controller in connection with the sensor and the indicator, wherein the controller is configured to communicate with a fire alarm control panel of the fire detection system; wherein the controller is configured to operate the detector unit in a testing mode, the testing mode being for testing a response of the fire detection system to an environmental condition that is indicative of a fire; and wherein the controller is configured to cause the indicator to indicate an outcome of a test carried out on the detector unit when the detector unit is operating in the testing mode.

Claims

1. A detector unit for use in a fire detection system, comprising: a sensor for monitoring an environmental condition; an indicator for generating a visible indication; and a controller in connection with the sensor and the indicator, wherein the controller is configured to communicate with a fire alarm control panel of the fire detection system; wherein the controller is configured to operate the detector unit in a testing mode, the testing mode being for testing a response of the fire detection system to an environmental condition that is indicative of a fire; and wherein the controller is configured to cause the indicator to indicate an outcome of a test carried out on the detector unit when the detector unit is operating in the testing mode.

2. The detector unit as claimed in claim 1, wherein the detector unit is configured to enter the testing mode in response to receipt of a command from the fire alarm control panel by the controller.

3. The detector unit as claimed in claim 1, wherein the controller is further configured to cause the indicator to indicate whether the detector unit has been tested during the testing mode.

4. The detector unit as claimed in claim 1, wherein the indicator comprises one or more LEDs and/or an LCD screen.

5. The detector unit as claimed in claim 1, wherein the outcome of the test is indicated by a colour of the indicator and/or a flashing light pattern of the indicator.

6. The detector unit as claimed in claim 1, wherein the controller is configured to cause the indicator to indicate what kind of test the detector unit should be subjected to.

7. The detector unit as claimed in claim 1, wherein, in the testing mode, the controller is configured to transmit a notification to the fire alarm control panel when an environmental condition that is indicative of a fire is detected by the sensor, and to determine the outcome of the test based on a response to the notification from the fire alarm control panel.

8. A fire alarm control panel for use in a fire detection system, comprising: a control unit for controlling operations of the fire detection system, wherein the control unit is configured to communicate with a plurality of detector units of the fire detection system; wherein the control unit is configured to trigger a testing mode in at least one detector unit of the fire detection system, the testing mode being a mode for testing a response of the fire detection system to an environmental condition that is indicative of a fire; and wherein the control unit is configured to process a communication received from a detector unit operating in the testing mode, and communicate an outcome response to the communication to said detector unit.

9. The fire alarm control panel as claimed in claim 8, wherein the control unit is configured to trigger the testing mode only in detector units that have passed a detector unit self-test, the detector unit self-test being a test carried out by the detector unit to test the functionality of one or more internal components of the detector unit.

10. The fire alarm control panel as claimed in claim 9, wherein the control unit is configured to notify each detector unit in the testing mode of the type of test that the detector unit should be subjected to.

11. The fire alarm control panel as claimed in claim 8, wherein the control unit is configured to trigger the testing mode of operation in all detector units within a given zone of the fire detection system.

12. A method of testing a fire detection system, comprising: triggering, through a control unit of a fire alarm control panel in the fire detection system, a testing mode in a detector unit in the fire detection system; indicating, through an indicator of the detector unit, that the detector unit has not been tested; sensing, through a sensor of the detector unit, an environmental condition that is indicative of a fire; indicating, through the indicator of the detector unit, that a test has been carried out on the detector unit; notifying, through detector unit, the sensed environmental condition to the fire alarm control panel; indicating, through the indicator of the detector unit, an outcome of the test based on a response to the notification of the sensed environmental condition from the fire alarm control panel.

13. The method as claimed in claim 12, comprising: notifying, through the fire alarm control panel, the detector unit of the type of test that the detector unit should be subjected to.

14. The method as claimed in claim 13, comprising: indicating, through the indicator of the detector unit, the type of test that the detector unit should be subjected to.

15. The method as claimed in claim 12, comprising: triggering, through the fire alarm control panel, the detector unit to return to a normal mode of operation after a predetermined time.

Description

BRIEF DESCRIPTION OF FIGURES

[0052] Certain embodiments of the disclosure will now be described by way of example only and with reference to the accompanying drawings, in which:

[0053] FIG. 1 shows a fire detection system comprising a fire alarm control panel and a plurality of detector units;

[0054] FIG. 2 shows a schematic drawing of a detector unit and its components;

[0055] FIG. 3 shows an exemplary detector unit with indicators;

[0056] FIG. 4 shows an alternative exemplary detector unit with an indicator;

[0057] FIG. 5 shows a schematic drawing of a fire alarm control panel and its components; and

[0058] FIG. 6 shows a fire detection system split into zones.

DETAILED DESCRIPTION

[0059] FIG. 1 shows a fire detection system 10 comprising a fire alarm control panel 12 and a plurality of detector units 14.

[0060] The fire alarm control panel 12 is the controlling component of the fire detection system 10. The fire alarm control panel 12 is configured to receive information from the detector units 14 regarding environmental conditions indicating possible fires, and to monitor the operational integrity of the detector units 14.

[0061] The detector units 14 are arranged along a loop 16, which has either end connected to the fire alarm control panel 12. The fire alarm control panel 12 is able to communicate with the detector units 14 through this loop 16, i.e. by modulating the voltage in the loop 16. Similarly, the detector units 14 are able to communicate with the fire alarm control panel 12 through the loop 16, i.e. by modulating the current in the loop 16. The fire alarm control panel 12 communicates with the detector units 14 in a master-slave relationship. The fire alarm control panel 12 is configured to periodically transmit a request for information to each detector unit 14 in the loop 16, and each detector unit 14 is configured to respond with the requested information. In this way, the fire alarm control panel 12 is able to continuously monitor the entire fire detection system 10 and determine appropriate action.

[0062] The detector units 14 detect an environmental condition that can indicate the presence of a fire, such as smoke, carbon monoxide, or heat. The fire alarm control panel 12 periodically requests the detected environmental condition from each detector unit 14 in the loop 16. If the fire alarm control panel 12 determines that a received environmental condition meets a predetermined condition, which is indicative of the presence of a fire, the fire alarm control panel 12 will raise an alarm in one or more of the detector units 14 or in a separate alarm unit (not shown).

[0063] In addition, the detector unit 14 will automatically notify the fire alarm control panel 12 of a detected environmental condition if the detector unit 14 determines that the environmental condition is indicative of a fire. The fire alarm control panel 12 will then analyse the received environmental condition. If the fire alarm control panel 12 also determines that the environmental condition is indicative of a fire, the fire alarm control panel 12 will respond by raising an alarm at least in the detector unit 14 that sent the notification.

[0064] Typically, the detector unit 14 will undertake basic processing in order to determine if a sensed environmental condition is indicative of a fire (e.g., by comparing the detected condition with a predetermined threshold value), whilst the fire alarm control panel 12 will undertake more complex processing that involves a number of factors, such as the conditions detected by surrounding detector units 14, the type of detector unit 14 that has detected the condition indicative of a fire, and the historical data from the detector units 14.

[0065] FIG. 2 shows a schematic drawing of a detector unit 14. The detector unit 14 comprises a sensor 18, a controller 20, and an indicator 22. The controller 20 is in communication with the fire alarm control panel 12 via the loop 16, as well as being internally connected to the sensor 18 and the indicator 22. The sensor 18 is configured to detect one or more environmental conditions that can indicate the presence of a fire, such as smoke, heat, or carbon monoxide. The sensor 18 is configured to communicate the detected environmental condition to the controller 20 on a periodic basis. The controller 20 is configured to process the detected environmental condition in order to determine whether it meets a predetermined condition and is indicative of a fire. When the controller 20 determines that the sensed environmental condition is indicative of a fire, it transmits the detected environmental condition to the fire alarm control panel 12 via loop 16. In response, the detector unit 14 will typically receive a communication from the fire alarm control panel 12 instructing it to enter an alarm state. The controller 20 is configured to trigger the alarm state in the detector unit 14 in response to the instruction from the fire alarm control panel 12. In the alarm state, the detector unit 14 will indicate the alarm to users. The detector unit 14 will indicate the alarm state through indicating means (not shown in FIG. 2), such as audible or visual indicating means.

[0066] As shown in FIG. 2, the indicator 22 is arranged on an outer surface of the detector unit 14, thus allowing the indicator 22 to be visible to occupants of the building in which the fire detection system 10 is placed. The indicator 22 in the example of FIG. 2 is an LED light. Though not visible from the Figures, the indicator 22 is capable of lighting up in a number of different colours and flashing patterns.

[0067] The detector unit 14 can operate in two modes: a normal mode, and a testing mode. In the normal mode, the fire detection system 10 may enter an alarm state if that detector unit 14 detects environmental conditions indicative of a fire. In contrast, in the testing mode, the fire detection system 10 will not enter an alarm state when conditions indicative of a fire are detected by that detector unit 14.

[0068] The testing mode of operation is a mode in which the response of the fire detection system to conditions indicative of a fire is tested. In particular, the testing mode is a mode for testing the response of both the fire alarm control panel 12 and the detector unit 14 when conditions indicative of a fire are detected. During the testing mode, the detector unit 14 will be subjected to a test by an operator. As part of this test, conditions indicative of a fire are simulated within the vicinity of the detector unit 14, such that the response of the detector unit 14 to such conditions can tested.

[0069] The controller 20 is configured to operate the detector unit 14 in either the normal mode or the testing mode. The controller 20 operates the detector in the normal mode as a default, and triggers the testing mode when instructed to do so by the fire alarm control panel 12.

[0070] In the testing mode, the controller 20 is configured to cause the indicator 22 to operate in certain colours and flashing patterns in order to communicate information to an operator. In particular, the indicator 22 communicates the status of the detector unit 14 within the testing mode to an operator. Once the detector unit 14 has entered the testing mode, the controller 20 determines its status within the testing mode. This status includes whether or not the detector unit 14 has been tested yet, and, if so, what the outcome of that test was. The controller 20 then determines what indication the indicator 22 should provide based on the determined status, and instructs the indicator 22 to provide the determined indication.

[0071] As mentioned previously, the controller 20 is configured to receive an instruction from the fire alarm control panel 12 to enter the testing mode. Upon receipt of this instruction, the controller 20 is firstly configured to cause the indicator 22 to indicate that the detector unit 14 is in the testing mode. The indicator 22 indicates this by lighting up, allowing an operator to be able to see that the detector unit 14 is in the testing mode rather than the normal mode. This prevents an operator from accidentally triggering an alarm in the fire detection system 10 by performing a test on a detector unit 14 that is not in the testing mode.

[0072] As mentioned above, the indicator 22 also indicates the status of detector unit 14 during the testing mode. As part of this status indication, the indicator 22 indicates whether or not the detector unit 14 has been tested since it has entered the testing mode. Though not visible from the Figures, the indicator 22 in the example of FIG. 2 indicates that the detector has not yet been tested by turning yellow. Meanwhile, when the detector unit 14 has been tested, the indicator 22 will switch to a colour different from yellow. In this way, an operator carrying out the test can keep track of which detector units 14 have been tested, and which are still waiting to be tested.

[0073] Upon entering the testing mode, the controller 20 will initially determine that the detector unit 14 has not yet been tested, and shall cause the indicator 22 to indicate this (i.e. by turning yellow). The controller 14 will cause the indicator 22 to remain in this state until it has determined that a test has been undertaken on the detector unit 22. As the test involves simulating conditions indicative of a fire within the vicinity of the detector unit 14, the controller 20 is able to determine that the detector unit 14 has been tested if it receives a sensed environmental condition from the sensor 18 that is indicative of a fire. Upon determining that the detector unit 14 has been tested, the controller 20 will cause the indicator to switch indications, such that it no longer indicates that the detector unit 14 is waiting to be tested. In addition, the controller 14 will transmit the sensed environmental condition that is indicative of a fire to the fire alarm control panel 12, just as it would do in the normal mode.

[0074] Once a test has been carried out on the detector unit 14, the indicator 22 will indicate the outcome of that test. The outcome of the test may be negative or positive, and the indicator 22 will indicate as such. Though not visible from FIG. 2, the indicator 22 indicates a negative outcome by turning red, and the indicator 22 indicates a positive outcome by turning green. In the time period between the test on the detector unit 14 taking place and the outcome of the test being determined, the indicator 22 will flash green to indicate that the detector unit 14 is under test, i.e. the detector unit 14 has successfully registered that a test has been administered, but has not yet determined an outcome.

[0075] The fire alarm control panel 12 is configured to determine the outcome of the test, and the controller 20 is configured to receive the outcome of the test from the fire alarm control panel 12. The controller 20 therefore determines the outcome of the test based on the received outcome from the fire alarm control panel 12. The controller 20 then causes the indicator 22 to indicate the outcome accordingly. The controller 20 will cause the indicator 20 to indicate that the detector unit 14 is under test when it has transmitted the sensed environmental condition indicative of a fire to the fire alarm control panel 12, but has not yet received the outcome of the test from the fire alarm control panel 12.

[0076] In some cases, the fire alarm control panel 12 may be unable to transmit the outcome of the test to the detector unit 14. For example, there may be a communications issue or an internal issue of the fire alarm control panel 12 or the detector unit 14 that prevents the detector unit 14 from receiving the outcome from the fire alarm control panel 12. In this case, the outcome of the test is clearly negative, but the controller 14 will not receive this outcome from the fire alarm control panel. To resolve this, the controller 14 is configured to automatically determine that the outcome of the test is negative if it has not received the outcome from the fire alarm control panel 12 within a predetermined amount of time from sending the sensed environmental condition to the fire alarm control panel 12. For example, the controller 20 may cause the indicator to indicate a negative outcome if the controller 20 has not received the outcome from the fire alarm control panel 12 within 30 seconds from sending the sensed environmental condition to the fire alarm control panel 12.

[0077] Thus, in accordance with the above, an operator carrying out a test on the detector unit 14 is able to see the results of that test in real-time by simply looking at the indicator 22 of the detector unit. This is advantageous as it allows an operator to immediately identify if a detector unit 14 has failed the test, thus allowing the operator inspect that detector unit 14 and potentially carry out any necessary maintenance at the earliest opportunity. Furthermore, it is generally advantageous for an operator to be able to easily track the overall progress of a test in real-time, as this reduces the chance of the operator making any errors during the test. In comparison, prior art systems generally require the operator to return to the fire alarm control panel 12, or to communicate with a second operator stationed at the fire alarm control panel 12, in order to see the progress of the test and see to any issues that have arisen during the test.

[0078] In addition to the above, the controller 20 can determine the type of test that should be conducted on the detector unit 14. The fire alarm control panel 12 is configured to communicate the type of test to the controller 20, and the controller 20 is configured to determine the type of test based on this communication from the fire alarm control panel 12. The controller 20 is then configured to cause the indicator to indicate the type of test that should be carried out on the detector unit 14. Though not shown in FIG. 2, the indicator 22 may indicate the type of test through a particular flashing pattern. The controller 20 causes the indicator to stop indicating the type of test needed once the controller 20 has determined that a test has been carried out on the detector unit 14. Thus, the operator can also keep track of what test they should carry out on each detector unit 14 in the fire detection system 10, which is especially advantageous for systems in which there are large numbers of different types of detector units 14, which all require different tests.

[0079] Although shown as a single LED light in FIG. 2, the indicator 22 may take any suitable form. Alternative forms of the indicator 22 are shown in FIGS. 3 and 4.

[0080] In FIG. 3, the indicator 22 comprises three LED lights 22a-c. The controller 20 can cause different ones of the lights 22a-c to light up depending on the status of the detector unit 14 in the testing mode. For example, the controller 20 may cause light 22a to turn on when the detector unit 14 is waiting to be tested, may cause light 22b to turn on when the detector unit 14 has been tested with a positive outcome, and may cause light 22c to turn on when the detector unit 14 has been tested with a negative outcome. The controller 20 may cause light 22a to flash when the detector unit 14 is under test, and may create a particular flashing pattern across all three lights 22a-c to indicate the type of test that the detector unit 14 should go under.

[0081] In FIG. 4, the indicator 22 comprises an LCD screen, with a symbol on the screen to indicate the status of the detector unit 14 in the testing mode. The LCD screen can show any suitable symbol or text for indicating a particular status of the detector unit 14 in the testing mode. The LCD screen can also show any suitable symbol or text for indicating the kind of test that should be carried out on the detector unit 14. In FIG. 4, the LCD screen shows a cross, which indicates a negative outcome of the test. However, the LCD screen may alternatively show, for example, a tick to indicate a positive outcome of the test.

[0082] FIG. 5 shows a schematic drawing of the fire alarm control panel 12. The fire alarm control panel 12 comprises a control unit 24, a user interface 26, a wireless transceiver 28, and a memory 30. The control unit 24 is in communication with the detector units 14 via the loop 16, as well as being internally connected to each of the user interface 26, the wireless transceiver 28, and the memory 30.

[0083] The control unit 24 is configured to send out polling signals to the detector units 14 in the fire detection system 10, and to receive responses to those polling signals. The responses generally contain the latest environmental condition detected by the detector units 14. The control unit 24 is configured to process the received environmental conditions and determine a response. For example, if one or more of the received environmental conditions are determined to be indicative of a fire, the control unit 24 will typically transmit instructions to one or more of the detector units 14 to enter an alarm state. Simultaneously, the control unit 24 can transmit an alarm notification to the wireless transceiver 28, which will then transmit the alarm notification to an external device, such as a mobile phone or computer of building occupants or emergency services. The control unit 24 will also store the received environmental conditions in the memory 30.

[0084] The user interface 26 allows an operator both to access information from the fire alarm control panel 12 and to input commands to the fire alarm control panel 12. Thus, an operator can view, for example, the environmental conditions measured by the detector units 14 via the fire alarm control panel 12. In addition, an operator can input a command, via the user interface 26, to the fire alarm control panel 12 instructing the fire alarm control panel 12 to trigger the testing mode in one or more of the detector units 14. The user interface 26 communicates this command to the control unit 24, and the control unit 24 transmits commands to the selected detector units 14 instructing those detector units 14 to enter the testing mode. In addition, the control unit 24 keeps track of which detector units 14 are currently operating in the testing mode, and which are not.

[0085] When the control unit 24 receives a communication from a detector unit 14 containing a sensed environmental condition, the control unit 24 is configured to analyse that environmental condition. As part of this analysis, the control unit 24 may, for example, compare the environmental condition with historical data, a threshold value, the environmental conditions detected by surrounding detector units 14, and/or data from other devices in the building. The control unit 24 may determine, based on the analysis of the received environmental condition, that the environmental condition is indicative of a fire. The control unit 24 will then determine an appropriate response to the received environmental condition.

[0086] In order to determine this response, the control unit 24 will determine whether the received environmental condition has originated from a detector unit 14 operating in the normal mode or the testing mode. If the detector unit 14 is one that is operating in the normal mode, then the control unit 24 will determine an alarm response based on the received environmental condition, i.e. the control unit 24 will determine whether or not an alarm should be raised in one or more detector units 14 within the fire detection system 10 based on the received environmental condition. The control unit 24 will then transmit commands to selected detector units 14 or alarm units (not shown) accordingly, instructing them to enter an alarm state. In this way, the fire alarm control panel 12 can alert occupants of a building to the possible presence of a fire.

[0087] If the detector unit 14 is one that is operating in the testing mode, the response from the control unit 24 will differ to the response it would determine if the detector unit 12 were operating in the normal mode. In particular, for detector units 14 operating in the testing mode, the control unit 24 will determine an outcome response instead of an alarm response. In this case, the outcome response will reflect the outcome of the test carried out on the detector unit. A positive outcome response will be determined if the control unit 24 is able to successfully analyse the received environmental condition, and determine that it is indicative of a fire. In contrast, a negative outcome response will be determined if either the control unit 24 is unable to properly analyse the received environmental condition, or if the control unit 24 determines that the received environmental condition is not indicative of a fire. Once the control unit 24 has determined the outcome response, the control unit 24 is configured to transmit the outcome response to the detector unit 14 from which the environmental condition has originated. In this way, the fire alarm control panel 14 can communicate the outcome of a test to a detector unit 14, and the detector unit 14 can subsequently indicate that outcome as described above with reference to FIGS. 2 to 4. This differs to known prior art fire detection systems, where the detector units 14 are not informed of the test outcome, and operators must consult the fire alarm control panel in order to view the test outcomes.

[0088] FIG. 6 shows a diagram of the fire detection system 10, wherein different zones of the fire detection system 10 are shown. Two zones, zone A and zone B, are shown in FIG. 6. Zone A can be considered to represent a first floor of the building in which the fire detection system 10 is located, whilst zone B can be considered to represent a second floor of the building. As such, zone A comprises all of the detector units 14 located on the first floor, whilst zone B comprises all of the detector units 14 located on the second floor. The fire alarm control panel 12 stores, in its memory 30, which detector units 14 are located in which zone. The control unit 24 of the fire alarm control panel 12 will determine responses to communications from the detector units 14 based on their zone. For example, the control unit 24 may raise an alarm in only zone A if the received environmental condition indicative of a fire has originated from a detector unit 14 in that zone.

[0089] Generally, it is advisable to retain at least some of the detector units 14 operating in the normal mode at all times in order to minimise how much of the fire detection system 10 is disabled at any one time. As such, it is typical for a test to be carried out on selected groups of detector units 14 at a time. Meanwhile, the remaining detector units 14 continue to operate as normal. If the fire alarm control panel 12 receives an environmental condition indicative of a fire from a detector unit 14 operating in the normal mode, it will raise an alarm in the appropriate detector units 14. In addition, the control unit 24 will trigger the detector units 14 operating in the testing mode to return to the normal mode. In this way, it can be ensured that, in a possible fire situation, all detector units 14 are returned to normal functionality as soon as possible, allowing the fire alarm control panel 12 to be able to gather all the information needed to raise an appropriate alarm.

[0090] The control unit 24 is configured to trigger the testing mode in all of the detector units 24 in a given zone, whilst leaving the detector units 14 in the other zones operating in the normal mode. In the example shown in FIG. 6, the control unit 24 has triggered the testing mode in all the detector units 14 in zone A, as shown by the indicators 22 of the detector units 14 in this zone being turned on. The detector units 14 in zone B have been left in the normal mode, as shown by their indicators 22 being turned off. Thus, an operator walking past the various detector units 14 of the fire detection system 10 is able to see which detector units 14 they should test, and which they should not test.

[0091] The memory 30 of the fire alarm control panel 12 stores a testing sequence for the detector units 14 operating in the testing mode. Based on this testing sequence, the control unit 24 will trigger the testing mode in the detector units 14 in a predetermined order. For example, the control unit 24 will trigger all detector units 14 in zone A to enter the testing mode initially. Once the control unit 24 has determined that all detector units 14 in zone A have been tested, the control unit 24 will consult the testing sequence to determine which zone should enter the testing sequence next (e.g., zone B), and will consequently trigger the testing mode in the all of the detector units 14 in that zone. The operator is therefore guided between zones based on this testing sequence, and the indications provided by the detector units 14. Furthermore, this prevents the operator from having to return to the fire alarm control panel 12 to input a command for a particular zone to enter the testing mode each time they finish a test in another zone.

[0092] The testing sequence may further dictate in what order each individual detector unit 14 should be tested. In this case, the control unit 24 will, based on the testing sequence, communicate to each detector unit 14 operating in the testing mode if it is next in that sequence. In response, the controller 20 of the detector unit 14 will cause the indicator 22 to indicate if it is next in the testing sequence. Though not visible from the Figures, the indicator 22 will flash yellow to indicate that it is next in the testing sequence. Thus, an operator can be guided from one detector unit 14 to another during the test operation.

[0093] In some cases, not every detector unit 14 within a zone will be instructed to enter the testing mode.

[0094] Each detector unit 14 is configured to perform a detector unit self-test on a periodic basis. In this detector unit self-test, the detector unit 14 will test certain of its internal functions and monitor for any errors. If no errors are detected, the detector unit self-test is considered to have a positive outcome. If one or more errors are detected, the detector unit self-test is considered to have a negative outcome. Upon completion of the detector unit self-test, the detector unit 14 is configured to transmit the outcome of the detector unit self-test to the fire alarm control panel 12. The fire alarm control panel 12 is configured to store each outcome of the detector unit self-test in its memory 30, such that an operator can access these outcomes via the user interface 26.

[0095] When triggering the testing mode in selected detector units 14, the control unit 24 is configured to check the latest detector unit self-test outcome for each detector unit 14. If the latest outcome of the detector unit self-test for a detector unit 14 is negative, the control unit 24 is configured to not instruct that detector unit 14 to enter the testing mode. This prevents an operator from testing a detector unit 14 that is already known to be faulty, as well as preventing internal issues within the detector unit 14 from impacting the testing carried out in the testing mode.

[0096] The control unit 24 is configured to trigger each detector unit 14 in the testing mode to return to the normal mode when it has detected that each detector unit 14 in the testing mode has been tested. The control unit 24 detects that each detector unit 14 in the testing mode has been tested once it has received a sensed environmental condition from each detector unit 14 in the testing mode. Additionally, an operator can manually trigger an end to the testing mode by inputting a command to do so at the user interface 26 of the fire alarm control panel 12. In order to ensure that detector units 14 are not kept in the testing mode erroneously, the control unit 24 is configured to end the testing mode in a detector unit 14 when a predetermined amount of time has elapsed since the testing mode was triggered. This is advantageous in cases where an operator has forgotten to manually end the testing mode at the fire alarm control panel 12, or has had to abandon the test partway through, thus leaving some detector units 14 untested. This is also advantageous in cases where a detector unit 14 has failed a test due to the fire alarm control panel 12 not receiving a sensed environmental condition from that detector unit 14, e.g. due to communication errors. In this case, the fire alarm control panel 12 will assume that the detector unit 14 has not been tested, and will not end the testing mode accordingly. By automatically ending the testing mode after a predetermined amount of time, this issue can be overcome.

[0097] Thus, a fire detection system 10 is provided that enables an operator to keep track of the progress of a test carried out on that system 10 in real-time as the operator conducts the test. As such, an operator can ensure that the test is completed in its entirety before returning to the fire alarm control panel, and can also take real-time action in order to fix or examine issues that are identified during the test. This is in contrast to prior art systems, where an operator would either have to liaise with another operator stationed at the fire alarm control panel, or would have to physically be present at the fire alarm control panel themselves, in order to know the outcome and progress of the test.