WO1992004758A1

WO1992004758A1 - Improved communications and testing for emergency lighting systems

Info

Publication number: WO1992004758A1
Application number: PCT/AU1991/000409
Authority: WO
Inventors: Mohammed Abdelmoniem Helal; Larry Puckeridge
Original assignee: Minitronics Pty. Ltd.
Priority date: 1990-09-04
Filing date: 1991-09-04
Publication date: 1992-03-19
Also published as: NZ239665A

Abstract

The invention relates to the monitoring and testing of emergency systems (10) to ensure that they are at all times capable of performing their required emergency function. Emergency lighting systems (10) installed in buildings are required to function to provide illumination (22) in times of emergency. These systems are generally provided with a back-up power supply (25) which maintains the function should the primary power supply be cut off. Frequent testing of such systems is necessary to ensure that they are capable of performing the emergency function. In buildings, with many emergency units (10), testing requirements impose a large burden. The invention provides a system whereby test parameters for each particular unit (10) can be instructed by a single control unit (11), and test results can be received and processed by the control unit (11). The control unit (11) employs means to communicate (i.e. UHF) (28) (13) with each emergency unit (10). This simplifies test procedures for such emergency systems (10). The invention is also applicable to smoke, fire, burgler alarm systems.

Description

IMPROVED COMMUNICATIONS AND TESTING FOR EMERGENCY LIGHTING SYSTEMS

The present invention relates generally to emergency systems for installation in buildings and the like, and in particular to an emergency lighting and/or burglar alarm and/or fire alarm systems having a testing facility for maintenance purposes.

In many buildings, such as, for example, hotels and office buildings, should the mains power supply to the lighting system fail, due to fire, for example, emergency illumination must be provided, usually by lighting units having their own emergency power supply (e.g. battery driven) . Further, buildings may be provided with clearly illuminated signs marking exits and directions towards exits, as part of the emergency lighting system.

In most countries, strict standard requirements are provided for such emergency systems.

In Australia, the present Standard states that all emergency lights should be tested every six months i.e. to make sure they are capable of correct functioning in an emergency. However, due to cost and neglect, the Standard is seldom complied with. The Standard (Australian Standard AS2293.2-1987) includes two parts, as set out below:- Part It Design and Installation. Reads in part: "The nature of an emergency lighting system is such that one can never predict when it may be called upon to function. Consequently while it is important that the system be correctly installed and operate satisfactorily initially, it is equally important that regular inspection and maintenance procedures be instituted to ensure that the system will be in a state of readiness for operation at all times" .

Part 2; Inspection and Maintenance. Describes the precise inspection and maintenance procedures necessary to ensure that the system is in a state of readiness at all times. With previous Australian systems, inspection is carried out physically on a six monthly basis and performance details manually recorded. This is a time-consuming and costly exercise. Failure to carry out prescribed maintenance will result in deterioration of the system, particularly with regard to battery life and efficiency - both of which will be drastically reduced.

Due to the high cost of maintenance, and neglect, these inspection procedures are seldom met. It is also a fact that replacement of damaged batteries is considerably more expensive than periodic manual maintenance. Paramount to maintenance costs is the necessity that the installation should be fully operational in the event of an emergency. The proper operation of an emergency lighting system can prevent injuries and save lives.

There is therefore a need for an emergency lighting system wherein testing and maintenance procedures are facilitated.

There are also a number of other types of emergency systems, other than emergency lighting systems, which need to be maintained in good working order in case of emergency. Examples are emergency systems such as smoke, detector systems, fire alarm systems, burglar alarm systems, etc. There is also a need for reliable testing and maintenance procedures for systems such as these.

The present invention provides an emergency system for providing an emergency function, comprising a plurality of emergency units each having means for providing the emergency function, and testing means for testing predetermined parameters of the unit relating to its capability of providing the emergency function and a control unit having wireless means for communicating with each emergency unit, whereby to obtain results of a test by the testing means and/or to instruct test parameters for each unit. The emergency function is preferably arranged to be provided in the event of failure of a primary power supply to the emergency unit. For example, a lighting unit in a building will normally run off the mains power supply to which the building is connected. On failure of the mains power supply, in a fire for example, an emergency unit in accordance with the present invention may operate to continue to provide illumination, by use of a back-up power supply, for example. The control unit preferably includes a communication transceiver for wireless communications between the portable unit and the emergency unit. A corresponding transceiver is preferably included in the emergency unit. The wireless communications between the control unit and the emergency unit is preferably by means of ultra high frequency (UHF) radio communications.

The control unit may be exportable unit, or it may be a unit fixed in a predetermined location - in a control room for a building, for example. An advantage of using UHF communications is that it is possible to communicate with a plurality of emergency units from a fixed location. Each unit is preferably allocated an address which the control unit will use to identify the particular emergency unit to be communicated with for individual access.

The emergency system may be an emergency lighting system and the emergency unit is preferably an emergency lighting unit having means for providing illumination as the emergency function even in the event of failure of the primary power supply. The emergency lighting unit preferably includes a processor for carrying out testing functions and for controlling the emergency illumination function.

The parameters monitored in the case of an emergency lighting system preferably include the voltage and the current of a back-up power supply (e.g. Ni-Cad batteries), preferably used to provide power for the emergency illuminations in the event of failure of the primary power supply (e.g. standard mains power supply), and the light on/off status of an emergency lamp.

The processor of the emergency lighting unit, when included, can preferably be programmed to perform specified tests at predetermined intervals.

The control unit preferably includes a processor for controlling its functions, and also preferably includes memory means for storing test results obtained from the emergency unit.

The control unit preferably includes means for programming the emergency unit to set parameters, for example, the predetermined time interval for performing testing. Processing means in the control unit is preferably arranged to be able to respond to an input device, such as a keyboard on the control unit, for example, to allow input of test parameters for communication to an emergency unit.

The system preferably includes a plurality of emergency units.

The control unit preferably further includes means for allowing communication with a computer, so that, for example, test information can be taken from the control unit and entered to the computer for processing. The control unit may be connected to a computer. Alternatively the control unit may comprise a device including UHF means for communicating with the emergency unit and a computer for processing test results.

The lighting units, where the emergency system is an emergency lighting system, may provide illumination for signs (eg EXIT signs) building areas and any other illumination application. The present invention further provides a control unit for an emergency system for providing an emergency function wherein the emergency system comprises an emergency unit having means for providing the emergency function and testing means for testing predetermined parameters of the unit relating to its capability of providing the emergency function, said control unit comprising wireless means for communication with the emergency unit, whereby to obtain results of a test by the testing means and/or to instruct test parameters for the unit.

The control unit may have any of the preferred features discussed above in relation to the control unit of the above aspect of the present invention. The emergency system may be an emergency lighting system as discussed above.

The emergency units may be arranged to provide the emergency function in the event of failure of a primary power supply, as discussed above in relation to the first aspect of the invention. The communication is preferably by means of UHF, as discussed above.

The present invention yet further provides CLAIM 16

The wireless communication means is preferably a transceiver means which allows communication using UHF radio, as discussed above.

The emergency unit may be arranged to provide the emergency function in the event of failure of a primary power supply, as discussed above.

The fact that self testing facilities are provided in the emergency urits in accordance with the present invention means that testing and maintenance procedures for the emergency system are facilitated.

Provision of a central control unit or portable unit with wireless communications for gathering the test results when desired and possibly programming the emergency units for predetermined test intervals and test parameters facilitates the maintenance of the emergency system to the required standard.

Utilising wireless communications has the advantage that it is not necessary to connect the emergency units in an emergency system with a plurality of units by a wiring loop. Installing such wiring for communication between units and a central control unit would be expensive and require a great deal of labour. Nor is it necessary to provide special communication interfaces for communication along mains wiring.

Features and advantages of the present invention will become apparent from the following description of an embodiment thereof, with regard to an emergency lighting system, by way of example only, with reference to the accompanying drawings in which:-

Figure 1 is a schematic block diagram illustrating a generalised emergency lighting system in accordance with an embodiment of the present invention. Figure 2 shows a schematic block diagram of an emergency lighting unit of an emergency lighting system n accordance with the present invention;

Figure 3 is a graph showing typical characteristics of Ni-Cad batteries, which may be used as an alternative power supply in accordance with an emergency lighting system of the present invention;

Figure 4 shows a schematic block diagram of a control unit for use with an emergency lighting system in accordance with the present invention; Figure 5, a to k, show"examples of displays which may appear on a display of the control unit of Figure 4;

Figure 6 shows a schematic diagram of the key pad of the control unit of Figure 4; and

Figure 7 shows an example of a print out from a computer used to process test results obtained from an emergency lighting unit via a control unit as described in relation to Figure 4.

An emergency lighting system in accordance with the present invention can be comprised of three types of devices as schematically illustrated in Figure 10: i) The "Single Point Units" 10 (emergency lighting units) (SPUs) which have the function to supply light in the event of mains power failure and include a microcomputer which carries out self-checking functions, charging control and emergency detection - thus making the SPU an "Intelligent" product. Each SPU 10 also includes a UHF communications transceiver, to enable communication with a control unit (CU) (which may be a portable or stationary unit) . ii) The Control Unit (CU) 11 which controls all SPUs. The CU has a 2 line by 16 character alphanumeric display (any other size or type of display could be used), key pad and a UHF transceiver. The control unit may be a hand held portable device, or a non-portable device provided in a fixed central location for communication with all SPUs 10 from the central location. The control unit 11 may be interfaced with a computer for processing of test results, iii) The Personal Computer (PC) 12 which retrieves data from the CU, stores the data on file and prints out reports.

The CU 11 and SPUs 10 are arranged for two way wireless communications 13 to enable the CU to retrieve data from the SPUs with various test parameters. The CU 11 and PC 12 also have a communications link 14 to enable downloading of data from the CU 11 to PC 12. The communications link 14 may be two-way. The communications link 14 may also be by means of wireless communications, or alternatively, it could be by means of a wired connection (plug in connection for example) . If one wishes to communicate with a particular SPU10 via the CU 11, one will key in the address of the particular SPU10 (each SPU has a preset unique address) on the key pad of the CU 11 prior to communication, so that the particular SPU knows it is being "talked to".

Each SPU 10 will indicate by means of a flashing LED if it is faulty or otherwise operational. The system may consist only of the SPUs 10 and a CU 11. The CU will display test results from each of the SPUs 10 (one at a time). The system may comprise all three devices, in which case the CU 11 may transfer the test data for all SPUs 10 back to the PC 12 for storage and printout in a format for retention in the log book required by the Standard (Australian Standard or any other standard for which the system is programmed) .

A Single Point Unit 10 comprises (diagrammatically shown in Figure 2) an emergency luminaire containing a battery 25, battery charger 30, inverter 21 (where used), and controls 26 necessary for sensing failure of the mains power supply and for changing over to the emergency supply and vice versa.

The SPU 10 has a microcomputer 20 at its heart that . controls all f nctions. When the microcomputer detects loss of mains power supply or a test start command from the CU 11 or a preprogrammed test command, it disconnects the SPU 10 from the mains supply^'and starts the inverter 21 operating the emergency lamp 22 or, where the inverter 21 is not included, starts operating the emergency lamp 22 directly. It also monitors battery voltage and current and light output. In a test command situation, switchboard mains power supply is unaffected - only the supply to the SPU 10 under test is affected. When battery voltage drops to a pre-set cut-off voltage the microcomputer 20 records the time, voltage and current and then turns-off the inverter 21 and reconnects the unit to the mains power supply.

The SPU 10 also has means for allowing an address change 100 of the SPU 10, should one require that the address be re-set. In a test situation the mains supply is unaffected. On instigation of a test a relay (not shown) switches mains power away from the battery charger 30 and emergency lamp 22 for the particular SPU, and connects the battery 25 to drive the inverter 21, or lamp 22 directly. This provides a "simulated failure" for test purposes. The relay may be internal to the SPU.

At present, in most dual rate battery charging systems, the battery is charged for a fixed pre-set period no matter how long the previous discharge. So, for example, if mains supply failed for a mere 30 seconds (or even if a momentary test were activated) the battery would receive a full charge period. ...This may result in overcharging the battery and reducing its life. From typical charging characteristics of Ni-Cad batteries (see Figure 3), battery voltage increases during charging and, when fully charged, it starts to drop.

With the automatic self-checking system, the battery 25 will not be charged unless the mains failure (or test) lasts longer than one minute. The system will then charge the battery 25 until the battery voltage peaks and starts to drop. Thus the battery 25 will only receive as much charge as it needs to reach full capacity.

In extreme environments battery voltage peak does not occur. This situation is catered for in that the charging period is pre-set to a maximum of 32 hours, to protect the battery 25 from overcharging.

Emergency lamps can be either incandescent or fluorescent. Incandescent lamps are operated through a relay or a solid-state switch controlled by the microcomputer. Fluorescent lamps are operated through a high frequency, high efficiency inverter that provides stable light output during the emergency or test period. This approach improves the luminaire's classification and hence reduces the number required to cover a specific area according to Standard AS2293.1 - 1987.

A pre-set cut-off voltage is used for different batteries - related to the number of cells used in the case of Ni-Cad batteries or to battery voltage in the case of Lead Acid batteries. This extends battery life. In the automatic self-checking system of the present invention the LED 27 indicates one of five things:

(1) LED OFF - This indicates that either the mains power is off or the SPU 10 is under test.

(2) LED ON CONTINUOUSLY - This indicates that the battery 25 has been charged and the SPU 10 has no data for the CU to retrieve.

(3) LED FLASHING (Normal Speed¹) - This indicates that the battery 25 is being charged and the SPU 10 has no data for the CU 11 to retrieve. (4) LED FLASHING (Slow Speeds - This indicates that the SPU 10 has test data to transmit to the CU 11 and that it passed test. (5) LED FLASHING (Fast Speeds - This indicates that the SPU 10 has test data to transmit to the CU 11 and that it failed test.

Any other procedure can also be incorporated in the system to meet user specifications.

The CU 11 incorporates hardware as diagrammatically shown in Figure 4. The CU 11 is controlled by the key pad 44 and push buttons.

The CU's 11 normal display mode is shown in Figure 5(a). The display will only change when a function is selected.

The CU 11 has six functions which are detailed below. Other functions can be incorporated as desired. 1) Start Test Function:-

This function is initiated by punching in the address (the address will be preallocated) of the particular SPU 10 to be tested on the key pad 44 of the CU 11, and pressing the Start Test button on the CU 11. UHF communication will then take place if the UHF communication is successful the CU 11 display will change to "Test Started" (as shown in Figure 5(b). The display will remain for a period of two seconds and then revert to the normal display.

If the CU 11 did not successfully communicate with the SPU 10 the display will change to "Communications Failed" (as shown in Figure 5(c). Again the display will remain for a period of two seconds and then revert to the normal display.

When a test is started mains power failure will be simulated, the emergency lamp 22 on the SPU 10 will illuminate, and the LED 27 will turn off. The SPU 10 will remain in this state until the battery reaches cut-off voltage or for a maximum period of three hours (or such other maximum test period as required) or until the Stop Test function is selected. While under test the SPU 10 will record the time that the test lasts or the time until the battery reaches cut-off voltage. 2) Stop Test Function:-

This function is initiated by keying in the address on the CU 11 of the particular SPU 10 and pressing the Stop Test button on the CU 11. If the UHF communication is successful the display will change to "Test Stopped" (as shown in Figure 5(d). The display will remain for a period of two seconds and then revert to the normal display.

If the CU 11 did not successfully communicate with the SPU the display will change to "Communications Failed" (as shown in Figure 5(c). Again the display will remain for a period of two seconds and then revert to the normal display.

The Stop Test function has the effect of returning mains power to the SPU 10. 3) Program Next Test:-

The SPU 10 can be programmed to do a test any selected number of days ahead. If the SPU 10 is not programmed then it has a default period of 90 days and a maximum test period of 3 hours or until battery cut-off voltage is reached. The default parameters can be varied to suit any requirement. The test is programmed by the CU 11 as follows:-

The "1" key on the key pad 44 (shown in Figure 6) is pressed.

The display on the CU 11 will change to "Enter Number of Days" (as shown in Figure 5(e)).

The user should then enter the desired number of days, key the address of the SPU 10 and press the "Enter" key. If an incorrect number of days is pressed it can be cleared with the "Clear" key.

If the UHF communication is successful then the display will change to "Programmed" (as shown in

Figure 5(f). The display will remain for a period of two seconds and then revert to the normal display.

If the communication was unsuccessful the display will change to "Communications Failed" (as shown in

Figure 5(c) .

After the pre-set number of days have elapsed, the 10 SPU will automatically enter test mode and remain in such mode until the battery 25 reaches cut-off voltage or until a maximum period of three hours has elapsed (or such other maximum test period as has been programmed) . At the end of the test the LED 27 on the SPU 10 will either flash at the fast rate (2 Hz) indicating that the test result was faulty or flash at the slow rate (1/8 Hz) indicating that the test result was successful. The criteria for faulty test result are - that either the emergency lamp did not illuminate or that the SPU 10 could not sustain light output for a period greater than 90 minutes (note that any time period could be chosen, depending on requirements of particular standard) .

The flashing LED 27 indicates that there is test data in the SPU 10 for the CU 11 to retrieve. 4) Retrieve Days:-

This function will load the number of days to the next test and the number of days between tests from the SPU 10 into the CU 11. This is done as follows:-

The " 2 " key on the key pad is pressed. - The CU 11 display will then change as shown in Figure

4(g).

Key the address of the particular SPU 10 and press the "1" key.

If the UHF communication is successful the display will change as in the typical display shown in

Figure 5(h). This display will remain until the "Cancel" key is pressed. If the communication failed the display will change as shown in Figure 5(c) for a period of two seconds. 5) Retrieve Test Data:-

This function enables retrieval from the SPU 10 of full test data. The data retrieved is the last test data. It is possible, depending upon user requirements, for the SPU 10 to store (and make available for retrieval) test data for the last five tests. This function is operated as follows:-

If commencing from the normal CU 11 display (as shown in Figure 5(a), press the "2" key on the key pad to change the display to that shown in Figure 5(g). - Key the address of the SPU 10 and again press the "2" key. If the UHF communication is successful the display will change as in the typical display shown in Figure 5(i). This display will remain until either the "Cancel" key or the "Enter" key is pressed. If the communication failed the display will change as shown in Figure 5(c) for a period of two seconds. The typical display shown in Figure 5(i) provides the following information:

"Lmp = Yes - The emergency lamp illuminated. "T = 207" - The battery could sustain light output for 207 minutes. "V = 4.10" - Battery voltage was 4.10 volts. "I = 1.03" - Battery current was 1.03 Amp. "Test-Program" - The test was a programmed test and not a mains supply test.

(If the test were conducted by switching off mains power supply the display would appear as shown in Figure 5(j) . - Following successful communication between the SPU 10 and the CU 11, the SPUs 10 LED will either remain on continuously (indicating that there is no further data to be retrieved) or flash at normal speed (1/2 Hz) (indicating that the battery is under charge and that there is no further data to be retrieved) .

If the user does not desire the test data retrieved by the CU 11 to be taken back to a personal computer (for storage and printout) pressing the "Cancel" key will cancel the display. To store the data in the CU's 11 memory press the "Enter" key. The display will then appear as shown in Figure 5(k). The CU 11 requests that a SPU 10 number be allocated to this data. To enter the SPU 10 number simply press the number between 1 and 255 (representing one byte) allocated to the particular SPU. The system can be designed for. installations having a greater number of SPUs 10 than 255, depending upon user requirements.

6) Dump Data:-

The data that has been retrieved from the SPUs 10 by the CU 11 can be dumped into a personal computer so that reports such as the typical report shown in Figure 7 can be stored and printed.

To dump the data into the PC 12 connect the CU 11 to the PC 12 via a convenient interface (in this case utilising an RS232 transceiver) and then run a retrieve program on the PC 12. When the retrieval of data is completed the PC 12 will tell the operator to disconnect ^■ ' the plug.

7) Re-allocating or Pre-setting SPU address:- The CU 11 may instruct each SPU 10 to change its present address and replace with a new address. This can be achieved by opening communication through present/ existing address and to be followed by a change command allocating new address, i.e. if serial number is allocated during production process the SPU 10 may, if desired, be allocated a new address in relation to its location in the installation in a building. The original address could be inserted during production or installation of the SPUs 10. Note that, in the CU 11, the START TEST BUTTON and STOP TEST BUTTON could be incorporated in the keypad 44. The CU 11 communicates with the SPU 10 via UHF. However, the system is not restricted to UHF communication. It can utilise any other wireless method selected. The system communicates back to the Personal Computer 12 via an interface.

This system will allow cost efficient testing of SPUs, the retrieval of test data and the permanent computer storage of such data and printout thereof. The printout can be in log book format or other such form to accord with, regulatory requirements in various countries. The system will also extend battery life, because of the charging method, and will allow the pre-determination of battery life and consequent planned battery replacement. The system further allows testing of SPUs without interruption to mains power supply to the building or installation generally. There is thus no disturbance of normal activities.

The design of software to run a system such as described above is within the knowledge of a person skilled in the art.

The particular embodiment described above was specifically developed to facilitate compliance with Australian Standard AS 2293.2-1 (inspection and maintenance) . The invention can be applied so as to meet other national and international standards, however.

A portable unit may be used as the control unit, or, alternatively a central control unit which may be situated in a permanent location could be used, the central control unit having wireless means for communicating with a plurality of SPUs in order to access them for that information. Each SPU is allocated an individual address. An advantage of using UHF communications is that one may communicate with all SPU's from a central location without the need for running wires from the central location to each SPU.

Other types of wireless means could be used for communication between the SPU's and the CU, other than UHF communications. For example, it is possible that communications could be based on infrared transceivers. In some forms of the invention it would not be necessary to allocate an individual address for each SPU. For example, a communication system could be used where communication between the CU and SPU will only occur when they are within a certain range of each other. For example, it may be necessary to take the CU to the SPU and point CU at the SPU (consider infrared communications, for example) in order for communication to take place. In such a case, the SPU wouldn't require an individual address to identify it, because the user of the CU would know exactly which SPU he was pointing the CU at at any given time.

An emergency system or emergency unit can include any type of system or unit which is arranged to provide some sort of emergency or back-up function. Examples are emergency lighting systems, where illumination is still provided even in the event of failure of a mains power supply, for example, smoke alarms (which must be operable even if a primary power supply has failed), fire alarms, etc. It could cover any system requiring operation in the event of an emergency in a building, for example. -

Where an emergency system is provided with a back-up power supply to provide power in the event of failure of a primary power supply, the primary power supply will usually be the mains power supply to a building, for example, but could be a locally generated power supply for the building but not for the unit.

An emergency system of the present invention may comprise an emergency system in which the emergency unit is merely programmed by a control unit as regards test parameters - status of the unit would be monitored by observing a display on the unit itself (eg LEDs). Alternatively, the emergency system may not include provision for the emergency unit to be programmed by the control unit, only for ihe test results to be unloaded into the control unit. The emergency system may include both these functions.

A system in which the emergency units are smoke detectors, fire alarms, burglar alarms, etc., could also be provided. A system including all these types of components together and emergency lighting units could also be provided.

In the case of an emergency lighting system, the "predetermined parameters" tested by the testing means and monitored by the control unit will generally relate to the ability of the back-up power supply (e.g. Ni Cad batteries) to provide power for illumination in the event of a mains failure. Similarly, where the system is a burglar alarm or fire alarm system or a combination of systems incorporating a number of capabilities, the testing will generally normally relate to a back-up power supply, e.g. for providing power to power an alarm in event of mains cut-off. Other parameters may be tested, however, such as whether the alarm works or not (e.g. sound monitor) , and the present invention is not limited only to testing of back-up power supplies.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS :

1. An emergency system for providing an emergency function, comprising a plurality of emergency units each having means for providing the emergency function, and testing means for testing predetermined parameters of the unit relating to its capability of providing the emergency function and a control unit having wireless means for communicating with each emergency unit, whereby to obtain results of a test by the testing means and/or to instruct test parameters for each unit.

2. An emergency system in accordance with claim 1, wherein the emergency units are arranged to provide the emergency function in the event of failure of a primary power supply. 3. An emergency system in accordance with claim 1 or 2, wherein the control unit is a portable unit. 4. An emergency system in accordance with claim 1, 2 or

3. wherein the wireless communication means comprises a UHF transceiver. 5. An emergency system in accordance with claim 4, wherein each emergency unit includes a corresponding UHF transceiver.

6. An emergency system in accordance with any preceding claim, wherein the control unit includes means for communicating with a computer, whereby to enable downloading, of test results obtained to the computer for processing.

7. An emergency system in accordance with any preceding claim, wherein he control unit includes storage means for storing a plurality of test results.

8. An emergency system in accordance with any one of claims 2 to 7, wherein the testing means is operative to simulate failure of the primary power supply to the unit in order to test said predetermined parameters. 9. An emergency system in accordance with any one of claims 2 to 8, wherein a back-up power supply is included to provide power for the emergency function in the event of failure of the primary power supply, and the testing means is arranged to test predetermined operating parameters of the back-up power supply.

10. An emergency system in accordance with any preceding claim, wherein the system is an emergency lighting system and each emergency unit is an emergency lighting unit arranged to provide illumination as the emergency function. 11. A control unit for an emergency system for providing an emergency function wherein the emergency system comprises an emergency unit having means for providing the emergency function and testing means for testing predetermined parameters of the unit relating to its capability of providing the emergency function, said control unit comprising wireless means for communication with the emergency unit, whereby to obtain results of a test by the testing means and/or to instruct test parameters for the unit. 12. A control unit in accordance with claim 11, wherein the control unit is portable.

13. A control unit in accordance with claim 11 or 12, wherein the wireless communication means comprises a UHF transceiver. 14. A control unit in accordance with claim 11, 12 or 13, wherein the control unit includes means for communicating with a computer, whereby to enable downloading of test results obtained to the computer for processing.

15. A control unit in accordance with any one of claims 11 to 14, wherein the system is an emergency lighting system and each emergency unit is an emergency lighting unit arranged to provide illumination as the emergency function.

16. An emergency unit for an emergency system, wherein the emergency unit comprises means for providing an emergency function, testing means for testing predetermined parameters of the unit relating to its capability of providing the emergency function and wireless means for communication with a control unit, whereby to provide results of a test by the testing means to the control unit and/or to receive test parameter instructions from the control unit.

17. An emergency unit in accordance with claim 16, wherein the emergency unit is arranged to provide the emergency function in the event of failure of a primary power supply to the unit.

18. An emergency unit in accordance with claim 16 or 17, wherein the wireless communication means comprises a UHF transceiver. 19. An emergency unit in accordance with claim 17 or 18, wherein the testing means is operative to simulate failure of the primary power supply to the unit in order to test said predetermined parameters. 20. An emergency unit in accordance with claim 17, 18 or 19, wherein a back-up power supply is included to provide power for the emergency function in the event of failure of the primary power supply, and the testing means is arranged to test predetermined parameters of the back-up power supply. 21. An emergency unit in accordance with any one of claims 16 to 19, wherein the system is an emergency lighting system and each emergency unit is an emergency lighting unit arranged to provide illumination as the emergency function.