Introduction

This invention relates to automatic smoke detection and alarm systems as used in buildings comprising of one or more residential parts to provide an early warning in case of fire, and to methods of testing the integrity of the warning devices of such systems by occupants of the apartments in which they are installed. In another aspect, this invention also relates to methods for integrating automatic smoke detection and alarm systems within apartments with those installed outside of the apartments for improved occupant warning efficiency.

Background and definitions

In Australia, Volume one of the National Construction Code Series (NCC), also known as the Building Code of Australia (BCA) Volume 1, sets out the smoke detection and alarm system requirements for buildings comprising of one or more residential parts that are served by common areas, which include but are not limited to the following:

• Separate dwellings, apartments, and flats of single storey and multi-storey residential buildings;

• Boarding houses, guest houses, hostels, lodging houses or backpackers accommodation;

• Residential parts of hotels and motels;

• Accommodation for the aged, children or people with disabilities;

• A residential part of a health-care building accommodating staff members; and

• A residential part of a detention centre.

The automatic smoke detection and alarm system requirements of the BCA Volume 1 for residential parts of buildings are summarised below:

As used herein, the term "automatic" is to be taken to mean designed to operate when activated by a heat, smoke or fire sensing device, as defined in the Building Code of Australia (BCA) Volume 1. Other terms used herein are to be taken to have the following meanings:

Smoke alarm system

One or more self-contained smoke alarms powered from mains supply, and where more than one smoke alarms are provided, they are able to be interconnected by dedicated wiring for common alarm communication between all alarm devices when smoke is detected by any one or more of the interconnected smoke alarms. The self-contained smoke alarms each incorporate a smoke detector and an alarm sounding device and may also include a standby battery of the rechargeable or non-rechargeable type. Some smoke alarms do not have internal batteries, in which case the standby battery supply is an external rechargeable battery.

Self-contained smoke alarms each include a test switch for alarm functionality testing, and may also include a silence facility and switch to enable the self-contained smoke alarms to be silenced for a short period of time when the self-contained smoke alarms are accidentally activated by non-fire events, for example domestic activities such as cleaning, showering, cooking and spraying. Smoke alarm systems are often enhanced by the use of other types of alarm devices that sense by-products of fire other than smoke, such as heat and carbon monoxide. Thus, manufacturers often offer heat and carbon monoxide alarms as compatible devices suitable for interconnection with smoke alarms within their range.

It is to be noted that smoke alarms are extremely sensitive and are often activated by dust, steam or smoke generated during common and regular activities carried out within residential buildings. Thus, dust is often produced during cleaning, steam generated during cooking and showering, whereas smoke and other particulates may be produced as a result of bread toasting, showering, or the use of aerosols such as fly and hair sprays. When installed in separate dwellings, apartments and flats, the smoke alarms only provide a local alarm within the apartment in which they are installed, and these nuisance alarms are effectively managed by residents / occupants in each dwelling, apartment or flat by operating the silence facility/switch of any smoke alarm which has been activated. The purpose of the smoke alarms in each dwelling, apartment or flat of a residential building is for each of the interconnected smoke alarms to provide a warning, with typically a minimum sound output of 85 dB(A) at 3m, when smoke is detected in the dwelling, apartment or flat where the smoke alarms are installed. This warning is local in that it is only provided within the dwelling, apartment or flat, and is considered to be sufficient for awakening and alerting occupants of the dwelling, apartment or flat in the event of a fire so as to initiate their timely evacuation.

Smoke alarm systems are also installed in common areas outside of dwellings, apartments and flats of residential buildings which are directly associated with the dwellings, apartments and flats. These areas include egress paths and corridors as well as other areas used in common by residents. These smoke alarm systems comprise of one or more smoke alarms powered from mains supply or from an extra low voltage power supply derived from mains supply. Where more than one smoke alarm are provided, they are interconnected by dedicated wiring for common alarm communication between all alarm devices when smoke is detected by any one or more of the system's smoke alarms.

The purpose of the smoke alarms installed outside of dwellings, apartments and flats of residential buildings is for each of the interconnected smoke alarms to provide a warning, with typically a minimum sound output of at least 85 dB(A) at 3m, when smoke is detected in areas outside of the dwellings, apartments and flats. Although this warning is provided outside of the dwellings, apartments and flats of the residential buildings, the Building Code of Australia fire safety requirements are met if the smoke alarm system is able to provide a sound pressure level of not less than 85 dB(A) at the door of each dwelling, apartment or flat of the residential buildings. Since smoke alarms are designed to comply with Australian Standards must provide a minimum sound pressure level of 85 dB(A) at 3m, it therefore necessarily follows that a smoke alarm is required to be installed outside each dwelling, apartment or flat within 3m of the entry door. This is conservative and most smoke alarms have a sound output in the range of 95-105 dB(A), which is 10 to 15 dB(A) above the exceeding this minimum level required to comply with Australian Standards. For that reason, calculations of bedroom sound power levels in subsequent sections of this specification are based on a smoke alarm sound output of 95 dB(A).

If required, a smoke alarm system of the type installed outside of dwellings, apartments or flats of residential buildings can be used to activate additional occupant warning sounders outside of common areas, for example in dwellings, apartments or flats to boost fire warning sound power levels. In this way, a smoke alarm system installed in common areas outside of dwellings, apartments or flats can be taken to do exactly the same detection and warning functions as a smoke detection system which, when smoke is detected, activates an occupant warning system that includes occupant warning sounders. The main difference between the two systems is that the smoke detection system is able to be connected to a fire station or a fire station dispatch centre whereas a smoke alarm system is not. Therefore, for the purposes of this specification, smoke detection systems and smoke alarm systems for installation in common areas outside of dwellings, apartments and flats of residential buildings are directly interchangeable. Similarly, an embodiment of this invention describing a smoke detection system installed in common areas and which activates additional occupant warning sounders located outside of the common areas, is to be taken to equally apply to a smoke alarm system in common areas which activates additional occupant warning sounders located outside of the common areas.

Smoke detection system

Smoke detection systems consist of discrete point type smoke detectors configured to activate a building occupant warning system when smoke is detected by any one or more of the smoke detectors. Both the smoke detection system and the occupant warning system are connected to control panels which include a primary power supply derived from mains supply, together with a standby battery power supply. The occupant warning system comprises of one or more warning devices such as audio speakers, alarm sounders or visual alarm devices such as flashing lights.

In a smoke detection system, the smoke detectors are connected to a control and indicating equipment which is commonly referred to as a "fire panel". When any smoke detector detects smoke, an alarm is registered at the control and indicating equipment and an occupant warning system is activated to operate the audio speakers, sounders and flashing lights to provide an alarm to initiate the evacuation of building occupants. Smoke detection systems are enhanced by the use of other point type fire detection devices that sense by products of fire other than smoke, such as heat and carbon monoxide. Thus, manufacturers have compatible heat and carbon monoxide point type fire detectors in their range to suit environments where a regular smoke detector may not be appropriate.

Depending on what other functions are performed by the control and indicating equipment, and also upon the type of facility being protected, smoke detection systems installed in residential buildings may require connection to a fire station or fire station dispatch centre so as to comply with Building Code requirements.

Smoke detection and occupant warning systems can be installed throughout residential buildings, in and outside of dwellings, apartments and flats. Alternatively, smoke detection and occupant warning systems can be installed outside of dwellings, apartments and flats of residential buildings, with smoke alarm systems provided within each of the dwellings, apartment and flat. Where the smoke detection and occupant warning systems are installed outside of the dwellings, apartments and flats of residential buildings, the fire safety requirements of the Building Code of Australia are met if the occupant warning system is able to provide a sound pressure level of not less than 100 dB(A) at the door providing access to each dwelling, apartment or flat. This is conservative as most occupant warning sounders easily achieve a sound output of 105 dB(A). For that reason, calculations of bedroom sound power levels in subsequent sections of this specification are based on an occupant warning sounder output of 105 dB(A).

Figures 1 through to 5 are plans of a typical floor of a multi-storey residential building with eight single bedroom apartments served by a central corridor and two fire escape stairs. Each apartment has a laundry / bathroom, an entry area, a kitchen which is contiguous with a living and dining room and a balcony. The fire stairs also serves as access stairs for all apartments on the typical floor. These plans are best described as follows: FIG. 1 - A smoke detection system within all apartments and within the central corridor and fire stairs - Building Code requirement in all State and Territories - Referring to Fig. 1, a smoke detection system is provided throughout the apartments, central corridor and fire stairs. The smoke detection system comprises of smoke detectors S in the central corridor and fire stairs, and within the apartments, in bedrooms and living rooms, whereas heat detectors T are provided in apartment laundries and kitchens where smoke detectors are unsuitable. The detectors are connected to a central control and indicating equipment or "fire panel" which, and when any of the detectors detects a fire, registers an alarm and operates the occupant warning system sounders SR throughout the building, including within each apartment.

FIG. 2 - A smoke detection system and an occupant warning system within the central corridor and fire stairs, and a smoke alarm system in each of the apartments - Building Code requirement in the State of Queensland - Referring to Fig. 2, the smoke detection system comprises of smoke detectors S in the central corridor and fire stairs. The detectors are connected to a central control and indicating equipment or "fire panel" which, and when any of the detectors detects a fire, registers an alarm and operates the occupant warning system sounders SR in the corridor to provide a minimum sound output of 100 dB(A) in the corridor at each apartment entry door to comply with Building Code requirements.

Also referring to Fig. 2, the separate smoke alarm system in each apartment comprises of interconnected smoke alarms SA in every bedroom, between areas containing bedrooms and the rest of the apartment, and in the hallway / entry of each apartment serving bedrooms. The provision of interconnected smoke alarms in all bedrooms and other areas as previously described is mandated for the state of Queensland and provides an enhanced level of fire safety when compared to the requirements for smoke alarms installed in apartments mandated in all other States and Territories (Reference Fig. 3).

FIG. 3 - A smoke detection system and an occupant warning system within the central corridor and fire stairs, and a smoke alarm system in each of the apartments - Requirements for all States and Territories except Queensland - Referring to Fig. 3, the smoke detection system comprises of smoke detectors S in the central corridor and in the fire stairs. The detectors are connected to a central control and indicating equipment or "fire panel" which, and when any of the detectors detects a fire, registers an alarm and operates the occupant warning system sounders SR in the corridor to provide a minimum sound output of 100 dB(A) in the corridor at each apartment entry door to comply with Building Code requirements.

Also referring to Fig. 3, the separate smoke alarm system in each apartment comprises of interconnected smoke alarms SA outside of every bedroom. The provision of interconnected smoke alarms outside of bedrooms only is mandated for all States and Territories except Queensland, and provides a reduced level of fire safety when compared to the requirements for smoke alarms installed in apartments mandated in the State of Queensland (Reference Fig. 2).

FIG. 4 - A smoke alarm system within the central corridor and fire stairs, and a smoke alarm system in each of the apartments - Building Code requirement in the State of Queensland - Referring to Fig. 4, the smoke alarm system in the central corridor and fire stairs comprises of interconnected smoke alarms SA to provide a minimum sound output of 85 dB(A) in the corridor at each apartment entry door when any of the interconnected smoke alarms detects a fire. This minimum sound output level is required to comply with Building Code requirements.

Also referring to Fig. 4, the separate smoke alarm system in each apartment comprises of interconnected smoke alarms SA in every bedroom, between areas containing bedrooms and the rest of the apartment, and in the hallway / entry of each apartment serving bedrooms. The provision of interconnected smoke alarms in all bedrooms and other areas as previously described is mandated for the state of Queensland and provides an enhanced level of fire safety when compared to the requirements for smoke alarms installed in apartments mandated in all other States and Territories.

FIG. 5 - A smoke alarm system within the central corridor and fire stairs, and a smoke alarm system in each of the apartments - Requirements for all States and Territories except Queensland - Referring to Fig. 5, the smoke alarm system in the central corridor and fire stairs comprises of interconnected smoke alarms SA to provide a minimum sound output of 85 dB(A) in the corridor at each apartment entry door when any of the interconnected smoke alarms detects a fire. This minimum sound output level is required to comply with Building Code requirements.

Also referring to Fig. 5, the separate smoke alarm system in each apartment comprises of interconnected smoke alarms SA outside of every bedroom. The provision of interconnected smoke alarms outside of bedrooms only is mandated for all States and Territories except Queensland, and provides a reduced level of fire safety when compared to the requirements for smoke alarms installed in apartments mandated in the State of Queensland (Reference Fig. 4).

Advantages of having smoke alarm systems within dwellings, apartments and flats

One of the advantages of having a smoke alarm system within each of the dwellings, apartments and flats of residential buildings is that nuisance alarms are local and are effectively managed by residents / occupants in each dwelling, apartment or flat by operating the silence facility/switch of any of the smoke alarm activated, or by opening windows and doors to the outside to clear smoke, steam, dust or sprays. Thus, occupants of other dwellings, apartments and flats in the same residential building are not inconvenienced by a nuisance alarm in one of the dwellings, apartments or flats.

Similarly, when an alarm is raised within a particular dwelling, apartment or flat due to smoke being detected, only occupants of the dwelling, apartment or flat are alerted so that immediate action and/ or evacuation of occupants of the dwelling, apartment or flat of fire origin can take place.

A further advantage of having smoke alarms within each dwelling, apartment or flat of residential buildings is that the alarm devices can be tested regularly by occupants / residents for increased reliability and without disturbing occupants of other dwellings, apartments and flats in the same residential building.

The above-mentioned advantages result in smoke alarms systems being preferred for the protection of dwellings, apartments and flats of residential buildings, with separate smoke alarm systems or separate smoke detection systems installed outside of the dwellings, apartments and flats to provide coverage for the remainder of the residential buildings. To comply with the Building Code of Australia requirements, the smoke alarm systems and the smoke detection systems installed outside of dwellings, apartments or flats of residential buildings are designed to provide the required sound pressure level of 85 dB(A) and 100 d B(A) respectively at the door providing access to each dwelling, apartment or flat.

Disadvantages of having separate smoke alarm systems or smoke detection systems outside of dwellings, apartments and flats of residential buildings

There are disadvantages in having separate smoke alarm systems or smoke detection systems outside of dwellings, apartments and flats of residential buildings, namely:

(1) the sound power level provided at the door providing access to each dwelling, apartment or flat by the smoke alarm system, or by the occupant warning system activated by the smoke detection system, may be insufficient in some situations for wakening a sleeping occupant. This is because the alarm signal is attenuated when it passes through rooms and doors before reaching an occupant who is asleep in a bedroom of a dwelling, apartment or flat. This problem was extensively researched by Halliwell and Sultan, and the research findings resulted in the issue of Building Practice Note (BPN) 62 by the National Research Council Canada (NRCC) in June 1986. BPN 62 clearly established the following important and easily understood parameters that determine the effectiveness of any given alarm signal for awakening an occupant who is asleep:

(a) that a sound power level of 75 dB(A) at the ear is required for awakening the majority of occupants;

(b) that sound is attenuated much less by doors than by walls such that most of the sound that leaves a room is via the door, which when closed, provides a sound attenuation of around 10 dB(A);

(c) that the sound power level produced in a room depends on the room size, the room furnishings, the type of floor, wall and ceiling covering, and the type of window treatment with rooms categorised as HARD (no carpets, drapes or upholstered furnishings, e.g. kitchen, bathroom, etc.), NORMAL (carpets, light drapes, upholstered furnishings, e.g. living / dining, halls, etc.), and SOFT (thick carpets, heavy drapes, soft furnishings, e.g. bedrooms, etc.); and

(d) that a system of ducts connecting rooms of a dwelling, apartment or flat provides a path for sound to travel from room to room, and when such a system is not installed, a sound attenuation of 6 dB(A) applies.

Thus, and again according to the previously cited research by Halliwell and Sultan, the sound attenuation in a dwelling, apartment, or flat as sound travels from one room to the next can summarised as per the table given below for the room into which the sound is going: The method taught by Halliwell and Sultan for calculating sound attenuation when sound travels from room to room, when applied to a typical apartment as depicted in Figs. 1, 2, 3, 4 and 5 provides the following results:

Referring to FIG. 1 and the fire detection and warning provisions of Apartment 1 - A smoke detection system installed within Apartment 1 and within the central corridor and fire stairs serving the apartment

In this case the smoke detection system and the occupant warning system are installed throughout the building as depicted by Fig. 1, including within all apartments, and the occupant warning system sounder installed within the bedroom of Apartment 1 provides a sound output of 105 dB(A) at 3 metres distance from the sounder when activated. Occupant warning sounders are activated when any one or more smoke detectors detects smoke. It can reasonably be assumed that the ear of an occupant asleep in the bedroom will be within 3 metres of the occupant warning system sounder resulting in the minimum sound power level of 75 dB(A) at the ear required to awaken the majority of occupants being exceeded.

Referring to FIG. 2 through to FIG. 5 and the fire detection and warning provisions of Apartment 1

Smoke alarm system activation in bedroom of Apartment 1

When smoke is detected by any one or more of the interconnected smoke alarms of Apartment 1, the Apartment 1 bedroom smoke alarm provides a sound output of 95 dB(A) at 3 metres distance from the smoke alarm. It can reasonably be assumed that the ear of an occupant asleep in the bedroom will be within 3 metres of the occupant warning system sounder resulting in the minimum sound power level of 75 dB(A) at the ear required to awaken the majority of occupants being exceeded.

Smoke detection system activation or smoke alarm system activation outside of Apartment 1

Sound power level in corridor outside of apartment 1 to comply with BCA: 85 dB(A) minimum and 100 dB(A) minimum with a smoke alarm system and a smoke detection and occupant warning system installed in the corridor respectively, with the apartment not having a system of ducts connecting rooms. Accounting for the above total sound attenuation of 66 dB(A), the sound power level in the Bedroom with a smoke alarm system installed in corridor outside of apartment providing a sound power level of 85 dB(A), with Entry and Bedroom doors closed with no ducts connecting rooms = 85 - 66 = 19 dB(A).

If the Bedroom door is open and the apartment is provided with a system of ducts connecting rooms, then the sound power level in the Bedroom with a smoke alarm system installed in the corridor outside of the apartment would be improved to : 19 + 10 + 6 = 35 dB(A).

If a smoke alarm sound output power level of 95 dB(A) is used in the calculations instead of the 85 dB(A) required by the Building Code, the adjusted sound power levels in the bedroom would then be 29 dB(A) and 45 dB(A) respectively.

Accounting for the above total sound attenuation of 66 dB(A), the sound power level in the bedroom with an occupant warning system sounder operated by the smoke detection system installed in corridor outside of apartment providing a sound power level of 100 dB(A), with Entry and Bedroom doors closed with no ducts connecting rooms = 100 - 66 = 34 dB(A).

If the Bedroom door is open and the apartment is provided with a system of ducts connecting rooms, then the sound power level in the Bedroom with a smoke detection and occupant warning system installed in the corridor outside of the apartment would be improved to : 34 + 10 + 6 = 50 dB(A).

If an occupant warning sounder sound output power level of 105 d B(A) is used in the calculations instead of the 100 dB(A) required by the Building Code, the adjusted sound power levels in the bedroom would then be 39 dB(A) and 55 dB(A) respectively.

The above calculated bedroom sound power levels for a typical single bedroom apartment have established that a smoke alarm system or a smoke detection system and occupant warning system, installed in the corridor to provide the minimum sound power level of 85 and 100 dB(A) respectively at the entrance doorway of an apartment in order to comply with the Building Code requirements, would fail to provide a sound power level in the bedroom of 75 dB(A) required for awakening the majority of occupants. Although sound power levels in the bedroom are improved if sound power outputs of 95 dB(A) and 105 dB(A) are used in the calculations for the smoke alarm and occupant warning sounder respectively, in both cases the sound power level in the bedroom of 75 dB(A) required for awakening the majority of occupants would still not be achieved.

(2) As previously established, the sound power levels inside the bedrooms of dwellings, apartments and flats of residential buildings are often below the 75 dB(A) required for awakening the majority of occupants. For this reason additional sounders, activated by the separate smoke alarm systems or smoke detection systems outside of the dwellings, apartment and flats, are sometimes provided inside the dwellings, apartments and flats to improve the available sound power levels in the bedrooms. Although the additional sounders within apartments results in improved sound power levels in bedrooms of the dwellings, apartment and flats, the provision of additional sounders has the following disadvantages:

(a) the additional sounders result in increased cost of fire protection and occupant warning systems for dwellings, apartment and flats of residential buildings; and

(b) when the smoke alarm systems or the smoke detection systems outside of dwellings, apartments and flats of residential buildings are tested, occupants of all dwellings, apartments and flats are inconvenienced; and

(c) to ensure that all the additional sounders in the dwellings, apartments and flats of residential buildings are operating as intended, it is necessary to access the individual dwellings, apartments and flats when the sounders are tested by activation of the smoke alarm systems or the smoke detection and occupant warning systems installed outside the dwellings, apartments or flats. Access to residential areas for the purpose of carrying out a test is disruptive, time consuming, and difficult to coordinate. Furthermore, when access to some dwellings, apartments and flats of residential buildings is not able to be arranged, as would be the case when occupants are away at the time of the test, testing is incomplete and substandard as it is not possible to fully ascertain that the sounders within the dwellings, apartments and flats are operating as intended. This situation can result in defective sounders remaining undetected and the overall safety of occupants from fire being compromised.

Objects of the invention

It is an object of this invention to overcome the shortcomings of prior art automatic smoke detection and alarm systems for dwellings, apartments and flats of residential buildings by providing an automatic smoke detection and alarm system in which:

(1) separate smoke alarm systems comprising of interconnected smoke alarms are provided in each dwelling, apartment or flat; and

(2) a smoke alarm system or a smoke detection system is provided in areas outside of the dwellings, apartments or flats to activate occupant warning sounders outside of the dwellings, apartments and flats; and

(3) one or more additional occupant warning sounders provided within each dwelling, apartment or flat which are also activated by the smoke alarm system or the smoke detection system provided in areas outside of the dwellings, apartments and flats; and

(4) testing means provided within each dwelling, apartment or flat to enable occupants of each of the dwellings, apartments or flats to test the additional sounders in the dwellings, apartments or flats; and

(5) all the above characteristics resulting in:

(a) an improved occupant warning sound power level in each dwelling, apartment or flat when the additional sounders in each dwelling, apartment or flat are activated by the smoke alarm system or the smoke detection system provided in areas outside of the dwellings, apartments or flats; and

(b) reduced disruption and inconvenience to occupants of adjoining dwellings, apartments and flats when the additional sounders in a dwelling, apartment or flat are tested; and (c) an increase in the reliability of the additional sounders in the dwellings, apartment or flats as they are always available for regular testing by occupants of the dwellings, apartments or flats in the same way a smoke alarm system in a dwelling, apartment or flat is tested by occupants.

It is another object of this invention to provide an automatic smoke detection and alarm system for dwellings, apartments or flats of residential buildings as previously described, except that:

(1) the additional sounders provided in the dwellings, apartments and flats are those of the smoke alarms installed in the dwellings, apartments and flats; and

(2) the smoke alarm sounders in the dwellings, apartments and flats are activated by the smoke alarm system or the smoke detection system provided outside of the dwellings, apartments and flats by the application of an appropriate voltage on the interconnect wiring of the smoke alarm system within each of the dwellings, apartments or flats; and

(3) each dwelling, apartment and flat includes a test facility which, when operated by occupants of each dwelling, apartment or flat, applies an appropriate voltage on the interconnect wiring of the smoke alarm system within the respective dwelling, apartment or flat to simulate an alarm condition of the smoke alarm system or the smoke detection system provided in areas outside of the dwellings, apartments or flats and cause the smoke alarm system sounders to operate and provide a warning for occupants.

It is yet another object of this invention to provide an automatic smoke detection and alarm system for dwellings, apartments or flats of residential buildings as previously described where the additional sounders provided in the dwellings, apartments and flats are those of the smoke alarms installed in the dwellings, apartments and flats, except that:

(1) the smoke alarm sounders in the dwellings, apartments and flats are activated by the smoke alarm system or the smoke detection system provided outside of the dwellings, apartments and flats by the operation of an alarm switch, such as an addressable relay contact, connected in parallel with the test switch of one of the interconnected smoke alarms forming part of the smoke alarm system within each of the dwellings, apartments or flats; and

(2) each dwelling, apartment and flat includes an alarm test facility consisting of a switch which is also connected in parallel with the test switch of one of the interconnected smoke alarms forming part of the smoke alarm system within each of the dwellings, apartments or flats; and

(3) wherein the operation of either the alarm switch or the alarm test switch causes one of the interconnected smoke alarm to be tested to turn on its sounder and to apply an appropriate voltage on the interconnect wiring of the smoke alarm system within the respective dwelling, apartment or flat to simulate an alarm condition of the smoke alarm system or the smoke detection system provided in areas outside of the dwellings, apartments or flats and cause the smoke alarm system sounders to operate and provide a warning for occupants.

Depending on situations, the testing of discrete occupant warning sounders of automatic smoke detection and alarm systems can be done in two ways, namely:

• Individually, with each occupant warning sounder having dedicated testing means to allow the sounders to be tested one at a time. This method is useful in situations where, for example, it is required for the test signal to only be provided locally so as not to inconvenience occupants in other parts of the building.

• As a group, with each group of occupant warning sounders having common testing means to allow the sounders to be tested simultaneously. One example is a group of occupant warning sounders installed outside of the dwellings, apartments and flats of residential buildings which can be tested without inconveniencing occupants of the dwellings, apartments and flats. Another example is a group of occupant warning sounders provided inside a dwelling, apartment or flat, the occupant warning sounders being those sounders of the smoke alarms installed within the dwelling, apartment or flat, and the occupant warning sounders are tested as a group by the application of an appropriate voltage on the interconnect wiring of the group of smoke alarms in the dwelling, apartment or flat. The advantage here is that testing is simplified and quicker to carry out whilst still being local so as not to inconvenience occupants outside of the dwelling, apartment or flat where the occupant warning sounders are being tested.

It is therefore a further object of this invention to provide an automatic smoke detection and alarm system for dwellings, apartments or flats of residential buildings as previously described, wherein:

(1) the additional sounders provided in the dwellings, apartments and flats that are activated by the smoke alarm system or the smoke detection system provided outside of the dwellings, apartments and flats are able to be tested individually or as a group for each dwelling, apartment and flat; and

(2) all the above characteristics resulting in reduced disruption and inconvenience to occupants of dwellings, apartments and flats when the occupant warning sounders outside of the dwellings, apartments and flats are tested.

It is yet another object of this invention to provide an automatic smoke detection and alarm system for dwellings, apartments or flats of residential buildings as previously described, wherein:

(3) the occupant warning sounders provided outside of the dwellings, apartments and flats that are activated by the smoke alarm system or the smoke detection system provided outside of the dwellings, apartments and flats are also able to be tested individually or as a group; and

(4) all the above characteristics resulting in reduced disruption and inconvenience to occupants of dwellings, apartments and flats when the occupant warning sounders outside of the dwellings, apartments and flats are tested. It is to be realised that under some circumstances, the testing of occupant warning system sounders in a dwelling, apartment or flat by occupants may not be able to be relied upon. An example is in serviced apartments that can be hired by transient occupants for short stays, and where it would not reasonably be expected for the occupants to regularly test occupant warning system sounders. In such a case, it would be advantageous to have an occupant warning system sounder test switch for each dwelling, apartment or flat located outside of the respective dwelling, apartment or flat, so that the occupant warning system sounders can be tested by management of the residential building without the need to access the dwellings, apartments or flats.

Depending on situations, as in the case of serviced apartments referred to above, it may be preferred to have one occupant warning system sounder test switch outside of each dwelling, apartment and flat. In other situations, it may be preferable for two occupant warning system sounder test switches to be provided, one outside and one inside of each dwelling, apartment or flat. Thus, management of the residential building may choose to do a minimal number of occupant warning system sounder tests, for example say two per year, whilst the occupants of the dwellings, apartments and flats tests would have the responsibility of testing the occupant warning system sounders on a monthly basis.

Where an occupant warning system sounder test switch is provided outside of a dwelling, apartment or flat, it is a further advantage that an indication is provided outside the dwelling, apartment or flat if all the occupant warning sounders within the dwelling, apartment or flat have operated when tested.

Furthermore, it is to be understood that, where discrete occupant warning system sounders are not installed inside the dwellings, apartments and flats, and where the sounders of smoke alarms in the dwellings apartments and flats are instead used to warn occupants of a fire outside of the dwellings, apartments and flats, a test switch and a test indication outside of each dwelling, apartment and flat can be incorporated in the design provides the same advantages as those described for discrete occupant warning system sounders. It is to be noted that the provision of an indication outside of each dwelling, apartment or flat when all occupant warning system sounders or smoke alarm sounders have operated when tested has wider applications in that:

• The indication outside each dwelling, apartment or flat can be used confirm or check that all the occupant warning system sounders or smoke alarm sounders inside each dwelling, apartment or flat have operated when a fire panel test simulating an alarm condition is carried out. This feature of the invention is advantageous as it saves time during commissioning of the building's occupant warning system and makes it possible to determine that the system is fully operational without physically having to check the operation of each occupant warning system sounder or smoke alarm sounder of each dwelling, apartment or flat.

• In an evacuation as a result of an alarm condition being registered at the fire panel, a floor fire warden can advantageously ascertain if any of the dwellings, apartments or flats on the floor does not have an indication provided outside the dwelling, apartment or flat, for example in the corridor. Under this condition, if an indication is not provided for any dwelling, apartment or flat, the floor fire warden may advantageously alert the occupants of the dwelling apartment or flat by knocking on the door of the dwelling, apartment or flat.

It is also to be noted that it is not always necessary to have the occupant warning sounders or the smoke alarm sounders of this invention powered or controlled directly from the control and indicating equipment or fire panel. An alternative to this arrangement is to have the occupant warning system sounders or the smoke alarm sounders of this invention powered and controlled from a separate power supply, preferably incorporating its own battery back-up supply for times of mains failure, and with supply wiring to the occupant warning sounders or smoke alarms sounders monitored for short circuit and open circuit faults. With this alternative arrangement, the separate power supply would be required to receive an alarm condition signal from the fire panel to operate the occupant warning sounders or the smoke alarm sounders. Description of the Preferred Embodiments of the invention

Embodiments of the invention are described in detail in the following subsections of the specification and as illustrated by the accompanying drawings. The drawings, however, are merely illustrative of how the invention might be put into effect and are not to be understood as limiting on the invention.

First Embodiment

Fig. 6 is a wiring diagram for a control and indicating equipment of a conventional smoke detection system connected to an occupant warning system comprising of one or more occupant warning system sounders SR. The sounders are connected to the control and indicating equipment or fire panel via a pair of alarm condition relay changeover contacts RC1 and RC2. Each of the occupant warning sounders SR is connected in series with a diode D1 across the occupant warning system conductors 1 & 2.

Referring to Fig. 6, it can be seen that under quiescent condition with no alarm registered at the fire panel, diodes D1 are reversed biased with their anodes negative with respect to their cathodes. Therefore, no current flows through the diodes and the occupant warning system sounders SR are turned off.

Fig. 7 shows the previously described smoke detection and occupant warning systems under alarm condition, after a fire is detected by the smoke detection system. Under alarm condition, the alarm condition relay changeover contacts RC1 and RC2, located at the fire panel, operate to reverse the polarity of the voltage applied to the occupant warning system conductors 1 and 2. Thus, the diodes D1 in series with the occupant warning sounders SR become forward biased and conduct to cause all the occupant warning system sounders to operate.

In the first embodiment of the invention, and referring to Fig. 8, the wiring of the occupant warning system sounders SR is as previously described, except that each occupant warning sounder is provided with a momentary action test switch incorporating two changeover contacts TSC1 and TSC2. Under quiescent condition, with no alarm registered at the fire panel, diodes D1 in series with the occupant warning sounders are reverse biased and the occupant warning system sounders SR are turned off. It can be seen by referring to Fig. 9 that operating the test switch of the First Sounder results in the polarity of the voltage applied to diode D1 of the First Sounder to be reversed. This causes the diode D1 in series with the First Sounder to be forward biased and the sounder to operate. It is also to be noted that, as shown by Fig. 9, the test switch of the Second Sounder SR is not operated so that the polarity applied to the diode D1 of the Second Sounder is unchanged and the Second Sounder remains turned off.

The first embodiment of the invention, with each occupant warning sounder provided with a test facility, and additional occupant warning sounders installed within apartments as depicted in Fig. 10 to improve the alarm sound power levels within apartments, is advantageous in that:

With respect to the additional occupant warning sounders within the apartments

• the occupant warning system sounders within the apartments can be tested on a regular basis by occupants of the apartments for increased device reliability and occupant safety; and

• the occupant warning sounders within the apartments can be tested individually in one particular apartment without inconveniencing occupants in other apartments or other areas of the residential building; and

• the testing of the occupant warning sounders within the apartments can be carried out at the most appropriate time that suits occupants of the individual apartments; and

• access to apartments by a third party for carrying out the testing of the occupant warning system sounders within apartments is not required. With respect to the occupant warning sounders outside of the apartments, the sounders can be tested individually, and on their own, without inconveniencing occupants of the apartments.

Fig. 11 shows how the occupant warning system sounders can be wired to serve a number of apartments and as well as a central corridor and common areas of a residential building as depicted by Fig. 10. Fig. 11 also shows how, when the test switch of the first occupant warning sounders of the central corridor / common areas and that of the first occupant warning system sounder of apartment 1 are operated, these sounders are turned on as their respective diodes D1 are forward biased. Similarly, it can be seen by referring to Fig. 11, that the test switch of the last occupant warning system sounder of the central corridor / common areas and that of the last occupant warning system sounder of apartment 1 are not operated and these sounders are turned off as their respective diodes D1 are reverse biased.

Also referring to Fig. 11, it is advantageous for the fire panel to include an isolate switch ISC1 and a test indicator LED1 to provide a fire panel test with the following functions:

• prior to the panel being tested, the fire panel normally closed isolate test switch ISC1 is operated to open and disconnect the occupant warning system sounders; and

• the smoke detection system connected to the fire panel is tested, for example by the application of smoke to one of the system's smoke detectors; and

• if the smoke detector test is successful, an alarm condition is registered at the fire panel to cause the alarm condition relay to be energised and the change-over contacts RC1 and RC2 of the alarm condition relay to operate; and

• the operation of the change-over contacts RC1 and RC2 reverses the polarity of the voltage applied to the test indicator LED1 in series with resistor Rl, LED1 providing an indication that the complete panel test has been successful. At the conclusion of the panel test, the fire panel is reset and the fire panel isolate switch ISC1 is closed to restore power to the occupant warning system wiring. The fire panel test and the testing of occupant warning system sounders together represent a complete functionality test for the occupant warning system, to include detector activation, alarm registration at the fire panel, and operation of occupant warning system sounders.

Second Embodiment

In this form of the invention, the occupant warning sounders are tested in groups, and a single test switch is provided for each group. Fig. 12 shows a group of occupant warning sounders serving the central corridor / common areas, and another group of occupant warning system sounders serving apartment 1. Each group of occupant warning system sounders is provided with a common momentary action test switch, and when operated, the change-over contacts TSC1 and TSC2 of each test switch reverse the polarity of the voltage applied to their respective group of occupant warning system sounders resulting in the sounders being turned on simultaneously as a group.

Referring to Fig. 12, it can be seen that the test switch of the group of occupant warning system sounders of the central corridor / common areas is operated, reversing the polarity of the voltage applied to the diodes D1 in series with each occupant warning system sounders installed in the central corridor and common areas which are turned on. Also referring to Fig. 12, it can be seen that the test switch of the group of occupant system sounders of apartment 1 is not operated and diodes D1 in series with the occupant warning system sounders of apartment 1 remain reverse biased and all the occupant warning system sounders of apart 1 are turned off.

The advantages of the second embodiment of this invention are as described for the first embodiment. However, the second embodiment of this invention has the following further advantages:

• only one switch is required to be operated for testing each group of occupant warning system sounders which simplifies the testing process and saves time; and • the occupant warning system is more cost effective as the number of occupant warning system sounder test switches required is reduced.

Third Embodiment

Fig. 13 is a wiring diagram for a control and indicating equipment of an addressable smoke detection system connected to an occupant warning system comprising of one or more occupant warning system sounders SR. Each occupant warning system sounder is connected to the control and indicating equipment or fire panel via a normally open programmable alarm condition relay contact PACRC in parallel with a normally open test switch contact TSC. To activate the occupant warning system, all the programmable alarm condition relays associated with each of the occupant warning system sounder are programmed to operate with their normally open contacts PACRC closing when an alarm condition is registered at the fire panel.

Referring to Fig. 13, it can be seen that under quiescent condition with no alarm registered at the fire panel, and with the programmable alarm condition relay contact PACRC and the test switch contact TSC of the first occupant warning system sounder SR open, the first sounder is switched off. Similarly, also referring to Fig. 13, under quiescent condition with no alarm registered at the fire panel, the programmable alarm condition relay contact PACRC of the last occupant warning system sounder SR is open, whilst the test switch contact TSC of the last occupant warning system sounder SR is closed. Closure of the test switch contact TSC of the last occupant warning system sounder SR results in the last occupant warning system sounder SR being turned on.

Fig. 14 shows the occupant warning system configured to operate as for Fig. 13, except that the fire panel is in alarm condition, with the programmable alarm condition relay contact PACRC of each occupant warning system sounder SR closed to turn on all of the occupant warning system sounders SR. The advantages of the third embodiment of this invention are the same as those described for the first embodiment.

Fourth Embodiment

Fig. 15 of the fourth embodiment of this invention shows how a single programmable alarm condition relay contact, and a single momentary action test switch, can be used to turn on a group of occupant warning system sounders under alarm and test condition respectively. Referring to Fig. 15, when an alarm is registered at the fire panel, the normally open programmable alarm condition relay contact PACRC closes to turn on the group of occupant warning system sounders. Similarly, also referring to Fig. 15, when the momentary action test switch is operated, its normally open contact TSC is closed to turn the group of occupant warning system sounders on.

The advantages of the fourth embodiment of this invention are as described for the first embodiment. However, the fourth embodiment of this invention has the following further advantages:

• only one switch is required to be operated for testing each group of occupant warning system sounders which simplifies the testing process and saves time; and

• the occupant warning system is more cost effective as the number of occupant warning system sounder test switches required is reduced.

Fifth Embodiment

Figs. 16 and 17 are depictions of the fifth embodiment of the invention which are identical to the second embodiment of the invention depicted by Fig. 12 with the exception that the occupant warning sounders of apart 1 are those of the interconnected smoke alarms of apartment 1.

Referring to Fig. 16, a number of smoke alarms are installed in apartment 1 which are powered by an extra low voltage derived from mains supply and applied to the smoke alarms via conductors 1 and 2. All the smoke alarms of apartment 1 are interconnected for common alarm communication via interconnect conductors 3 and 4. When there is no alarm condition registered at the fire panel, and with the test switch of apartment 1 not operated with test switch contacts TSC1 and TSC2 as shown, diode D3 in series with apartment 1 relay coil REL is reversed biased. The relay is therefore not energised and the relay contact RC3 is open and no current flows through zener diode Z1. Under these conditions no voltage is applied to the common interconnect conductors 3 and 4, and the sounders of the smoke alarms of apartment 1 do not operate unless one or more of apartment 1 smoke alarms is being tested or has detected a fire.

Fig. 17 shows that when the test switch of the central corridor occupant warning system is operated, the polarity of the voltage applied to the occupant warning system first sounder to turn it on as previously described for the second embodiment of the invention.

Also referring to Fig. 17, when the test switch of apartment 1 occupant warning system is operated, test switch contacts TSC1 and TSC2 of apartment 1 reverse the polarity of the voltage applied to relay coil REL in series with diode D3, and to the zener diode Z1 in series with resistor R2. Thus, the apartment 1 relay REL is energised and apartment 1 relay contact RC3 closes to apply the voltage developed across zener diode Z1, usually between 6 and 10 volts DC, to the interconnect conductors 3 and 4 of the smoke alarms of apartment 1. The application of this voltage on the interconnect conductors 3 and 4 results in all the interconnected smoke alarms of apartment 1 to sound to providing an effective test for the sounders.

It is to be noted that the under alarm condition, when the fire panel relay contacts RC1 and RC2 operate, the polarity of the voltage applied to the apartment 1 relay coil REL in series with diode D3, and that applied to the zener diode Z1 in series with resistor R2, is reversed. This polarity reversal causes the apartment 1 relay coil to be energised as described for the test mode, resulting in apartment 1 relay contact RC3 closing to apply the voltage developed across the zener diode on the interconnect conductors 3 and 4 resulting in all the interconnected smoke alarms of apartment 1 sounding to provide an effective warning for occupants of apartment 1. The advantages of the fifth embodiment are as previously described for previous embodiments except that the fifth embodiment provides the additional advantage of providing a very cost effective occupant warning system for apartment 1 by eliminating the requirement for discrete occupant warning sounders.

Sixth Embodiment

The sixth embodiment of the invention is as shown by Figs. 18 and 19 wherein a programmable alarm condition relay contact PACRC in parallel with and a test switch contact TSC1. These contacts are used to operate the central corridor and common areas occupant warning sounders SR in alarm mode and in test mode respectively as previously described for the fourth embodiment of the invention.

Also referring to Figs. 18 and 19, a programmable alarm condition relay contact PACRC in parallel with a test switch contact TSC2 are used to energise a zener diode Z1, in series with resistor R1 and diode Dl, in alarm mode and in test mode. The voltage developed across the zener voltage in alarm and test modes is applied to the interconnect conductors 3 and 4 of the interconnected smoke alarms of apartment 1. This causes the sounders of all the interconnected smoke alarms of apartment 1 to operate in alarm and test mode.

The interconnected smoke alarms of apartment 1 are powered by an extra low voltage derived from mains supply and applied to the smoke alarms via conductors 1 and 2.

The advantages of the sixth embodiment of the invention are the same as those described for the fifth embodiment.

Seventh Embodiment

The seventh embodiment of the invention is as shown by Fig. 20 in which the central corridor and common areas occupant warning system sounders and test facilities operate as previously described for previous embodiments of the invention. However, the difference here is the way the sounders of the interconnected smoke alarms of apartment 1 are turned on if an alarm condition is registered by the fire panel. Referring to Fig. 20, under quiescent condition with no alarm registered by the fire panel, diode D3 in series with relay coil REL is reversed biased with relay de-energised. Relay contact RC3 connected in parallel with the test switch of one of the interconnected smoke alarms of apartment 1 is open and the sounders of the smoke alarms are silent unless any one or more of the smoke alarms is tested or detects smoke.

When the test switch TSC is operated or the fire alarm panel registers an alarm condition, the polarity of the voltage applied to the relay coil REL in series with diode D3 is reversed with diode D3 now being forward biased. The relay coil REL becomes energised and relay contact RC3 in parallel with the test switch TS of the first smoke alarm of apartment 1 closes to simulate a smoke alarm test. Thus, the sounder of the first smoke alarm of apartment 1 operates and the first smoke alarm of apartment 1 provides a voltage on the smoke alarm system interconnect conductors 3 and 4 to cause the sounders of all the interconnected smoke alarms of apartment 1 to sound.

It is to be noted that the smoke alarms of apartment 1 shown in Fig. 20 are powered from an extra low voltage derived from mains, and the power source of the occupant warning system is electrically isolated from the power supply of the smoke alarms of apartment 1. Thus, the interface between the occupant warning system and the smoke alarm system of apartment 1 is through a clean relay contact RC3 only, and for this reason, the power source of the smoke alarms of apartment 1 can be of any voltage and type, including direct mains supply. Fig 22 shows how the interfacing of the occupant warning system with mains powered smoke alarms of apartment 1 can be achieved.

Eighth Embodiment

The eighth embodiment of the invention is as shown by Fig. 21 in which the central corridor and common areas occupant warning system sounders and test facilities operate as previously described for previous embodiments of the invention. Like the seventh embodiment of the invention, the sounders of the interconnected smoke alarms of apartment 1 are turned on if an alarm condition is registered by the fire panel. Referring to Fig. 21, the apartment 1 interface incorporates a test switch contact TSC2 and a programmable alarm condition relay contact PACRC connected in parallel with the test switch of one of the interconnected smoke alarms of apartment 1. Thus, under quiescent condition with no alarm registered by the fire panel, the programmable alarm condition relay contact PACRC and the test switch contact TSC2 of the apartment 1 interface unit are open and the sounders of the smoke alarms are silent unless any one or more of the smoke alarms is tested or detects smoke.

When the test switch TSC2 is operated or the fire alarm panel registers an alarm condition and the programmable alarm condition relay contact PACRC closes to simulate a smoke alarm test. Thus, the sounder of the first smoke alarm of apartment 1 operates and the first smoke alarm of apartment 1 provides a voltage on the smoke alarm system interconnect conductors 3 and 4 to cause the sounders of all the interconnected smoke alarms of apartment 1 to sound.

As described for the seventh embodiment of the invention, the interface between the occupant warning system and the smoke alarm system of apartment 1 is through a clean relay contacts TSC2 and PACRC only, and for this reason, the power source of the smoke alarms of apartment 1 can be of any voltage and type, including direct mains supply. Fig 23 shows how the interfacing of the occupant warning system with mains powered smoke alarms of apartment 1 can be achieved.

Ninth Embodiment

The ninth embodiment of the invention is as shown by Fig. 24 in which the central corridor and common areas as well as all apartments are provided with discrete occupant warning sounders powered by a battery backed power supply derived from mains supply. The battery backed power supply incorporates a transformer / rectifier circuit, a battery charger circuit, a rechargeable battery, and a voltage stabiliser circuit to provide a suitable voltage to operate all of the system's devices. Also included in the battery backed power supply are the following: (1) an alarm condition relay comprising of a relay coil REL1 and a pair of change-over contacts RC1 and RC2, the relay being energised when an alarm condition is registered at the control and indicating equipment or fire panel to operate the change-over contacts RC1 and RC2; and

(2) an isolate switch ISC1 to allow the testing of the interface between the fire panel and the battery backed power supply without operating the systems occupant warning sounders; and

(3) LED1 and series resistor R1 to indicate that the alarm condition relay change-over contacts RC1 and RC2 have operated when a fire panel test simulating an alarm condition is carried out, or when an alarm condition is registered at the fire panel.

In accordance with Fig. 24, two change-over test switches are provided, namely one test switch in the corridor outside of apartment 1 with change-over contacts TSC3 and TSC4, and a second test switch inside of apartment 1 with change-over contacts TSC5 and TSC6.

Quiescent condition: Referring to Fig. 24, it can be seen that under quiescent conditions, that is with no alarm registered at the fire panel and no testing under way, the diodes D1 in series with all the occupant warning system sounders in apartment 1 as well as those in the corridor and common areas, are reversed biased so that no current is drawn by the occupant warning system sounders which do not operate. Similarly, and because diodes D1 are also in series the relay coils RL2 associated with each of the occupant warning system sounders in apartment 1, the normally open relay contacts RC3 of each occupant warning system sounder remains open. Relay contacts RC3 are connected in series with current limiting resistor R3, LED2 located in the corridor outside of apartment 1, and LED3 located within apartment 1. As in the case of diodes D1 in series with each of the occupant warning system sounders, under quiescent conditions LED 2 and LED3 are reverse biased, which together with the relay contacts RC3 of each of the occupant warning system sounder of apartment 1 being open, results in LED2 and LED3 being turned off. Alarm condition and test mode: Also in accordance with Fig. 24, any one of the following conditions / operations will cause the polarity of the power supply to all or some of the occupant warning system sounders to change over as follows:

• When an alarm condition is registered at the fire panel and the isolate switch 1SC1 of the battery backed power supply is in closed position: All occupant warning system sounders in the corridor, common areas, and in apartment 1 operate.

• When a fire panel test simulating and alarm condition carried out and the isolate switch 1SC1 of the battery backed power supply is in closed position: All occupant warning system sounders in the corridor, common areas, and in apartment 1 operate.

• When the corridor and common areas momentary action test switch (switch contacts TSC1 and TSC2) is operated: All occupant warning system sounders in the corridor and common areas operate.

• When apartment 1 momentary action test switch located outside of apartment 1 (switch contacts TSC3 and TSC4) is operated: All occupant warning system sounders in apartment 1 operate.

• When apartment 1 momentary action test switch located inside of apartment 1 (switch contacts TSC5 and TSC6) is operated: All occupant warning system sounders in apartment 1 operate.

Again, referring to Fig. 24, under any alarm or test condition as described previously, the reversal of the polarity of occupant warning system sounder power supply downstream of the change-over contacts causes diodes D1 in series with each sounder to be forward biased and all the occupant warning system sounders operate. However, in the case of apartment 1 occupant warning system sounders, the operation of the sounders causes sufficient voltage to develop across resistor R2 of each apartment 1 occupant warning system sounder to turn the PNP bipolar transistors Q1 on and to charge capacitors C1 through resistors R3. When the voltage across capacitors C1 reaches approximately 2 volts, the NPN FET transistors Q2 of each of apartment 1 occupant warning system sounders is turned on to operate the relays REL2 of each sounder and to close each of the normally open relay contacts RC3. As the reversal of the polarity of the power supply under alarm and test condition also causes LED2 and LED3 to be forward biased, and because these LEDs are connected in series with the normally open relay contact RC3 of each of apartment 1 occupant warning system sounder, it necessarily follows that LED2 and LED3 will only turn on if all apartment 1 sounders are operating under alarm or test mode. Any faulty occupant warning system sounder that does not operate will not draw current and will have its corresponding normally open relay contact RC3 in series with LED2 and LED3 remaining open to prevent LED2 and LED3 from turning on.

The operation of LED2 located outside of apartment 1 when the test switch outside of apartment 1 is operated provides means by which a person can test apartment 1 occupant warning system sounders and ascertain that they are all operating without entering the apartment.

Referring to Fig. 24, resistor R4 associated with each occupant warning system sounder is a bleeder resistor having a resistance value much higher that the resistor R3. The function of resistor R4 is to discharge capacitor C1 after an alarm condition or a sounder test has been completed. Discharge of capacitor C1 results in the relay REL2 of each occupant warning system sounder of apartment 1 to be de-energised and relay contacts RC3 to open.

Diodes D3 associated with the apartment 1 occupant warning system sounders are protection diodes to protect against damage by the back-emf generated when relay coils REL 2 are switched on and off.

The provision of an LED indication outside of apartment 1 has the following additional advantages: • In the case of one or more occupant warning system sounders in apartment 1 has not operated when an alarm condition is registered at the fire panel, and the LED indication is not turned on outside of apartment 1, the floor fire warden is alerted that one or more occupant warning system sounders within apartment 1 has not operated. The floor fire warden can then advantageously attempt to alert the occupants of apartment 1 by knocking on the door of the apartment.

• The LED indication outside of apartment 1 can be used to ascertain that all occupant warning system sounders of apartment 1 are operational when tested as part of commissioning. This is advantageous as it saves time during commissioning because the operation of each occupant warning system sounder of apartment 1 does not need to be physically ascertained by accessing apartment 1 .

Tenth Embodiment

The tenth embodiment of the invention is as shown by Fig. 25 and is very similar to the ninth embodiment previously described except for the following:

(1) Apartment 1 does not have discrete occupant warning system sounders, and instead, the sounders of smoke alarms installed within apartment 1 are used; and

(2) The smoke alarms of apartment 1 are interconnected for common alarm communication between all smoke alarms of apartment 1; and

(3) A bridge rectifier circuit comprising of diodes D4, D5, D6, D7 is used to provide a voltage of the correct polarity to power apartment 1 smoke alarms irrespective of whether an alarm condition has been registered at the fire panel, or a fire panel test simulating an alarm condition is being carried out, or an apartment 1 sounder test is being carried out by the operation of the sounder test switch outside of apartment 1, or an apartmentl sounder test is being carried out by the operation of sounder test switch within apartment 1; and

(4) An electrolytic capacitor C1 is connected across the bridge rectifier circuit comprising of diodes D4, D5, D6 and D7 to maintain supply to the smoke alarms of apartment 1 when the voltage changes over when an alarm is registered at the fire panel, or when a fire panel test simulating an alarm condition is carried out, or when the sounders of apartment 1 smoke alarms are tested by operating the sounder test switches inside or outside of apartment 1; and

(5) The sounders of the smoke alarms of apartment 1 are activated by applying a voltage, via diode D2 and resistor R6, to the interconnect wiring of the smoke alarms of apartment 1.

Referring to Fig. 25, the anode of diode D2 is connected to a circuit point before the bridge rectifier circuit comprising of diodes D4, D5, D6 and D7 to ensure the following:

• In quiescent mode, that is without an alarm condition registered at the fire panel, or a fire panel test simulating an alarm condition, or a sounder test from within or from outside of apartment 1 being carried out, the anode of diode D2 is of negative polarity and no voltage is applied to the interconnect wiring of apartment 1 smoke alarms. Therefore, the sounders of the smoke alarms of apartment 1 are silent unless smoke is detected within apartment 1.

• In quiescent mode, and without any smoke present within apartment 1, the voltage developed across resistors R2 by the small current drawn by the individual smoke alarms of apartment 1 is insufficient to cause bipolar transistors Q1 to conduct and for the relays REL2 to operate. Therefore, in quiescent mode smoke alarm relay contacts RC3 remain open.

• Referring to Fig. 25, when an alarm condition is registered at the fire panel, or when a fire panel test simulating an alarm condition is carried out, the polarity of the anode of diode D2 changes over to cause a voltage to be applied to the interconnect wiring of apartment 1 to cause the sounders of all the smoke alarms of apartment 1 to operate. Under these conditions, and assuming that all smoke alarms are in good working order, the current consumption of each smoke alarm is sufficient to turn bipolar transistors Q1 on and for the smoke alarm relays REL2 to be energised as previously described for the ninth embodiment. Smoke alarm series connected relay contacts RC3 close and both LED 2 and LED3 operate to provide an indication outside and inside apartment 1 that all smoke alarm sounders are operating.

• Also referring to Fig. 25, and as in the case of the ninth embodiment, sounder test switches outside and inside apartment 1 can be operated to cause contacts TSC3/TSC4 and TSC5/TSC6 respectively to change over to result in the operation of smoke alarm sounders of apartment 1 as previously described for an alarm condition registered at the fire panel and for a fire panel test simulating an alarm condition. The operation of LED2 located outside of apartment 1 when the test switch outside of apartment 1 is operated provides means by which a person can test apartment 1 smoke alarm sounders and ascertain that they are all operating without entering apartment 1.

• In the case of one or more smoke alarm sounders in apartment 1 has not operated when an alarm condition is registered at the fire panel, and the LED indication is not turned on outside of apartment 1, the floor fire warden is alerted that one or more smoke alarm sounders within apartment 1 has not operated. The floor fire warden can then advantageously attempt to alert the occupants of apartment 1 by knocking on the door of the apartment.

• The LED indication outside of apartment 1 can be used to ascertain that all smoke alarm sounders of apartment 1 are operational when tested as part of commissioning. This is advantageous as it saves time during commissioning because the operation of each smoke alarm sounder of apartment 1 does not need to be physically ascertained by accessing apartment 1.