Addressable Fire Alarm Systems

What is an Addressable fire alarm System?

An Addressable fire alarm is as the name suggest “Addressable”, which means that each device connected to the fire alarm panel can have its own unique “Address”. The address is allocated to each device by “hard” addressing which is a numerical binary code tag or switch within the device or “soft” addressing whereby the software within the fire alarm control panel allocates a unique number to each device in the order that the devices are wired to the panel.
With each device having a unique identification number this enables the panel software to allow the commissioning engineer to allocate a forty character text message to each device. For example the device allocated device number one, could have the text message of “Grd Floor Entrance Lobby”

This text identification system allows the user or the Fire & Rescue Service to quickly locate the source of the fire or activated device, reducing the seek and search time period. Locating a fire quickly can save lives and reduce damage to property.

Is an Addressable System right for you?

When considering this question, you have to consider your choices. The choices are between a conventional and an addressable system. Conventional systems are predominately used for very small installations of no more than twenty detectors, the only real benefit on choosing a conventional system over an addressable, is it anywhere between 30% to 50% cheaper than an addressable system on very small systems. However, on systems, over twenty devices addressable systems are by far the best option in many different ways, including cost.

How does Addressable Systems work?

Addressable fire alarm systems are an advancement of the conventional system. The conventional system is a radial circuit and by applying a “resistive” short circuit of anywhere between 220 ohms to 680 ohms, the fire alarm zone would activate into a fire condition. As you can see by this principle, the decision to activate the fire alarm is taken by the detector.

However, with the advancement of electronic technology in the 80’s a new breed of intelligent fire alarm was now possible and was called an analogue addressable fire alarm system. The new system operates with the devices sitting on a loop or ring type circuit. The devices, such as detectors, sounders or manual call points have electronic circuits that enable the addressable fire alarm control panel to send and receive data from each device. The panel would have set analogue levels for a “Pre-Alarm” or “Fire Alarm”. The addressable panel and devices are exchanging data at high speed as if the devices are talking to each other. Each device being questioned as to their condition and analogue reading. For example, if smoke enters the smoke detector, the analogue value within the chamber would begin to rise, on reaching the predefined levels, the panel observing the analogue values and the rate of the increase, would make a decision whether it was considered a fire alarm activation and sound the alarms.

Locating an activated device on an addressable system

An addressable fire alarm is a system that is capable of identifying each device on the circuit, whether it be a detector, manual call point, sounder or relay unit. Each device is given a unique identity usually in the form of a number. This unique number is then given a location text message during the programming of the system.
In the event of an activation of a device, the programmed location text message is displayed on the front of the fire alarm display screen. This information enables the user to locate exactly the location of the potential fire.
This type of system greatly reduces the “seek and search” time, compared to a conventional system where only the zone information is given.

How many devices can an Addressable system accommodate?

This is another huge advantage that addressable’s has over conventional systems. Addressable systems have the ability to connect panels together using a network configuration. The standard large panel will be able to handle four loops or circuits, and each loop accommodates 127 to 256 devices. Therefore, depending on what panel and protocol you are using, if you multiply that by four, you will get either 508 or 1024 devices.

As stated, addressable fire alarm control panels can be networked, and the size of the networks can vary depending on the manufacturer, but some of the larger networks can handle as many as 200,000 devices.

Reducing false alarms

With false alarms becoming a big issue and some fire and rescue services not attending commercial buildings, unless they have confirmation of a fire, many commercial buildings are programming their addressable fire alarms to provide them with a 3-minute delay time period before the bells may sound or the fire brigade called.

The way it usually works is as follows:

• Detector is activated.
• The location of the activated detector is registered on the fire alarm control panel display.
• The local panel buzzer and any programmed strobes will activate.
• 3 minute time has started.
• If the activate device is located and found the be a false alarm the fire alarm system is silenced.
• If a second detector is operated within the 3 minutes, this will override the timer and activate the sounders and any outputs such as calling the fire brigade.
• Should a manual call point be activated at any time the sounders and outputs would activate.
Usually, manual call points and heat detectors are not governed by any timer.

How is the Zoning Configured?

The loop wiring and devices are distributed through all areas of the building, according to the design criteria. Whereas, with the conventional system, you had to allocate a specific radial circuit to cover a fire compartment of a building, with an addressable, this does not apply. The circuit can go across or through different fire compartments. The zoning is not determined by the physical location of the wiring, but by the software programming of the system. Each device can be given a unique identification and zone number. A device zone location can be changed at any time using the software configuration tool.

Programmable Relays

On many large, complex buildings, especially where more than one building is involved, there is usually a need to for the fire alarm to provide relays that will operate on alarm to operate or shut down various pieces of equipment. This could be items such as: lifts, Plant, Boilers, Gas Shut off, fire doors, Smoke Vents, BMS, etc. This can easily be achieved on an addressable system by programming the relays in the cause and effects section in the software programming. This can also be done across a network of panels, so that an alarm in building “A” can activate or operate the plant in building “B”.

A big advantage for addressable fire alarms is their ability to adjust the sensitivity of the detectors via the software or to programme a certain chain of events before an individual output or the sounders operate.

Programmable Sounders

In some buildings, phase evacuation will be required. This will involve providing two types of fire signal, an alert and evacuation signal. Addressable systems can provide programmable relay outputs to operate the voice alarm system, or if the system has bells or sounders, the addressable system can be programmed to pulse the bells or sounders for an alert standby signal or ring the sounders or bells constantly to indicate an evacuation signal for different parts of the building.

Manufactures of addressable systems

The main addressable fire alarm panel manufacturers are companies such as: Kentec, Advance Electronics and Morley. These panels will operate equipment from such companies as Apollo, Hochiki and Argus.

Beware of Fire Alarm Systems that are “Closed Protocol”

Or another name is “Restrictive Access”

However, when deciding on what type of addressable fire alarm system to have installed, make sure that you or your consultants are aware of certain fire alarm manufacturers that have a restricted access policy for their software. For example, Kentec and Advance mentioned above, will allow any fire alarm company access to the required software to program the fire alarm panel; however, some companies will not give you the access to the required software to carry out any changes or amendments that may be required in the future. To make any amendments, you will have no choice, but go back to the manufacturer or one of their chosen fire alarm companies. Because the choice is limited to a selected few who has access to the software for that type of particular panel, you may find that the prices charged are more expensive than what you would be paying for a “non-restrictive” system.

Fire Equipment Standards

The standard for the addressable fire alarm control panel is BS EN 54-2:1997