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Security & Safety

Apollo’s revolutionary the card when slotted into the base.

Apollo offers Xpert fire protection

Correct programming of intelligent fire detectors is crucial to swift and accurate pinpointing of an incident, writes ROWLAND DAVIES, marketing manager, Apollo Fire Detectors.

01 January 2006

In the 1980s, there was a revolution in fire safety.

The first ‘intelligent’ fire detectors had arrived, bringing enormous benefits to fire protection. For example, they had the ability to report a pre-alarm state that could be thoroughly investigated before raising a full alarm. This has drastically reduced the number of unnecessary evacuations from buildings, as has the intelligent fire detector’s capacity to alert the user to a fault or the need for maintenance.
The term ‘intelligent’, although widely accepted as a generic description today, is something of a misnomer. These devices were originally referred to as analogue addressable fire detectors: a name that accurately summarised the new technology involved.

Analogue addressable
‘Analogue’ describes the type of signal generated by these detectors. The signal goes up and down steplessly, with each point on the analogue “wave” indicating a particular value. Signals that record the increase in smoke or heat are necessarily analogue at source: this is why, even today, fire detectors are described as analogue even though they may use digital protocol to communicate. Of course the ability to report ambient levels of smoke or heat continuously is of limited use without the ability to be location-specific. It is the “addressable” nature of intelligent fire detectors that enables the system to pinpoint the individual device raising the alarm.
Addressability saves lives. It enables occupants to be guided away from the fire source or evacuated in phases. It also saves time because emergency services can be directed to a specific location straight away.

Technological weakness
So, the benefits of using fire detectors that can report their status and their position is enormous. However, there is a weakness in the technology: the potential for human error when programming in the address of each detector. The consequences of a detector that has been misprogrammed could be catastrophic. The device in alarm would then report a wrong location, misdirecting the emergency services and causing them to lose valuable time in reaching the seat of the fire. Even worse, a wrong location could lead to occupants being directed towards the conflagration, rather than away from it.
In the early years, the process for addressing detectors did little to minimise the risk of error. For installers of early addressable fire detectors, programming involved manually setting a series of DIL (dual-in-line) switches in the detecting head.
The process was fiddly, time-consuming and open to error. This was an issue that the fire detector manufacturers were determined to resolve.

Approaches to addressability
Fire systems manufacturers have approached addressability in a number of ways. One option is purely electronic and eliminates human interaction from the addressing process completely. This is often referred to as ‘soft addressing’. It uses the control panel to run a programming sequence once the fire system is installed that numbers each detector in turn.
This seems a quick and reliable method, but there are two major drawbacks. Firstly, commissioning a fire system that has been addressed in this way entails walking around the building and physically verifying that each address is where the panel thinks it is. There is no way that this walk-round can be eliminated. Secondly, if the building is extended or undergoes a change of use that affects the fire system configuration, the entire programming sequence has to be rerun. Spurs and branches off the main loops can be difficult to accommodate using this type of programming.
A second means of programming involves the use of a hand-held device to programme the detecting heads prior to fitting. Each head is inserted into the programmer and the address is input via a keypad. The programmer sets the detecting head accordingly. On larger systems, this process can be very time-consuming. In addition, the system installer has to remember to carry the programmer around at all times. This piece of equipment is not something that just slips into a pocket; a busy installer can easily leave it behind.
As can be appreciated, these solutions introduced different problems whilst trying to solve the original challenge. What the fire industry actually required was an addressing system that was simple, user-friendly and gave accurate identification of detector location. In addition, the addressing system should not compromise ease of maintenance or make system extension too laborious. The solution was a purely mechanical device.
The reasoning behind a mechanical device was simple enough. Address information does not need to be held in the detecting head: indeed, there are major benefits to be derived from putting the address information in the base. Also, electronics are susceptible to damage and power failure, so a more robust method of holding the information must be an improvement on panel or hand-held programming.

Address card
This was the route that Apollo took when developing its own range of intelligent fire detectors. The result is called the Xpert card; a simple coded plastic card that is fitted into the base and can then be read by the detector once it is plugged in.
Setting the address simply involves the removal of ‘pips’ from the card using a screwdriver. The pips on the Xpert card are numbered 1, 2, 4, 8, 16, 32 and 64. The pips that are removed add up to the detector’s unique address. To set the address to 43, for example, pips 1, 2, 8 and 32 would be knocked out. Each card is supplied with a simple chart that shows which pips to remove to make up the required address. The coded card is then inserted into the base where it locks into position. As the detecting head is rotated into the base, the remaining pips on the card operate address buttons on the base of the detector and the address is read by the detector electronics.
The mechanical solution to addressing fire detectors is therefore simple to use, but taking this route has brought additional advantages during installation and commissioning. Holding the address information in the base enables “once-only” programming of detector locations, which makes system installation quicker and easier. Changes in use or replacement of detecting heads for maintenance reasons are also easily accommodated without the need to reprogramme. In addition, extension of the fire system is much simplified because mechanical addressing does not involve reconfiguration of the entire system when adding further detectors.
It is now 12 years since Apollo introduced the mechanical approach to addressing in its intelligent fire detectors. There has been no adverse feedback to suggest that the method requires modifying in any way – the reaction has been entirely positive. In fact, many regular Apollo users find the Xpert card system so simple and failsafe that they can confidently remove pips without reference to the coding chart supplied.
A whole range of buildings is currently protected by intelligent fire detection systems incorporating Apollo’s mechanical approach to addressing. They include retail complexes such as Seef Mall, Bahrain; sports stadia such as the Olympic Equestrian Centre, Greece: oil and gas terminals on Sakhalin Island, Russia; major transport hubs such as the Rotterdam Metro, Holland: and numerous landmark projects throughout the UAE and Saudi Arabia.