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The integration of fire detection and alarm systems with other building controls is perceived as a good thing. But Rowland Davies of Apollo Fire Detectors says the regulatory and practical issues are far from straightforward.
On the face of it, integration of fire detection systems with building management systems and other control equipment seems a sensible and desirable goal. It is surely practical to have all the functions involved in modern building control combined into a single system. Integration would allow the actions of non-alarm equipment such as heating and ventilation, energy management, building management and lighting to be interdependent with those of the fire and security alarm systems. It also presents the possibility of equipping the user with a single, common interface so, in theory it should make things much simpler.
However, there are other considerations to take into account. A fire detection system is safety-critical, so there is an argument that it should remain completely independent of other building control equipment. Is it worth the risk that a fault in, say, a ventilation unit could knock out the fire protection? Keeping different systems separate also means that there can be no confusion between the visual and audible warnings of a fire alert and any other alarm signal.
Recommendation, not legislation
Even if integration is desirable, its achievability is another question. The regulations governing integration of fire systems are complex and there are many of them. It takes a highly accomplished system designer and installation engineer to understand the application standards and work out which takes precedence where different systems meet.
Again, it becomes a question of theory and practice. Theoretically, the fire detection requirements should take precedence over those of any non-safety critical equipment. For example, where the information from a building management system and a fire alarm system is channelled through a common information-gathering system, all cabling must be fireproof. A simple wire connection from the fire detection system to the BMS may be outside this rule. Accommodating all the implications of different codes and applications standards can simply make integration too complex, too time-consuming and too expensive.
The potential for conflict is not only present in relation to different system recommendations. There are also critical decisions to be made about the operational processes of an integrated system. This is particularly the case with command facilities. The designer and engineer must ensure that command signals do not reduce or impede the safety and security of the people the fire system is intended to protect. If a room fills with smoke, for instance, should the doors be told to open or close? Which takes priority – containment or escape?
What is perhaps surprising is that there is no legislation on the topic of integration, only recommendations. BS 5839-1: 2002, the code of practice for system design, installation, commissioning and maintenance, implies that the fire system should always stand alone. Full integration, therefore, would negate this code. However, there is no law to insist on this. The Building Regulations refer to, but do not insist upon, compliance with the British Standard. BS 7807: 1995, the current code of practice dealing specifically with integrated systems, is almost ten years old.
The code is only now coming under revision. A new European standard is due for publication and the intention is to harmonise the existing British Standard with this new code. However, DD CLC/TS 50398 – 2002, as its current designation indicates, is still at the discussion stage and may take around three more years before it is adopted.
However, it is not only the codes and standards relating specifically to fire detection that need to be taken into account. There are broader regulations concerning public safety and corporate responsibility that could affect integration too. For example, the Workplace Regulations state that an employer must provide a safe working environment, and this requirement can add a whole new dimension to the question of fire system integration.
It presents the possibility that a well-engineered and designed integrated building management system incorporating a technically non-compliant fire detection element, could be installed to meet the overall needs of a premises. If a fire incident then resulted in serious injury or death, the employer would have to prove that the fire detection system was fit for purpose and functioning correctly, despite being at odds with the recommendations in the current codes. The alternative could be a charge of corporate manslaughter.
To date, there is no case in law to give a precedent in this situation. The possibility of prosecution under these circumstances is, however, very real, which may explain why, in practice, most building owners and system designers comply with the guidance documents and sacrifice true integration along the way.
Producing the goods
It is interesting that regulations based on theoretical good practice appear to discourage integration, when in reality some degree of interaction is not only desirable but also necessary if safety-critical procedures are to be effective. The ability for a fire signal to tell a security system to release certain access doors for use as escape routes is one example. Fire detection manufacturers have responded by providing products that will give some practical degree of integration.
One example of simple integration is in applications such as sheltered housing and other shared accommodation, where there is a requirement for both safety and security, but installing two completely separate systems is impractical. For these circumstances, manufacturers have developed fire detectors that can work on security system voltages (typically 12V). This enables a single control panel and a single set of wiring to be installed, preventing the ‘doubling up’ of these items that a separate fire system would entail. A loop of the security system is then designated as a fire zone to provide adequate protection.
Making the actions of one system or component dependent on the signal from another can also achieve a simple degree of integration. There is a wide choice of ancillary devices and interfaces designed to enable a fire alarm signal to trigger other pieces of plant and equipment. Actions include opening and closing doors, shutting down air conditioning to prevent smoke spreading, or stopping passenger lifts safely at ground level.
Even at this simple level of integration, however, practical considerations must be taken into account. Standard interface units need to have separate isolating devices fitted on either side of them, to prevent a short circuit disabling part of the fire system. So the installer is effectively fitting three devices every time the fire system is required to interact with another piece of equipment. This prolongs installation time and could, therefore, add significantly to the project time and cost.
Fire detection manufacturers have overcome this problem by developing interfaces with built-in isolators, thereby simplifying the installation procedure. For example, Apollo’s Mains Switching Input/Output Unit is loop powered and therefore does not require a separate power supply or slave relays, simplifying and speeding up the fixing process. This particular interface can receive information from devices (inputs) and operate equipment (outputs). The device can be used to activate equipment such as door closers and smoke extractors, in the event of an alarm.
Communication is key
So far, we have established that the benefits of having diverse building products and systems co-operating with each other are highly desirable. Faster response times, co-ordinated strategies in case of emergency or failure, pre-planned and pre-programmed evacuation procedures are a few of them. The difficulties arise when there are differences in opinion about how integration should be achieved. In the end, it becomes a question of communication.
Originally, it was thought that a single, unified system could one day cope with all the demands of modern building control. In reality, total integration has proved impractical and brings a number of unacceptable risks, including the possibility of compromising safety-critical functions. Instead, practical and regulatory pressures have produced another possibility: keep each system separate but integrate communications.
The advent of web-based information management has gone a long way to making this solution a reality. It has led to the development of an integrated network that provides a platform for the management and control of a building. The network provides a communications platform that enables all the different elements of the building – lighting, air conditioning, access, fire, security – to co-operate fully while retaining each system’s integrity.
The shift in emphasis away from system integration to information integration brings a number of benefits. It provides the user with a familiar interface: typically a computer or graphics display. More importantly, it enables the different system manufacturers to concentrate on the evolution of features that are most needed in their particular field of expertise. They no longer have to worry about the potential impact of their own development programme on the functioning of other parts of the BMS system that are not their specialism.
The same principle applies to maintenance of such a system: if a valve on the HVAC system needs upgrading or changing, it can be achieved by an engineer specialising in that field. The change cannot adversely affect the functioning of any other system because the systems are still essentially separate. Equally, it will not affect the way in which the HVAC system responds to signals from other equipment or systems and vice versa, because the information network controls what response will be made.
The question of maintenance also raises lifetime costs. In a fully integrated system, if the protocol becomes obsolete or the manufacturer withdraws some components from production, the building owner could be faced with replacement of the entire building management system. Where individual systems are retained but only communications is shared, there is far less risk that obsolescence in one system can affect the entire network.
The attempt to integrate all building control equipment onto a single system was a false dawn and has proved neither desirable nor practical. The issues involved in true integration are simply too complex. In addition, the benefits are outweighed by issues of cost, in-built obsolescence and risk to life-critical functions.
A common communications platform offers the benefits of integration while removing most of the risks. It is hoped that the proposed new regulations on integration will take these points into account, and will provide us with a regulatory framework that encourages continued but responsible development.
Picture 1: An integrated fire detection system at Manchester Piccadilly enables progressive managed evacuation in an emergency.
Picture 2: The GB pound 80 million Broadway Plaza retail, leisure and residential development in Birmingham where around 1,000 Apollo XP95 devices, and some bespoke interface units enable the integration of tenant fire detection systems.
Picture 3: Apollo fire detectors can be used as part of an intergrated system.