Sponsored by System Sensor

Almost half of the calls to the fire and rescue service are false alarms, and most of these are false alarms from fire-detection and fire-alarm systems. They are a nuisance and a danger for a variety of reasons:

- For a workforce they give rise to attitudes of apathy and complacency as its "Just another false alarm". The constant disruption and time taken from busy work schedules can even begin to foster an anti-fire safety sentiment.
- For a business they are a disruption to workflow and profit, also seemingly demonstrating a lack of competency on the part of the corporation and management.
- For the local fire service false alarms are an unnecessary use of resources. Should a genuine alarm be triggered it may prove that not enough fire fighters or apparatus are currently available to deal with the real fire.

Means of Escape are launching the new Guide to Reducing False Alarms. The guide gives an overview of the topic and focus more on what a responsible person needs to know in order to reduce false alarms at their premises.

It has been sponsored by System Sensor, formed in 1984 to focus on the fire alarm systems market, today System Sensor is one of the largest manufacturers of fire detection and notification products in the world. A specialist in smoke detection technology, they place a high premium on research and development.

The result is a line of products that are reliable, sophisticated and designed for real-world applications.

Advances in fire detector technology improve performance and reduce false alarms
Stuart Ball
Marketing Manager, System Sensor Europe

In a rightly conservative industry such as life safety, new products tend to be evolutionary developments of existing, proven and accepted technology rather than revolutionary ground-breaking advances. Rigorous third party testing to international standards such as UL and NFPA from the US and EN from Europe ensures that in such a critical industry, where the protection of people's lives and property is the objective, detectors perform in accordance with a comprehensive specification. Approved fire detectors, installed in accordance with well-understood principles, will offer rapid detection of incipient fires ranging from slow smouldering ones through to fast flaming alcohol or petrol-based ones.

Obviously, it is intrinsically difficult to produce a single detector that can operate across such a wide input spectrum with equal effectiveness at all points. It is an accepted fact that the smoke detector offers the best combination of speed of response with immunity to false alarms for the majority of "normal" applications; the ionisation smoke detector, originally developed in 1941, was the foundation stone for today's multi-billion pound global life safety industry. The ionisation technology is particularly effective in detecting the small particles of combustion produced by fast flaming fires; it is a less effective detector of the larger particles produced by smouldering ones. The optical smoke detector's effectiveness is the mirror image of the ionisation unit's, and, while initially the optical unit was far more expensive to manufacture, today's production engineering advances coupled with the health and safety requirements of working with the tiny amount of radioactive substances have eliminated the cost differential. The optical detector is by far the most popular general purpose unit in use today; legislation and environmental considerations are heavily weighted in favour of optical technology. In most countries, it is becoming harder to obtain approval for an ionisation detector, and the regulations surrounding the transportation of radioactive materials are becoming more stringent and consequently more expensive. These two factors are rightly driven by environmental concerns and it is sensible that the use of products incorporating radioactive sources should be discouraged where a true alternative exists. End of life disposal costs of an ionisation detector are also significant.

All recent developments by the major smoke detector manufacturers seek to address one or more of four key technical objectives. The first two are fundamental to the device's operation; the third focuses on ease of installation, commissioning and use and the last driver addresses the need to extend the reach of the fire system into previously unprotectable areas. The four main criteria are:

- To improve detection efficiency
- To improve false alarm immunity
- To improve operational functionality
- To enhance system capability

It is generally accepted that addressable systems have inherent advantages over conventional ones, mainly because the ability to interrogate and control detectors individually from the panel offers significant advantages in terms of system configuration, earlier detection of a possible fire through pre-alarm status monitoring and more precise identification of a fire's location. While the different manufacturers have all developed their own communications protocols between device and panel, with some being open, some managed and some closed, in general all variants of a protocol provide robust and resilient systems communications. It is also now taken for granted that all optical addressable and conventional detectors, apart from those at the very lowest price point, will feature automatic drift compensation that automatically adjusts the sensitivity of the device with age and will possibly include other features such as remote interrogation and test.

Standards conformance
No reputable fire engineer would consider using unapproved smoke or heat detectors, but manual call points sometimes seem to be regarded as less important elements of the system. Several manufacturers or importers supply unapproved and untested call points, which are often promoted with meaningless statements such as "meets the requirements of", "designed in accordance with" or "conforms to" the relevant product standard.. While it is not mandatory in many countries, third party testing by a reputable test house to the appropriate standard does far more than simply confirm the physical construction and operation of the device. Extensive tests for environmental factors such as operation at elevated temperatures, corrosion tests, EMC tests and shock and vibration are carried out, so a third party test certificate gives the installer and user confidence that the call point conforms in all respects to the requisite standard. To use non-approved devices is a false economy, and all reputable suppliers will have submitted their products to specialist independent test houses such as FM, UL, BSI, LPCB or VdS.

Conclusions
As an important part of the life safety industry, the world's leading fire detector manufacturers are constantly improving their products to increase the protection levels and false alarm immunity provided to the users of the buildings they protect. The provision of higher levels of performance than ever before is a trend that looks set to continue for the foreseeable future.

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