Feature Fire Safety False alarms - the battle continues


Simon Adams of Gent by Honeywell explains how the number of false alarm incidents is still causing concern for the fire industry, triggering serious implications not only for the fire service and those individual businesses involved, but the UK economy as a whole


T


he Department for Communities and Local Government state that fire services attended 231,100 false alarms between 2012 and 2013 - with a cost to the UK economy of over £1bn each year, according to the Fire Industry Association (FIA). The FIA has attempted to combat the problem with the launch of the cam- paign, ‘Cut False Alarm Costs’. The initiative focuses on businesses and emphasises the opportunity to save money through properly managing detection systems.


False alarms have been a prime industry focus for many years, partic- ularly since the 2011 changes to UK fire legislation and the introduction of the Chief Fire Officers Association (CFOA) Protocol. The FIA’s Memorandum of Understanding with the CFOA and Fire and Rescue ser- vices across the UK resulted in a review of policies on attending auto- mated fire alarms. The plans state that if the ratio of false alarms from a specific site is high, there may be a reduction in the level of response from the fire authorities.


The effect of false alarms can never be underestimated. Aside from the costly burden facing individual com- panies affected by the disruption, loss of business and increased insurance premiums, the industry recognises that unwanted fire signals are a threat to fire safety as a whole. Recurring false alarms could lead to complacency among the public, mean- ing they may not react with the required sense of urgency in the event of a real fire signal.


Most fire alarm and detection systems do not actually cause false alarms. Instead, it is often down to mismanagement of the apparatus. It is therefore crucial to provide robust and innovative fire detec- tion and alarm technology. The key to eliminating false alarms further lies in predicting the type of fire and selecting the best sensor, or combination of sensors, to suit the par-


as dust, steam, cigarette smoke and cooking fumes. There are other options, including the more recently developed CO (Carbon Monoxide) sensor, which is not affected by steam, dust, insects or anything that doesn’t give off carbon monoxide gas. However, these types of sensors tend to be more resilient to false alarm reactions but may not be as effective at prompt detection of real fires.


A winning combination


ticular installation. Generally, the choice of sensor falls between a single point smoke or heat sensor, although there are many other specialist sensors that are used for more specific applications, such as detection in large open areas or roof apexes. The heat sensor is considered to be the simplest device, yet it comes in 12 different choices, each with different temperature character- istics, and therefore needs to be selected for each application.


Heat sensors / smoke sensors Most heat sensors have two operating elements - one simply a fixed temperature limit, the other is looking for steady increases in tem- perature over set peri- ods of time or ‘rate of rise’. This, for example, helps to cope with the opening of an oven door in a kitchen, or some- one switching on the heating in a hotel bed- room. Heat sensors are virtually impervious to most common causes of false alarms, other than steam which could still be hot when reaching the sensor.


In terms of smoke sensors, the most


common choice is the optical smoke sensor. However, this standard device is prone to many of the common causes of false alarms such


Electrical Engineering SEPTEMBER 2013


Above and below left: largely used in medium to large projects, Gent’s S-Quad sensor range can switch from ‘state’ to ‘state’ and use a combination of heat, CO and opti- cal elements, depending on the ambient conditions at any given time


Below: Simon Adams, business manager, Gent by Honeywell


Building on the benefits of each of the individual sensors is the aptly named multi-sensor, such as Gent’s S-Quad sensor range, which offers a combination of sensing elements. Largely used in medium to large pro- jects, the multi-sensor can switch from ‘state’ to ‘state’ and use a combi- nation of heat, CO and optical ele- ments, depending on the ambient conditions at any given time. This allows this type of sensor to avoid false alarms during specific times of the day, but be ready to react quickly to a real fire at other times. Multi- sensors can help to minimise the risk of false alarms as they are much more accurate at identifying whether there is a real fire, or if the alarm is being triggered by an environmental factor, such as dust or steam.


Aside from the performance of the system, the positioning of the sensors also plays a vital role in reducing false alarms. The recommendations for opti- mum positioning of the sensors are clearly set out in the design process of the relevant British Standard. The standard on false alarm man- agement also covers who is responsi- ble for managing-out false alarms, the different categories, and what is an acceptable rate. Incidences that trig- ger appropriate remedial action have to exceed more than one false alarm per 25 detectors a year, or ten false alarms within a period of six months. Despite the startling statistics, man- ufacturers and industry bodies are working hard to tackle the false alarms issue. The FIA states that as part of its new initiative it is ‘on a mission to stamp out false alarms’. A combina- tion of education, increased awareness and the latest advancements in sens- ing technology, will hopefully provide the solution required to put a stop to this escalating problem.


Gent by Honeywell www.gent.co.uk T: 0116 246 2000


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