By continuing to use the site you agree to our Privacy & Cookies policy

Fire watch

Remotely monitored CCTV systems detect fires, as well as preventing arson attacks and helping to secure prosecutions The sad reality is that in many areas of the UK, arson accounts for a worryingly high proportion of fires.

In some locations this can add up to around 70 per cent of all incidents, causing disruption and tens of millions of pounds of damage to businesses every year.

Fortunately, technological advances, particularly over the last 10 years, now mean that protection against the threat of criminal attack, and specifically arson, can be provided by remotely monitored CCTV, 24 hours a day. This is especially important when a location is unmanned overnight or at weekends, requiring effective cover to be maintained. It is also a practical method of monitoring an extensive site where other methods such as manned guarding would not be economical.

Early warning signals The reasons for arson are many and varied. It may simply be mindless vandalism, playing with fire, revenge or an attempt to conceal a crime. Whatever the motive, if undetected, the perpetrators may attempt to set fire to combustible materials lying around the outside of a building, or try to gain access to the building where the consequences of their actions could be even more damaging.

With conventional alarms, a fire may take hold before effective action can be taken. There is little doubt that the resources of UK fire brigades were stretched when the number of malicious primary fires they were called to attend doubled during the 1990s, so any measures that can prevent fires happening in the first place must surely be welcome.

Using remotely monitored CCTV, strategically placed detectors are triggered if an incident occurs, and the relevant images from a series of onsite CCTV cameras, next to the specific event, will be transmitted, typically via an ISDN line, to a dedicated remote video response centre.

1Here, operators can visually confirm what is happening and issue verbal warnings (through on-site speakers), if necessary, to intruders. Experience suggests that this step alone is a sufficient deterrent for over 90 per cent of intruders. Where offenders are more determined, operators can rapidly alert the emergency services and key holders so they can take appropriate action.

Focusing on smoke It is not just a question of capturing intruders who may commit arson;

fire needs to be detected before extreme damage is caused. Recent developments in video smoke detection (VSD) 2could be the beginning of the end of fatal fires, by discovering smoke in the early stages and triggering an alarm to inform the authorities and relevant staff members.

This is obviously of considerable interest to property owners and occupiers faced with the reality of escalating premiums in a tough insurance environment. But the real attraction of VSD is the smartness and accuracy of the system compared with other methods. It is much more sophisticated than a conventional smoke alarm, which is, even at its best, a blunt instrument.

If a conventional alarm is triggered in an unoccupied building, the only option for the monitoring station, without any means of cross-checking the validity of the activation, is to call out the fire brigade, a process that frequently results in frustrating false alarms. Smart video content analysis allows operators to actually see the event that has caused the alarm and reach an informed decision as to whether the emergency services are really required, with huge potential to reduce the prevalence of false alarms and keep the authorities and insurers happy.

A traditional beam-activated system may be set off by dust particles, birds or even insects (such as in a recent problem with thunderflies in National Trust properties). Such false alarms can be readily eliminated with video content analysis. A good example is London Underground's Jubilee Line Stratford Market Depot, where high-level beam detectors were being set off by pigeons, by sunlight heating the building and causing movement in the structure (leading to misaligned detectors), and by everproblematic dust particles. The remedy in this situation (two unwanted alarm signals a day later) was to replace the existing beam detectors with a VSD system with the very latest video content analysis software at its heart.

The good news from a CCTV perspective is that such systems are able to take advantage of standard cameras to act as the 'detectors', with detection zones placed anywhere within a specific camera view on or around the items or areas to be protected. The cameras are then linked to a self-contained processing system capable of using video content analysis.

The real beauty of video content analysis is its ability to identify, automatically, distinct smoke patterns by looking for small areas of change within an image at the digitisation stage only, passing these pixel changes to the main processor for further filtering. The system can then alert the local operator who can visually confirm the alarm condition and its cause and take appropriate action. Additionally, visual confirmation can be performed remotely, often without the need for any extra hardware.

VSD has certainly reached a new level of sophistication; the most recent systems are extremely accurate - it is now perfectly possible to differentiate between steam and smoke based on images alone, for example.

Breaking with convention Remotely monitored CCTV is eventdriven, and offers much greater cost-effectiveness, flexibility and reliability than more conventional solutions such as intruder alarms, manned guarding, patrols and continually recorded CCTV.

The most basic and common option for security of a site is probably the intruder alarm. Most police forces quote false alarm rates as high as 90 per cent, leading to the very real threat of a loss of police response and a knock-on effect on insurance and insurability. Manned patrols do provide some protection from attacks, including arson, but a major drawback is that there are unavoidable and dangerous gaps as guards visit a number of sites, creating windows of opportunity allowing the determined vandal to move in.

If patrols do not work then there is always manned guarding. The advantage here is someone constantly on site; the disadvantages are cost (at least £30,000 per year), poor quality of staff, the need for guards to work long hours, implications of a limited attention span and ultimately damage to the site as incidents are missed.

Added to this are the lone worker and minimum wage regulations, which have added considerably to overnight manned guarding costs.

Another strategy is to install CCTV cameras, which can deter the opportunist. Unfortunately, the most common method is to record continuous camera images to be viewed later, which is really only of help after an event to secure a conviction; it cannot stop the incident taking place.

CCTV can be monitored on site by a security guard, but this is just as expensive as manned guarding and there is still the problem of the guard maintaining motivation and alertness when watching a monitor continuously for several hours.

Remote monitoring complying with the recently published BS 8418:2003 standard (Installation and Remote Monitoring of Detector-activated CCTV Systems. Code of practice supersedes PAS 38:2000), which stipulates that key factors such as the layout of trigger devices and cameras are effectively addressed, means that users can look forward to the peace of mind that comes from knowing their sites have been transformed into secure, controlled environments, ready to meet the threat of attack.

The emergency services will also benefit from significant reductions in false alarms. Already, they are only responding to incidents reported by remote video response centres with a unique reference number that meet their quality requirement. BS 8418:2003 should help to distinguish between good and bad practice and, vitally, support more effective prosecutions from video evidence.

Adam Wiseberg is chair of the British Security Industry Association's CCTV section

Have your say

You must sign in to make a comment.

The searchable digital buildings archive with drawings from more than 1,500 projects

AJ newsletters