Alarms – are you listening?

27 April 2012

Security systems need to work, but they also need to fit within budgetary demands. Stephen Murphy believes that audio intruder alarms could be the way forward.

You’d be hard pushed these days to find an organisation that doesn’t have an intruder alarm system in place. In fact, it’s a pre requisite for most non domestic insurance policies, which specify a type – or Grade – of system to be installed, based on the nature of the property and its contents and the profile of the likely intruder. These start from Grade 1 for low risk domestic properties where the burglar is opportunistic through to Grade 3 - 4 high risk properties such as banks, where intruders could be expected to plan a burglary in advance and have the knowledge and equipment to alter parts of the intruder alarm system to prevent detection. The majority of commercial systems are either in Grades 2 or 3.

An intruder detection system does just that: it detects the presence of an intruder and alerts you to that fact. It also provides some degree of preventative protection, especially at the lower risk end where an opportunistic burglar will pick an easier target, i.e. a property without an alarm. But that’s all it does. It clearly doesn’t offer any physical element to prevent the intruder entering in the first place and it doesn’t have a means of removing them from the property once detected.

In order to do the latter, you must have a means of reacting to that alarm, which will generally involve a call to the police and / or a key holder via an approved Alarm Receiving Centre (ARC).

Whilst a call to the key holder, such as the business owner or a private manned guarding company for organisations that have the resources, is straightforward enough, calling the police is where you can start to get unstuck.

If you want police response to an intruder alarm, the monitored alarm system must conform to the relevant standards and the alarm must be verified or ‘confirmed’. In other words, one detector going into alarm is not adequate to generate police response. This policy was designed to help reduce demand on Police resources from attendance to sites where there was no intruder – what the security industry refers to as ‘false alarms’. These false alarms can be generated by any number of different things, from someone forgetting to turn the alarm system off before entering the premises through to faulty or poorly sited electronic security equipment.

A risk assessment of your property will lead to a recommended minimum grade of intruder alarm system which should be verified with your insurance company, but the type of verification deployed is a matter of choice. Different security installers will offer different methods of verification which have varying degrees of effectiveness, but they will fall into one of three distinct categories: visual, sequential and audio verification.

Starting with the premium category, visual alarm verification utilises a CCTV system to ‘look’ at what is happening on site when an alarm is generated by an intruder detector. Systems vary considerably in their features and functions.

Being able to see what is happening in the area where an alarm has been generated is obviously extremely beneficial as you can glean most of the information you need in just a few seconds. But this comes at a price, especially if the site doesn’t already have a CCTV system in place into which you could integrate the intruder alarm system. Even if a CCTV system is in operation, extra consideration may have to be given such as relocating or adding further cameras or using more specialist equipment depending on environmental considerations.

At the other end of the spectrum, and by far the lowest cost option, is sequential verification. This relies purely on the intruder alarm system and no additional equipment. Even if one detector in the system is activated, a confirmed alarm will not be generated until a detector of different technology in the same area or alternatively a detector in a different room / area is activated. The theory is that a person walking through an area will naturally trigger more than one detector, but a bright car headlamp or other heat source is unlikely to. The main downside here is that no real information is gleaned from this system as to what the cause of the alarm might be, although there are extended signalling formats such as Contact ID and SIA that provide zone descriptions to trace the path of an intruder. It’s certainly not going to distinguish between a genuine intruder and someone who has returned to pick up his forgotten car keys without remembering to switch the alarm system off for example.

The third option, which sits in between visual and sequential verification in terms of security level and cost, is audio verification. As the name implies, this involves listening to the ambient noise in the area where an alarm has been generated. Whilst you may not have the luxury of being able to see what is happening in the area, you can glean a lot of information very quickly from simply listening; a breaking window, for example, is rarely a good sign!

A recent Stanley internal annual apprehension report showed that 35% of intruders came in through a door, 26% through a window, 25% through unconventional entry points (wall or ceiling) and 14% failed entry altogether. It is unlikely visual and sequential verification systems would have been able to detect the latter two meaning that nearly 40% of these illegal intrusions would not have been apprehended if audio verification had not been deployed.

As with visual verification, there are a variety of audio verification systems on the market. When an audio alarm is triggered, the system immediately alerts the ARC and transmits the sounds of the break-in attempt and a code describing the location of the activated audio sensor. Professional operators on duty around the clock listen silently to determine the nature of the noise and take appropriate action, such as calling the police or resetting the system. Audio systems can be used in most environments but are best suited to large sites such as schools and warehouses.

Stanley provides all three types of alarm verification system. Whilst visual and sequential verification clearly have a role to play depending on security risk and budget available, it’s audio verification with detection that we believe offers the best compromise between these two and, in many cases, the most suitable option.

Apart from just the cost factor, audio verification systems have a number of significant advantages over visual systems that you may not have considered. The first, and most obvious, is bandwidth usage; video uses up a lot, whereas audio’s impact on bandwidth is negligible. This therefore has further cost implications for organisations, as well as network management issues.

Also unlike visual verification systems, as well as sequential verification for that matter, an audio system isn’t dependent on line of sight. Cameras and motion detectors cannot see around barriers such as wall or cubicles. An audio verification system on the other hand doesn’t need to; you can hear a disturbance at any entry point to a facility, wall to wall, floor to ceiling.

With audio verification systems, the on-site equipment, including the audio sensors, are extremely unobtrusive and are less likely to be noticed by an intruder (even if they knew what they were looking for) than a CCTV camera. As a result, audio verification is the most likely system out of the three to result in catching a crime in progress – particularly welcomed by the police. Not only is the intruder entirely unaware he has been detected, but he often gives away a lot more information than he realises by audio, all of which can be passed to the police for a swift and appropriate response.

As police forces in England and Wales face cuts in central funding in the next two years of 4% then 5%, using police resources wisely is all the more essential. Ensuring police are only called to a genuine scene of a crime – and not a false alarm – is vital, as is the ability to provide genuinely useful information to allow them to allocate resources and direct officers on the ground to specific locations. Audio alarm verification, with detection incorporated into the system, is an affordable and efficient means of achieving this.

Stephen Murphy is Service Manager at Stanley Security Solutions