There was a time – a few decades ago admittedly – when site lighting was an important part of overall security system design. The importance of lighting diminished as PIR-operated security lights aimed at DIY users flooded the market. This, coupled with misapprehensions about light pollution, meant that often the inclusion of lighting in security systems was not considered financially viable. However, lighting remains an important part of any security approach and its role becomes more appealing if you consider advanced control options.
Talk to many security installers or system integrators about lighting and they will immediately think about video surveillance. The lowlight performance of cameras is a critical issue in the security sector. Despite what some marketeers may want us to believe, the reality is that video does not work without some element of light. Image sensors require light to fall upon the pixels in order to create a signal. If there is no light (there is a significant difference between low light and no light) then there is no video signal. It is a simple matter of physics.
The issue of additional illumination for surveillance applications is one that is well understood in the modern security market. Changes in manufacturing processes and the introduction of surface mount technology LEDs have meant that illuminators – both infrared and white light – are now affordable for the vast majority of applications.
Where illumination was once the almost exclusive preserve of high-risk sites with deep pockets, today even the smallest and most budget-conscious users can enhance the performance of surveillance systems by adding dedicated lighting products.
Whilst the drive for the industry’s wider acception of surveillance-based lighting was undoubtedly driven by a desire to sell infrared products, the growth in white light alternatives does illustrate that more traditional lighting options are still popular with end-users.
At one time illumination manufacturers’ marketing efforts deliberately highlighted statutory nuisance legislation designed to reduce levels of light pollution. This message was designed to switch attention from general site lighting to surveillance-specific illumination products.
Whilst infrared illumination has many benefits for surveillance applications or video-based products, it does not often add value for any other part of the security system. Infrared illumination is not visible to the human eye, but can be used by IR-sensitive devices.
It allows the use of day/night cameras for around-the-clock protection, enabling the implementation of covert protection and does not impact on the environment. For those sites where light pollution is an issue, it is seen as a simple fix. However, in terms of general lighting it cannot provide anything.
There is always some debate around whether infrared lighting or white light illumination is the preferred option in surveillance. Whilst there is no definitive answer, it must be recognised that white light has more ‘pros’ than infrared lighting. That said, it also has a significant addition to the list of ‘cons’ in certain applications.
Whilst this article is considering the use of lighting in the wider sense, it is worthwhile considering how illumination is used in surveillance as this can impact on decisions relating to wider system design.
Visible or invisible?
Because lighting is most commonly associated with surveillance in security systems, it is probably a good place to start. Both infrared and white light illumination will enhance the performance of cameras in low light, harsh light and dark conditions.
With infrared illumination, IR-sensitive cameras are required and footage is delivered in black and white. Because infrared light is not visible to the human eye, it does allow systems to operate in a covert or semi-covert mode. Dependent upon the frequency of the infrared light, illuminators may emit a red glow which is only discernable at the lamp itself. There are no issues with light overspill into neighbouring properties when IR is utilised.
When white light illumination is deployed, standard video surveillance cameras can be retained and video footage can be streamed in colour. This is a benefit with regards to detection and identification of targets.
Colour is an easy-to-understand concept and simplifies recognition. With monochrome images, a suspect may be wearing grey, red, blue or green clothing, but an operator will not be able to specify the actual colours with any degree of certainty. With colour footage such details can be clarified and passed on to those responding to an incident, and will be understood. Colour recognition is a natural thing for most people.
An additional benefit is that the presence of white light allows passers-by and people in neighbouring premises to see what is going on during the hours of darkness. For many criminals, especially opportunists, this represents a significant deterrent.
An alarm sounding on a property shrouded in darkness may not raise interest or a response from those in the vicinity.
However, with white light illumination, that alarm will be combined with a visible indication of any activity. A siren coupled with clearly visible people loading items into a van will inevitably receive a different reaction and somewhat changes the scenario, increasing the likelihood that action will be taken. This obviously increases the threat of arrest for the criminals involved, acting as a deterrent.
Many applications are affected by the longer nights during the winter in the UK. With clock adjustments, it is not unusual for businesses to start the working day – or to end it – during hours of darkness. There are also an increasing number of businesses that operate 24 hours a day.
If white light is deployed, then this adds the benefit of general area lighting. For those with limited budgets, the fact that such an approach ticks boxes with regard to health and safety and provides a more convivial environment does make the additional expense easier to justify.
Given that the price differential between modern infrared and white light illuminators is not significant, the arguments for white light outweigh those for infrared illumination in the vast majority of applications. The same is true when considering the cost of ownership. It therefore makes sense for installers and integrators to consider the role of white light as a security tool.
Understanding pollution
There is one important proviso when looking at the use of white light: light pollution. The subject of light pollution is often misunderstood and part of the reason is because lighting manufacturers have – in the past – oversimplified it to stress the case for the implementation of infrared-based products.
The reality is that in the majority of cases adding white light to a premises will not constitute light pollution. Even where there are issues which need consideration, the design of the system can minimise the impact of lighting whilst preserving its effectiveness.
There has often been talk of artificial visible light being ‘banned’ due to the fact that it creates pollution. However, this is not the case. Councils are obliged to investigate complaints about artificial visible light if it can be classed as a statutory nuisance. In order for it to be judged as a statutory nuisance it must either ‘unreasonably and substantially interfere with the use or enjoyment of a home or other premises’ or ‘injure health or be likely to injure health’.
If visible lighting meets one of those criteria then councils may serve an abatement notice. This in effect requires the user of the lighting to cease its use or to implement restrictions on the lighting.
If the business or organisation has implemented the best practicable means to reduce the level of light pollution, this can be presented as evidence in an appeal against an abatement notice or a defence if a prosecution follows due to non-compliance with the notice.
Because there are no specific lux levels for artificial visible light to be considered a nuisance, any investigation regarding complaints has to consider all the circumstances surrounding its use and its impact on the environment. Any assessment of the situation will be based upon how it affects an ‘average person’. This means that arguments relating to the impact of lighting on people or properties with unusual conditions are not considered when deciding if the light constitutes a nuisance.
Whether or not the use of illumination in a security system would be considered a nuisance, it is imperative that installers and integrators always follow best practice when designing solutions. It should be a standard approach to try and minimise overspill, and ensure the location of lamps will not cause effects such as skyglow or light clutter.
Smarter control
Designing a security system which includes supplementary lighting controlled in a smart and effective way can counter issues with light pollution. However it must be remembered that lighting as a security tool offers a depth of benefits and increases the value of the system, and so it is important that designs are based upon the delivery of a more secure and safer environment rather than attempts to reduce pollution.
Introducing a level of smart control can actually enhance the effectiveness of lighting, both in terms of general use and protection of an area. A well designed and carefully considered lighting implementation should have a minimal environmental impact as a matter of course. Misdirected light is wasted light, after all!
Adding lighting products to a network opens up possibilities when it comes to control and automation. Whether integrated with dedicated lighting software, VMS or PSIM packages, alarm control panels, building automation or smart solutions, network connectivity enables a higher degree of remote control. This, coupled with power management options that deliver variable power outputs, opens up a variety of possibilities.
In the past, the options for lighting were invariably ‘on’ or ‘off’. Even when triggering was deployed, sites often moved between states of darkness and bright illumination. Because standard security lighting used integral PIRs which generally left much to be desired in terms of quality and stability, these were triggered randomly by a variety of objects ranging from an intruder, through animals and birds, to wind-borne debris. The limitations of such an approach are made obvious when you consider the so-called security lighting systems behaved in the same way whether triggered by a gang of criminals or a crisp packet!
With network-connected security illuminators, if the functionality of the device can be controlled by software then there is the potential for advanced control of certain aspects. For example, many dedicated surveillance illuminators have a feature to manage variable output power. This allows the installer or integrator to set the intensity of illumination. If this function can be software-controlled, there is an option for site-wide illumination to be set at a lower level which is suitable for general activity. When an alarm or event is signalled, the output power can be increased and the level of illumination will subsequently rise.
Such an approach ensures that visibility at the site is increased and video captured during an event is of the highest possible quality. At other times power is saved and issues such as skyglow are minimised. However, the site continues to enjoy the benefits of general security illumination.
If the lights are zoned, then different parts of the site can be treated appropriately. For example, if one boundary edges a residential area it may be necessary to treat lighting in that sector in a different way to other parts of the site.
The use of smart control also allows lighting to be used as a visual warning, either in conjunction with or as an alternative to audible devices. A first-stage alarm, such as a person entering the site, could be responded to by lights either being flashed or brightened. If the target continues to make their way into the protected area and approaches a building, then the flashing lights could be supplemented by an audible alarm such as a siren or a recorded voice message.
If a VMS with a comprehensive rules engine is being deployed, lighting could also be used after an event to direct responders such as security guards or the police to the location of the incident. This allows lighting with smart control to be used in a proactive way.
In summary
The term ‘security lighting’ brings to mind a DIY floodlight with integral PIR. However, given advances in network-based technology this need not be the case. If anything, installers and integrators should consider the implementation of lighting as part of a wider security approach.
Because many applications will require additional illumination to supplement surveillance devices, it makes sense to extend coverage where it can add value. The use of smart control with network-based systems adds flexibility and ensures that lighting enhances the level of protection on offer.
Maybe it is time that lighting once more became an integral part of a holistic security package.