Blinded by the light

Light pollution – defined as the excessive or inappropriate use of external, visible lighting – is an issue we are likely to hear more about in the coming year.

The Clean Neighbourhoods and Environment Act, which comes into effect in 2006, extends the list of statutory nuisances to include light pollution. That means it will affect you and your company’s CCTV installations if they do not meet the terms of the Act.

The new Act clears the way for a widespread clampdown on light pollution, and represents a major triumph for campaigning groups who have fought against the problem (the British Astronomical Association being one of them).

Already listed as a ‘nuisance’ under common law, light pollution was not included in the Environmental Protection Act 1990 (meaning that, to date, few local authorities have taken action against those responsible for causing artificial ‘sky glow’ and ‘sky glare’). The new laws allow local authorities to impose orders to “put right” any badly-designed lighting schemes, while affording them the overriding power to fine companies and individuals who fail to do so.

The security industry’s practitioners need to view the debate as a shot across its bows, because security lighting has been identified by both Government and campaigning groups alike as a key offender and major contributor towards light pollution.

It is important to understand that it’s not the use of security lighting itself that is the target of complaints. Such lighting only becomes a problem when it is excessive, poorly designed or badly installed. An area can be well illuminated without causing light pollution if the right illumination is installed in the correct way.

For CCTV purposes, the answer is to make use of low voltage infrared illumination which causes no light pollution at any wavelength, and which is specifically designed to help given cameras work to the best of their ability.

Light pollution: the major causes

Light pollution results from any external lighting that causes a nuisance or detriment to the surrounding area. It is caused when light ‘leaks’ out of its intended target area, either into neighbouring areas or up into the sky.

Light pollution results from any external lighting that causes a nuisance or detriment to the surrounding area. It is caused when light ‘leaks’ out of its intended target area, either into neighbouring areas or up into the sky

British astronomers have been particularly vocal on the issue of light pollution, claiming it ruins their appreciation of the night sky. As stated, the British Astronomical Association has been active in promoting public awareness of the issue. Groups such as the Council for the Protection of Rural England also campaign vociferously against the use of excessive lighting in the countryside, declaring that it destroys the character of rural areas and adversely affects wildlife.

Light trespass – caused when unwanted light spills from a commercial or domestic property into neighbouring ones – is another example of how light pollution can negatively impact upon our quality of life. Often the result of poorly-designed or misdirected security lighting, it is at best distracting and annoying. At its worst, light trespass can cause long-term health problems (including insomnia and anxiety), and can even give rise to a reduction in property values.

The security industry has been identified as a particular offender in the light pollution debate, chiefly due to the use of flood lighting as a security measure. Flood lighting illuminates an area for all to see, creating a visual deterrent to criminals and enabling CCTV cameras to see at night. However, it is also a major cause of light spill (and thus light pollution), and therefore must be addressed.

Solutions to the problem

The practical answer for security purposes is, in the first instance, the more intelligent use of detector-triggered systems as opposed to continuous flood lighting, while for CCTV surveillance the solution is to use infrared lighting (which is invisible to the human eye but visible to CCTV cameras).

For many years several prominent manufacturers have argued that infrared (IR) is the best illumination solution for night-time CCTV, chiefly because it is specifically designed to maximise the effectiveness of the CCTV camera. IR is an extremely effective illumination tool, and does not cause any light pollution at any wavelength. At lower wavelengths (around 730 nm) all that is visible from an IR lamp is an unobtrusive red glow. At 830 nm a very dull glow is visible and, at 940 nm, the light becomes totally covert.

There is sometimes a misconception that IR illumination is more expensive than visible illumination. However, when illuminators are installed correctly, the opposite is true. Energy efficient IR illuminators last longer and cost less to run. Illuminators with lower power consumption also provide other environmental benefits, such as lower carbon dioxide emissions resulting directly from reduced electricity use.

White lights that are properly installed and well-designed need not necessarily be the cause of light pollution. Areas can be very well lit as long as the illuminators direct light down towards the ground – very little light is reflected from normal ground surfaces, except under snowy conditions. All-too-often, however, visible security lights are not directed downwards, but outwards from the building towards the perimeter. This not only causes light pollution, but can arguably help intruders by dazzling onlookers.

White lights that are properly installed and well-designed need not necessarily be the cause of light pollution. Areas can be very well lit as long as the illuminators direct light down towards the ground – very little light is reflected from normal ground surfaces, except under snowy conditions...
...All-too-often, however, visible security lights are not directed downwards, but outwards from the building towards the perimeter. This not only causes light pollution, but can arguably help intruders by dazzling onlookers”

Targeted lighting is essential

The problem with a white light illumination scheme is that it is usually more expensive to illuminate perimeters and grounds correctly. Clearly, there is less cabling and installation work involved if lamps are mounted on a building, at the CCTV camera head, or at a single, central point and directed outwards to cover a wide area. That said, this does not necessarily provide enough light for CCTV cameras to see at night. The more costly alternative is to set up lights on posts at regular intervals. Only this design will provide the wide coverage needed, at the same time avoiding light pollution.

IR provides the ideal solution for situations where targeted illumination is needed (for example, where particular points on a perimeter have to be monitored). IR illuminators can be mounted at one point and directed horizontally outwards. Since IR is virtually invisible to the human eye, no light pollution is caused. This technique works with all CCTV installations, including static, pan and tilt and fully-functional domes.

Responsible system designers and planners need to be aware of the implications and legislation regarding light pollution, and take this into account during the design stage.

Philip Lynskey – managing director of Wakefield-based Calder Security – was recently asked to design and light a CCTV system at a warehouse adjacent to a residential area. “One elevation of the building is adjacent to a residential area, and the client asked us to cover the point with CCTV but avoid light spill,” he told Security Management Today.

Lynskey has been in the business since 1974, but this is the first time that light pollution has been raised as an issue by a client. “We’ve brought it up ourselves with customers in the past, particularly when dealing with residential installations, but it’s the first time that a commercial client has talked to us about it from the outset.”

For end users, the message is clear – forewarned is forearmed. The time to think about reducing light pollution is now. By phasing out wasteful lighting, security managers can avoid any hassle and expense when the new laws come into being.