Light Pollution and CCTV
Light pollution is a global problem caused by inefficient, intrusive and unnecessary use of artificial light. Symptoms include glare, clutter, over-illumination and sky glow. Light pollution is an increasingly hot political topic given recent government legislation to control and punish light pollution.
It is the responsibility of CCTV professionals to provide lighting systems that provide high quality images and minimise light pollution.
The Categories of Light Pollution: Light Trespass - When light enters a zone or area where it is unwanted it is known as light trespass. This includes light leaking through a window, or into a neighbouring area. CCTV lighting must be designed to respect privacy zones..
Clutter - Dense groups of lights cause an intense clutter of illumination that can actively grab attention and distract from the true target of a human eye either directly, or through a camera system.
Over-illumination - If light is used in excess quantities it causes illumination beyond what is necessary. It is normally caused by poor specification and contributes to energy wastage and overexposure in areas of the image.
Sky Glow - The general glow over populated areas is known as sky glow. It is caused by a combination of badly directed light and light reflected from target subjects. Sky glow reduces contrast in the sky enough to obscure the stars at night.
Regulations Concerning Light Pollution
The Clean Neighbourhoods and Environment Act is designed to improve the quality of the local environment. It gives Local Authorities additional powers to deal with statutory nuisances including light pollution. The Act does not preclude the use of white-light illumination for CCTV, but it does state that the lighting should not cause a nuisance. The key term is “prejudicial to health or a nuisance”. As a result installers need to install lighting that has greater consideration to the surrounding environment. Correctly specifying the angle of illumination (or using Adaptive Illumination), to match the lighting to the target area or operating the light only upon an event trigger are all good practice.
The use of highly directional white-light illumination will help to minimise light pollution. Infrared lighting units cause no light pollution.
BS 8418 - The British Standard, BS8418 states there should be sufficient lights on site to illuminate the camera’s field of view making lighting an integral part of any CCTV system. However, it also states that cameras should not look directly into the sun or other light sources highlighting the need for dedicated CCTV lighting rather than relying upon existing lighting for CCTV.
Data Protection Act - There are requirements that all CCTV systems should have appropriate, sufficient lighting to ensure 24/7 operation. The Data Protection Act promotes the use of professional CCTV lighting.