Now, before you attack paper with pen in vitriolic defence of your profession, let me expand and explain. Where once, the brighter the better would have been the mantra of a lighting designer – think cathedral illuminations of a few years ago – with large floodlights blasting the exterior of a building and illuminating the night sky with a white glare, now exterior lighting should focus on the minimum lux levels required and directional beams.
Exterior lighting has changed a lot in the last 15 years. An industry that used to count roadside lighting as its mainstay now sees a proliferation of public and private exterior installations – almost every urban conurbation now has some form of public building or monument lit up against the night sky. And there is the problem: countless floodlights, uplighters, spotlights, security lights and decorative installations shining up and out into the night.
Light pollution has come to the forefront of debate within lighting circles for two reasons. Firstly, it is spoiling our night skies. In most major cities in the UK you will be hard pushed to pick out a constellation on a clear night, let alone get a good view of the Milky Way. And, to this end, the British Astronomical Association’s (BAA) Campaign for Dark Skies (CfDS) has been battling to get light pollution recognised and reduced. Second is something not as obvious to the casual observer but blindingly so (pardon the pun) to the contractor: power consumption – the more lights and the more light overspill, the more electricity used. This is no good for the CfDS, the client or the environment.
To answer to the debate on where, when and how much exterior lighting should be used is impossible. The ideal answer for the BAA would be no exterior illumination and thus no light pollution. This is impossible. Exterior lighting is needed for safety/security and even for purely decorative installations.
Making light work
Taking on board all that the BAA would like to see done can be quite a task, especially when trying to illuminate a large project such as a retail park. However, with some imaginative thinking and well-planned design even large car parks and external retail areas can be lit without too much light pollution.
Glasshoughton is a £200 million retail and leisure complex in Yorkshire. Contrary to the popular indoor out-of-town schemes such as Bluewater in Dartford and Meadowhall in Sheffield, Glasshoughton is an exterior development that opens both in the daytime and evening. To this end the lighting of all external areas has had to be designed to provide minimal light pollution, a safe environment for shoppers, as well as being an attractive feature. Contractor
N G Bailey, architect S&P and Thorn Lighting collaborated to pull off this feat of illumination engineering.
Lighting in the car park area uses lamp-posts between the bays. The post-top lanterns direct light down on to the parking bays and enable the use of cctv. The pedestrian areas linking the car park with the retail area have been lit using illuminated bollards. These ‘candle’ luminaires, dotted along the pathways, produce a low intensity light that denotes where the pathway is rather than illuminating it brightly.
The bollards continue right into the shopping area, where the need for greater illumination is tackled in two ways. Recessed ground luminaires have been set into the walkways along the malls. These throw up light on to the shop windows and overhanging canopies. There is little or no spill into the night sky. Three large squares dominate the intersections between the malls. These are lit brightly, as they are meant to be used to stage public events. However, an innovative solution to light spill has been achieved with the use of huge white tent-like structures. The tents are stretched over the squares and floodlights sited on the tents’ supporting columns. Pointing skywards, the floods illuminate the underside of the tents. The reflected light illuminates the area underneath with no light spill.
Decorative elements have also been incorporated into the project. Fibre optics illuminate water features, with colour-changing effects. A stream links the corner points of the site, meandering between pedestrian areas. This stream is actually a heavy-duty glass covered trough, housing over 4·8 km of fibre optic lighting. The optical fibres are arranged so that the blue light seems to flow along the stream. Features such as these add interest and originality but do not give off enough light to cause pollution.
Clearly, lighting schemes can be innovative, eye catching and bold, but they can also be intelligently designed and installed so as to create as little light pollution as possible. Dim is good, you see. You just have to be a little clever to work it out.
Source
Electrical and Mechanical Contractor
