External lighting: its implications and effects

18th February 2015


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Tim Jones of CH2M Hill considers the need for careful design of outside lighting to reduce light pollution

Well-designed external artificial lighting is very beneficial in the broadest sense, enhancing public safety, making roads safer, deterring criminals and allowing people to participate in evening outdoor sports activities. Essentially, it gives us a higher quality standard of life and boosts the night-time economy.

Despite such obvious benefits, concern remains at the increasing number of developments involving proposals for external artificial lighting, often in sensitive locations, and the effects such lighting has on the natural environment. This has resulted in complaints about “obtrusive light” or ‘light pollution”. So there is a growing need to consider the impact of external lighting on the environment, particularly in planning applications, where lighting schemes are a significant factor.

The raised profile of obtrusive light as an environmental issue is highlighted by the inclusion of light pollution in central government guidance on lighting matters, most notably in sections 101 to 103 of the Clean Neighbourhoods and Environment Act (2005) and light pollution guidance contained in the National Planning Policy Framework (NPPF). Paragraph 125 of the NPPF advocates that “By encouraging good design, planning policies and decisions should limit the impact of light pollution from artificial light on local amenity, intrinsically dark landscapes and nature conservation.”

There are number of different forms of obtrusive light. Typically this includes:

- sky glow, which is the result of wasteful and poorly directed lighting and reduces the ability to view the natural sky at night, a particular problem for astronomers. This is a problem found not only in urban areas but also in rural areas where dark skies at night are one of the special qualities of the rural landscape. Artificial lighting can also affect local character when poorly designed lighting systems introduces a suburban feel to rural areas.

- Glare, which can have serious implications for the visibility of motorists who may become distracted or blinded by lights spilling out on to the highway.

- Light spill or trespass is an issue where an artificial light source can intrude on the residential amenity in both urban and rural settings, causing stress and anxiety for people affected.

In development proposals it is essential that a balance is sought between the scale of lighting required and the implications it may have on the surrounding environment. From the outset, it is important to consider the “real” need for lighting early in the design process, focussing the requirements on those areas of a development that need to be lit to satisfy safety requirements and safeguard potential future occupants. The layout of a development proposal can also be used as an effective method of minimising the effects of external lighting if considered at an early design stage. The development’s location and what neighbouring areas are used for also needs consideration. Finally, the overall design of the lighting requires careful consideration. The emphasis should be to minimise the amount of lighting required and avoid over-illumination. This balances the lighting’s safety benefits and aesthetic qualities with the impacts on surrounding sensitive receptors.

In addition to ensuring effective design for new external lighting schemes, there are examples, of local authorities consulting on reducing existing sources of street lighting within their boundaries. This process is aimed not only at reducing light pollution but also at reducing the authority’s energy consumption and carbon footprint. The options include switching off the lights in some areas between midnight and 5.30am, thus potentially reducing light levels in those areas by 50 per cent.

Efficient and sustainable lighting is still a maturing technology but is becoming increasingly more common. LEDs, for example, can provide the required light levels with improved energy efficiency, reduced maintenance and cost savings and more easily controlled and efficiently designed lighting, and has the potential to lead to a reduction in light pollution. LEDS are now being installed by major supermarkets, particularly in car parking and operational outside areas.

The previous planning system supported supplementary planning guidance on lighting and a thorough approach to planning applications that involved the consideration of the obtrusive impacts of lighting when preparing local plans. However, while the new planning policy framework puts more emphasis on the effects of outside lighting, there may be more room for local authorities to take differing approaches and stances to dealing with light pollution.

This increased emphasis on reducing the effects of obtrusive light on local amenity and the natural environment is a step in the right direction, it remains to be seen whether this will have the wide-ranging impacts on planning policies and decisions on external lighting that many interest groups seek.

Tim Jones MSc AIEMA*

* The above article represents the personal opinion of the author and not necessarily those of CH2MHILL

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