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JANUARY 2016
1.1 Professional Lighting Design (PLD) have attended a number of design meetings regarding the proposed Laxey Bridge replacement where a design brief has been verbally issued. A study of the environment and how the areas are presently used by the public has been undertaken. 1.2 PLD created lighting concept proposals based upon the architect's concept produced by Niall McGarrigle.
2.1 The present lighting is standard roadway lanterns mounted at approximately 6 m onto telegraph poles either side of the bridge, the lights are of utility appearance, with a small protruding glass bowl, this results in a poor control of the light distribution of the surrounding areas, light spill and light trespass, with a large amount of general glare. Both these factors contribute to a negative pedestrian, visitor experience.
3.1 The general lighting concept is to illuminate the bridge and surrounding area responsibly ensuring that there is only positive impact from lighting additions. 3.2 All lamps specified for this project will be energy efficient, as recognised within the UK and IOM building regulations which identify energy efficient lamps as producing greater than 40 lumens per watt. All lamps will have a colour rendering index (CRI) of more than 60 CRI and likely to be more than 80 CRI (Appendix A 7.3.3)
3.3 The illumination of Laxey Bridge adjacent areas will achieve BS EN 13201-1:3003 under the classification for Lighting Class S4 - an average of 5 lux and a minimum of 1 lux. The relevant lighting guidelines which are being followed can be found in Appendix B.
3.4 Only specify luminaires which have published photometric data, ensuring performance can be verified, for example a high light output ratio for UK building regulations require 55 luminaire lumens per circuit watt. This will ensure the best solutions for efficiency and sustainability can be measured and proved.
3.5 Sustainability and Value Engineered solutions to include Whole Life Costings, low ongoing maintenance and running costs, will be followed as outlined in the IOM Government Procedure Notes for Management of Construction Projects. Also consideration of the Guidance Notes for the Reduction of Obtrusive Light as layout by the Institution of Lighting Professionals (Appendix C).
4.1 The proposal is to replace general roadway lighting with controlled luminaires reducing spill light and light intrusion, and illuminate particular features of the proposed Laxey Bridge Replacement as listed below. This solution can be developed due to the recent technological advances in the miniaturisation, greatly extended lamp life along with improved colour temperature and colour rendering properties of certain Light Emitting Diodes (LED) products.
4.2 Illumination of the river from the deck of the bridge to the river using linear LED allowing for the bridge's shape to be reflected in the water.
4.3 Illumination of the edge of the bridge deck itself using linear LED to highlight the bridges form. 4.4 Illumination of the seating area from two spotlights mounted upon the feature mast. 4.5 Staggered illumination of the lighthouse replicas to emphasise its form and features. 4.6 Handrail illumination to produce a general illumination in the pedestrian areas. 4.7 A drawing showing the lighting layout of the proposed luminaires can be found at drawing P1635160112-01P (Proposed Lighting Layout).
Lighting Classification. The lighting design has been based on the following assumptions. 1.1 Environmental Zone Category: E2 Laxey can be considered within the Environmental Zone for exterior lighting control as defined by the Institution of Lighting Professionals, as a Category E2: Low district brightness areas, as a rural, small village, or relatively dark urban locations. 1.2 BS EN 1301-2:2003 Road lighting classes: Laxey Bridge, Old Laxey Hill and Glen Road can be considered a Lighting Class S4: Subsidiary roads (pedestrian and cyclist). 1.2.1 The area is considered to have a low crime rate 1.2.2 Colour rendering will be greater than 60 Ra . 1.2.3 Normal traffic flow refers to areas where the traffic usage is a level equivalent to housing estate access road and can be associated with local amenities such as clubs, shopping facilities, public houses, etc.
Illumination Guidelines The lighting design has been based on the following assumptions. 1.1 The BS EN 13201-1:3003 states Lighting Class S4 - an average of 5 lx and a minimum of $1 \mathrm{~lx}$. This would apply to the areas lit currently, whereby the entrance to Breeze Hill and the roadway outside the Shore Hotel are illuminated. 1.2 Consideration has been given to the Institution of Lighting Professionals - Guidance Notes for the Reduction of Obtrusive Light GN01 1.2.1 Sky Glow upward light ratio, with special care to minimise any upward waste light by proper application of suitable directional luminaires and light controlling attachments. 1.2.2 Light Trespass (into windows) pre and post curfew (23:00) 1.2.3 Source Intensity - This applies to each source in the potentially obtrusive direction, outside of the area being lit. 1.2.4 Building luminance - This should be limited to avoid over lighting, and related to the general district brightness.
"Think before you light - The right amount of light, where wanted, when wanted."
Man's invention of artificial light has done much to safeguard and enhance our night-time environment but, if not properly controlled, obtrusive light (sometimes referred to as light pollution) can present serious physiological and ecological problems.
Obtrusive Light, whether it keeps you awake through a bedroom window or impedes your view of the night sky, is a form of pollution, which may also be a nuisance in law and which can be substantially reduced without detriment to the lighting task.
Sky glow, the brightening of the night sky, Glare the uncomfortable brightness of a light source when viewed against a darker background, and Light Intrusion ("Trespass"), the spilling of light beyond the boundary of the property or area being lit, are all forms of obtrusive light which may cause nuisance to others and waste money and energy. Think before you light. Is it necessary? What effect will it have on others? Will it cause a nuisance? How can you minimise the problem?
Figure 1 - Types of obtrusive light
Do not "over" light. This is a major cause of obtrusive light and is a waste of energy. There are published standards for most lighting tasks, adherence to which will help minimise upward reflected light. Organisations from which full details of these standards can be obtained are given on the last page of this leaflet.
Dim or switch off lights when the task is finished. Generally a lower level of lighting will suffice to enhance the night time scene than that required for safety and security.
Any lighting scheme will consist of three basic elements: a light source, a luminaire and a method of installation.
Remember that the light source output in LUMENS is not the same as the wattage and that it is the former that is important in combating the problems of obtrusive light.
Most nightime visual tasks are only dependant on light radiated within the visual spectrum. It is therefore NOT necessary for light sources to emit either ultra-violet or infra-red radiation unless specifically designed to do so. It is also understood that light from the shorter wavelengths of the spectrum has important effects on both flora and fauna that should be considered.
Research indicates that light from the blue end of the spectrum has important non-visual effects on the health of the human body, in particular in our sleep/wake patterns. It is therefore important to appreciate that while in obtrusive light terms the use of blue light should be minimised, there are many night-time tasks such as driving and sports where to be fully awake is an important aid to safety.
Care should always be taken when selecting luminaires to ensure that appropriate products are chosen and that their location will reduce spill light and glare to a minimum.
Use specifically designed lighting equipment that minimises the upward spread of light near to and above the horizontal. The most sensitive/critical zones for minimising sky glow are those between $90^{\circ}$ and $100^{\circ}$ as shown in Figure 2 and referred to as the lower, upward light output zone (UL).
Figure 2 - Critical luminaire angles For minimising sky glow
For most sports and area lighting installations the use of luminaires with double-asymmetric beams designed so that the front glazing is kept at or near parallel to the surface being lit should, if correctly aimed, ensures minimum obtrusive light.
Appendices 1 and 2 to these notes gives more details of how to choose and if necessary modify luminaires.
In most cases it will be beneficial to use as high a mounting height as possible, giving due regard to the daytime appearance of the installation. The requirements to control glare for the safety of road users are given in Table 3.
Keep glare to a minimum by ensuring that the main beam angle of all lights directed towards any potential observer is not more than $70^{\circ}$. Higher mounting heights allow lower main beam angles, which can assist in reducing glare. In areas with low ambient lighting levels, glare can be very obtrusive and extra care should be taken when positioning and aiming lighting equipment. With regard to domestic security lighting the ILP produces an information leaflet GN02:2009 that is freely available from its website.
Figure 3 - Luminare aiming angles
When lighting vertical structures such as advertising signs, direct light downwards wherever possible. If there is no alternative to up-lighting, as with much decorative lighting of buildings, then the use of shields, baffles and louvres will help reduce spill light around and over the structure to a minimum.
For road and amenity lighting installations, (see also design standards listed on Page 5) light near to and above the horizontal should normally be minimised to reduce glare and sky glow (Note ULR's in Table 2). In rural areas the use of full horizontal cut off luminaires installed at $0^{\circ}$ uplift will, in addition to reducing sky glow, also help to minimise visual intrusion within the open landscape. However in some urban locations, luminaires fitted with a more decorative bowl and good optical control of light should be acceptable and may be more appropriate.
Figure 4 – Façade Illumination
Since 2006 “Artificial Light” has been added to the list of possible Statutory Nuisances in England, Wales and Scotland. The monitoring of such nuisances will be the responsibility of Environmental Health Officers (EHOs) for which separate guidance is being produced.
With regard to the planning aspect, many Local Planning Authorities (LPAs) have already produced, or are producing, policies that within the planning system will become part of their local development framework. For new developments there is an opportunity for LPAs to impose planning conditions related to external lighting, including curfew hours.
The Scottish Executive has published a design methodology document (March 2007) entitled “Controlling Light Pollution and Reducing Energy Consumption” to further assist in mitigating obtrusive light elements at the design stage.
It is recommended that Local Planning Authorities specify the following environmental zones for exterior lighting control within their Development Plans.
| Table 1 – Environmental Zones | |||
| Zone | Surrounding | Lighting Environment | Examples |
|---|---|---|---|
| E0 | Protected | Dark | UNESCO Starlight Reserves, IDA Dark Sky Parks |
| E1 | Natural | Intrinsically dark | National Parks, Areas of Outstanding Natural Beauty etc |
| E2 | Rural | Low district brightness | Village or relatively dark outer suburban locations |
| E3 | Suburban | Medium district brightness | Small town centres or suburban locations |
| E4 | Urban | High district brightness | Town/city centres with high levels of night-time activity |
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