Greengauge Director Hannah Jones has recently completed the Institute of Lighting External Lighting course, and on successful completion of some case studies, hopes to receive the Diploma in External Lighting. Greengauge have assisted with external lighting design on a number of projects in the past and Hannah’s new skills and knowledge reinforce our expertise in this surprisingly complex area of design.

External lighting is often overlooked, or is low down the list of priorities when it comes to both design and sustainability. Visualisations in project pitches rarely showcase the nightscape, and the impact of external lighting on the energy consumption is low down the list of priorities; the associated carbon emissions are ‘unregulated’, i.e. not accounted for in Part L, nor in Passivhaus. BREEAM does offer one credit but the criteria are rather simplistic. Often, responsibility for these systems is passed over to the local authority, who impose their own requirements, but this means that there is little incentive to achieve good levels of efficiency. On the other hand, LA requirements are usually driven by ease of maintenance and functional compliance, with little or no emphasis on creative, beautiful design. But it doesn’t have to be this way.

The course, reflecting the disciplines within the field, is divided into three sections (each requiring a week’s intensive study, plus coursework): Residential lighting, streets and roads; motorway and tunnel lighting; and Architectural lighting – including sports arenas, bridges and decorative lighting.

The design of external lighting is covered by a series of Standards, which set requirements for various situations. Much of the course is dedicated to understanding and interpreting the standards. However, there is always some degree of interpretation, and occasionally it is appropriate to deviate from the guidance. For example, in a Historic town such as our home of Bradford on Avon, designing in strict compliance with the BS would result in over lighting – increasing installation and running costs; where as more thoughtful approach taking into consideration wider aspects enables you to come up with a more sensitive, cost-effective and energy efficient scheme.

Hannah is looking forward to applying all this theory when working with local authorities and local councils. External Lighting has a huge impact on new developments and how they are perceived; it can make the difference between an interesting, and welcoming street scape and one that is threatening and even dangerous.

External lighting has a huge impact on how people move around the built environment. Safety is the fundamental factor – being able to see where you are going at night is taken for granted, but it takes careful design to achieve that effectively and efficiently. External lighting changes the way you perceive that space. If you can move around safely and have access to the centre of town, to cafés, to the night life of the space, local business will benefit. At a wider scale, good external lighting can facilitate more cycling and walking, and therefore heathier, more sustainable lifestyles.

The simple approach adopted in many cases is to over-light a space and rely on dimmable controls to address any complaints. It is our intention to be more pro-active as designers. For example, on a current project at Wimbourne Street in London, the employer’s requirements are simply to comply with a particular Lighting Class (set of specifications within standard). This enables us to use light as a powerful design tool in space-making; to encourage people into specific spaces such as play areas, and to lead them along key routes, while highlighting interesting features.

This can be a difficult job. Adding a new housing scheme adjacent to an existing residential area can present challenges in terms of how it is linked to the existing lighting scheme. Integrating a design that is visually similar but may need to comply with different standards is not always straight forward.

At Greengauge we are interested in delivering truly sustainable and low energy schemes that help people engage with their built environment. An important way of achieving this is to deliver light more efficiently to spaces, both inside and out. It is critical to carefully consider the control, type of light and how much energy it demands.

Another important aspect of external lighting design is minimising the impact on sensitive surrounding areas. This means avoiding light spill into neighbouring properties, as well as avoiding adverse effects on the natural environment. This can mean strict criteria on light levels, for example to protect corridors for bats and other nocturnal animals. Typically it is not just a limit on the Lux level but also a requirement of the colour spectrum. Often, a separate specialist consultant must be appointed to complete such designs, so we are proud to be able to offer this in-house, meaning one point of contact for our clients and the teams we work with. We are looking forward to continuing and developing our work with ecologists and landscape architects to ensure that our schemes have a positive impact not a negative one.

So perhaps the time has come for external lighting to step out of the shadows, and be acknowledged as a critical aspect of sustainable design, with the potential to influence energy consumption, beauty, safety, security, sustainable transport, ecological diversity and health.


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