How to Light, Outdoor

How to Light: High tech campus

We have called this exterior space a high tech campus but the architecture is similar to many modern hospitals and universities.   

The general layout is that there are groups of buildings, often with colonnades or covered areas, linked by open pathways and surrounded by lawns. There is often a central area where people can congregate and talk.

It’s a golden rule of exterior lighting that people don’t like crossing unlit open spaces at night. As such, the main factor in your design is that the lighting should clearly illuminate the route from beginning to end without any dark areas. As well as the illumination level, most national standards also give guidance for the level of uniformity. This is described in terms of the minimum to the average illuminations and is typically >25 percent.  Pools of light look good on a computer rendering but can be a nightmare for people with impaired vision.

In terms of illumination level, you should check what lighting guidance is available. For the basic functional requirements of the lighting, you should refer to a national standard such as EN 13201. Some people argue that because these spaces and buildings are often privately owned, there is no need to conform to a “public” standard. However, it would still be necessary to conduct a risk assessment and this may well conclude that you need lighting. In which case, you might as well follow a recognised standard.

Another consideration is what time the lights should switch off. The simplest solution is to leave the lights on from dusk to dawn but this can be unnecessarily wasteful of electricity. Switching off completely after a certain time (the curfew time), say midnight, is a good solution if you are sure the pathways will not be used after that time.
However, for a hospital or university with halls of residence, the best solution is to use movement detectors to dim the lighting down to about 20% when the path is not in use and then trigger full light output once someone is detected.

Lastly, there is the thorny issue of what colour temperature, CCT, to use for the light source. Any opinion on this topic will be met by someone else who disagrees. My own would be to follow the general trend to use Warmer, rather than, Cooler light sources. I am saying no more!

The area in the image is about 80m from front to back and the paths are 2m wide.



This combines two new products from DW Windsor. The lighting on the main footpath uses the Sephora. This is a circular  lantern and can be used in a single “disc” version, a halo shape or a combination of the two. The big advantage of the Sephora is that it is a complete family with light output from 1,000 – 16,000 lumens.  There is also a range of optical distributions which can illuminate anything from a narrow footpath to a dual-carriageway.

The 450mm (18”) diameter unit used here is mounted on 5m columns. These are typically at 20 – 25m spacings (65 – 85’).  We have used the B type optic which is specifically designed for footpaths and narrow roads. You can see that the light extends a little way behind the column and just beyond the far side of the path.

On the subsidiary paths, we have used the brand new REN bollard. This is designed for functional level wayfinding. It has clean, simple lines and gives enhanced vertical illumination. I.e. it emits some upward light to illuminate people’s faces. We have used the 1m tall version and other models are 400 and 600mm high. We have used the nominal 2W version at 5m centres.

Tech spec A
  • LuminairesSephora 450 and REN bollardSpacingTypically, 20 – 25m and 5 – 6m
  • ArrangementSingle-sided
  • Mounting height  5m and 1m
  • Wattage per luminaire  Nominal 24W and 2WPros  Plenty to attract the eye

Clean lines

Clean lines

This again uses the Sephora on 5m columns with similar spacings. However, this time we have increased the illumination in the central square by using the Sephora with a symmetrical C1 optic. This light distribution is ideal for area lighting, town squares and car parks.

As a result of the broader spread of light, we have reduced the number of bollards on the smaller footpaths. We have also increased the illumination at the entrance to the three main buildings.  In this way, the central section of the path can be at a lower level of illumination because either end acts as a visual “goal”.

This is a small scale application for the symmetrical optic but you could use the Sephora at 8m, and even higher, with a 16,000 lumen light engine.

Tech spec B
  • LuminairesSephora HaloSpacingTypically, 20 – 25mArrangementSingle-sided
  • Mounting height  5m
  • Wattage per luminaire  Nominal 24W and 2WPros  Draws your attention to the centre



This third option uses the highly popular Kirium Pro family of luminaires.  For this small scale application, we have use the Kirium Pro Mini with a delivered output of 350 – 5,950 lm. There are larger versions of the Kirium up to the Pro 3 with a whopping 36,470 lumen output. The Kirium Pro has a huge range of optics but, like the Sephora, we have used the B1 type for footpaths.

The Kirium Pro gives excellent uniformity on long, narrow roads and footpaths and you can achieve very wide spacings thus making it a very economical choice where budgets are tight.

As an alternative to a centrally mounted column in the square, we have used the shorter versions of the REN bollard. These provide low level pools of light in the seating area.

Tech spec C
  • LuminairesKirium Pro Mini and 600mm high REN bollardSpacingTypically, 15 – 25mArrangementSingle-sided
  • Mounting height  5m and 600mmWattage per luminaire  Nominal 24W and 2WPros  Economical