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How to light a building facade

Modern building facades can be just as worthy of floodlighting as historic ones. It’s the quality of architecture that counts rather than the age of the structure.

Floodlighting a building façade is a classic case of 'it’s not about the numbers' design. Of course, you can always calculate the vertical illuminance, luminance and uniformity values for a building but that’s not the primary goal.

That’s not say you can use any old floodlight. You will need good quality optics and tight beam control to achieve the effect you want. WE-EF are one of just a few companies who offer such a wide range of beam control accessories, visors, snoots and filters. Also, for the technically minded, their photometric files are easy to understand.

When floodlighting a façade, there are many non-engineering decisions to be made such as do you want the building to stand out or blend in with its background? Do you want a subtle or 'in your face' effect? Which parts of the building are worth highlighting? Do you want colour on the building? My default answer to this last question would be no, not unless you are sure of what you are doing. My own opinion is that colour on buildings is more often a blight than a benefit.

A related point is that you can save a great deal of energy by highlighting the attractive and architecturally important areas of a building rather than flooding the whole façade with uniform light. Similarly, switching off the lights (maybe after midnight) when no-one is around to see the building makes a lot of sense and can halve your energy cost.

The various options are meant to show different effects and styles of approach. The illumination level required to achieve the effect would depend on the location of the building. I.e. you would need a higher illumination level on a building in a city centre compared with the same building in a rural village. You decide on the effect first and crunch the numbers after. 

Our façade is about 35m wide and six storeys high, say 20m high.

The eagle-eyed amongst you will notice that some of the internal lights are on and some are off. That’s what happens in real life and means the building never appears as you planned it! 

Twin beam NTY100 bollards are used in all the options. 

• Option A
• Option B
• Option C

This scheme is designed to balance the various masses of the building. The main emphasis is on lighting all the front faces uniformly across the width. Recessed, ground mounted ETV140 units are used in an almost continuous line. We have used narrow beam units to achieve greater height.

Lighting a façade in this way means that there is a lot of reflected light on to the pavement and can avoid the need for extra lighting from columns which might obscure the view. You can see that the seating is clearly illuminated.

In the roof garden, we have used the IP rated DOC200 series recessed downlight to illuminate the flowers and shrubs. Beam spreads are available from 5° to 25° so you can precisely highlight just the plants and nothing else.

The window reveals, themselves, have been left unlit.

Tech Spec 

Luminaires

ETV140 recessed linear plus DOC200 downlight

Optical control

Asymmetric and symmetric pmma lenses

Pros

Creates a big impression