Three ways to light an outdoor car park

Outdoor car parks have three common requirements: people must be (and feel) safe, vehicles and circulation routes must be well lit, and the luminaires must have optics that minimise upward and stray light.

Small car parks are often illuminated from the perimeter, and the high-angle throw required means tall columns are needed. Taller columns also have a greater daytime visual impact. This is especially relevant to car parks bordered by housing. Rearward spill light can also be a problem.

For these reasons, large car parks often have columns at the centre. These columns must have a barrier to protect them from vehicle impacts, but light can be directed in all directions from one position, thus reducing the number of columns needed. For larger areas, several lanterns can be arranged in a cross on top of the column.

How much light do you need? It is important to design car parks so light comes from several directions. This is to reduce deep or long shadows between the cars. Guidance on illumination levels is found in EN 12464-2 or BS 5489. There is sometimes a problem adapting to darkness when moving from a brightly lit supermarket to the outside. It is worth considering whether to light this zone to an intermediate level, although sometimes the spill light from the windows will accomplish this for you. A brightly lit supermarket car park is 20-30 lx.

Car parks may be empty for most of the night. Rather than switching off the lights, it is better to dim them to a low level and install sensors to brighten them when they detect movement.

This car park is 30m across and more than 50m long. All options use 8m-tall columns.

Lighting from the perimeter works best with narrow car parks. This option uses Kingfisher’s recently launched Viva-City street lighting lantern. The advantage is that we could have had very wide lateral spacing between the columns. We only needed the third to boost the illumination to the (comparatively high) lux level. An advantage of this scheme is the excellent uniformity throughout.

As with all streetlighting optics, less light is directed forwards, so we had to use some extra columns to boost the illumination in the central area.

This scheme would work almost as well with 6m-tall columns. These would have less visual impact by day and would be preferable in residential areas.

 

Tech spec

  • Luminaires Twelve Viva-City luminaires
  • Optical control Individually lensed LEDs
  • Arrangement Perimeter and centre
  • Average horizontal illuminance at ground level 17 lx
  • Electrical load for main car park 500W
  • Pros Good for lighting circulation routes
  • Cons The streetlighting distribution means low forward throw

Here we are using a 100W LED floodlight, the Aludra from Kingfisher. These are positioned only on the perimeter, keeping the central area clear. Whenever you use this type of solution, you must make sure that the beams cross over in the middle. If they don’t, you will get silhouetting and poor vertical illumination.

Also, you must take care that the aiming angle isn’t too high. If it is, you risk wasting energy by overshooting the area. If you are aiming the floodlight more than three or four times the height of the column, you might also find that glare could be a problem.

 

Tech spec

  • Luminaires Six Aludra floodlights
  • Optical control High purity aluminium reflector
  • Arrangement Perimeter only
  • Average horizontal illuminance at ground level 25 lx
  • Electrical load for main car park 600W
  • Pros Keeps the central area clear
  • Cons Watch you don’t aim them too high

There is a lot going for this scheme. It uses just two columns. On each, there are four Kingfisher 60W T-Led flat glass floodlights. The peak of the beam is emitted at about 60 degrees from downward vertical, with none above 90 degrees, so there is no upward light.

There is plenty of light along the driving routes and where people are loading their cars. Illumination does tail off towards the perimeter, but this is normally supplemented by spill light from the surrounding areas.

The advantages of this scheme are the low running and maintenance costs.

 

Tech spec

  • Luminaires Eight T-led floodlights
  • Optical control High purity aluminium reflector
  • Arrangement Centrally mounted only
  • Average horizontal illuminance at ground level 25 lx
  • Electrical load 475W
  • Pros Fewest columns and lowest power
  • Cons Rather low levels at the perimeter