Outdoor car parks vary enormously in size and location. However, they all have three basic requirements. People who use the car park must be (and feel) safe. Related to this, the vehicles and circulation routes must be well illuminated. Lastly, the luminaires need to have well controlled optics to minimise upward and stray light.
Firstly, the car park needs to be safe. If it is near a shopping centre, there can be a confusing mix of distracted shoppers with trolleys, young children and drivers thinking about which way to go. From a lighting perspective, you don’t want any dark shadows. Good uniformity not only makes moving around safer, but helps people getting in and out of their cars. Have you ever dropped your keys in a shadowy car park?
It is important with car parks to design them so that light comes from several directions. This is to reduce the chance of deep shadows between the cars. Guidance on illumination levels is found in national standards such as EN 12464-2 or BS 5489.
Small car parks are often illuminated from the perimeter. If the car park already exists, it saves digging the surface to install cabling. The disadvantage of this method with wide car parks is that due to the high aiming angle of the beam required, taller columns are needed compared with locating them in the centre. 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 an issue with tall columns. However, an advantage of tall columns is that you need fewer of them.
For these reasons, where possible, large car parks often use columns inside the area. Centrally located columns need a physical barrier to protect them from vehicle impact. However, they have the advantage that light can be directed in all directions from one position, thus saving on the actual number of columns required. For larger areas, it may be necessary to mount several lanterns in a square shape or cross arrangement on top of the column.
Car parks are often used for limited periods of time and may well be empty for most of the night. No-one wants to enter a dark car park, even if it does switch on once you are inside. Rather than completely switching off the lights, it is better to dim to quite a low level and install sensors so that the lighting can be brought up to full brightness when they detect movement.
There is often CCTV. If possible, find out where the cameras are so you don’t block or dazzle their line of sight.
You should also consider the daytime appearance. The choice of lantern or floodlight should match that of its surroundings. DW Windsor has a wide range of heritage style lanterns to match the period of the surrounding architecture. Likewise, modern architecture deserves stylish, well-designed contemporary luminaires.
Similarly, a few tall columns may be the most cost effective solution but they can be “impersonal”. Shorter columns are much human scale and more likely to give an inviting appearance to the space.
This car park is 50m across and approximately 70m long. The designed horizontal illumination level in all the options is 20 – 30 lux.
It is interesting to see that all three options have a very similar power consumption. This is due to all the lanterns having efficient optical systems and LED light engines.
The Kirium 2 lantern is designed specifically to optimise the use of LEDs. It isn’t a converted HID streetlight but, instead, every part of it has been designed purely for LEDs. It is available in four sizes and there are 23 different optical distributions.
Here, we have used them on 8m columns, approximately 20m apart, in the centre of the car park mounted back to back in pairs. There are also single units on the two long sides. You can use a symmetric light distribution where you want uniform light all round and a “street” type optic for illuminating the driving lanes.
We have given the lanterns a 15° upward tilt in order to project more light towards the driving lanes.
Tech spec A
- LuminairesKirium 2
- Arrangement4 single lanterns on long sides, two rows of twin lanterns centrally
- Average horizontal illuminance
- 29 lx
- Lantern wattage
- Pros Efficient and wide choice of optics
The Katana range of floodlights is mainly designed for lighting large areas. The most powerful emits 88,000 lumens and has precise optical control.
Ours is a mid-size car park and so we used one of the smaller wattage versions. These are mounted on 10m columns around the perimeter of the car park. Just four columns on each long side are needed.
In essence, the Katana is a weatherproof LED module measuring 221 x 860 mm (8.7” x 34”) and this can be grouped in to one, two or four modules. Each module can be individually adjusted in 5° increments and there is a wide range of wattages. There is the option of a top visor for use in locations where there must be no upward light.
This has the lowest running cost of the three options.
Tech spec B
- LuminairesKatana IndustrialArrangementFour on each side with one module on eachAverage horizontal illuminance
- 28 lxLantern wattage
- Pros Ideal for large areas
DW Windsor has a huge range of traditional and heritage lanterns to meet almost any architectural style. In its time, gas lighting was the very latest in illumination technology and this concept has been extended so that these traditional style lanterns incorporate the latest LED technology.
It is often the case that a car park is surrounded by both modern and traditional architecture. Designers may need to offer both styles of lantern and let the client choose which they prefer.
Four different light distributions and three wattages are available as new or retrofit solutions to the whole DW Windsor range of traditional lanterns.
We have used the ever popular Windsor lantern but remember that the whole range of traditional lanterns can be fitted with the latest LED optics.
Tech spec C
- LuminairesWindsor Arrangement4 single units on long sides, two rows of twins centrallyAverage horizontal illuminance
- 22 lxLantern wattage
- Pros Blends with architecture