Which column height: 3, 4 or 6 metres for streets, sites and cycle paths

Mounting height drives the whole design

An outdoor lighting design does not start with the luminaire but with the mounting height: the height of the light source above the road surface. It sets the light pool, the column spacing and therefore the number of columns, the wattage per luminaire and the risk of glare. Get the height wrong and the only fixes later are extra columns or heavier luminaires.

Light falls off with the square of the distance: the same luminaire at 6 metres gives roughly a quarter of the illuminance directly below the column compared with 3 metres, but spreads the light over a far larger area. Higher is more uniform and needs fewer columns, lower is more economical per column. Lichtplein supplies fixed combinations for both: steel columns TURRIS of 4 and 6 metres from stock, aluminium columns CIVIS of 3, 4 and 6 metres on a project basis and street luminaires VIA that fit them.

3 metres: footpaths, parks and entrances

Three metres is the height for places where people walk and linger: footpaths, park paths, small squares and the entrance to an office or business premises. A post-top luminaire with symmetrical optics works best here, for example from the POLARIS series with 16 to 60 W and adjustable colour temperature, preferably warm white at 3000 K or lower.

Keep the spacing short, in practice 12 to 18 metres, and the wattage low: at 3 metres the luminaire sits almost at a cyclist's eye level and a high lumen output blinds before it helps. The 3 metre aluminium column from the CIVIS series fits here: light, corrosion resistant without a coating and clean in appearance.

4 metres: cycle paths and residential paths

Four metres is the working height for cycle paths, pedestrian routes and narrow residential paths that fall under a P class of EN 13201. As a guide: P3 requires an average of 7.5 lux with a minimum of 1.5 lux, P4 an average of 5 lux with a minimum of 1 lux. Usually the minimum value between two columns is the limiting factor, and that is exactly where a slightly taller column helps.

Combine a 4 metre column with a street luminaire of 25 to 40 W and a Type II optic, which spreads the light along the path rather than into the verge. The VIA series offers the 25 W luminaire with 1,500 lm for this, matched to a mounting height of 4 metres; with modern optics spacings of 20 to 28 metres are achievable. For the column, choose the conical steel TURRIS of 4 metres from stock, or the aluminium CIVIS of 4 metres where weight or appearance is decisive.

6 metres: residential streets, car parks and business parks

As soon as cars drive, you move to 6 metres. Residential streets, car parks, loading zones and the internal roads of a business park need a wider light pool and benefit from spacings of 25 to 35 metres. For car parks, EN 12464-2 gives guide values of 5 lux for light traffic, 10 lux for medium and 20 lux for heavy traffic.

At 6 metres, street luminaires of 50 to 100 W fit, with a Type III optic for a carriageway or a symmetrical optic for a parking area. The luminaires in the VIA series (IP66) deliver up to 160 lm/W, have 10 kV surge protection and tilt on the 60 mm spigot, so you can aim the light pool at the road. Watch for houses close by: the higher the light point, the sooner light reaches a bedroom; a smaller tilt angle or a rear shield usually solves it.

Column spacing and wattage: the rule of thumb

For a first sketch: the spacing is 4 to 7 times the mounting height on paths and 3 to 6 times on carriageways; a wider optic reaches the higher factor. From that follows the output per column:

• 3 m: 12 to 18 m spacing, 1,000 to 2,500 lm, symmetrical post-top

• 4 m: 20 to 28 m spacing, 1,500 to 4,000 lm, Type II

• 6 m: 25 to 35 m spacing, 4,000 to 10,000 lm, Type III or symmetrical

These are starting points, not a design. Tree canopies, parking bays, bends and the colour of the road surface change the result. For a project, have a lighting calculation made: you receive the position, tilt angle and luminaire wattage per column and know for certain that the class is met.

Steel or aluminium, and what else belongs with it

The TURRIS steel columns are conical to the Dutch standard, hot-dip galvanised or additionally powder coated in RAL 9005, and are available in 3 to 5 weeks at a sharp price on request, answer within 48 hours. The CIVIS aluminium columns are lighter, do not rust and are supplied per project with price on request; they suit representative locations and combine with the solar column and the CityCharger charging column from the same series.

Do not forget the connection: every column gets a cut-out box in the door opening with fuse, earth lead and screw cap; the NEXUS series is matched to our steel and aluminium columns. Allow 3 to 6 weeks delivery and project prices from 20 columns. Lichtplein supplies businesses only, prices excl. VAT.

Frequently asked questions