When lighting a car park there are several factors which must be taken into consideration prior to selecting the light fittings or control mechanisms most suitable.
Lighting Scenario 1
Application: Open staff car park serving a private factory, low risk environment.
Here widely spaced low level lighting columns with High Pressure Sodium, (HPS), head units would probably be the most suitable for the application.
HPS, lamps are widely used for amenity lighting, and can be recognised by their characteristic pinkish orange glow. For the same reasons the fittings are used as amenity lights they would be equally suited to this application.
In low powered small quantity applications with low burn rates where there are large gaps in switching cycles the HPS lamp still returns excellent value, even when compares against LED and induction lamps. This is due to low maintenance, long lamp life, good light output in relation to running cost and cheap unit purchase cost. Maintenance would be cheap due to the good lamp life and low level access.
The above scheme could be controlled using a simple cheap and cost effective time clock and photo cell combination. Using this method of control the lights would be switched on during hours of darkness and held off during none operational times via the time clock. As this is a private car park and would only be accessed by site staff during operational hours it would be safe to switch off the lights outside of operational hours. This would ensure that the lights are only energised as they are required and in turn properly maintained would represent the most cost effective scheme.
Due to the relatively short burn times of the lights it would be hard to justify other lesser wattage more expensive head units as it would be almost impossible to see the commercial benefit, (payback).
Lighting Scenario 2
Application: Open customer car park, (same size as Scenario 1), serving a 24 hour public occupied city centre shop, medium risk environment.
Here the columns would be placed closer together, would possibly be taller with higher output head units installed in order to achieve the higher lighting levels required due to the higher risk environment.
With the columns being closer together there would be an increase in head unit quantities and the power output of the head units would probably be increased with the brighter lighting levels required.
In this application there is still no need to concern ourselves with the colour of the light so HPS head units could be considered for the same reasons as above.
The scheme could be controlled via a simple dusk to dawn photo cell as the area would have the potential to be occupied 24 hours a day. So, due to the increased quantity, longer burn times and higher power output requirements you may now start to see financial benefits from installing a lower wattage, all be it more costly energy saving variant of head unit such as LED or Induction.
Also worth factoring in to the above scenario is the cost of maintenance. Whilst the HPS lamps have a good life expectancy giving burn rates of between 10,000 and 40,000 hours we now have the choice of even longer lamp lives with LED and induction lamps returning typical burn times of 50,000 to 100.000 hours.
Using these examples further savings would be seen in maintenance costs as expensive access equipment would be required less often for lamp replacement and obviously labour costs would equally be reduced. One other benefit from LED and Induction lighting is the white light.
If in the future CCTV were to be installed then the white light would be required in order for cameras to function properly and to aid in the identification of individuals.
Whilst the two examples above could be the same car park the most suitable and cost effective choice of light fitting would vary due to the application.
If you now consider the individual aspects of internal lighting and the many more complexities including control systems available, from simple presence detection through to day light linking of dimmable schemes where natural light is present and then consider the almost unlimited applications you can start to see why good design pays, or in this case saves.
C Gascoigne Ltd. have many years worth of experience in helping companies make the right decision in lighting design. For a more professional approach and informed decision, contact us on 01509 341971 or via our contact form.