Lighting for the offices and facilities

Lighting

For the offices and facilities

Figure 1 : Path of the sun during a year

For the offices and the facilities we chose to maximise the use of natural light.

After studying the path of the sun in summer and winter, we decided that the best way to use daylight is to make a semicircular argon filled double glazed facade facing south.

Figure 2 : Argon filled double glazing

So according to average illuminance value[2] we need:

For the stairs and corridors : 150 Lux at floor level
For the restaurant/ WC/ kitchen : 200 Lux at floor level
For the open space and offices : 450 Lux at desk level

We chose to use PSALI, Permanent Supplementary Artificial Lighting of Interiors. It’s a system combining artificial lighting and daylight where the two are blended together to provide an even illumination.

The principle of PSALI is to provide illumination that appears like daylight thats why we decided to use 162 Ceilling Smart LED of 45 W for the open space and 2 LED in each cellular office. This will provide 423 Lux at desk level according to estimation made by Dialux.

PSALI also control the switching of lights on and off as daylight levels go up and down thanks to outside detector of light. It also integrates occupancy sensors for the stairs, corridors and WC.

Why argon filled?[1]

Energy saving
Acoustic performance
U-value from 1.8 to 1.9
Cost only 5% more than air filled
More efficient if we combine it with low emissivity glass

Figure 3 : Heat loss reduction

Figure 4 : Typical office lighting

References

[1]Double Glazing Info. (2008). Air or Argon gap. Available: http://www.double-glazing-info.com/Choosing-your-windows/Air-or-Argon-gap.

Last accessed April 2015.

[2]Apollo Energy Tech. (2014). Cibse recommended lighting levels. Available: http://www.apolloenergytech.co.uk/cibse-recommended-illumination-levels/. Last accessed April 2015.