In this post we use a recent project to discuss the benefits of a lighting audit.
The project was a refurbishment of an entire office building which was constructed in the early 1990s. The building has a 2.6m high ceiling with over 1,200 custom made fluorescent luminaires.
The existing lighting creates several issues:
- High energy usage due to fluorescent tubes and old drivers
- Increasing maintenance costs
- Aluminium reflectors create a narrow beam leading to poor uniformity of light levels across the floors
- The narrow beam creates a dark ceiling giving a cave like effect as all light is directed downwards
- Poor glare rating, especially for a modern office where smartphones and tablets are used
- Poor vertical illumination – upper parts of walls dimly lit making ceiling appear lower
You can see from the picture below the dark ceiling and high glare
Client Requirements
The client wanted to upgrade the lighting to create a bright, modern workspace that is attractive to prospective tenants.
We also recommended to the client that we produce documentation to prove compliance with LG7. This documentation can then be provided to prospective tenants providing surety that the lighting is installed to the latest standards and will provide a comfortable visual environment for staff.
Solution
Given the large number of custom made luminaires we recommended the existing fittings were refurbished, replacing the fluorescent tube with a new LED gear tray and driver.
We specified the latest Tridonic LED boards and drivers mounted on a custom made steel tray. The high quality of the components allowed us to provide a 5 year guarantee and show the maintenance costs would be zero during this time.
The second part of the design was a new opal diffuser. This was designed to protrude only 5mm from the face of the fitting and to give a diffuse spread of light across the ceiling and a high level of uniformity across the floor space.
The highly efficient LED boards and driver use significantly less power than the fluorescent fittings giving the savings shown in the table below:
| Light type | Power consumption | Total power consumption | # hours per day | kWh/day | kWh/year |
| Fluorescent | 45W | 55.4kW | 10 | 554 | 140,162 |
| LED | 27W | 33.2kW | 10 | 332 | 83,996 |
| Energy saving per year | 56,166 kWh | ||||
In summary the lighting now complies with LG7, uses significantly less power and creates a low glare, visually appealing office space.
Before picture
Dark ceiling and high glare levels.
After picture
Diffuse glow from refurbished luminaires can be seen in the foreground. Note the light cast onto the ceiling makes it much brighter.
