Are you in control?

There has never been a better time to argue for digital lighting control. Part L of the Building Regulations and the Climate Change Levy are two reasons why it should be on the agenda – after all, for many buildings lighting represents up to 50% of the energy costs.

So why do most commercial lighting installations not have such systems? In reality the mass market remains unconvinced. The truth is that arguments about payback and end-user functionality will fall on deaf ears if the main contractor is concerned with bottom line costs. In fairness it is not they who will benefit from improved energy efficiency or functionality and they may lose the job if the tender price is too high.

As a result, lighting control solutions tend to be either a simple on/off switch or a sophisticated scheme that might even be wrapped up in a building management system. The former might not meet the needs of the end-user or Building Regulations, while the latter is expensive to install and commission, involves a lot of post-installation debugging and ultimately may not be fully exploited.

Currently there are few alternatives. Several top-end complex systems have attempted to satisfy the mass commercial lighting market. While these systems are undoubtedly simplified they do not reflect common lighting installation practice. So what is the answer for medium-sized commercial buildings?

It could be to approach the issue from the other direction. Examine what is common installation practice for basic on/off commercial lighting schemes and build from there. If the basic installation system is similar but intelligence is added, time and labour costs will remain broadly the same and energy efficiency and functionality will be improved.

Most commercial projects use marshalling boxes, where the hard wiring for power is terminated then fed to the individual fittings by this plug and socket interface. These luminaires are controlled by switches or sensors. Sensors offer a simple route to sophisticated lighting control. They also ensure compliance with Part L, where the control has to be within eight metres of the light fitting, and reduce on-site cost since cable runs to manual switches are not necessary.

For dimming control the problems begin when considering how to link the sensors to the luminaires. Do you need one sensor for every fitting with cabling between each. And then there is the issue of commissioning.

Do we really need individually addressable fittings? It's not practical if you want a system that meets the cost constraints of most projects. Also, luminaires do not work in isolation; even cellular offices will have at least two fluorescent fittings. If the answers are no, then there is no reason why marshalling boxes cannot be used for distributing power and data for multi-luminaire control.

Why not combine power and data in one cable and use the same plug and socket interface for both? If this is done there is virtually no change in installation practice between an off/on lighting system and a sophisticated dimmable one.

Commissioning such systems also needs demystifying. There is no reason why it should be complicated. Most installations want simple control linked to natural daylight levels and occupancy. Light levels and time-out settings are easily set, however adding too much choice after this simply causes confusion and makes the system harder to commission.

There is a huge latent demand for dimmable lighting control. The trick however, is not to ask what technology can offer but what the mass commercial lighting market wants.