Out with the old

One of the many environmental initiatives to come out of Europe is the gradual phasing out of older, less efficient light sources, and this process has already begun. As a result, building operators who hang on to older light sources such as T12 fluorescent tubes and some high pressure sodium (SON) lamps are now finding they have to pay a lot more for replacements.

For example, my experience of visiting many buildings shows there are still many factories in the UK using suspended T12 batten fittings to light the workplace. Now that these T12 lamps are being phased out, the price of each lamp could be as high as £15 – so for a factory with 500 fittings, just the cost of buying new lamps could be £7,500. And on top of that is the cost of wasted energy through using inefficient light sources, and the increased maintenance costs resulting from the short life of these lamps.

So just from a commercial point of view, there’s very little sense in keeping these installations going, and the environmental drivers are also starting to take their toll. For instance, the Carbon Reduction Commitment Energy Efficiency Scheme (CRC EES) penalises participating organisations that don’t make year-on-year improvements in energy efficiency.

In addition, given the likelihood that the Display Energy Certificate (DEC) scheme will be extended from just public sector buildings to all non-residential properties means that even those companies not participating in the CRC EES will need to look for energy savings. Plus, of course, saving energy increases profitability.

In my view, one of the most cost-effective ways of doing that is to upgrade the lighting, unless it’s already a relatively new installation using modern lamps, control gear and luminaires. I also feel this is an area where building services engineers should be providing suitable advice to their clients. In this respect they can also help them access additional support, such as Carbon Trust loans and Enhanced Capital Allowances (ECAs).

The first stage, of course, it to evaluate the existing lighting to establish whether there is room for improvement in light sources, light distribution and control strategy. For instance, an area that is currently lit with 4 x 18W T8 fluorescent fittings can be upgraded with 2 x 14W T5 luminaires to provide comparable light output at a fraction of the electrical load. Our experience shows that, when ballast losses are taken into account, the installed electrical load can be reduced by as much as 60%.

Similarly, where SON lamps are used for high or low bay lighting, they can also be replaced with high output T5 fittings. A 400W SON lamp running on wire-wound control gear, for example, may consume as much as 440W because of ballast losses. These can be replaced with 4 x 40W or 4 x 55W T5 fittings (depending on mounting height) – while maintaining illuminance levels and improving colour rendering.

In all of these cases, the replacement of luminaires can usually be carried out on a point-for-point basis so that re-wiring requirements are minimised to keep the capital costs of the project down. In many such cases, there are also loans available for upgrades that improve energy efficiency and companies like ours can help to identify those opportunities.

At this point, it’s important to stress that the lamp is only part of the equation. T5 lamps are quite different to their predecessors and require a different photometric configuration to maximise the light output ratio (LOR). It’s important, therefore, to use luminaires that are specifically designed for use with T5 light sources.

Control is also important and T5 lamps offer more flexibility in this respect than the older light sources we’ve been discussing as they can be dimmed, when combined with the right control gear, and provide light very quickly when switched on. In contrast, SON lamps have a relatively long warm up time when re-struck, so switching them on and off in response to changes in the space just isn’t an option.

Consequently, upgrading to T5 lighting creates an opportunity to introduce sophisticated lighting management regimes that massively reduce the wasted energy when lighting is left on unnecessarily. Linking the lighting to occupancy sensors and photocells measuring daylight levels are obvious examples of this.

It is now very clear that the UK is only going to achieve its emissions reductions targets by improving the energy efficiency of existing building stock. Assessing the lighting is an obvious step that will deliver quick energy savings with a fast return on investment.

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