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What should we expect from �green� light fittings?

26-04-2011

There is a green haze spreading over the lighting world, blurring the edges and confusing the landscape. What exactly is a �green� light fitting � what should we expect from such a simple adjective?


For many, many people, the idea of �green-ness� in a light fitting (or a lamp) begins and ends with it�s energy performance; how few Watts get expended by it for how much light comes out of it. It�s the bedrock issue, I suppose. Energy bills are spiralling away into the stratosphere and all of the �get out of jail free� options seem to rely on the base-cost of energy production being expensive in the first place. So reducing the energy bill at the point of consumption is a sound economic choice � and if it helps with carbon reduction and climate change, that�s two gold stars instead of just the one.

But let�s investigate what �green-ness� can really mean. What should we expect from a �green� light fitting.

1. The energy consumption:
Building Regulations (Part L) currently determine that �low energy� status begins at 45 lamp lm/cctW (lamp lumens per circuit Watt) for domestic installations or 55 luminaire lm/cctW for non-domestic installations.
(There�s other stuff going on, but this will do for our purposes).
How should we read these figures?
For domestic work it�s fairly straightforward. If you�re using a light fitting that takes a lamp with a better efficiency than 45lm/cctW then you�re over the first hurdle to a �green scheme�. Also, it doesn�t matter what the light fitting is � you could hide a CFL (compact fluorescent lamp) in a hessian sack and it would still comply.
For non-domestic specifications the goalposts get shifted around to make life a bit more difficult. Now we�re talking about luminaire lumens/cctW so it�s all about the efficacy of the light fitting as well as the light source. Light fittings tend not to be 100% efficient, so the inherent losses push up the required efficacy of the lamp, perhaps by 20%, maybe more, depending on the luminaire � and you can forget the hessian sack!
Its possible to do it, but it risks a brutal outcome if the light planning�s not been done properly.
The GreenLight says: in the huge domestic market, don�t look for any lamp that�s less than 50lm/cctW.
In the commercial sector, beware the brutality of excess light output in luminaires that are carrying too much of a punch; it may be big, but its not clever. Be kind to people.

2. The light source:
The Part L requirements did an odd thing in October 2010; they shifted the definition of a �low energy� light fitting. Before then, only light fittings that had lamp-holders designed for low energy lamps complied with Regulations. It put pressure on luminaire designers to put a bit more effort into bringing low energy fittings to market, but it was the right thing to do.
Surprises all round, then when the October 2010 edition sweeps all that way and permits �ordinary� lamp holders like bayonet cap and Edison screw.
And why should this be?
Let�s assume that there�s a HUGE potential market developing for retro-fit low energy lamps, intended to fit into existing light fitting up and down the country and �. well, do I really need to go on?
A huge backwards step at a time when national newspapers are still running lunatic campaigns against the low energy lobby.
As far as I�m concerned, the current Part L provides a very simple cop-out for designers, contractors and clients who continue to specify/install/use the type of equipment that we really should be putting out to grass.
The GreenLight says: as much as it�s possible (and I know the problems), avoid the use of light fittings with �conventional� lampholders. Force the issue and use top quality low energy sources.

3. Health and well-Being:
It�s at this point that we part company with the conventional wisdom of what constitutes a �green� light fitting, because I believe that we should also ask a few qualitative questions as well as counting up the numbers.
Is this fitting really necessary / what happens if we don�t use it?
Who is this fitting for / does this fitting make life better for everyone?
What�s the driving emotion behind this fitting � fear / pride / joy?
Questions like this ought to be part and parcel of every lighting design process, but I seriously wonder sometimes.
The GreenLight says: become more conscious of your design process, and generally do less.

4. Working with other services:
There�s another section to Part L  that few lighting designers bother to read, which is a shame, because there are a lot of grumpy mechanical services engineers wishing that we would.
It�s a requirement that all new buildings are tested for air-tightness (its all about reducing heat loss caused by buildings leaking warm air). And every time that a hole is cut into a ceiling to fit a recessed downlight, it jeopardises the results of the air-tightness testing.
The GreenLight says: be aware of the needs of other services and don�t specify so many downlights!

5. LEDs:
Much as I�m trying to reconcile these new sources with the rest of the lighting world, LEDs still bring their own peculiarities to bear on specification.
There are basically three type of LED light fitting:
* where the LED is permanently embedded into the housing. If anything goes wrong, the entire fitting has to be replaced.
* where the LED is a �retro-fit� lamp intended for installing in existing light fittings. There have been incredible improvements in the performance of these lamps, but there are issues to be resolved in terms of their true power rating.
* where the LED is a �cassette� � the LED engine can be removed / replaced from the main housing. These are appearing at the top end of the market and I�d suggest that this is the real future of the �green� LED. Watch this space.
The GreenLight says: Think outside of the conventional downlight mindset for LEDs. And encourage new designers and makers to come up with the kind of radically new design that LEDs deserve.

6. The people who make and sell these things:
Once we�ve sorted out the relative green-ness of a product its time to look at the credentials behind the name on the packaging. We�ve all heard stories about some of the biggest retail names on the planet and some of the dodgy practices they�ve been involved in. There�s no difference when it comes to lighting product.
The GreenLight says: This is a whole extra topic, covered elsewhere on this site. But the essential thing is that the �green-ness� of a product is ultimately determined by the practices of the company/ies behind it.

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