Lighting LEDs
> than CFLs, they are 10 times more efficient than The housing also affects efficacy and lifetime. ‘The
incandescent, they are five times more efficient than best quality product could fail if produced in the wrong
halogen. The technology continues to develop and they way,’ says Barton. ‘The fundamental issue is heat
will become even more efficient. It’s not a matter of dissipation. If they run too hot, and you don’t thermally
whether they are more efficient, it’s that they still cost manage them properly, they will fail.’
considerably more.’ So how will specifiers sort the wheat from the
While the white LED is effectively a substitute for chaff in terms of quality? Barton is among those
traditional lamps, there is also a drawback when that reputable manufacturers which are pushing for the
is interpreted too literally. As a solid state source its introduction of standards so that buyers can believe
photometric distribution is different to other lamps what’s said on the tin and have some sort of redress if
and it therefore requires appropriate optics. A classic it’s misleading.
case has been the LED fluorescent tube replacement.
Lighting designer Mary Rushton-Beales of Lighting
Design House originally raised objections to it in
We need an independent body
the lighting press. ‘The differences are obvious: the
distribution, the appearance, the quality and the colour
that can look at claims on the label
of light. This will change the appearance of the space and decide whether or not it’s a load
completely...’ she wrote in a recent letter to a lighting
of twaddle – Peter Barton
magazine.
Shaw agrees with her: ‘These are the spawn of ‘What we are pushing for is getting some kind of
the devil and the most stupid application for LEDs. kitemark system to indicate the product’s passed some
Fluorescent lamps are a distributive light source, sort of standard. We need an independent body that
LEDs are directional. These things instantly destroy can go along and look at the claims made on the label
the optical design of any fitting they are installed in and and and decide whether or not it’s a load of twaddle.’
so make a nonsense of any design that has been done Roger Beckett, director of Light Projects Group, is
for the original installation. LEDs are their own thing among those who are exercised by the current claims
and need fittings that suit their characteristics.’ made for LEDs. ‘LED drivers are, in the most part, built
They ‘hold promise’ in directional lighting, he adds, to such a price that they will fail before 10 years, so
and predicts the same kind of revolution as the MR16 forget what the LEDs are meant to be doing. 50,000
caused when it rapidly displaced the PAR 38 and crown hours? For a client if their light is out, it’s out. If the
silvered spotlights of the 1970s. ‘For some reason the driver manufacturers would only spend an extra
current generation of lamp marketeers don’t think we £2 on the build of their drivers, some good quality
can handle a revolution in lamp type any more and capacitors, for instance, it would help. And even
LEDs are used to light up
keep trying to force LEDs into existing lamp form when manufacturers conform to the “recommended
Buckingham Palace
factors. I really think this is a very dumb thing to do.’ junction temperature, or below”, the chips still decide
to go slightly green to pink to blue.’
‘We have to get a grip on this issue,’ says Shaw. ‘LEDs
will never be the same as other light sources. The
nature of the manufacturing process results in a range
of characteristics in every batch so there will always be
issues with specification until there are standards that
all manufacturers follow.’ In the meantime how does
the specifier know what they’re getting?
‘We don’t,’ says Shaw. ‘We have to rely on developing
trust relationships with manufacturers and suppliers.
Traceability is entirely down to paper trails as you
cannot identify specific LED types and specifications
by inspecting the LEDs themselves.’
Routledge advocates a common sense mix: ask
the right questions, demand guarantees and go for
well-known, established names: ‘Specifiers should
demand the same information as for any other fixture
– photometrics, quality approvals and, dare I say it,
longer warranties. Manufacturers should stand behind
their products – it’s well proven that LEDs can last the
distance. Ultimately, work with trusted brands.’ l

LED Guidelines, jointly produced by professional
Sumner/Philips
lighting bodies, is available from the SLL. Visit www.
Edmund sll.org.uk
48 CIBSE Journal February 2010 www.cibsejournal.com
CIBSEfeb10 pp44-45,46,48_Leds.indd 48 28/1/10 16:39:51
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