LED tape is on a roll

9 January 2012

These are exciting times for LED products and one format, LED tape, is helping designers achieve previously unattainable goals. Mark Ridler, lighting director at multidisciplinary design practice BDP, celebrates this far-reaching innovation and shares with Lighting readers the results of BDP’s own internal product study.

The design community has long called for manufacturers to develop new products that are not simply LED versions of old ones, but to use this exciting technology to solve design problems in innovative ways that play to the technology’s strengths. One of the new kids on the block is LED tape. And what a wonderful tool this is, potentially. It is like nothing we have had before: small, cheap, bendy - and now sufficiently powerful for it to illuminate objects effectively. At BDP we have found more and more projects, across all sectors, where we want to use this form of lighting. External canopies, shelving, backlighting, coves, hidden details, kick details, and edge lighting, are examples.

For years I have been negotiating with exasperated architects and interior designers, fighting for space for lighting, and now here is a wonderful solution that can fulfill their dreams and mine. But, like all things in life, and in particular new technologies, there are drawbacks, and we need to be cautious. There are new parameters to be assessed and real-life lessons to be learnt. So at BDP we have made a close study of LED tape products and we present the results in table form on pages 34-35. The aim was not to declare a favourite, but rather to set out the different specification considerations to help designers avoid disaster, to help manufacturers help us specify their product and to disseminate our on-site experience. This is an exciting new product range with massive potential, but let’s avoid some traps that could quickly give this tool a bad name.

The survey
Normally the progress of new technology is that one manufacturer hits the market first. Early adopters excitedly jump aboard and start exploring potential uses. Then one or two other manufacturers join the fray and the applications proliferate. By this time, the whole manufacturing community perceives that everyone needs to have some of this and the market becomes chaotic. This is where we are now with LED tape. There is a lot on the market and a lot of it is of appalling quality. BDP’s survey aims to make sense of the chaos.

We have selected a range of products from reputable manufacturers and tested them across a number of objective and subjective criteria. It is not an exhaustive test, and there are some we tested whose manufacturers wished not to be published. Nor is the test definitive. Rather it’s a data source for future comparison of new products that cross our desk. But we did think it would be useful for Lighting’s readers, because it sets out one way that designers can evaluate product for their projects.

Click image to view the LED Tape Study results.

It should also help manufacturers understand what designers need to consider when specifying and to provide information simply and clearly to help them do so. The tests we chose are an enhancement of the Lighting Industry Liaison Group’s Guidelines for Specification of LED Lighting Products. It is an excellent document that many manufacturers and designers know nothing of. It is now on revision 2 and I think that a revision 3 could be developed to improve it even further

Life, output and colour
Rated life, light output, and colour (its consistency, rendering and stability) are the essential specification requirements for LED tape. Anything that degrades performance in these categories is a deal-breaker. For retail, extreme long life is less important than other properties but, even here, predictability is still essential. Kilometres of shelf lighting failing in the first year because of poor thermal management is bad. All the samples were rated 3,000K. No two tapes were the same. Beware encapsulation of LED tape, as this can raise the colour temperature. Manufacturers: please quote the performance of finished product, not the colour of the LED chips! Life should only be quoted with an associated lumen maintenance factor.

Installation
LED tape must be fixed to a clean, flat surface. Many contractors find this difficult. Building sites are dirty and screw heads and general debris seem difficult for many contractors to avoid. If glue is used, holding 5m lengths of spaghetti waiting for the glue to go off is a bit of a challenge for those with sausage fingers. The result is poor adhesion, poor thermal transfer and premature failure, not to mention unsightly droop. As an alternative, consider off-site prefabrication and, even if heatsinks are not required, fixing to metal strips of specified dimensions.

Making the grade

Luke Smith-Wightman and Tom Niven compare different samples

Heatsinks
Some need them, some don’t, apparently. Where the product needs them, would manufacturers please explicitly tell the designers what is required? The words “No heatsink required unless mounted on wood, in which case performance will be reduced”, translated, means a heatsink is required. Oh, and do tell us what size the heatsink needs to be.

Conformability
One of the great things about tape is that it can bend around corners. Check what the minimum radius is. Most tape can only bend in one dimension or a gentle helix. Consider your design details. We have found that the overwhelming majority of our projects require long, straight runs. The chain systems can accommodate any kind of curve, but need more specification in terms of fixing pitch and, potentially, more labour to install.

Cost
The cost per metre of LED tape varies by a factor of six. Lumens per pound sterling is a convenient measure of value.

Safety
Most LED tapes are extra-low voltage and safe to touch. But some run at temperatures that can burn and potentially damage nearby objects. Designers and intstallers should consider the fi re risk in dirty coving.

Stats
Some manufacturers’ quoted fi gures for power consumption (W/m), lighting intensity (lm/m), and effi cacy (lm/W) were not consistent. This may seem petty, but it throws doubt on the accuracy of quoted information.

Conclusion
There is no one killer LED tape, and some will serve some applications better than others. Information about the product needs to be assembled in a much more consistent fashion. Manufacturers need to work harder to explain installation both to designers and to contractors. On its side, the lighting profession needs to communicate more clearly the standards it wishes to see delivered and perhaps the category standard for ‘life’ should be extended to colour performance, so that products could market themselves simply, and protect quality players.