A few years back, the LED tube was the form factor everyone loved to hate. All the big lamp companies were briefing against them: they were inefficient, they had terrible light distributions, they didn’t last 10 minutes.They were also dangerous: some had terminals that would go live when the other end was inserted into a luminaire. Also, why did we need them when we had a perfectly good option: the good old T5?
In short, the LED tube was an LED development too far.
But the tsunami of Chinese products showed there was a market for the category – and all the big lamp companies have now unveiled their own versions. Osram was first to break ranks, revealing its T8 LED at Light + Building in Frankfurt last year. Now they all have them.
The cost – about £40 – is obscene compared with £1.50 for a T5, but the manufacturers believe they can tell a good story about maintenance and life. Maybe.
Creating the market
It’s been the Chinese who have created and developed the LED tube market. So we decided to test one of the best ones we could find. We chose a 28W version, made in China but developed by a Dublin-based engineering company, Lita Lighting.
Originally a Spanish company, Lita Lighting is headed by entrepreneur Sean Carthy, who believes that the LED takeover of the T5 market will be rapid: ‘In 10 years there won’t be fluorescent. There won’t be incandescent. It will all be LED.’
The results from the LED tube are extremely impressive: the lamp delivered a whopping 2,732 lumens, and a luminous efficacy of 98lm/W, just a whisker shy of the magic 100lm/W metric. This more than matches a high efficiency T5 lamp with a rated efficacy of 104lm/W.
So far so good. Sure, this is a stonking performance, measured in strict conditions, but efficacy isn’t everything. The thing to remember is that LED tubes aren’t direct replacements for fluorescent lamps. So don’t even think of putting them into a luminaire designed for fluorescent. Fluorescents have true omnidirectional distributions, but LED are directional sources, and it takes a lot of optics to change this. Still, LED tubes will have their place – especially if their performance is as good as ones like this.
HOW WE DID THE TESTS
The benchtest took place at Lux magazine’s official test house, the highly respected laboratories of 42 Partners in Wolverhampton. The tests were conducted in a 3.5m integrating sphere, one of the largest in the UK, and all measurements were taken in accordance with EN13032 and performed with the lamp in a horizontal, LEDs-down orientation. The lamp was treated as a luminaire with the LED cluster treated as an integral part. The photometric centre of the luminaire was taken as the geometric centre of the cover and the photometric nadir was taken to be perpendicular to the front face of the cover. The luminaire has been treated as though it has two planes of symmetry through the 0°/180° plane and the 90°/270° plane.
No measurement of the absolute lumen output of the LED cluster or of individual LEDs separate from the lamp assembly was made. For calculation purposes, the lumen output figure should be used in conjunction with a LOR of 1. No measurement of the ballast factor of the control gear was made.
The lumen output and power consumption of the lamp was determined at 25°C after 100 hours of burn-in.
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