I recently read a story on LEDs magazine about Toronto’s Palace Pier condominium tower becoming the largest residential LED conversion in North America. The Palace Pier is an upscale, 44 floor condo building with spectacular views that the designers wanted to carry over into the interior of the building. They replaced the existing 1300 MR16 halogens with direct MR16 replacement LED modules. The halogens consumed 35 watts of electricity versus 4 watts for the LED replacements. Kudos on being green!
The thing that I found most interesting here is that the contracted company providing the replacement LED fixtures does not put up complete specifications for either of their replacement LED products: no datasheets, nothing specific. Just a general 300+ lumens for their MR126 replacement product. I question the comparison in brightness between MR16 halogens and the LED replacements. The story just says comparable brightness but when you go to the CRS website, all you see is the 300+ lumens. Ignoring the fact that lumens is not brightness but total light output in all directions as measured in an integrating sphere, 300 lumens isn’t even close to the 1000+ lumens light output you get from a typical 35 watt, 12 VDC MR16 halogen lamp. What I am sure they are referring to is center beam candela, which is a brightness measurement but their website doesn’t have that specification. Perhaps the MR16 halogens they are replacing weren’t particularly bright, a very real possibility but who knows? I’m sure the fixtures were tested, at least by their own eyes, to make sure they were as bright or brighter but the published specs alone don’t bare that out. I am also sure that in this case it is just an oversight but it does lead me to ramble on about something that is all too common in the industry these days: confusing. missing, or misleading specifications.
Unfortunately, beam candela measurements have to take into account the measurement distance and the angle at which the beam is sampled, neither of which needs to be defined in the results. So a manufacturer that took a measurement at 4 feet away from the lamp over a 26 degree sampling angle and only came up with 480 Candela could retake the measurement at 3 feet from the lamp for a 10 degree sampling angle and get a more favorable 950 Candela and publish that as their spec without saying it was measured at 4 feet at a sample angle of 10 degrees. If these were separate manufacturers and separate lamps, how could you make a direct comparison based on 480 candela versus 950 candela without knowing the missing information? You couldn’t, really. Beam candela refers to how bright a narrow beam of light will look to an average human observer at some specific distance away. A lamp such as the replacement lamps used at the Palace, may only output 300 lumens but at a very narrow 15 degree beam angle so the brightness at, lets say 4 feet away may be quite high compared to an MR16 halogen at the same 4 feet with a more impressive 1000 lumen output but with a broader beam angle of 30 degrees. Kind of confusing isn’t it? One lamp manufacturer may publish their 1000+ lumens as a measure oft their lamps brightness while another may publish 850 Candela as theirs. So which one is brighter? You’d have no clue without actually buying each and testing them both. Errr!
As an LED manufacturer and distributer, I have a real problem with LED lamp manufacturers that do not put up their specifications and when they do, they only put up generalities or use the more confusing numbers such as lumens as an indicator of brightness. This leads to confusion and hurts the industry as a whole. I know of several large companies/institutions that would switch over to LED lighting if the market weren’t full of confusing and misleading numbers. They just won’t take the chance. The DOE, working on standardized testing methods for LED based architectural lighting, has run into this big time with submissions that had stated outputs no where near what the DOE’s testing bore out. Click here to read more about the DOE’s efforts on standardized testing methods for solid-state lighting.
Well I’m not going to go on much further. I said what I wanted to say. I’m not impugning the company in the story. In fact, congratulations to them on their success on this project. I’m merely citing the story as an example of an industry-wide practice that needs to improve if solid-state lighting hopes to make it into every home.:(