Jeanine Chrobak-Kando, Business Development Manager, LED EUMEA, Verbatim

Transcription

1 A guide to lamps for recessed lighting Jeanine Chrobak-Kando, Business Development Manager, LED EUMEA, Verbatim The idea of a recessed light, or downlight, that has a near-flush fit to a ceiling or other surface, is perhaps perceived as a relatively recent phenomenon. But it was an American, Ivan Kirlin (b.1863, d.1940) who first introduced recessed lights back in the 1930s. The company he founded in 1895, Kirlin Lighting, is still in business today. Recessed lights consist of a trim, the visible part of the light, and the housing, or fixture, which is sometimes called the lamp holder. The fixture is fitted into the ceiling or other surface. Recessed fixtures are used for background and task lighting and there are now many different types as a result of technology development, regulatory requirements and evolving consumer preferences. At the same time, light sources, reflectors and lenses specifically suited for recessed fixtures have been developed. The parabolic aluminised reflector (PAR) lamp Lamps for recessed lighting need to direct the light if most of it is not to be wasted going up into the ceiling. The first and most common way of controlling the width of the light beam was by integrating a parabolic aluminized reflector (PAR) into the lamp. Early PAR lamps used incandescent light sources and usually had screw fittings, most commonly E14 or E27. Later PAR lamps used halogen light sources, often with GU10 bases. The socket types are shown (not to actual size) in Figure 1. The tendency for early halogen light sources to explode upon failure meant that glass covers were needed on either the lamps or the fixtures as a safety precaution. These directional lamps are widely used in commercial, residential and transportation applications. Two standard nomenclatures were developed for them. The first was the R series designation R50 denoting a lamp with a 50mm surface diameter and R63 a lamp of 63mm diameter.

2 The second nomenclature defines their size with respect to a PARxx designation. For example, a PAR64 lamp has a nominal 8-inch diameter and a PAR16, a 2-inch diameter you simply divide the PAR number by eight to determine the size. An R50 is equivalent to PAR16 and an R63 to a PAR20. Each size of lamp will also have a defined beam width. Wider beams are used for general lighting and narrower, more intense beams for task lighting. The beam widths are defined as very wide flood (VWFL) of 60 degrees or more, wide flood (WFL) of 55 to 60 degrees, flood (FL) of 35 to 40 degrees, spot (SP) of 8-20 degrees, narrow spot (NSP) of 8 to 15 degrees, and very narrow spot (VNSP) of less than 8 degrees. The definitions vary slightly by manufacturer. In today s LED lamps, a lens, which can further focus the beam, is often used. Verbatim LED PAR16 GU10 downlights only consume 4W, providing a 90 per cent reduction in energy costs when compared to the 40W halogen lights that they replace. The multifaceted reflector (MR) lamp In 1965 another kind of directional lamp was developed. The multifaceted reflector, or MR lamp, was originally designed for use in 35mm slide projectors. Just like PAR lamps, dividing the part reference number by eight gives you the diameter of the lamp in inches. For example, and MR16 has a lamp face that s 2 inches across. Most of these lamps use aluminium coatings as the reflector and, until recently, virtually all of them used halogen light sources. They are available with GU10 turn-and-lock base pins or bi-pin versions that simply plug straight in and are held in place by the force of the connector socket. Bi-pin bases are now by far the most common for low voltage applications where lamps are typically powered by 12V AC or DC. In directional lamps the most common bipin bases are designated as GU5.3 or GX5.3, which are physically identical. Suppliers sometimes confuse the nomenclature, referring to GU10 MR16 lamps as GU10 type and GU5.3 MR16 lamps as MR16 type when both are in fact MR lamps, they just have different bases. (Pictured: Verbatim LED MR16 GU W lamp)

3 SIDEBAR: The bi-pin base was around long before recessed lighting. It was invented by Reginald Fessenden and first used at the 1893 World s Fair in Chicago, USA, in Westinghouse s AC lighting scheme for the event. Before this show, most lighting was DCpowered. (Photo credit: Heinz History Center, USA) When used with halogen bulbs, these are compact, high brightness lamps but they generate a lot of heat halogen bulbs can reach up to 200 degrees C. This limits the life of the lamps and makes effective ventilation essential. Like PAR lamps, the beam widths may be defined using the flood and spot terminology but there is also an ANSI standard specifically for MR16 lamps, shown in Figure 2. Figure 2: Power and beamwidth designations for MR16 lamps The choices available today Searching for luminaires on the web site of a leading European wholesaler presents the site visitor with a choice of 910 products. Of these, 17%, or 155 items, are downlighters or recessed lights. The same wholesaler stocks 656 kinds of lamp, of which 142 are halogen types. Exactly half of the halogen lamps, 71 in total, are designed for use in recessed lighting, the most common base fittings being GU10 for VAC lamps and GU5.3/GX5.3 for low voltage operation. From the same wholesaler, the choice of LED

4 lamps is much smaller, just 17 models are shown as stock items and 14 of these are directional lamps: eight with GU10 bases and six with either GU5.3 or GX5.3 bases. Part of the reason for the very much smaller range of LEDs versus halogen downlights is that LED lamps are relatively new products. Also, they re more expensive than the traditional halogen lamps used in recessed fixtures. But there s another reason too. Competing manufacturers, located all over the world, have been developing halogen lamps for recessed fixtures for over 80 years. The plethora of choice we see today is the result of this diversification of design and lack of standardization or emergence of competing standards. Developments in LED downlights With respect to LED lamps for residential and commercial applications, it is becoming clear that customers are perfectly satisfied with a much more limited choice of styles. This helps manufacturers drive down costs by focusing R&D effort on a relatively limited product range and then producing a few products in high volume, rather than a large number of lamps in low volumes. It also reduces inventory costs for wholesalers and distributors in the sales channel. How can presenting a more limited choice still satisfy customers? The answer lies in examining the close similarities between the physical attributes of lamps used in recessed lighting. Although there may be many different part numbers in a given supplier s inventory, the differences between some of them are negligible, and certainly of no significance to the vast majority of customers. The physical format and performance of an R63 lamp of a given illuminance specification will often be almost identical to that of the closest PAR20 or MR16 equivalent. For general lighting, most LED manufacturers are therefore just producing MR types. Ultimately, the more limited choice may actually make it easier for customers to select the most appropriate lamp for their application. The benefits of LEDs in directional lighting LEDs are attractive light sources as replacements for halogens in recessed lighting. Their much greater efficiency offers energy savings of up to 85%, recent versions are both dimmable and, in some instances, color tunable with the appropriate electronic controls. High efficiency is not just about energy saving. It means that much less of the electrical energy entering the lamp is dissipated as heat, so ventilation requirements may be reduced. However, the operating life of an LED downlight will be affected by heat, so providing plenty of ventilation is still good practice. When properly installed, the service life of an LED directional lamp in a downlighter will typically be five to six times greater than that of the halogen equivalent. In short, they run cooler, are more controllable, and deliver quality light for much longer than their halogen equivalents. Prices for LED lamps are coming down slowly, but even at today s levels they represent a compelling value

5 proposition when all factors are taken into account over the 25-year life of LED-based recessed lighting. +++ Photographs / datasheets Download all the other images in this article as hi-res in a zipped folder (4.4MB): ftp://ftp.publitek.com/pub/pressphotos/verbatim_recessedlighting.zip Download an overview of the LED range for consumers available from Verbatim: ftp://ftp.publitek.com/pub/pressphotos/led_overview_flyer_consumer.pdf Download an overview of the LED range for professionals available from Verbatim: ftp://ftp.publitek.com/pub/pressphotos/led_overview_flyer_professional.pdf Presskontakt: Jan Ström/ janne@notrocketscience.nu