The temptation to move towards LED Lighting is going main stream, due to the expected energy savings and stated low life-cycle costs. However, the results can be different than expected because the details matter a lot with this type of technology. Since many purchasing agents don’t know how to choose the best LED lighting products from the available options, they tend to make a gut decision based on information that may have been embellished by a salesperson. This article will review how a major restaurant chain was able to choose the best products for their application. To get to the “right” product, they tested several samples from numerous manufacturers.
Straight Facts on the New LED
LM-79 is the IESNA-approved test method for measuring LED Luminaires accurately and repeatable under normal operating conditions. The resulting test reports total flux (Lumens), electrical power (Watt), efficacy (lm/W) and chromaticity (CRI/ CCT). These absolute photometry procedures test the luminaire as a whole and produce reliable results that allow users to compare SSL fixtures based on the same criteria. While LM-79 does not guarantee quality, it does ensure the user that the stated performance is accurate.
LM-80 is the IESNA-approved test method for measuring the lumen maintenance of LED light sources. LM-80 specifies procedures for determining lumen maintenance of LEDs and LED modules (but not luminaires) related to effective useful life of the product. LED Luminaires that use LEDs with LM-80 test reports increase the likelihood of a quality fixture. However, it is still up to the luminaire manufacturer to properly use the LED with adequate heat sinking and suitable power supplies.
TM-21 provides a method for determining an LED luminaire or integral replacement lamp's expected operating life, based on initial performance data collected per IES-LM-80. This test procedure has just received final approval from the IES board last week. It will give SSL Fixture manufacturers a test method for determining the projected lifetime of a luminaire as a whole under normal operating conditions.
What is compelling is that after only small amounts of investigation, over 50% of the original suppliers were eliminated because they couldn’t meet the pre-requisite requirements. This is important because if the restaurant chain did not ask these “tough questions” up-front, the lighting system would be sure to fail. Ultimately, the results provided the restaurant chain with peace of mind, knowing their product choices would perform to the expectations of their sustainable lighting project goals.
Here is the case study from the lighting consultant’s perspective:
When we were given the task to decipher the enormous bulk of information provided by manufacturers it became obvious that the metrics did not align well. To make a fair comparison, we created our own metric of about 90 questions to organize; company, manufacturing, product, availability and warranty. Pricing information was collected, but initially removed as a qualifying factor since this could be negotiated later. As we contacted the list of manufacturers about the project, some refused to provide the information or sample products, a choice which disqualified them as a possible supplier. It was also discovered that some did not manufacture LED products that met the client’s criteria for warrantee or quality. Thus, based on pre-requisites, the list of manufacturers was reduced from 18 to11.
The test LED data was loaded into a spreadsheet to compare and sort using an “apples to apples comparison”. Almost immediately, we noticed the range of specifications was startling. After this basic comparison, we eliminated two more manufacturers.
Why is it so important to eliminate manufacturers, you may ask? Is their product inferior? The answer to this question is NO, but they did not meet this client’s criteria for this application. A different client may not provide the same criteria, altering the conclusion. Therefore, understanding and/or determining the lighting specifications in the beginning is paramount to finding the manufacturer(s) that can support and fulfill the project. Unfortunately, this type of testing is rarely done. Often a lighting salesman can convince a client that a product is cheaper, better or lasted longer. The client may not find out that it won’t work in the application until it’s too late. Problems can be as simple as variations in Beam Intensity as indicated by the pictures below.
How much could a mistake like that cost? Probably more than the savings that was so carefully calculated and presented. With site-specific testing, clients can see which systems fail, which ones don’t dim right, flicker or which ones have an inappropriate beam angle which could make the customer feel uncomfortable in the space.
Within the testing process the remaining lamps were weighed, measured and compared to their standard lamp counterpart. This was done to disqualify products that would be too heavy for an adjustable fixture or may have been designed to fit the electronics and not necessarily the fixture. Finally, our task moved to the performance of the six sample lamps submitted by each manufacturer, compared to each other, as it relates to; consistency, beam quality, beam spread, light quality, color and foot-candle output. Each lamp was powered-up, allowed a 3 minute warm up at 96” from a projection screen without any ambient light. Some lamp types were given dimming requirements and were tested for smooth, flicker-free dimming. Samples of each were sent to a lab to determine the more intricate effects of dimming on the system. The data was collected; photographs of the products and beams were taken and compiled into a 180 page report. The conclusion provided the first and second choices of each lamp type that best fit into the client’s criteria.
The pre-purchase testing led to a 15 store test which proved very successful and expanded to an additional 120 test locations. The balance of the chain is expected to be completed by mid-2012. The conclusion of this testing provided the client with comfort in the knowledge that the LED products that they decided to purchase match their specifications. It proved that the line of products would enhance their restaurants, not detract while performing to or exceeding expectations. With the information that was collected, the price negotiations were left in the favor of the client, allowing them to receive the best price and warranty available. Although some isolated issues have come up, mainly related to compatibility with old-style dimmers, all issues were easily rectified. The client was left with a feeling of security that their investment would provide years of worry-free service with minimal up-keep and maintenance. Their brand image of a comfortable, family-dining experience can remain intact, while reducing their utilities as related to lighting by between 60 to 70% across their portfolio.
The case study above was contributed by Garry Gleason, LEED AP O+M, CRM. He is the Director of Energy & Environmental Studies for Lighting Management, Inc., in Tuxedo, NY. As part of their test procedure, they incorporated new LED testing standards that have been released by the US Department of Energy and the Illuminating Engineering Society North America (IESNA).
