I. Tests in the lighting laboratory
1. Luminaire test report
2. What parameters are measured in the lighting laboratory?
a. Luminous flux and light output
b. Lamp power
II. Light testing of luminaires
1. The test report of a luminaire is more important than the list of completed objects
2. How to choose the right supplier of LED lights?
a. Tender winner selection algorithm
Tests in the lighting laboratory
LED lamps are now ubiquitous in our lives. Due to the high demand for them, many began to produce their own models. Due to increased competition, the price dropped sharply, so some manufacturers had to look for opportunities for optimization. tests in the lighting laboratory, namely lamp test report, will help to identify a product with clearly overestimated parameters. After all, you can buy a “weak” product with (supposedly) excellent parameters.
Potential customers found themselves in a difficult situation, who are forced to blindly choose a supplier. But there is a way not to fall into the trap of experienced “sellers” – before buying, contact an independent lighting laboratory. It is to the independent laboratory that will not lobby anyone. You can be sure that if a manufacturer with its own laboratory “draws” a lamp test report for itself, then you will not know about it until you hand it over to an independent one.
Luminaire test report
You may find yourself in a difficult situation competing with an LED luminaire manufacturer with its own accredited laboratory. Firstly, testing in the lighting laboratory for them will not cost anything. Secondly, if they decide to inflate the parameters of their product, then you will need to prove it. You shouldn’t get upset. If the client is not motivated to buy a competitor’s product, then he will give you their lamp. It is important to receive exactly the goods from the real delivery, and not a sample.
You will test it in an independent laboratory and they will prepare a lamp test report for you. If its declared parameters are confirmed, then we recommend disassembling the lamp and inspecting its components. This information will allow you to understand how the competitor achieved such indicators. Be aware that the protocol only applies to the product under test. You can make a lamp test report for a sample of expensive efficient components, and sell a cheaper option to the client.
What parameters are measured in the lighting laboratory?
Luminous flux and light output
Light output is the ratio of the total luminous flux of the luminaire, taking into account losses in the diffuser, to the total active power of the luminaire consumed from the network, taking into account the efficiency of its driver. In simple terms: the total luminous flux is divided by the total power of the lamp. As they say, we and you have light output, but there is one caveat! Some manufacturers consider a different value for light output. They take the luminous flux of the LEDs and divide by the useful power of the driver. Let’s explain what’s the catch here.
Any diffuser, such as Plexiglas, has a transparency of about 94%. It is used in LEDiL optics, which we use in our fixtures ledz e-Industry and e-Road. Glass eats up 6% of the luminous flux of the lamp. Surprised? Prismatic glass Novattro Prism made of PMMA has a transparency of 88-92%. Simpler plastic formulations have lower performance. Even the matte diffuser from Mitsubishi, which we use in our luminaires ledz e-Trade, transmits only 82% of the light flux.
The driver also has two powers. Usable is the power of the LEDs. Consumed – this is the total power of the lamp, which it consumes from the network. These powers differ by the efficiency of the driver. It ranges on average from 80% in inexpensive Chinese drivers to 94% in drivers from well-known manufacturers, such as TCI, Vossloh-Schwabe. If the passport does not indicate exactly what power is indicated in it, then there is a possibility that the manufacturer indicated the useful power of the LEDs.
A 50W driver will consume 56.8W. This is more than the rated power by exactly the value of efficiency, or 88% according to the parameters of the Argos IPS 50-300 drivers. Having calculated the total (supposedly) advantage over competitors, we will see that the manufacturer in this way can “improve” any of his lamps with real light output, for example, 110 lumens/W to a value of 138.9 lumens/W (110/0.88/0.9 = 138.9). Now you know what formula to use to calculate the light output of your competitor.
Light testing of luminaires
Light testing of luminaires is carried out for various reasons. The most common is to check the characteristics at the request of your client, for example, in a tender. You can also order a luminaire test report to improve its design. For example, you are going to use new LED strips in fixtures, and you need to check its light output. Let’s list a few reasons that may degrade the performance of your LED lamp:
- luminaire in sheet metal body
Sheet metal is known to be very poor at dissipating heat from LEDs. Since any LED heats up at any current, its resource is sharply reduced due to poor heat dissipation. Compared to an aluminum case, sheet metal loses more than five times in terms of heat dissipation, and powder coating further worsens heat dissipation by another half. The aluminum case is made thicker (1-3 mm), while the sheet metal is made thinner to make the case lighter and cheaper.
- LED bars don’t fit close to the case
There are lamps in which the rulers are isolated from the body with the help of a strapping tape cut into pieces. Since air is a very poor conductor of heat, this design impairs heat dissipation and reduces the life of the LEDs. Many experienced manufacturers use thermal pastes and compounds from various manufacturers to eliminate the air gap between the ruler and the case and improve heat dissipation.
- too light body with high power
This mistake is most common among young luminaire manufacturers who do not know the performance dependencies of the various components. Or if the competition is great and you need to form a good price, the manufacturer can save on the profile. As a result of such savings, the case will overheat greatly, the light output will deteriorate and the life of the LEDs will sharply decrease.
LED strips from a luminaire with an excess of the optimal heat dissipation power
The test report of a luminaire is more important than the list of completed objects
Testing lamps by a manufacturer in his own laboratory is tantamount to giving a deputy the right to count the votes of his electors. He will always count them in his favor. Despite the fact that all laboratories continue to work in parallel and periodically undergo interlaboratory comparisons, this does not protect you from the facts of overestimating the parameters in their favor. As we wrote above we recommend choosing an independent laboratory for testing lighting fixtures.
How to check if the laboratory data is correct? This can be done by obtaining from the manufacturer his own test report for the luminaire, then independently handing over the luminaire to the manufacturer’s laboratory and after that to an independent one. If the figures in the protocols differ by more than the margin of error, then with a high probability we have discovered the fact of falsification. Of course, we admit that any laboratory sometimes makes mistakes, but in our practice it was only once.
How to choose the right supplier of LED lights?
When comparing any lamps, other parameters are important, except for the price. Among them are the power consumption and luminous flux, confirmed by the protocol of an independent laboratory, the resource of LEDs according to the datasheet of their manufacturer, the resource of the driver, and the guarantee for the lamp. Business owners we must warn you: choosing an LED lighting system based on price alone, you risk buying a product that will have to be repaired frequently and possibly replaced again in 3, 5 or 7 years.
If you are offered to buy the cheapest lamps, take the decision into your own hands. Ask applicants to make lighting calculations with equal illumination and parameters. Check the height of the suspension, the safety factor, whether the equipment is equally spaced. From the calculations obtained, take the total luminous flux (Flux) and total power (P) of all lamps, specify the guarantee (G), LED life (R), check the parameters of the lamp from the calculation with the protocol of an independent laboratory.
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Tender winner selection algorithm
The parameters in the calculation and the protocol should not differ by more than 5%, otherwise reject this applicant. Take the cost of decisions (Price) and for each applicant calculate the X value using the formula: Price/(Flux/P)/G/R = X, where X (rub*kW/(lm*h*years )) is the ratio of the cost of fixtures for the entire facility to the average light output, warranty and LED life. The bidder with the least X will have the best offer with the most savings. Ask them to make a table like this for you:
It will not be difficult for your employees to calculate these numbers. For example, the applicant Number 2 has an average illumination of 885 lux, the cost is 60.9 thousand rubles, the luminous flux of all lamps is 3.07 Mlm, the total power is 23.3 kW, the warranty is 5 years, the service life of Samsung LEDs is 70 thousand hours, and the candidate Number 3 has an average illumination of 1061 lux, the cost will be 72.8 thousand rubles, the luminous flux of all lamps is 3.48 Mlm, the total power is 29.7 kW, the warranty is 5 years, the service life of OSRAM LEDs is 100 thousand hours.
The X value of Number 2 will be 60.9/(3.07/23.3)/5/70 = 1.32, the X value of Number 3 will be equal to 72.8/(3.48/29.7)/5/100 = 1.24. Number 3 showed a lower X indicator, which means that this option is more beneficial for the owner than Number 2, even though it is more expensive. Please note that the Number 3 LED luminaire has a longer LED life and a 5-year warranty, and its effectiveness has been confirmed by this luminaire test report in an independent laboratory of the Central Solar System of the National Academy of Sciences of Belarus.
Once you have chosen a candidate, look at the list of implemented objects and their photos, it is also worth looking at reviews about the company. If you have enough time, visit at least a couple of objects and make sure that you are satisfied with the result. Search the site for failed fixtures or possible faults, and if you find more than one, they probably fail too often and are not worth buying. Call us if you need expert help with lighting objects!