Questions Every Engineer / Client / Contractor Should be Asking Their LED Supplier

I’ve seen a lot of consumer guides on the internet which give “mom and dad” advice on selecting quality LED products for their home. These guides are often regurgitation's from the Department of Energy recommendations in the States or from other consumer advocacy groups. While helpful, there is not quite as much at stake when purchasing a handful of $10 LED globes when compared to replacing a few hundred 400W Metal Halides in a warehouse.   

In my experience I’ve found that clients employing LED technology for brown field projects are more likely to take advice from their electrical contractor than employ an electrical engineer to assist in choosing the best technology. No fault of the contractor, but they are likely to go with what they know, or if they haven’t been exposed to LED technology on this level, what they’ve heard works well.   

This isn’t always the best bet for obvious reasons (and most obvious is that every application has its own particular challenges), but by asking your LED luminaire supplier some questions, risk can be minimized and providing the perfect solution for the client is more likely.

I’ve assembled 10 questions here which everyone (contractor/wholesaler and particularly end-user) should be asking their potential supplier(s).  I have kept the information very brief, and in layman’s terms to keep you all from “flipping the page”, and provided answers specific to our Andromeda™XPB series of luminaires as an example – but if you would like further information on any of these points please contact me directly.

1.       Is the product electrically safe and conform to EMC standards?

 

The Regulatory Compliance Mark (RCM) (logo on left) indicates compliance to both electrical safety standards and Electromagnetic Compliance standards required for electrical equipment in Australia.

Our Andromeda™ series has the RCM for Australia, cETL for Canada/US, CE and TUV for Europe.

2.        Are IES files available?

IES files are a digital representation of the lamp/luminaire’s performance characteristics, and these files are used by lighting designers or electrical engineers to simulate the lighting for a given application (digital proof of concept).  All reputable companies should be able to provide IES for their products.

We have IES files for most of our 9000 versions of Andromeda™ available on our website for easy download.

3.       What diode is being used and does it have IESNA LM-80 documentation?

The brand of diode is worth knowing, as with everything there are premium brands (such as Nichia, CREE, Seoul Semi-Conductor, etc…) which are well established and may indicate a better product or at least quality of light. 

But more important is the LM-80 report which is an approved method for measuring the lumen maintenance and chromaticity shift of LED light sources.  In layman’s terms this test report provides information how about how long the LED engine in the luminaire should last, and how well the quality of light will be maintained. 

Further, TM-21 calculations should be included in the report which can be used to predict the lifespan of the luminaires under varying conditions.

Our Andromeda™XPB uses Nichia 219B LEDs, for which a detailed LM80 report is available HERE. This diode is tested at three separate ambient temperatures (55⁰C, 80⁰C, 100⁰C) with values for lumen maintenance, chromaticity shift, and a TM-21 projection (L₇₀(10K)) for each temp, which are all greater than 60,000 hrs.

4.       What is the Ingress Protection (IP) Rating of the Luminaire, and has it been salt spray tested?

If the luminaire in question is going to be used externally, or will be subjected to wet or adverse conditions it should have a relevant IP rating.  You can look at a chart of IP ratings HERE. As a general rule luminaires used externally and subjected to the weather should have an IP rating of IP65 at least.  Salt spray tests are also a necessity if the luminaires are placed in a corrosive environment (Category C- Category E) – from 50km from the Ocean.  Further, specific tests should be conducted for environments with unique or especially challenging environments.

Our Andromeda™XPB series is rated IPI66, and has been salt spray tested to GB/T 10125 and GB/T 6461 for the pixel rail components.  We also have conducted extra testing for our luminaires placed in highly corrosive environments, such as the high chlorine environments found in pulp and paper mills.

5.       What is the Lamp Circuit Power (LCP) of the luminaire, and how much power does it consume in the “off” state?

Lamp Circuit Power is the actual power usage of the entire luminaire.  This includes the driver (transformer), LED engine, and any other electrical components attached to the unit.  The LCP should be tested by a NATA certified laboratory, particularly if calculations based on the LCP are to be used to apply for power/carbon saving based incentives.

As part of our LM79 reports we’ve included testing for LCP.  For instance, our 300W Andromeda™XPB LCP is only 283.3W.  In the “off” position our 150W driver for our Andromeda™ consume 1.3W of power (an Andromeda™XPB 300W has two 150W drivers – therefore 2.6W of power).

6.       What is the maximum junction temperature (Tj) specification (at highest ambient temperature)?

Junction temperature (TJ) is the temperature measured at the semi-conductor (LED) itself during operation.  Tj is typically measured at various ambient temperatures to ensure that the recommendations of the diode manufacturer are being met.  Tj temperatures that meet, or are lower than the LED manufacture’s recommendation indicate excellent thermal management and will ensure that the diodes meet both their performance and lifespan characteristics.  Tj temps which exceed stated limits typically mean poorer performing diodes and shorter lifespans (if not outright failure).

Our Andromeda™XPB series, driven at 600mA, has a Tj temp of 102⁰C at an ambient temp of 55⁰C.  The Tj max for the Nichia 219B diode is 150⁰C.  This indicates exceptional thermal management, guaranteeing performance and lifespan even at high ambient temperatures.

7.       Quality of light.  CCT ranges and CRI.

The quality or characteristics of light required for a given application vary widely.  And without going too much into appropriate Colour Correlated Temperature (CCT) or Colour Rendering Index (CRI) it is useful to know what your application requires (practicality, or through and applicable standard) and ensure that your choice of LED mirrors or exceeds the requirement.  The important question to ask here is “Does your choice in LED luminaire provide variability in both CCT and CRI to accommodate your requirements?”.

We offer a multitude of options in both CCT from amber (2300K) to very cool white (8500K )in a single diode, to 20,000K with colour mixing, and everything in between.  We also offer high CRI options (95Ra+) for specific applications.  Our CCT is binned within 175k for most of our luminaires.  The most common Andromeda™XPB is ~4500K & CRI >75.

8.       What is the power factor of the luminaire?

Power factor (PF) is expressed as a ratio of “real” vs. “apparent” power – with a perfect power factor being “1”.  PF is important because it measures how effectively you are using power, and improving it can maximize current-carrying capacity, improve voltage to equipment, and reduce power losses – which leads to lower electricity bills.

The Andromeda™XPB series has a power factor of greater of >0.9, with typical luminaires in the series at 0.95 or greater.  These are excellent values for lighting (for example, fluorescent technology often has PF values less than .80).

  

9.       What is the lifespan of the luminaire?  What is its warranty?

The DOE in the US limits lifespan claims at 50,000 hours, and Energy Star Standards require a 3 year warranty at least on LED lamps/luminaires. Most quality LED products should have at least a lifespan of 50,000 hours and a 3 year warranty.

By using the information in question 3 and 6 above, it can be shown that even in the most extreme conditions (ambient of 55⁰C) the Andromeda™XPB with Nichia 219 diodes will perform past 60,000 hours (to L₇₀).  As such we have a comprehensive warranty of 5 years on this product.  It’s worth noting that at 12 hour per day, 365 day per operation, the luminaire would be expected to last for ~13 years.

  

10.   What is the efficacy (lm/W) of the luminaire – post optics?

This measurement has become a benchmark of LED performance.  It is not necessarily always relevant, however, when replacing high intensity discharge luminaires it can indicate potentially large savings in power.  The higher the efficacy, the greater the savings in power as compared to lower performing luminaires.  It is important, however, to know the POST-OPTIC efficacy, not the luminous flux.  As all that matters to an end-user is how much usable light is actually being emitted by the luminaire – versus how much is being generated (and lost) in the first place.  This information is often available on the LM79 report.

Our Andromeda™XPB series has an efficacy of 115+lm/W post-optics which you can view HERE.  This is very high compared to both traditional lighting and other LED products, and sets our luminaires apart as some of the most efficacious available.

Why You Shouldn’t Buy a High Bay Which Looks Like a High Bay?!

NOTE: Quick answers below in RED
If you’re shaking your head at the moment, I don’t blame you.  The above statement is logic which escapes consumers and LED luminaires manufacturers alike… including Empyrean Lighting for a period of time!

An overriding philosophy in the development of new LED luminaires and lamps has been to design products that either 1) look exactly like it’s traditional counterpart (luminaires) or 2) works/fits in a traditional fitting for ease of retrofit (lamps). 

The merits and inherent problems of point #2 will be the topic of a future post, but here I would like to address point #1, and specifically in relation to high and low bay lighting.

Metal Halide High Bay (Traditional High Bay Light)

Let’s firstly consider a traditional high bay light used typically in industrial warehouses for close to the last century.  They are usually ~400W metal halide, mercury vapour or high pressure sodium lamps which fit into the large conical fittings where the lamp is recessed into the bell shroud which extends ~.5m below the ballast, starter, and other control gear.

These lamps are relatively inefficient, use large start-up currents, contains significant amounts of mercury, are difficult to dim or control, have multiple failure points, do not start-up immediately (re-strike time) and have maximum lifespans around 20,000 hours. These facts have made replacement of this technology a prime target for consumers and LED luminaire manufacturers alike.  

The problem is that both groups are trending toward designs which mimic the traditional design and appearance the high bay light.  Whether the lack of vision is due to trying to promote consumer confidence by minimizing change, or a lack of creativity by designers, one can’t be sure.  But what is apparent is that substituting these radically different light sources within the same design does play to the strengths of the LED, and worse will leave consumers disappointed.

Consider the following reasons to choose a purpose designed LED highbay (such as our Andromeda Series) over the alternative – layman’s terms in red:

1. Design – LED light sources are uni-directional by nature as opposed to metal halide or other filament style high intensity discharge (HID) luminaires which are omnidirectional.  To put a single source, restricted beam angle into a luminaire which further restricts the beam angle (bell reflector) is, frankly, counter intuitive and ultimately does not play to the strengths of the technology. Tight beam angles (LED) + a bell shroud = limited light spread & use.
2. Thermal Management - single source high bay luminaries count largely on conduction of heat from the diodes (which are very hot - given they are positioned together as a single source) through large heat sinks. This does not work in a typical warehouse environment, because to get the heat sink to work effectively there must be heat exchange between the surround air and the heat sink material. Often the ambient air temperature in the ceiling of a warehouse can exceed 50⁰C - the heat sink will likely have an equal temperature to this, meaning there will be no exchange at all with the atmosphere, and your LEDs will "cook". Reducing performance, increasing failure rate and shortening life expectance. Our Andromeda luminaries are individually places, and each diode uses both conduction and convection to ensure that the heat is removed efficiently form the diodes even in areas with high ambient temps (one of the reasons we do so much mining work - warehouses in the outback are as hot as you will find on earth). Big, heavy, chunky heat-sinks are not all their cracked up to be in high ambient temperature environments... like most of Australia.  
3. Single Point Failure - simply – you have a single point of light intensity with no 

   

   Common LED High Bay Solutions

   redundancies – if the diode fails the luminaire is “dead”.  The Andromeda's individual pixels are wired so that a single pixel failure (which is very rare) does not affect the rest of the luminaire.  Redundancies in any system prevent total failure – single source LED luminaires typically do not have ANY redundancies.
4. Restricted driver (ballast/transformer) access – the most common failure on an LED luminaire is the driver.  The drivers on these units are buried and difficult to access and replace.  Replacement drivers were also not available from the manufacturer who preferred to replace the entire luminaire.  Our drivers are rated for the life of the luminaire, however, should one fail they are easily accessible and quick release, meaning a driver change takes less than 120 seconds. Accessibility to drivers (transformers) are key – should they fail quick changes keep maintenance costs low.
5. Beam Angle & Variance – this luminaire projects a very tight beam of high intensity light at the workplane.  This results in quite a few issues, but two of the biggest are glare and variance.  A single high intensity lights source can temporarily blind workers and is more likely to cause glare issues.  Also, the higher areas of light intensity on the ground cause variance issues – which means that an even light spread is not achieved -  again, potentially causing issues with workers (low visibility, eye fatigue).  The Andromeda, due to multiple light sources all individually lensed avoids both issues and provides a very homogenous level of illuminance throughout the facility (this can be seen on DIALux/AGI32 reports). Multi-point LED high bays (such as the Andromeda) provide more homogenous light and less glare than single point sources = “better light”.
6. Strength of fitting – the bell reflector  on these luminaires is weak – even the slightest impact can dent it which requires replacement as it will affect the light distribution. These fittings are also only rated as IP54 – a significant leak in the ceiling could cause major damage to the luminaire or circuit.   The Andromeda fitting is IK08 and IP66 – tough as nails. Further, as the Andromeda is lower profile it is less likely to come to grief with forklifts or equipment working below. Throw a basketball at an LED bell shaped high bay… now throw one at the Andromeda… don’t have a ball, stay tuned to our website and we’ll be doing this for you soon enough!
7. Light Projection Surface – the large lens on this luminaire means the possibility of acute build up of dust and other particles which limit light transmission.  Unlike a HID luminaire these particles are not burned off – so they can pose a real issue.  The Andromeda uses a very small surface area for light transmission which is also electrostatically charged meaning very little dust/dirt can settle on our lenses and light transmission is retained even in the dirtiest, most challenging environments. Less surface area = less cleaning, and IP66 means quick efficient cleaning by power washer or air jet.
8. In a recent project, another supplier had recommended bell shaped LED highbays at 250W and 100lm/W – the Andromedas we specified (after simulating to required lux levels) were 200W and 110 lm/W.  Significant power savings when weighted up over ~222 luminaires

   

   Andromeda Flood Luminaire

   in the project.  Further, due to the tighter beam angles of the LED bell-shaped luminaires 10% more luminaires would have been required to meet the lux levels provided by our solution.  Choosing a better, purpose built Andromeda series luminaire will save you money – both short term and long term. 

So if you’ve made the tough decision to switch over to LED technology for your facility, please make the easy decision to choose purpose built LED technology to ensure your project is a success.

Contact us directly with any queries or concerns! info@empyreanlighting.com