Archive for the ‘General Commentary’ Category

EMF: Another Outrage Fizzle?

Posted: September 18, 2018 in General Commentary

There has been a bit of a to-do about EMF emission from LED products on the usual outlets carrying SM punditry.  The alarmist assert that EMF from lighting products is harmful to human health, and the EMF emissions from LED light sources is damaging to the eye.

Some of this may be founded on studies like ‘Electromagnetic Field Radiation and Your Eyes‘, published on the EMF-Health web site, which references ‘Scientists Link Eye Cancer to Mobile Phones‘ and ‘Cell Phone Radiation May Cause Visual Damage‘.  Another expert warning of EMF and electronic devices is Dr. Mercola, who wrote ‘The Real Dangers of Electronic Devices and EMF’s‘. While none of this mentions LED lighting, the association of electronics and solid-state lighting is apparently too attractive to avoid for some. One such reference to this, with a list of additional references to weed through, is the article ‘Replacing CFL, Halogen and LED Light Bulbs‘, in which they point out that some LED GU10 bulbs produce radio frequencies of 30MHz-300MHz. The remainder of that article continues the blue light critique, with not more mention of EMF. Anyone in the industry might have furrowed a brow at the claim of 30MHz to 300MHz, since most products, even those driving LEDs with PWM, use far lower frequencies, with the 2KHz to 20KHz very common, although some may be as high as 1MHz. Microwave Induction lamps may operate at these extreme frequencies, but not LEDs. The exception to this might be LiFi technology, which operates at around 43Mb per second (something around 4GHz), with future development in the 10+Gb (9+/- GHz) range. However, this operates as a carrier within the existing EM range of light, which spans 400THz to 700THz- which is just what it is. If we want to see, we have to expose ourselves to this, as this is what light is – Electromagnetic Radiation. That said, LiFi is hardly used in a broad enough context to make this a central issue, even in street lighting applications. But, I’m getting ahead of myself, as the real topic here is EMF from LED products, not the larger discussion of the increase in Radio Frequency EMF we find ourselves surrounded in from a wide range of products, portable and fixed within our environments.

For purposes of this exploration, I am not going to get into inclusion of volts, or frequencies – other than the range of between 30Hz to 300Hz most refer to when discussion non radio frequency EMF. I am also going to skip over Stetzers or other peripheral metrics, for purposes of clarity. For the most part, EMF issues are discussed in units of µT (Microteslas) or mG (Milligauss), so that is what I will remain focused on here.

A Lot to Consider – None of it Very Damning

Excessive EMF radiation in our environment is suspected to be the cause a wide range of health issues. However, what levels are causing what damage is not yet fully defined or understood. The WHO has created ‘The International ELF Project‘ with the intent of creating more solid data and conclusions with which to create recommendations, establish limits to work from. The National Radiation Laboratory (NZ) has also published an informational brief called ‘Electric and Magnetic Fields and Your Health‘.  The IARC (International Agency for Research on Cancer), has published as statement ‘IARC Classifies Radiofrequency Electromagnetic Fields as Possibly Carcinogenic to Humans‘, which is not fully relevant to LED Lighting.  Another comprehensive review of the topic of EMF and human health can be found in ‘Health Effects of Electromagnetic Fields‘ by the Expert Group of the Department of Communications, Marine and Natural Resources, Dublin, Ireland. The Hawaii Department of Health has also issued a very informative booklet on the topic of EMF ‘Electromagnetic Fields Associated with the Use of Electrical Power‘, that is work reading through for anyone interested in this topic. Hindawi (UK) has produced an interesting paper as well, ‘Health Implications of Electromagnetic Fields, Mechanisms of Action, and Research Needs‘ that outlines the concepts involved as well as the limits of knowledge at this point. For those completely obsessed with this topic, the IEMF Alliance offers a collection of books on the topic. However, none of these references have mentioned LED lighting specifically. In a few, CFL products, particularly the earliest versions using magnetic ballasts, were found to be somewhat offensive little EMF sources.

As a side note, if you read these papers and articles, you will find LED lighting not mentioned, but will find several references to the effect of Radio Frequency EMFs on men’s testes and brains. Before reading any further, or worrying about turning off the lights, it appears the first plan of action is to never put a cell phone in a pants pocket, or try to talk with it stuffed in the front of your drawers. Not much can be done about the brain thing it seems… Moving right along….

One group attempted to link EMF to LEDs – the EMF Safety Network – published their broad condemnation of LED street lighting in ‘The Perils of LED Streetlights‘. In this article, they eluded to the potential for damage from EMF, but actually did not make the case, as presented no data, then indicated queries to PP&G on the topic were unanswered – ominously indicating some effort to conceal the truth through power of suggestive writing. The rest of the article forwards all of the other well rehearsed issues of blue light, flicker,  CCT, dark skies, etc… unrelated to the EMF topic. One article commenting about the issues of artificial illumination, including LEDs, is ‘Make Light Healthier‘, by the International Journal of Science, which describes the issues and actual concerns very well. Meanwhile, contrasting that, is the work of an LED detractor/incandescent lamp advocate, Dr. Alexander Wunsch who published his thoughts on Mercola ‘The Dangers of LED Lightbulbs‘, recommending removal of all LEDs and use of incandescent lamps and candles in their place. He not only extols the dangers of blue light, but piles on with the argument that the absence of red light is a further danger to LED lighting. He does not mention EMF, so this reference may not be appropriate, but it is still interesting.

Summary of Threats

Probably the most interesting of all papers on this topic, is ‘A Summary of LED Lighting Impacts on Health‘ published by the Building Research Establishment, which included the following statement regarding EMF from LED products:

6. Electric fields generated by LED lighting: Lamps and control gear include electric and/or electronic components through which electric currents flow so that light output is initiated and maintained. These electric currents generate magnetic and electric fields of low frequency (50 Hz and harmonics thereof, eg 100 Hz, 150 Hz) and high frequency (30 to 60 kHz) depending on the type of lamp and control gear [14]. Above certain intensities, the magnetic and electric fields may induce electrical currents in the human body that can stimulate the nerves and muscles at low frequency, or even cause tissue heating at high frequency. Improvements in lighting technology have enabled a reduction in electromagnetic fields. For LED lighting, several studies have shown that the intensities of magnetic fields generated by LED lamps were significantly below the limits recommended by the International Commission for Nonionizing Radiation Protection (ICNIRP). Therefore LED lighting does not appear to generate electric or magnetic fields that can damage human health.

The paper also includes references to 39 other papers on the topic worth reading to those concerned about the technology. These include papers by two of the most well published experts in the field, Dr. Veitch, JA and Dr. Wilkins AJ, who serve on numerous study groups and committees discussing light and human health – so searching these two names will also produce even more to read about. However, if the focus is on EMF and LED lighting concerns, they have haven’t mentioned it, so you can save time in this regard.

Real World Observation and Metrics

As far as objective testing of LED products, an article on the Healthy Building web site ‘EMF from LED Lights – Magnetic Fields and Recessed LED Lights‘ reflects what most of us in the obsessive world of lighting have found when breaking out meters and turning them onto on various lighting products. The levels found were simply too low to be of any concern. Move 24″ away, and the readings drop to zero.

While the USA has no standards of exposure for EMF, individual states do, as does the EU, the UK, and other countries, which use the ICNIRP recommendation of 100µT (Microteslas), which equates to 1000mG (Milligauss). Switzerland has set a limit of 1µT (10mG). That said, a common standard for what is called “prudent avoidance” (see the NZ brief mentioned earlier) is set even lower at 0.4μT (4mG), which is what I would personally consider a goal for any long term exposures within any working or living environment.  Note that in the Healthy Building article, the highest reading was 2.72mG at 2″ from a Lutron dimmer. This is well within acceptable levels, even at 2″ distance.

My own experience mirrors that of the Healthy Buildings article. Here is a summary of results from products I have around the shop, office and home, taken at a distance of 12″, and 24″ which are closer than I experience when using most of these items:

  • LED task lights, table lights – 0.0mG @ 12″, 0.0mG @ 24″
  • Collection of (3) Wall wart power supplies used for task lights – 5.4mG @12″, 3.8mG at 24″
  • LED Recessed 2 x 4 troffer –  0.0mG @ 12″, 0.0mG @ 24″
  • LED Retrofit PAR30 lamp – 0.0mG @ 12″, 0.0mG @ 24″
  • OLED Light Panel Lights – 0.0mG @ 12″, 0.0mG @ 24″
  • 360W LED Driver with 300W Load – 0.3mG @ 12″, 0.0mG @24″
  • Microwave oven – 1700W – 77mG @ 12″, 18mG @24″
  • IR Sauna panel -0.1mG @ 12″, 0.0mG @24″
  • Street light at street level – 0.0mG
  • Philips Hue Light – 0.0mG @ any distance
  • T12 HO fluorescent shop lighting mounted at 12′ AFF – 0.0mG measured at 48″ A.F.F. (not going to climb a latter to prove they emit EMF at close distances, as that’s dangerous and the point is moot.)
  • Vu1 ESL Lamp – 0.0mG @ 12″, 0.0mG @ 24″ (to my surprise)
  • Very old coiled bulb CFL – 0.4mG @ 12″, 0.0mG @ 24″
  • Kim Wall Grazer LED Fixture – 0.0mG @ 12″, 0.0mG @ 24″

At this point, I gave up, as the exercise was not causing me to believe there was anything to see. I even included readings of non-LED sources, to see if there was anything of concern. Other than the Microwave, I found nothing. And from LED products – nothing.

In general terms, when I look into arguments against LED technology, I will find a few references from legitimate sources that point to the conclusions or support the voracity of claims on some level. In this specific case, I find nothing to back the claims of alarmists that EMF is an issue in LED Lighting. This correlates with several other reports, and is summarized nicely in the aforementioned BRE report, paragraph 6.

Okay, so what about RF Then…

When it comes to WiFi and Radio Frequency EMF, I will only say that these devices do not emit RF energy any longer than it takes to impart a control function. All of the transmitters and receivers I tested in house emit nothing unless a control is activated. In my opinion, this transient nature is not going to cause any harm at the energy levels involved, over the very brief and infrequent periods that they exist.

That does not mean that devices do not emit any RFI. In fact many do, and it can interfere with communications equipment. However, the RF energy levels even the worst of these products generates, is very low, well below wireless communications, so the risk of exposure to humans is not an issue. The issue is one of quality, where RF emissions is not fully considered or included in the design. RFI is not EMF.

Confusion of terms – EMI vs. EMF

I did note that there are references and videos on You tube, like ‘Dirty Electricity and LED CFL Light Bulbs Stetzeriser Filter Placement‘, indicating issues of EMI, which is Electromagnetic Interference, not EMF, caused by various lamps. The noise these products creates on the AC power system within a building is indeed a potential issue, as it can interfere with other electronic devices that do not include line filtering, controls, and radio receiver devices. Most products operating from line voltage sources include filters to eliminate this, but some older products don’t. Utilities have also employed methods of filtering this out of metering systems.  Modern electronics, including lighting products also have features to eliminate this as well. Regardless, this is not EMF, and I could not find any objective evidence that this interference is in any way creating emissions in the delivered light of products that will have any impact on human health.  It should not go un-noticed that the largest collection of articles on “dirty electricity” is on the Electra Health web site, and that the majority of those articles are on RF and Microwave radiation concerns, where links to the actual .pdf papers are 404. Also noteworthy, is that the Electra Health web site is a product of Stetzerizer US, which sells filters for cleaning up dirty electricity. One of the more entertaining videos linked from the site is ‘Don’t use curly bulbs (CFL) compact fluorescent or LED bulbs‘ which asserts that EMI is emitted from the lamps and wires into the air, but uses a plug-in meter to show the EMI present from the samples they chose. No proof of any of the EMI frequencies escaping the wires or fixtures is provided, except using a low end AM radio placed near the sample lamps, which distinctly emitted a 60Hz buzz on the transistor radio. The viewer of the video is obviously being asked to set aside any experience they have in spaces illuminated by fluorescent and LED products, with no incandescent, and no Stetzerizer devices, yet experienced no radio interference.

Perhaps the most revealing information attached to the video is the following statement:

ElectraHealth.com highly recommends using only regular incandescent (old fashioned) light bulbs or as a better alternative the Clean Halogen energy-saving bulbs like the kind we carry in our store. They work just like incandescents, but use 30% less electricity.

Case closed.

Additional Reads on the topic:

http://fms-corp.com/emfemibasics_overview

https://greenlivingideas.com/2016/06/07/leds-emfs-need-know/

 

 

According to marketers of Twitter, Facebook, LinkedIn, Instagram, et al, social media is the engine of change, the foundation for bringing information and real transformation to the people. With Social Media, we will see the world connected and refreshed through the voices of the previously unheard. Social Media is the new light, the symbol of freedom and ultimate new world order founded on the concrete foundation of the first amendment, the true voice of “the People”. It has enabled revolution and advanced the human cause. It all sounds so… amazing and spectacular, if not completely incredible.

Behind the scenes, social media is actually just a software/app product that generates (more…)

Recently, there has been news hysteria about the availability of 3D printed gun plans, and the implications of such a product being made available to the general public. There are several facts that must be squared away before this “news” story can be effectively (more…)

Follow along, and see if this sounds familiar…

In the process of designing a new light, you begin by collecting manufacturer data sheets. You rifle through the LED data to find lumen output for LEDs and select one with a rated lumen output of 390@700mA, 3000K CCT / 90CRI (test current), and 188 lumens per LED at 350mA (calculated value), @ 3.4 Vf, for 158 lumens per watt. Nice!

You calculate what you need to make the target 1000 output lumens, and design a product around the data and calculations, use 7 LEDs operated at 350mA, to include 30% over the target to compensate for optical losses and temperature per the manufacturer data sheets. Using first article parts to build a prototype, you send it off to the photometric lab, expecting to see results very close to what you calculated. You can live with a minimum of 900 lumens, but hope to see better than 1000, as the data provided by the component providers indicates this should be the case.

Your expectations are based on the following:

  • The LED data sheet says the LEDs can produce 188 lumens at 50mA
  • 188 lumens x 7 LEDs = 1316 lumens, providing 30% more than the desired end result
  • The optical data sheet claims an efficiency of 92% (8% loss)
  • The driver data sheet shows 97% efficiency at 350mA / at a voltage range of 18 to 34Vf, with a rating of 12W (covering the string voltage of 23.8 Vf – with a calculated watts load of 9.8W)
  • CCT selected is 3000K by LED data sheet, 90 CRI
  • Your LED case temperature tested at 40°C after 20 minutes, which the manufacturer data sheet shows minimal lumen loss, well within expectations and over-design of 1504 lumens.
  • Calculated and expected results >1000 lumens, 9.8W, 102 lm/W.

The results you are expecting

  • Luminaire total lumens 1100+
  • Watts with driver loss 10 +/-
  • Lm/W = 108+
  • CCT = 3000 / CRI = >90

The lab results come in, and you anxiously open the file and discover the following:

  • Luminaire total lumens 620.6
  • Watts load 8.7
  • Lm/W = 71
  • CCT = 2850 / CRI = 88.5
  • Measured LED case temperature 66°C
  • LED ambient temperature under the optic is 40°C
What happened?

There are numerous variables that come into play that will trim effective luminaire output from expectations built around manufacturer data sheets. Here are a few that this example will have suffered from:

  1. CCT is a generalized term. Actual LED CCT’s vary. Further, optical systems can impart a warming of LED color by as much as 200CCT. Operating LEDs at reduced current will also cause warming of CCT.
  2. CRI is an averaged value, and will vary somewhat by LED bin or production run.
  3. The actual LED lumens from purchased reals of product produce 167.32 lumens at 25°C Tj – a loss of 11% based on bin group purchased.
  4. The LED manufacturer data is based on tests of cherry picked LEDs strictly held to a Tj of 25°C, in an ambient temperature of 25°C, for a duration of 20 milliseconds – The actual LED case temperature of the LEDs was 66°C, with an ambient of 40°C, resulting in a junction temperature of 77°C – Result is a de-rated LED output of -15%.
  5. The LED manufacturer data is based on tests of LEDs that have never been populated onto a board, so have not experienced the thermal cycling processes involved there. One thermal cycle reduces the measured LED output by 7%.
  6. The driver manufacturer data assumes an ambient temperature of 25°C, operation at exactly 120VAC, operating at the maximum Vf. – Actual driver operating conditions are 42°C ambient – resulting in an efficiency loss of 3%
  7. The actual driver output is not 350mA, it is actually 340.4 mA, which is within the +/- 5% tolerance, for a current and LED lumen loss of 3%.
  8. The actual LED string voltage measures 22.4, indicating the LED Vf is 3.2, not 3.4 as shown on the data sheet – for a loss of 6% energy through the LEDs reducing lumen output
  9. The driver actually delivers 21.97Vf when connected to an LED string presenting a voltage drop of 22.4Vf while maintaining the output of 340.4mA, for a loss of LED lumens of 2%.
  10. The driver efficiency rating of 97% is at full load. The load connected in the design is 62%, resulting in a measured actual efficiency of 89%.
  11. The optic used has a measured efficiency of 97%, but that is based on simulated data derived from the manufacturers design software. Actual optical efficiency measures 88%, for a loss of 9%.

Add this all up and you get:

  • Lumen loss from actual LED lumens vs. manufacturer data = 33% (188 x .67 = 125.96)
  • Lumen loss from thermal conditions at the LED from manufacturer data sheet to actual applied conditions = 15% (125.96 x .85 = 107.066)
  • Lumen loss from driver under-current / under-voltage conditions = 9% (107.066 x .91 = 97.43)
  • Lumen loss due to actual optical efficiency = 9% (97.43 x .91 = 88.661)
  • Loss of driver efficiency due to ambient condition = 3% (.97 x .97 = .949)
  • Loss of driver efficiency due to low load condition = 8% (.949 x .92 = .873)

Total actual lumens per LED = 88.661
Total luminaire lumens = 620.63
Actual driver LED load = 7.625
Total driver efficiency at actual load = .873
Actual driver watts at 120VAC = 8.733
System lumens per watt = 71.07 lm/W

 What now?

The next step is to adjust current to the LEDs to push output up to 500mA, and get the following:

Total actual lumens per LED = 120.243
Total luminaire lumens = 841.70
Actual driver LED load = 10.9
Total driver efficiency at actual load = .903
Actual driver watts at 120VAC = 12.07
System lumens per watt = 69.73 lm/W

Now what?

The following is what happened:

  • The higher current increased LED output, but increased heat as well, so lumen increase was less than the increase in current supplied. The result is less than expected output increase and lower efficacy.

So, you push the LED to its maximum test current of 700mA and get:

Total actual lumens per LED = 159.59
Total luminaire lumens = 1117.13
Actual driver LED load = 16.3
Total driver efficiency at actual load = .88
Actual driver watts at 120VAC = 18.53
System lumens per watt = 60.28 lm/W

Now what happened?
  • More current increased heat even more, in both LED points and ambient inside the luminaire
  • The higher current increased the driver LED load beyond the original driver selected, requiring a change from a 12W capacity driver to an 18W capacity, which has a lower efficiency when loaded at 16.3W.
  • The composite of heat and driver selection compounded to reduce efficacy, but increased lumen output to exceed the design target.
The solution?

There are several:

  1. Lower expectations. The original target is obviously pushing the limits of the LED configuration selected. There is no solution to resolving the difference between manufacturer data and actual performance, this is simply the reality of this technology.
  2. Search for higher efficacy LEDs, more efficient optics, and higher efficiency drivers. An improvement of 10% at the driver, 5% in the optics and 10% at the LED will produce the following results:

Total actual lumens per LED = 144.3 (@ 500mA)
Total luminaire lumens = 1010.1
Actual driver LED load = 12.6
Total driver efficiency at actual load = .93
Actual driver watts at 120VAC = 13.55
System lumens per watt = 74.55 lm/W

  1. Further improvements in thermal design may also produce additional gains in efficacy by increasing lumen output without adding any additional power.

This is a common issue with designing LED products. Data sheet values simply do not stack up as they might seem and represent values that are not representative of application conditions. This applies to LEDs and drivers alike and will vary by product lot as well.

Then what happens is…

So, you dig around and find even better LEDs and drivers, have a custom optic made that reduces power and produces the best total package. Perhaps not at the 100lm/W you wanted, but close. Customers love it and you can make a profit from it, so off to market you go!

About this time, you will receive a notification from the LED manufacturer that their new version of the LED you are using will be discontinued at the end of the year, to be replaced with a Gen MCMVLXX product that will produce higher lumens by 10%, and operate at 3.1 Vf, while operating at a higher Tj temperature with less lumen loss.  The driver manufacturer will also send notification that it is out of stock on the driver selected, with no firm date when their Chinese vendor will deliver new inventory. The optic manufacturer will then announce that the optic you chose is not compatible with the Gen MCMVLXX LED update, but are working on it. This all means re-testing and re-evaluating all of the decisions made before, and potentially necessitating revisions to UL listing and investigations that could lead to re-testing there.

Welcome to the world of LED product design and development! 

Seriously, while this exploration is fictitious, it does represent the variables that make designing around component manufacturer data unpredictable, if not completely unreliable. There are some take-away’s from this:

  • Never assume you will get the lumens out of an LED that are shown in data sheets. Read all of the data and make corrections that more closely resemble actual application conditions – then subtract another 15% to be safe.
  • Never assume that drivers will deliver exactly the name-plate current and Vf. When in doubt, test the selected product under the conditions it will be used under. Also note that efficiency numbers are generalizations that rarely match actual application conditions. The only way to know what the exact efficiency is, is to test load the driver in question with the intended LED / LED array.
  • Never assume that optical manufacturer efficiency data is correct, or even based on actual test data. The difference in realized optical efficiency and manufacturer data can be significant.
  • Thermal conditions, for the driver as well as LED have a large impact on lumen production and system efficiency. You cannot have a system operate at too low a temperature. Also, remember that data provided is rarely realistic to actual application conditions, so this alone will have a significant impact on system performance.
  • A last side note: Verify system performance under all line voltages anticipated. Just because a driver functions at 120VAC on a bench for 5 minutes, does not mean it will work at 277V after 12 hours continuous operation. Dimming issues are far more common at high voltage (277V) than they are at 120VAC, so test at both, through the entire dimming range.
  • Oh, yeah… dimming driver are notoriously bad at holding efficiency, even at full brightness – and fall off as the product is dimmed from there.

The AMA has stepped in to take the stand that warm color LEDs are the only products suitable for street lighting. For anyone interested in this, please read it before assuming you know what it says. There are several factual errors in this document. Most in the lighting design business will see them. The LRC has issued a response to this document.  The IES has also issued its own response.   Again, for those interested, read all of these documents before blowing a gasket and spewing conspiracy theories into the realm, deriding the IES, the LRC or the AMA. It is probably worthwhile also to include the recommendations and statements of the IDA (Dark Skies) as they are the ones who actually initiated the <3000K solution. (more…)

Product development and management has evolved from the days of taking a shot on a hunch. In the days of fabricating products with minimal tooling, the risk of failure was low, and profit reward for success quite good. Who needed product management? Design it, build it, catalog it and get it to the reps and wait for the orders to roll in.

The lighting industry also has a long history of operating with lean management structures, particularly in small organizations. Ownership, Marketing, Engineering, Finance, Design, Engineering, and Sales all have a role in product development, planning and line maintenance. How well product management tasks are accomplished is (more…)

The “Internet of Things” has now become the newest, hottest marketing powerhouse. The scale of claims and the breadth of its application transcends lighting, so it eclipses popular lighting themes of Energy Efficiency and Human-Centric Lighting. The idea of everything being connected through the internet, accessible, upgradable, and monitored from anywhere at anytime is the big sell. Refrigerators that not only tell you when a product has expired, but automatically places an order for a replacement is one proposed far-reaching concept. Products that learn from our use cycles to adopt and send data to manufacturers for product development is another. Lighting that responds to local natural light conditions without local sensors. Power grids constantly adjusting in anticipation of user demand. Facilities managers, utilities, and end users accessing and monitoring building activity, condition, and (more…)