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#207161 09/29/12 02:47 PM
Joined: Nov 2007
Posts: 763
KJay Offline OP
So, this link from MH was in my inbox this morning. Based on the effects of UV damage from ordinary fluorescent and CFL lamps that most of us have seen for ourselves over the years, such as brittleness and discoloration of the insulation on wiring, tombstones, diffusers, other plastic parts, canopies, etc., it seems like it would be pretty self evident that there are at least some issues, but on the same note, haven't many of us been working under fluorescent lighting to some extent for decades already?

CFL UV Article

KJay #207164 09/29/12 05:20 PM
Joined: Dec 2002
Posts: 206
The plastic parts are in close proximity to source 100% of the time. Square law applies to the distance from source of radiation, and exposure time is likely to be far more
limited, so the actual dose dramatically less.
This is a bit like the chemists who give massive doses of something or other to a rat and announce that it killed it, hence deducing that whatever it was is potentially lethal!

KJay #207165 09/29/12 05:22 PM
Joined: Oct 2000
Posts: 2,722
Likes: 1
Broom Pusher and
Received the same message + link from MHE.
The creator(s) of the Article must had been bored, or they waited about 25 years too long before releasing their findings!

Of course a CFL will emit UV Radiation! UVA, UVC - and likely significant UVB (think Tanning Lamps!!!).
Any Discharge Lamp emits UV Radiation - as do CRTs, most LEDs, Arc Welders (when an Arc is established), Short Circuits, Stars (Hydrogen Fusion types, not the Hollywood types); anything that utilizes a Plasma, or functions as a result of Charges crossing a Depletion Region will radiate some levels of EMR in the UV and IR bands.

The Article does not provide the levels of UVA-UVC emitted by the test subject CFLs.
Article also left out a very important detail: Our Eyes are highly effected by Concentrations of UV Radiation! Much more vulnerable than Skin.

Best advice: do not stare at Discharge Lamps while they are in operation!
Diffuse the Light output either directly with Reflectors and Lenses, or indirectly by "Bouncing" the Light off some shiny surfaces - i.e. Indirect Lighting...

So, do not let the Article scare you about CFLs and Melanoma issues.
Refract or reflect the output of Discharge Lamps, and keep your Eyes from overexposure.
Distance and duration limits are effective.
If you have ever experienced a Sun Burn, you have been "Overdosed With UV Radiation"

"EMR" = Electro-Magnetic Radiation:
Particles Radiated in Waves, beginning at 0.0001 HZ, and extending out to the tiniest Cosmic Wavelength - includes the very small Visible White Light Spectrum, and of course all Radio Transmission,

"UV" = Ultraviolet (Light):
EMR at shorter Wavelengths than Visible White Light.
The UV Bands begin somewhat after the visible color of Violet Light ends; dropping off before the beginning of X-Ray bands,

"IR" = Infrared (Light):
EMR at longer Wavelengths than Visible White Light.
IR begins somewhere past the high end of Microwave Radiation, and tapers off before the lowest Frequency "edge" of Visible Red Light.

End of ranting... Now, who is next to take the Soapbox???!!! wink

-- Scott (EE)

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
KJay #207167 09/29/12 10:21 PM
Joined: Jul 2004
Posts: 9,869
Likes: 25
I think I remember that UV B and C are pretty much blocked by ordinary glass so it is only UV A that would get through the normal lamp globe. I assume it would be easy to filter the A if they really thought it was an issue.
I suppose the real question is how much gets reflected by painted surfaces. I doubt anyone actually has bare bulbs that you can see in their lighting plan. We really try to bounce the light off the ceiling or wall to soften the glare.
Most people think we have a pretty dark house anyway.

Greg Fretwell
KJay #207170 09/30/12 02:40 PM
Joined: Jan 2005
Posts: 5,411
Likes: 1
Cat Servant
Well, it looks like I've made some progress over the years.

It seems like only yesterday when every such 'study' was warmly embraced by all, and everyone found new ways to re-phrase the new "wisdom." Then, naturally, I'd pipe in with my skeptical / cynical or simply contrary attitudes. stirring the pot.

Today, I see several other posters have pointed out the omissions of the "study." We're not lining up to sip the Kool-ade. That's a good thing.

All I can say is that, for all my time under CFL's, I've never shown the slightest tan or sunburn. This puts the UV exposure at 'negligible.'

Contrast that to the huge expanses of upholstery and flooring that are routinely bleached by sunlight coming in the window. Now there's a spot that gets some UV! Yet, our "green" political agitators stack the certification deck in favor of "daylighting" schemes. Do they WANT us to suffer from UV exposure- even when we're "safely" indoors?

Even more cynical is the way they ban 'ordinary' bulbs, force us to switch to CFL's ... then tell us we cannot count those CFL's as 'energy efficient' lighting. Lithonia may never have heard of these guys - but I bet they send them a card every Christmas!

Joined: Jul 2007
Posts: 1,335
I better stop using CFL's and stop eating red M&M's. I don't want to catch somin'...

"Live Awesome!" - Kevin Carosa
KJay #207174 09/30/12 05:31 PM
Joined: Nov 2002
Posts: 794
Likes: 3
Home depot has "blacklight" CFLs for sale, and they had a demo display of them and a few other color CFLs. I placed my driver license up at the blacklight one, and I could see the security features in my license glow. Like my name and birthday, etc atop my picture. And a second picture of me in a blank area. Don't know if the UV from it causes skin cancer or not. They also had orange, pink, yellow and I think green ones too. Come Xmas time I could put up a string of them for decoration... smile

KJay #207186 10/01/12 11:32 PM
Joined: Apr 2002
Posts: 7,371
Likes: 7
Time to visit the Orange box! To check my ID!

KJay #207188 10/02/12 09:08 PM
Joined: Jul 2004
Posts: 9,869
Likes: 25
In the 60s and 70s, every kid had a black light in his room.

The assumption was that this was the normal amount of UV with the rest of the light filtered out. It only worked in a dark room. You could use a filter on a regular incandescent bulb but a fluorescent did work better.
The lights TSA uses look like a regular halogen bulb flashlight with a filter on it.

Greg Fretwell
KJay #207193 10/03/12 04:07 AM
Joined: Oct 2000
Posts: 2,722
Likes: 1
Broom Pusher and
Some Trivial Information, Regarding Ultra Violet Radiation

As discussed in previous Message Threads, I did some work for a Client who owned several Tanning Salons. I was asked to Bid on a new TI for this Client, where the Improvement was to incorporate an adjacent unoccupied Suite, to the then-currently leased Space.

In addition to the General Lighting, HVAC, Misc. Receptacles and Office outlets, the new Conditioned Space also included:

a. (6) 120/240V 20 Amp Tanning Beds - with 12 to 16 F72 T12 VHO Fluorescent Lamps per Unit,
b. (2) 120/240V 30 Amp Tanning Booths (Upright) - with 24 F72 T12 VHO Fluorescent Lamps per Unit,
c. (1) 10KW High Intensity Tanning Bed.

This was a very good Client, and we both learned from each other.

The Time Period was somewhere in mid 1992; around the Time when Intel introduced the 80486-DX2.

My knowledge base regarding Discharge Lighting was minimal at best, so it was time for me to dive in to Discharge Lighting Components and related Theories.
This lead to several years of studies, but the basics were grasped within a couple Months.

The High Intensity Tanning Bed was the "Push" to study all components involved.
This Unit consisted of (5) individual 2000 Watt High Pressure Mercury Lamps with Quartz Glass Envelopes.
Each Lamp had its own 3500 VA Tapped Magnetic Linear Reactor to Ballast the Lamp, and a High Voltage Pulse Ignitor mounted remote from the Lamp, yet within 18" of the Lamp.

Each Lamp incorporated Dichroic Filters - One "Clear" and One "Purple Tinted".
The Tinted Filter was thinnest - about 0.25" wide, whereas the Clear Filter was thickest - around 1.5" wide.

The combination of Dichroic Filters greatly reduced the UVB levels reaching the User, and completely reflected the UVC produced by the Lamp.

IIRC, the three levels of UV Emissions have the following results / constraints / parameters:

#1: UVA:

a. Not Absorbed by Glass,
b. Oxidizes Melanin,
c. Passes through the Upper Atmospheric Layers, and through the Gases between the Stratosphere and Troposphere with minimal losses at Earth Ground Level,
d. Not Blocked or Reflected by Dioxygen (O2), or Ozone (O3).

#2: UVB:

a. Causes Sunburns,
b. "Brings" Melanin to the Surface of the Skin,
c. Most is Filtered out by O3 prior to reaching Earth at Ground Level (pass below Troposphere demarcation)

#3: UVC:

a. Mercury Vapor Emission Wavelength is in the UVC range,
b. Not Filtered by Quartz Glass Envelopes,
c. Will be Blocked by O2.

Oh, and contrary to the "Report" which started this thread, Tungsten-Halogen Incandescent Lamps Produce / Emit UV Radiation.
The "Report" stated Incandescent Lamps did not Produce / Emit UV "Light".

In the quest to study and be aquainted with Discharge Lighting Equipment, the scope covered areas of:
  1. Electromagnetic Radiation,
  2. Transduction of UV emission to the visible Spectrum,
  3. Negative Resistance,
  4. Illumination Theories,
  5. Light and True Power relationships,
  6. Current Limiting Devices (Ballasts),
  7. Details of Discharge Lamp Operations,
  8. Details per the Operation, Designs, and Theories of Linear Magnetic Reactors.

If not for this Client, I would not been so inclined to study so heavilly and at an early time in my life!
My Career was positively influenced by the optimistic attitude and suggestions by this Client, along with the introduction to a whole new world of Electrophysics, etc.

Now I rant and spew out Techno-Babble, and use terms and definitions of Jargon and Engineer-eeze to describe simple things...
bash rolleyes

-- Scott (EE)

Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!
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