# Things to consider before agreeing to LED retrofit so you can avoid epic fail results



## Electric_Light (Apr 6, 2010)

With current technology, good linear fluorescent and LED luminaires are shoulder to shoulder in efficacy, at least when they're brand new. 

There are a few things you could put in specifications to avoid getting general purpose area lighting replaced by decorative light emitting devices. 

Generally, white LEDs have wide band spectrum and modern fluorescent lamps using rare earth phosphors have narrow band spectrum. The sensors used in light meter is usually calibrated to tungsten source. Unless it is specifically calibrated to match human eyes across many different sources, it can significantly misrepresent the outcome. 

So, in order to avoid false sense of successful retrofit especially in result dependent commission.. consider:

Light meter shall match photopic spectral response of human eyes for both original light source and LED source. Calibration should be verifiable. This avoids LEDs from possibly getting more favorable foot candle readings due to sensor sensitivity that responds stronger to LEDs. 

Foot candle measurements must be taken at multiple points to demonstrate uniformity similar to original install rather than directly beneath the luminaires, then deducted to match the expected output at 12,000 hours of use. BRAND NEW lamp output is a figure that should belong in parenthesis and is not appropriate as the main figure. 

Phrase it so that output after about 12,000 hours or so matches the mean lumen of existing system. If the brand new retrofit just match the pre-install right after install, that ain't acceptable!

Photograph the shadow cast by the existing fixture and document the details. If shadows are not desirable, add in specifications that retrofit should not cast a harder shadow than existing. This will produce extreme occupant discomfort and fatigue. 

Read the fine prints. LED replacements are quite often not meant to replace 32W T8. You'll see something indicating it's meant to be a drop in replacement for 48" T8 25W. They come in 25,28,30 and 32W. 

CREE LED drop-in tube is 2,100 lumens and gives you the above disclosure. 

fluorescent lamps: 
25W 48" lamps are 2,400 lumen new, 2,330 after 40% life. 
32W 48" lamps are 3,100 lumens new ~2,950 after 40% life.

http://www.usa.lighting.philips.com...N-LED-T8-InstantFit-bulletin-9-14-Digital.pdf

Well, what they DO NOT tell you is that most of the power savings is from having much lower output than 32W T8 lamps. 

So, it takes 38W to get 4,000 initial lumens with 50,000 hour life until it hits 70% output. Yeah, it saves like 30% input wattage compared to 32W, but you're going from 5,400 lm 54W to 4,000 lm 38W. (Initial lumen based on RE80 3,100 lumen lamps, which by the way do not degrade anywhere near as much as LEDs) :laughing::laughing:

http://www.gelighting.com/LightingW..._4_Ecolux_25W_Lamp_SellSheet_tcm201-21073.pdf
or it takes 43W to get 4350 lm new and 4090 lumens after 15,000 hours or so and well over 4,000 for remainder of life. Same 5 year warranty. 

The LED drop-in bulbs have a hair of advantage comparing brand new lamps, but T8 only degrades less than 10% of original, not 30% like LED. 

With good fixtures, 75-90% utilization is realistic with both LED and fluorescent. 

Comparing linear fluorescent vs LED: 

Photographed under identical conditions (same camera and hand height) 

FLUORESCENT: 
Estimated total 3500 MEAN lumens. 0.88BF ballast with 85% fixture efficiency. 
+very good life maintenance. 
+5 year lamp warranty. 
+very good color stability. Spot re-lamp almost unnoticeable. 
+nice soft, even, diffused light. 
+exceptional lumen maintenance. 
-limited cold temperature performance. 
-1.7mg of mercury. 
-glass. 









Decorative Light emissive device: 
+Good cold temp performance. Good for freezer interior. 
+No glass. Good where shatter-proof is required. 
-poor lumen maintenance. 
-expensive.
-poor color maintenance. 
-poor light quality with edgy shadow casting hard light. 
-LED module suffers accelerated wear at higher ambient. 
This is what happened when one of those flush mount LED fixture with an opaque acrylic diffuser was put right next to the above fixture. The white opaque diffuser has a lower transmission but a better diffusion than the K12 acrylic, yet it still did worse. Look at how much sharper and darker the shadow is. 

I think it's a very good replacement for CFL, but it's a joke when it's used to replace a linear fluorescent.


----------



## Ultrafault (Dec 16, 2012)

Thank you for this thoughtfull post.


----------



## Electric_Light (Apr 6, 2010)

There are some T8 lamps out there that are practically "lifetime". 

T8 lamps are practically lifetime lamps. (50,000 hrs to about 20% failure @ 12 hours per start. This is about 11 years @ 12 hrs per day). The reflector starts to chalk after this much use, so I'd say the fixture is done by the time it's due for group re-lamping. (rated 70,000 hours at 12hrs/start to 50% failure rate) 

They are standard 48" T8 and mounted in sockets so you can choose from many types of lamps available. The lamp element of the system is 5 year parts. Power supply element is 5 years parts + labor. This means you call them up, they send someone to replace the ballast or they pay "reasonable rate" at their discretion. So even if there's no agreement in reasonable rates, parts + modest $10/ballast labor allowance is still better than just parts in buildings that use hundreds of fixtures. http://www.gelighting.com/LightingW...scent-UltraMax-Instant-Start_tcm201-23541.pdf

Warranty is pretty much the same across all three brands. GE, Sylv. and Phil/Adv. 


So... the lumen maintenance is definitely better with fluorescent. 

LED advocates claim that burning out is rare. It's true LED strings are probably not going to go out like fluorescent lamps. This is a real concern when you're using a few high output lamps like 1,000W HIDs in a warehouse. LEDs and fluorescent lamps are used in a mass, so it's not a justified concern. 

Today's ballasts operate lamps in parallel, so a lamp failure will only take out that one lamp. One failed lamp in a fixture with four lamps is generally tolerable and if failure is well spread out evenly throughout the building, it's not going to cause issues. 

LED and fluorescent both use similar electronic power supply and they can fail either way. So, LED or fluorescent, ballast failure will take out that entire fixtures. LEDs or fluorescent. Ballast vs driver is exactly a difference of semantics. They can both fail and cause the same issue. 


Fluorescent lamps contain mercury and there are possible health concerns if they're broken. But, LEDs apparently have a whole new accelerated chronic retina damage during normal use due to higher proportion of harmful blue light content. Not in lumens, but mW of optical power. 

White LEDs excite the phosphor using a narrow band near violet deep blue LEDs. The same band used by dentists to cure dental glue. You notice how they use a filter plate or goggles when they use the cure light? That's because chronic exposure is not good for your retina. 

The white light that leaves the LED is a mixture of phosphor generated light and pass through blue added together. 
http://ehp.niehs.nih.gov/1307294/

Fluorescent lamps use deep UV (254nm) to excite the phosphors on the interior surface, but the glass used for the envelope is essentially opaque to deep UV.


----------



## chicken steve (Mar 22, 2011)

The _'epic fails'_ i see , at least on my turf, are not so much the product as the folks peddaling the product

In my states case, we have an entire department of losers who couldn't keep a job @ McD's auditing and crunching #'s for public businesses.:no:

This is inclusive of product specification, as well as labor install costs:no:

As most of these people never contracted anything on their own and/or for a public biz, many of us (who do survive doing it) find their #'s dubious:no:

I've little doubt the same disfunction exists up the food chain to the fed level :whistling2: ~CS~


----------



## Electric_Light (Apr 6, 2010)

chicken steve said:


> The _'epic fails'_ i see , at least on my turf, are not so much the product as the folks *peddling *the product
> 
> In my state*'*s case, we have an entire department of losers who couldn't keep a job @ McD's auditing and crunching *#s* for public businesses.:no:
> 
> ...


I audited the post and found at least four errors.


----------

