The discussion of the use of T5/T8 5000 lights sparked my interest - as
I had no idea what it was - and I've found tons of information on the
internet about it. But as usual, weeding through the contradictions is
Some people seem to view the T5 as superior to the T8, both in energy
usage and in output. Then I've also found pages saying it isn't true.
A T5 seems very small to be that good at producing enough light ... but
some people say they do in fact produce the same amount of ligth.
Who out there is using these and can you give me your opinion on which
to go for? I have outlets in the ceiling out the gazoo ... so I can
install as many of these as I need. My concern is that I get enough
natural looking light, but without an UV since I burn easy.
Jack, I assure you the T5 will produce a great deal of light. I have
hundreds of them installed in our dealerships and they are great. We are
using them as a replacements for the Metal Halide fixtures with T5s as well
as older T8s. I too am replacing the fixtures in my shop with T5's and
really put out the light.
I do not know about the UV levels but the T5 is the future of fluorescent
Total light output depends on the phosphors and design of the tube.
Different tubes vary as to color temperature and total light output.
(Yes, even within families such as 4 foot T-8 and T-5.)
HO and VHO bulbs increase light output, but at a loss of bulb life and
higher energy consumption.
Look at the bulb specs. Standard T-8 and T-5 bulbs are very similar.
There will be a rating of total lumens (after burn-in).
Note also the wattage/current it consumes.
The CRI is based upon a physiological rendering comparison of the
color to noon daylight - the higher the better.
Extrapolate the lumens per watt for the selected bulbs. ~Efficiency.
Find out which type is most affordable in your area.
Buy based upon sound research.
UV burning isn't much of a factor with fluorescent lighting - perhaps
with specialty actinic or UVa/b bulbs, but not std illumination bulbs.
It is more of a concern with Metal Halides, especially if the outer
envelope is damaged.
I'm actively researching lighting for my new shop right now.
I found a government report on ligghting and energy use. They actually
say the T8 is more energy efficient than T5 in many applications. A
popular energy saving application for T5 is the replacement of high bay
lighting in factories and warehouses.
I found that 96" (actually 92" I believe) T5 fixtures cost about twice
what 96" T8 fixtures. 96" T8 strip fixtures for two bulbs cost $58 to $65
or so. The only 96" T5 strip fixtures I could find were $121 each plus
the bulbs are very expensive.
T8 96" bulbs are 59 watts and T5 96" watt bulbs are 54 watts. I am
certainly not going to pay twice as much to save 10 watts per fixture. I
could save about 10 cents every 100 hours the fixture is used.
If anyone has any insight on where to buy the F96T8 strip fixtures for two
bulbs, I would appreciate it. So far, I know Grainger has them for about
$63 each with no shipping. I am also going to try the electrical supply
houses. Shipping on 96" fixtures isn't really worth it.
At one time in a past life I designed and sold a lot of lighting systems .
From that perspective, will off the following:
What you want to buy are lumens delivered on the surface you want to light.
By definition, one lumen per square foot = one foot candle.
What you pay for is KWH of electricity.
The lighting system converts KWH of electricity into lumens.
The more efficiently it does this process, the better the lighting system.
Trying to compare the inital cost of various componets is meaningless
with out also including the cost of installation, annual hours of
operation, efficiency of the lamps, cost of KWH, and the dirt factor of
the space you want to light.
Not exactly a simple problem.
Ya pays your money, ya takes your pick.
There are some, but frankly I never used them.
Good engineering and some basic SWAGs took care of things.
Your observation is correct.
Low ceilings are difficult.
When you design a work place lighting sysyem, you are trying to deliver
the light to the work surface assumed to be 36" above the floor.
The spacing between fixtures is a function of the mounting height above
the work surface and the "spread angle" of the fixture.
When it comes to lighting a workshop in a typical basement, it becomes a
"what works" situation.
A single lamp fixture located on 32" centers worked for me in my
basement shop a long time ago.
Well, as long as we're on the subject of lighting, I'm gonna take a
shot at butting in.
I'm also looking to light a shop (24 X 25 X 8' ceiling), and in
reading an article on workshop lighting, it suggested 80-100 fc for
old fogies (40+) like myself for a woodworking shop.
So, while I know there are probably 50 variables including the paint
color, machines, etc., how do I (even ballpark) get from KWH (or
wattage) to foot candles? Basically, after reading the article I know
I want "lots of light," but I still have no clue how to convert "lots
of light" into X-number of 2-bulb, 4' fixtures. Any suggestions on
how to make the conversion?
The 8' ceiling is the controlling factor in the above application.
Use 1 watt per square foot for 100 FC maintained.
24 x 25 = 600
600/40 = 15, 40 watt lamps.
I'd probab;y use 16 lamps in 4 rows of 4 each.
That will provide about 6 ft spacing between rows which id probably
BTW, those calculations were based on old lamps. Todays lamps provive
same lumens for less watts.
It's the 16, 4 ft long lamps that is important.
What about the OSHA rules that are often quoted of 3 watts per sq foot for
My proposed shop is 24x24 so I would need over 1,500 watts based on that.
That seems like a lot. A space heater is usually 1,500 watts.
My thinking for my new shop is 4 rows of 8' T8 double bulb fixtures two
per row. That is 944 watts which seems like a lot! Is that too much? I
don't really want to burn a kilowatt an hour just for lighting.
My present basement shop only has about half as much light as I am
planning for my new shop if I go full bore as described.
If they do not take the lamp source into consideration, the above makes
no sense at all.
Consider the following:
Incandescent: 18-20 lumens/watt on average.
Fluorescent: 60-70 lumens/watt on average.
Sodium vapor: 125 lumens/watt on average.
Those are initial values, but demonstrate the variation in efficiency of
various lamp sources.
It is lumens on the work surface, not watts, that are important.
Basically they do consider that in that if you want more light you
have to use the most effecient equipment. This is simplified as there
are adders for high ceilings, and you treat rack lighting different.
All though there is whats called the prescriptive method whereas you
can have as many 2/L T8 fixtures as you want. For an office building
it 1.2 watts per square foot.
...that and colour balance. In my business, the customer picks out the
colour for their countertops at their house, so I don't really care
about balance...just what's easy on the eyes. Too much light in my game
is bothersome too... virtual snow blindness can set in and the eye will
lose all detail when a white countertop is illuminated too harshly...
just can't see and sanding swirls after about 5 minutes of staring at
I also have some fluorescent lamps, vertical, against two walls inside a
fixture which I painted black. The lamps cast a nice picture of two
white vertical stripes which I use to check for flatness in an assembly.
That's also just enough light to show up sanding marks in darker
countertops. They're 4-foot bulbs and the centre of the tube is at
eye-height. It really shows off how well my parallign vacuum clamps
Level is level, flat is flat, no screwing around, not even with veneered
panels... and with all this low-angle lighting, I still can't see a
biscuit in a joint..<G>
I did a lot of searching of this newsgroup on Google. Many people quoted
some OSHA rule of 3 watts per square foot as a guideline for lighting.
They meant it as a guideline, not a rule that had to be followed.
Do you recommend 4' or 8' fixtures? 4' fixtures are a fair amount less
money, but a lot of wreckers recommend 8' for better lighting.
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