I am getting close to wiring my new shop. It roughly 30 x 40 with 9 foot
ceilings. It a daylight basement but I have a minimum of windows. The shop
ended up more below grade that I expected. My plan once we get it dried in
to paint the walls white to lighten it up. Then install T8 fluorescent
lighting. I am going to look at 8' and 4' fixtures and compare prices to see
which is the better deal.

But my question is spacing and how many fixtures? I read somewhere to use
single bulb fixtures spaced at 4 feet. But so far that is all I have found.
Search the web a good bit tonight and found nothing. Anyone know of a good
reference on this?

Kudzu *\\
The man that always tells the truth never has to remember what he said

You have a couple of choices: An array of lights all over the room
that are turned on simultaneously, or groups of fixtures that cover a
particular area. Here are some suggestions:

1. Put a 2-bulb, 4-foot, 34/40-watt fixture over each workbench so you
have strong lighting for fine work.

2. Put another over the table saw, bandsaw, jointer, belt/drum
sander, and sanding table, as applicable.

3. For general lighting, based on 30 x 40 feet, about 6-9 fixtures
in a 2 x 3 or 3 x 3 array would work nicely for general lighting.

There are no right or wrong answers. Lighting should be arranged to
fit your "style" and interests. 4-foot, 2-light fixtures are cheaper
to buy because they're a lot more common.

CE

Kudzu wrote:

I am getting close to wiring my new shop. It roughly 30 x 40 with 9 foot
ceilings. It a daylight basement but I have a minimum of windows. The shop
ended up more below grade that I expected. My plan once we get it dried in
to paint the walls white to lighten it up. Then install T8 fluorescent
lighting. I am going to look at 8' and 4' fixtures and compare prices to see
which is the better deal.

But my question is spacing and how many fixtures? I read somewhere to use
single bulb fixtures spaced at 4 feet. But so far that is all I have found.
Search the web a good bit tonight and found nothing. Anyone know of a good
reference on this?

Kudzu *\\
The man that always tells the truth never has to remember what he said

Kudzu wrote...
I am getting close to wiring my new shop. It roughly 30 x 40 with 9 foot
ceilings. It a daylight basement but I have a minimum of windows. The shop
ended up more below grade that I expected. My plan once we get it dried in
to paint the walls white to lighten it up. Then install T8 fluorescent
lighting. I am going to look at 8' and 4' fixtures and compare prices to see
which is the better deal.

But my question is spacing and how many fixtures? I read somewhere to use
single bulb fixtures spaced at 4 feet. But so far that is all I have found.

In the shop, work surfaces should receive 100 foot candles from the
general lighting alone. A foot candle is one lumen per square foot.
Additional task lighting is often desirable at individual work stations.

The 100 foot candles is what you want *after* losses. The major sources
of loss are fixture inefficiency, lamp age, dust on lamps, and wall and
ceiling reflectivity. Together, 8-10' ceilings, 3' work surfaces, and
typical values for the aforementioned losses result in almost exactly a
50% reduction in the initial luminance of your lamps.

Fluorescent tubes typically supply 60-80 lumens per watt. A 40W tube, the
most common and cost effective option, typically puts out about 3000
lumens when new. Accounting for the aforementioned losses, each tube will
actually put about 1500 lumens on the work surface. Since you need 100
lumens per square foot, a tube will illuminate 15 square feet.

40 x 30 = 1200 sf; 1200 / 15 = 80 tubes, or 40 fixtures.

By the way, 40 watts per 15 square feet is 2.7 watts per square foot.
Some lighting designers use 2 watts per square foot as a lower bound,
which yields 20 square feet per 40W tube.

1200 / 20 = 60 tubes, or 30 fixtures.

For a rectangular area, you can run the rows parallel to the long edge or
parallel to the short edge. Sometimes the choice is dictated by other
design considerations, such as dust collection ducting or other
obstructions. If not, be sure to consider both ways. You can often get
more uniform lighting by running a higher number of shorter rows.

Incandescent and/or halogen lighting can be a good idea for areas where
you finish pieces that will be used indoors. Fluorescent lighting has
different color characteristics, and the color of a piece can "change,"
sometimes dramatically and unpleasantly, when brought from the shop to
it's final destination.

Jim

My shop is about the same size as yours and I have dual lamp 8' T8's in my
shop and have them spaced about 6 feet apart in all directions. My ceiling
is 14 feet fwiw.
SH

"Kudzu" wrote in message
...
I am getting close to wiring my new shop. It roughly 30 x 40 with 9 foot
ceilings. It a daylight basement but I have a minimum of windows. The shop
ended up more below grade that I expected. My plan once we get it dried in
to paint the walls white to lighten it up. Then install T8 fluorescent
lighting. I am going to look at 8' and 4' fixtures and compare prices to
see
which is the better deal.

But my question is spacing and how many fixtures? I read somewhere to use
single bulb fixtures spaced at 4 feet. But so far that is all I have
found.
Search the web a good bit tonight and found nothing. Anyone know of a good
reference on this?

Kudzu *\\
The man that always tells the truth never has to remember what he said

"Jim Wilson" writes:

snip A lighting designer's senario.

Take your choice:

A lighting design engineer.

An electrical distributor's lighting specialist.

A lighting sales engineer.

Did I miss a profession?


--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: http://home.earthlink.net/~lewhodgett for Pictures

On Sat, 3 Jan 2004 20:10:35 -0600, "Kudzu"
wrote:

I am getting close to wiring my new shop. It roughly 30 x 40 with 9 foot
ceilings. It a daylight basement but I have a minimum of windows. The shop
ended up more below grade that I expected. My plan once we get it dried in
to paint the walls white to lighten it up. Then install T8 fluorescent
lighting. I am going to look at 8' and 4' fixtures and compare prices to see
which is the better deal.

But my question is spacing and how many fixtures? I read somewhere to use
single bulb fixtures spaced at 4 feet. But so far that is all I have found.
Search the web a good bit tonight and found nothing. Anyone know of a good
reference on this?


I don't know about a reference, but I did 2 shop rooms, one that
turned out very well and one that isn't so great.

The room that turned out well is a
daylight basement room about 19' x 38', with a ceiling slightly lower
than yours (about 8' 9"), white walls, and the same lack of windows
(glass panes in garage doors at one end, plus 2 small
windows high in the side wall at the end away from the doors).

I used the dual bulb 8' high output fixtures that Lowes/HD carry, with
3 continuous rows running the long direction. The
rows are spaced about 6 feet apart (3' from the sides) and suspended
4" off the ceiling (you have to do this with these fixtures, because
the ballasts get hot). The rows have 3 8' fixtures each; I don't
light the end of the room where the garage doors are because the door
doesn't allow clearance and because we park cars there most of the
time anyway. I switch them in 3 banks running perpendicular to the
long rows, and the shop is organized such that I typically turn on
only 1 or 2 banks at a time unless I'm just wandering back and forth
over the length of the room.

These bulbs are 110 watts each, and it's nice and bright in there
but I really don't think it is too much. For your shop, this
scheme would translate to about 5 rows, with maybe 4
or 5 fixtures per row, depending on what you do at the ends of the
room.

The room that turned out poorly is another
room in the same basement where I used
4' T8's instead of the 8' HO fixtures, with roughly 4' between rows.
The T8's are not not nearly bright enough for my taste. There are
also 4' T12 versions of the HO fixtures available, but Lowes and HD
don't carry them anymore. I plan to replace the 4' T8's with the 4'
T12 HO's, one of these days. To be fair, this room is not painted
white, and I think that makes a huge difference.




Tim Carver

Lew Hodgett wrote...

"Jim Wilson" writes:

snip A lighting designer's senario.

Take your choice:

A lighting design engineer.

An electrical distributor's lighting specialist.

A lighting sales engineer.

Did I miss a profession?


Mmm, afraid to answer, on grounds that I don't know where you're headed.
(G) Was my "dissertation" overkill, on target, or something else...?

Jim

"Jim Wilson" writes:

Mmm, afraid to answer, on grounds that I don't know where you're headed.
(G)

No guts, no blue chipsG.

Was my "dissertation" overkill, on target, or something else...?

As I read it, been there, done that.

Actually, I prefer the "LGB" theory of lighting design as follows:

1) Walk the job site and scope out the area, either indoor or outdoor.

2) Make design recommendation such as put luminaires here, here, and here to
the user while pointing towards the required area.

3) Ask question, "Are we done here?", If so, Let's Get a Beer.G

Over the years, managed to sell a few $ worth of HID lighting equipment that
way.

Only the names have been changed to protect the guilty B/G.

Now you can answer the question.

--
Lew

S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland)
Visit: http://home.earthlink.net/~lewhodgett for Pictures

Lew Hodgett wrote...

No guts, no blue chipsG.

True, true -- but it's so much easier to cut the losses! (G)

Actually, I prefer the "LGB" theory of lighting design ...

Yeah, it's certainly not rocket science. Still, a lot of home shops are
terribly under-illuminated. I know my first 15 years worth of shops were.

Now you can answer the question.

Truth is, I'm just a guy whose found over the years that it's often
profitable to pay attention to the pros instead of paying them cash. When
I needed some lighting design work done a few years ago, I spent a couple
weeks studying the subject and did it myself. It was time well spent and
has come in handy several times since then.

Cheers!

Jim