Blinding light

[USAFpj]

After using a pro light meter at my Uncle's shop, I decided that 70 foot candles would be adequate light for me in my 30x50 with white vinyl backed insulation. Based on the Electrician's schematic of 70 foot candles at 3ft above the slab, the print-out stated that 20 fixtures placed at 14ft above, would deliver that. The fixtures are 8ft Williams, 1amp, 4 bulb config, with Philips T8 4100 cool white.

We hooked up all 20 fixtures (originally were going to go with 25!) and turned on the power. Pictures will come soon, but the least amount of foot candles was 110 In the middle of my 30x50x14 shop, we were pushing 125. Now my family members are machinists and industrial maintenance techs by trade, so they were giddy about the amount of light.

Maybe I'll get used to them with time and age on these eyes, but man am I glad that I have each row of (5) fixtures on just (1) switch Also glad that I went with clear panels on the eaves as well.

 

[Shiftless]

Congrats on achieving a well lit work space. As we get older our eyes need more light to see as well as we used to in dimmer light.
Has your electrician designed lighting layouts with specific goals before? Sounds like he overshot the mark by quite a bit. But it is way easier to turn off a few of them than to go back after the job is done to add more fixtures. And fluorescents get dimmer as they age. When you add cabinets and shelves etc. to the walls, you will have a bit less reflected light.

Thanks for posting and can't wait to see your pics.

 

[larry_g]

Come back in a year after you fill the place with light suckers, dirt and grime, and the new wears off the lamps.

lg
no neat sig line

 

[BillK]

how do you have the fixtures layed out ?

 

[USAFpj]

Yep. I knew the dust and webs would get on the insulation, but forgot about the storage and pallet racks.

Bill, when you enter the shop on the 30ft eave side, the light are spaced 4 across, and 5 deep. My Uncle is very specific about what he prefers as an Industrial Maintenance guy for close to 30 years, so the panel is a true commercial Cutler Hammer, and all wiring was run with EMT, but flex between the lamps. To get even spacing, it wasn't good enough to just mount them to the joists. He gave me a parts list, and I headed down to the local specialty electrical shop to get threaded rod and Kindorf.

When I add pictures within the next couple of days, I'll show the layout. But each fixture hangs from the joists with j hooks, into eye bolts, into threaded rod, and rod connectors.

 

[BillK]

pj,
Thanks. I am trying to figure out how to do my shop as it is woefully underlighted. It is 30x60 with 14' to the metal roof trusses. I was leaning towards 8 four ft T-8 fixtures with 6 bulbs each, so 48 bulbs total. Now I am wondering if that will not be enough, or maybe the wrong type of fixtures. You have 80 4 ft bulbs total. Not quite double what I was thinking.

 

[bczygan]

My 9 1/2 x 19 1/2 has 16 4' tubes, or more than 1 1/2 times as many per SF as yours, with a 9' ceiling. And daylight bulbs. I consider it just adequate.

Bill

 

[Shiftless]

My 9 1/2 x 19 1/2 has 16 4' tubes, or more than 1 1/2 times as many per SF as yours, with a 9' ceiling. And daylight bulbs. I consider it just adequate.

Bill

My 10x20 has 10 four foot tubes but they are LED which are directional while fluorescents give off just as much light upwards as downwards so they rely on reflecance from the fixture.
This is certainly adequate for the middle of the space but I have augmented them with 3 more LED floodlights over my 7 foot wide bench and 4 more aimed at the wall where my open shelving is.
This results in plenty of light for me to work in and find small stuff stored on the shelves.

 

[cybrdyke]

Yikes.
Oh well. You can always turn out some of the lamps if it bothers you.

Curious as to how the electrician came up with his figures....??
CD

 

[wssix99]

My 9 1/2 x 19 1/2 has 16 4' tubes, or more than 1 1/2 times as many per SF as yours, with a 9' ceiling. And daylight bulbs. I consider it just adequate.

He's got 8 foot tubes, which gives him more light per square foot. The back of my napkin has you at .35 linear foot of tube per sq foot and the OP at .43 linear foot of tube per sq foot.

 

[wssix99]

When I add pictures within the next couple of days, I'll show the layout. But each fixture hangs from the joists with j hooks, into eye bolts, into threaded rod, and rod connectors.

Just make sure you don't damage the camera's sensor or sunburn your corneas with all the lights on.

Maybe I'll get used to them with time and age on these eyes, but man am I glad that I have each row of (5) fixtures on just (1) switch Also glad that I went with clear panels on the eaves as well.

Do you have conduit and the ability to move wires around easily in the future? So, you might use the switches to control the level of brightness overall vs. the lights row-by-row? I've found that keeping a softer light for walking around the garage, coming/going with cars, etc. is nice and then I use my extra switch to double the tubes for extra working light when I need it.


BTW - I have .08 linear foot of tube per square foot of my garage and find it just adequate. Maybe I'm not feeling my age as much as the rest of you all?

I have finished and painted ceilings with a light colored epoxy floors and light colored painted walls, which I actually things helps out a lot. If I had less reflected light, I'd probably need larger/more fixtures.

 

[bczygan]

He's got 8 foot tubes, which gives him more light per square foot. The back of my napkin has you at .35 linear foot of tube per sq foot and the OP at .43 linear foot of tube per sq foot.

Guess I better add some more fixtures! 3 to be exact!

Bill

 

[tyme2par4]

I would have went with a little bit warmer light. Color temperatures exceeding 4000K can cause excessive eye strain after long periods of time.

 

[Shiftless]

I would have went with a little bit warmer light. Color temperatures exceeding 4000K can cause excessive eye strain after long periods of time.

I have 4000K as general lighting and separately switched 2700 K floodlights over the workbenches. (all LED)
But a quick check says that clear weather blue sky sunshine is 6000 K.

I am at .20 ft. of tubular LED per square foot. I have not measured intensity at 3 feet above the floor, but I can say that it is plenty bright for my 67 year old eyes. my ceilings are only 7 feet.

BTW, that is the first time I have seen this way of measuring the fixture installation density.
I doubt the pro lighting designers would approve, but it is an interesting comparison metric.
Ceiling height and wall reflectivity will have a big part in explaining variations in real life comparisons with light meters.

bczygan:
You figured that the OP had four 8 foot tubes in each fixture. I think they are 4 foot tubes.
They are 8 foot long fixtures containing 4 four foot bulbs.
I have him at .213 ft. per sq. ft.
BTW, that draws over 20 amps when they are all on.

4x4x20 fixtures = 320 feet of tube
320 / 1500 = .213 ft. of tube per sq. ft. floor area

 

[CarCrazyRDM]

I was all ready to order 15 dual 4ft LED bulb fixtures for my 24x36 garage with 13ft ceilings but after reading through some of the responses to this post I'm beginning to wonder if that will be adequate. Sounds like 20 - 25 fixtures might be more appropriate.

 

[USAFpj]

Guys, I just flew into Dubai, but I'll get those pictures up soon. I don't regret having the availability of light. The difference is that with each row of (5) fixtures on a switch, I have complete control over the needed amount.

The guy that won the bid for placing the wiring said he runs EMT faster than Romex, and that it would be cheaper for him to do so. And his bid was indeed lower than my Romex guys. Was very pleased with his work and the cost. Wired 20 light fixtures at 14ft, placed 18 outlets at 4ft high, hooked up the panel, wired an interior man door light and installed (2) exterior floods for $3,400 cash. Just in case anyone is needing to check numbers.

 

[cowanrg]

I was all ready to order 15 dual 4ft LED bulb fixtures for my 24x36 garage with 13ft ceilings but after reading through some of the responses to this post I'm beginning to wonder if that will be adequate. Sounds like 20 - 25 fixtures might be more appropriate.

That's where I'm at too... My shop is roughly the same size as yours and I was thinking of either 15 or 18 dual 4 footers. I think 20 or 25 would be way too much though.

 

[James-W]

I was all ready to order 15 dual 4ft LED bulb fixtures for my 24x36 garage with 13ft ceilings but after reading through some of the responses to this post I'm beginning to wonder if that will be adequate. Sounds like 20 - 25 fixtures might be more appropriate.

The cost of LED fixtures and lamps is coming down, but they are still a bit pricey. I am using CFL's now and they are working out great. I have considered switching to LED but I hate to spend the money to change when what I have is working just fine. I am sure that at some point I will change, but for now I am sticking with what I have.

 

[CarCrazyRDM]

Wired 20 light fixtures at 14ft, placed 18 outlets at 4ft high, hooked up the panel, wired an interior man door light and installed (2) exterior floods for $3,400 cash. Just in case anyone is needing to check numbers.

Did that include the cost of the fixtures? Honestly that still seems high to me but I don't know the cost difference of EMT compared to Romex. But if that was the lowest bid I'm scared to ask what the highest was!

That's where I'm at too... My shop is roughly the same size as yours and I was thinking of either 15 or 18 dual 4 footers. I think 20 or 25 would be way too much though.

Yeah, I can't decide. There seem to be several different metrics to measure what is "needed" and 15 gets it done for some and others it seems like 25 is better. But I think with the LED fixtures a lot more of the light actually reaches your work plane compared to florescent so... All I know is I had six 8ft dual bulb T12 fixtures in my last garage (24x24) and was sufficient. But an LED to T12 bulb/fixture comparison is not apples to apples.

The cost of LED fixtures and lamps is coming down, but they are still a bit pricey. I am using CFL's now and they are working out great. I have considered switching to LED but I hate to spend the money to change when what I have is working just fine. I am sure that at some point I will change, but for now I am sticking with what I have.

Yeah, justifying the cost to swap stuff out might not be worth it but for me it's all new and I figure I might as well spend the little extra now and be set up for the future.

 

[USAFpj]

Did that include the cost of the fixtures?

Really? Heck no, the fixtures were $47 a piece, and I hung them! And that was "at cost" from the electrician supply house. Bulbs were another $2 a piece as well.

Not sure what rates Raleigh is getting, but $3,400 was very competitive from the 5 bids I received.

 

[Shiftless]

I think I shoulda been an electrician. Do you know how many days or better yet, how many hours it took the guy to do the install?

 

[CarCrazyRDM]

Really? Heck no, the fixtures were $47 a piece, and I hung them! And that was "at cost" from the electrician supply house. Bulbs were another $2 a piece as well.

Not sure what rates Raleigh is getting, but $3,400 was very competitive from the 5 bids I received.

Well your response made me go back and look at the one quote I got... turns out that seems fair. I had only quickly glanced at the quote I got because I hadn't really intended to have the inside work done by someone else. I only had them give me a rough quote since they were there hooking up power from my house over to the detached garage. What I failed to realize in looking at his quote the first time was that it was broken down into cost per fixture, per receptacle, and per breaker/circuit. So when I crunched those number with the approximate number of each I plan to have it came up much higher, lol. Which gives me even more incentive to just do the work myself and save thousands. But sorry for the confusion on my end.

 

[cybrdyke]

Lets not start with "feet of tube per square feet". It makes no sense and isn't a criteria for comparing light levels.
CD

 

[Xicaque]

looking forward to those pics

 

[wssix99]

Lets not start with "feet of tube per square feet". It makes no sense and isn't a criteria for comparing light levels.
CD

Its perfectly fine in (a very general assumption) two buildings of equal construction and finish. If we try to get more specific here, then we'll probably really end up with something that's more nonsensical.

 

[wssix99]

Guess I better add some more fixtures! 3 to be exact!

Bill

Don't forget the sunglasses!

 

[cybrdyke]

Its perfectly fine in (a very general assumption) two buildings of equal construction and finish. If we try to get more specific here, then we'll probably really end up with something that's more nonsensical.

The differences in 8' tubes and 4' tubes, not to mention T12 vs T8 vs LED, combined with fixture differences, beam angles, lumen output and different ballast factors make comparing feet of tube like comparing apples to lawn mowers. It doesn't work.

 

[wssix99]

The differences in 8' tubes and 4' tubes, not to mention T12 vs T8 vs LED, combined with fixture differences, beam angles, lumen output and different ballast factors make comparing feet of tube like comparing apples to lawn mowers. It doesn't work.

Do we need to get our slide rules out in order to have this discussion, then?

 

[USAFpj]

Here you go...

The math concluded that the middle 2 rows of fixtures needed to be hung from threaded rod that was attached to Kindorf. About $200 extra in materials, but those middle rows of fixtures were either too close together, or too far apart if we would have 'just hung them from the rafters'. Can you tell that my Uncle loves the 'Industrial' application more than the good ol' boy method?

Comments and critiques are always welcomed.

 

[cybrdyke]

Do we need to get our slide rules out in order to have this discussion, then?

I think that most people here can grasp technical discussions. It hasn't been a problem in the past. No need use bad information. There are tons of threads where these things are explained very well.
CD

 

[cybrdyke]

Here you go...

The math concluded that the middle 2 rows of fixtures needed to be hung from threaded rod that was attached to Kindorf. About $200 extra in materials, but those middle rows of fixtures were either too close together, or too far apart if we would have 'just hung them from the rafters'. Can you tell that my Uncle loves the 'Industrial' application more than the good ol' boy method?

Comments and critiques are always welcomed.

Very nice. Good job on taking the extra steps to get it right.
CD

 

[Shiftless]

I think that most people here can grasp technical discussions. It hasn't been a problem in the past. No need use bad information. There are tons of threads where these things are explained very well.
CD

I agree with cd on this one.

 

[hnsy]

lol nice

 

[wssix99]

4 bulb config

I thought this meant that the fixtures each had 4 bulbs.

That's still a ton of light, but I'll have to defer back to bczygan being the King of Lumens. But, I haven't done the proper paper or back-of-the-napkin math.

 

[CarCrazyRDM]

I thought the same thing wssix99. Which when I did the quick math with four 8' bulbs per fixture did come up at some crazy ratio, so I wasn't surprised that it was bright as hell, lol. Now I need to rerun those numbers and compare to what I am considering doing.

 

[USAFpj]

Yes- each fixture housing is 8ft. The bulbs are 4ft long. Each Williams housing accepts (4) bulbs. You're tracking, though.

 

[wssix99]

Yes- each fixture housing is 8ft. The bulbs are 4ft long. Each Williams housing accepts (4) bulbs. You're tracking, though.

OK. I was originally thinking 4 - 8' bulbs. Then I thought I saw 1 - 8' bulb. Now that I'm looking on a screen with better resolution, it looks like they are 8' fixtures that hold 4 - 4' bulbs?

 

[USAFpj]

they are 8' fixtures that hold 4 - 4' bulbs

You got it, brother.

 

[66HertzClone]

I think I would delete that photo of the light meter and repost is after removing his phone number.

 

[gnab2]

OK here is a stupid question: How many 8' 4 bulb lights are you getting on 1 switch with 12ga wire? Looking at the one setup there was 2 switches for 20 lights?