Too Many Lights?

[beartoothweb]

I just finished working up my diagram for my lighting, and after doing the math, I'm not sure I'm balancing budget vs. light here. I will effectively have 2 bays, one that's 12' high 15x30 and one that's 10' high 25x30 (total 40x30).

I want a couple of fans in there to move air around, and I'm also creating a "parking" area for my Cobra project I'm doing (this will be a nice area with floor tile, posters, lighting, etc. rather than fancying up 1200'.)

If you look at the diagram, you'll see some cans in that parking area, and positions for some track lighting over the benches. The rest will be 4' tube fixtures.

I tried to make sure there are no fans on top of the lights so I don't have some sort of seizure.

I ended up with 18 total 4' fixtures (10 in the big area, 8 in the small one), which I think might be overkill. I'm all for good lighting, but I don't to spend money now or on power later that I don't need to.

I searched for shop pictures and references, but I couldn't find too much on what I was asking.

Here is a pic:

http://picasaweb.google.com/beartoothweb/Shop02#5288551685578150962

 

[a3tripod]

Doesn't seem like overkill to me. Of course i'm still in the early stages of planning too, but when i sketched 4' lights for my ~22x30 garage w/10ft ceilings I have 5 fixtures in the single bay, and 8 in the double. there has been a lot of good conversation in my thread, if you want to check it: "Compact Fluorescent vs Tubes"

 

[hammlm]

Doesn't seem like overkill to me, either. Couple of questions for you:

1. Will the 4' lights be surface mounted, or will you have "lay in" fixtures flush with the ceiling (drywall or drop ceiling?)

2. How many tubes in your 4' fixtures? Do you have a preference on lamp / ballast type? T-8's?


Depending on your fixtures, you may not be able to get all your flourescents on one 20A 120V circuit. If they are two-lamp, you should be fine, but if you're looking at a 4-lamp lay-in fixture, you'll likely be overloading a 20A circuit.

Assuming 2-lamp fixtures, you have approximately 1150 watts of output from 32-watt T-8 tubes. In round numbers, that's 1 watt per square foot. It's probably adequate, and would pass the new commercial "com-check" codes for lighting loads, but I tend to think while 1w/foot might be ok for an office environment, it's somewhat on the low side of things for true task lighting. Strategic placement is key, and it looks like you've thought it out well.

I used 8' T-8 strip fixtures in my shop / garage (also around 1200 sf), and just last month, ended up adding 2 more around the cars to eliminate what I thought were "dark" areas. SWMBO thinks I'm crazy. But at the end of the day, I have now about 1250 watts of light and it's "adequate". If I add any more, she'll try to have me committed.

PS - Looks like you used Punch software. I started out hating it, but ended up using it for our addition and by the end, found it quite adequate.

Good Luck!

 

[ddrewyor]

One can never have too many lights! There are charts on how many foot candles one needs for certain activities. For example, machining and close up work requires more light than waxing your car. Look at your fixtures and calculate what your total light output (lumens) is going to be and then see if it supports what you will be doing in the shop. If you have light reflective walls and floor, less lumens will be required. In my shop 30 x 40, I have 32 4' T-8 fixtures. They are setup in banks so I can switch them on in groups to put the light where I need it. Over the workbenches and machining area they are closer together and also on separate switches. Also, try to get as much natural light as possible into the space. Tough to do at night, but will save $$s during the day. Good luck.

Dave
________
PENNY STOCK PICK

 

[ddawg16]

Good info guys....

In round numbers, that's 1 watt per square foot. It's probably adequate, and would pass the new commercial "com-check" codes for lighting loads, but I tend to think while 1w/foot might be ok for an office environment, it's somewhat on the low side of things for true task lighting.

hammlm....can you expand on the "com-check"?

ddrewyor....any chance you have those charts? Stuff like that would help a lot of us.

 

[beartoothweb]

I just found this post on another forum:

What you need to do is a simple calculation. Well, simple to some anyway. The basic calculation to determine the number of light fixtures needed in a room is called the Zonal Cavity Method. You need the following information:

Room Width - W, Room Length - L, Room Area - A, Ceiling Height - CH, Room Cavity - RC, Room Cavity Ratio - RCR, Lumens per Lamp- Lu, Coefficient of Utilization - CU, Lamps per Fixture - LPF, Maintenance Factor - MF.

Calculate the Room Cavity First. It is the difference between the height the fixture is mounted in the room and Horizontal plane in the room at which you want to calculate your footcandles. Usually we want to calculate the number of footcandles at a point 2.5' above the finished floor. That is where we do most of our work at desks, tables, counter tops, etc.,. So, if your fixture is mounted directly on the ceiling or recessed in the ceiling just subtract 2.5' from the ceiling hieght to get RC. If you have a fixture that is suspened 12" below the ceiling then you subtract 12" from this number. In other words instead of subtracting 2.5' from the ceiling height you decrease the ceiling height by 12" and then subtract 2.5'.

Calculate your Room Cavity Ratio:

RCR = (5 x RC x L x W)/(L x W)

With this done, you now need a spec sheet of the fixture that gives you what is called Coefficients of Utilization. This may be a little confusing but light fixtures have a chart on their spec sheets for CU's. The RCR is listed in a column on the far left of the chart. Choose a number close to the one you calculated above and come across and find your CU. Now, you will notice at the top of the chart that it is divided into sections that depend on what Ceiling Reflectance you are using. I would always use 70% to be conservative so come all the way across to the section of the chart that is for 70% ceiling reflectance. You will then also notice that each Ceiling Reflectance section is divided according Wall Reflectance. Use the 50% column for that. Now you have your CU.

Finally, here is the formula for how many fixtures you need in the room:

No. of Fixtures = (A x FC)/(LPF x Lu x CU x .8)

FC is the footcandle level you desire to have in the room. The last value that I used (.8) is a maintenance factor. What this does is put in a factor that makes allowance for fixtures getting dirty, lamp output deteriorating over time and other factors. You can make it smaller but .8 is good enough for our purposses.​

I haven't done the math yet, but seems fairly simple. I'm guessing someone has put this into an excel spreadsheet or javascript somewhere as well.

 

[Torque1st]

Flexible lighting is one reason I put in a duplex outlet in the ceiling for every permanent fixture so I can plug in those 4' florescent shop lights where I need them. Get the ones with pull chain switches if you can find them for added flexibility. Wire your lights in banks or areas on separate switches. In areas with lots of work benches or machines use dual duplex receptacles. When your lighting needs change the lights are easily moved to new locations. Some people go for cosmetics, I go for function.

 

[beartoothweb]

I just found this on GE's site:

http://www.gelighting.com/na/business_lighting/education_resources/tools_software/toolkit/layout.htm

If you use the a flouro's lumens of 3200 or so (found on another site) and a footcandle number of 100 (for hobby work), this thing said I need 62 32W bulbs for 1200feet.

That ends up being about 16 4-bulb 4' fixtures.

In terms of fixtures per 20A circuit, if you guess the ballast will be 1A or less on startup, then 16 puts me at the max continuous use guideline of 16A since they all start at the same time. I might end up splitting the lighting circuit into 2 20A ones as I want a few cans on there too.

I'm doing 100A to the panel, so hopefully I can make it work.

I wonder how many 100W single bulbs it would take to light this thing? I'm a little concerned about cold morning start up since I'm not going to heat the shop year around (can't justify the cost).

 

[ddawg16]

stuv169...........SPAMER!!!!!!!!!!

Take your machines, gold and "WOW" somewhere else...........

 

[beartoothweb]

stuv169...........SPAMER!!!!!!!!!!

Take your machines, gold and "WOW" somewhere else...........

Looks like the mods killed it already.

 

[beartoothweb]

I'm planning on just surface mounting the fixtures, using regular ceiling boxes.

I'm still researching whether the flouros are even the way to go. The cold is one issue, but real color is another since I plan on painting in there. Cost is a big concern for me too, especially up front.

This many fixtures might cost me $500.

I'm considering just wiring up some 100W cheapo lights, then replacing them overtime with the florescent, or using CFL's. Those things are like a $1. I have 3 of them in my 2 car garage, and it's actually pretty bright to me. If I wire the number that I have indicated on my plan, plus the task lighting and cans, I seems like this might work pretty well and save a bunch of cash.

I understand if I plan on spending 16 hours a day in shop, the flouros will be cheaper on electricity, but from what I understand, for short periods of times, not necessarily true.

Thoughts on this idea?

 

[beartoothweb]

PS - Looks like you used Punch software. I started out hating it, but ended up using it for our addition and by the end, found it quite adequate.

Yep, it doesn't allow for much customization and real editing, but it does the job for basic floor layouts and planning. I like it a lot.

 

[G-force]

I've got 20x25' with 10 T8 double 4' fixtures and it's not too much light. Nice and bright.

 

[hammlm]

Beartooth;

Couple of things I think I heard you mention:

1 - Color. The assortment of different "temperature" lamps for T-8 fixtures could make your head spin. You can get traditional "cold" flourescent, "wam" or almost pink flourescent, and a whole bunch inbetween. I ended up using "daylight" in most of my fixtures, and found them the best for me. I think they are 3200K...maybe 3500K. You should buy a couple of each and see which ones you like before you buy a case qty to lamp up all your fixtures.

2 - I hear you all too well about the economics and saving up-front -- but, if you can swing it, I'd get the lighting right up-front -- it's satisfying to have a well lit shop -- and you mentioned painting -- I'd think that warrants getting good light from the get go.

3 - You should look at the ballast rating for whatever fixture you end up using to determine. 1A is close, but there are differences.

4 - Just a guess, but from looking at your floor plan, I think you're going to be fine with a 100A sub in there.

5 - Cold start. I wouldn't worry about that too much. The newer electronic ballasts are oh-so much better than the old PCB ballasts for cold start. I'm not saying there is no diff on cold start, but it only takes a couple of minutes tops with the new ballasts. If you are thinking of heating to a reasonable level (I keep my shop at 58*), it's a non-event.

 

[Mr_fixit]

I have a building about that same size, I have 87 32 watt t8 bulbs. I would never want them all on at the same time, though. I think I have plenty of light...

What I did was wire a 3 bay garage with about 28 bulbs per bay. Most of the time I'm only working in one bay so I'll only have one bay on. That's about 14 bulbs. If I need more light in that bay I flick another 2 switches and the other 14 bulbs turn on.

Each bay is set up about the same.. except I have a little extra around the work bench. and parts cabinets..


Normally, when I want the whole garage lit I have 3 switches on and about 40 bulbs are lit. That's a decent amount of light, but not enough if you're doing fine work.. My walls are painted white.. 12 & 14' walls.


Bulb color will be important, earlier on, I got a great deal on 3500 degree bulbs, so I used them up , but I like the 4100 degree bulbs much better. From what I hear , now the wide or full spectrum bulbs have come down alot in price...Those would be even better.

Originally I had half as many t12 fixtures, but here in the winter, they wouldn't light.Then I had a couple 400 watt mercury halide? lights which light at any temperature but the light was way too little. So I bought a few cases of T-8 electronic ballasts and rewired all my t-12 fixtures and added a bunch more. Plenty of light. I decent quality t-8 ballast will light at zero degreees...

As I get older, I want more & more light.

 

[Torque1st]

Yep, it doesn't allow for much customization and real editing, but it does the job for basic floor layouts and planning. I like it a lot.

The Punch software does not produce drawings and documentation good enough for the codes officials. It is also very buggy. It is the worst waste of money I have ever made on computer software. Hell I can make a sketch on paper a whole lot easier. I can also make layouts in regular CAD software like AutoCAD variants faster and easier, and they ARE acceptable to codes officials. The only thing Punch seems to be good for is the visually impaired.

 

[hammlm]

I guess it all depends where you live. Our township official gave me no issues with my punch drawings. Even made a comment about the quality of information provided (more than just drawings). Every municpality is different I suppose.

Disclaimer: I didn't pay anything for Punch.

 

[Torque1st]

...Disclaimer: I didn't pay anything for Punch.

I wish I hadn't. I try to be good and pay the freight on software since I have written some myself.

 

[burger]

I just finished building my garage and I hope this feedback can help you.

In a 24' x 23' space, I have 12 2 bulb 4' flourescent fixtures spread out in an even pattern.

This should be considered as the absolute mininimum. It's OK for now, but I will be adding more lighting to the areas where I work.

DO NOT do less or you will strain your eyes and no one wants to deal with that ****.

 

[ddrewyor]

I cannot find the chart I used but this site has a calculator for lighting.

http://www.lithonia.com/Software/Lightware7/Visual/
It is the Visual 2.6 software and it lets you enter the dimensions of your space, and determine how many fixtures you need to achieve a user specified level of equal lighting. It takes into account the reflectivity of the ceiling, walls, and floor, and lets you use all the photometric data from Lithonia's website to compare different fixtures.

After you enter your specifications and choose your fixture. You specify a light level (lumens, or foot candles), and then it will show you how many fixtures you need and the reccommended spacing. It also can display a grid overview of the lighting level throughout showing the max and min levels.

This site has a chart for various activities:
http://www.signaturelighting.net/designing_light/howmuch.htm

I could not find the chart I used, but the one above was similar. Good luck
Dave
________
FORD SAF

 

[brad d]

im going with 16 T8 double 4' fixtures in my 35x40... i hope its enough

 

[porschedude996TT]

There is not such thing, "Too Many Lights", he who assigns to such a notion is either an albino or under 20 years old!

Just kiddin' I guess too many lights is when the breaker trips or you can't pay the electrical bill.

In my 30' x 40' shop that I am currently building has a T8 Tube Count of 124 on 7 zones. They are either at 8' off the floor on the parameter, or 14' off the floor in the center of the shop.

I may need to keep my sunglasses and hat on, but should need much task lighting.

 

[froggert]

i've got a total of 16 4' t8 bulbs in my 20' x 23' garage and it's the right amount of light. a little more wouldn't hurt, actually. they're on 3 seperate switches, so i can turn on just the 2 fixtures above the workbench and fridges, the 4 fixtures above the bikes or the 2 fixtures that are covered when the garage door is up. hope that helps.

 

[redsky49]

For general reference, a watt/square foot "rule of thumb" may be helpful for fluorescent lighting.

A corridor in an office building will be quite adequate at 0.6 - 1W/sq. ft. for general cleaning purposes, but most people would find the light level too low for comfortable reading.

Depending on the height of the ceiling, and to a great extent the type and placement of the fixtures, an office space might be more on the lines of 2-3 watts per square foot. This will allow a minimum lighting level of around 40cp at desk level. Areas with less than 2W/sq. ft. typically have task lighting (placed under cabinet) for proper lighting levels. If you are doing detail work in your garage you should aim for the higher lighting levels.

Reflective surfaces such as wall and ceiling are also important in achieving adequate and consistent lighting levels. White walls make a big difference.

Though perhaps a little overboard for a home garage, I have always liked switching the fixtures to control the inner two lamps, with a separate switch for the outer two lamps. This gives the user two easily selected lighting levels. Sometimes the lower light levels are actually preferred for some applications.

Remember that these 4' fixtures project their light to the sides, with very little light output from either end of the fixture. Position the fixtures accordingly.

Open lighting fixtures also collect dust so, if you are planning to spray paint or create sawdust or some other byproduct, you may wish to look at enclosed lighting fixtures.

As mentioned in an earlier post, be sure that you select a rapid start ballast, suitable for the temperatures you anticipate in the garage.

On a personal note, I would recommend that you purchase American Made for higher quality fixtures. Bear in mind there is a lot of junk out there, not all made in China.

 

[redsky49]

If performing hazardous operations,explosion-proof fixtures will be required. This is beyond amateur capability. Get an expert to assist.

 

[Dragster Racer]

As far as low temp startup, I have had good luck with my T8's down below zero so far. They are much better than the T12's.

 

[rinker1]

When its below zero I'm ticked and not workin in it till the building warms up!