Lighting layout

Can anyone give me some general guidelines (or point me to a good website) on lighting layout?

I've got a 40x40 horse barn that I'm trying to lay out the lighting - figure out how bright is enough, how many lights are required, what size, etc. Mostly general lighting, but there are a couple of areas that will need specific task lighting. Lights will be mounted overhead at an elevation of 11-12'.

Thanks for any help,

Bryant

 

What you require for lighting will depend on what kind of fixtures your using and how much you consider to be enough for brightness the color of your ceilling and walls also have to be taken into consideration.
The formula is as follows

N = [(Lighted Area) x (Desired Light Level)] ½ Lumens/Fixture x CU x LLF

Where the desired light level is in footcandles
Lumens determined by the type of fixture and what it produces
CU is coefficient of utilization use 0.62 industry standard
LLF is the light loss use between .60 and .70 as a guide
depending if walls and ceiling are light coloured

Without know all the factors it is hard to tell you what you need
but with this is a starting point .

 

Many things need to be considered when laying out lighting for a particular job but I'll offer some comments and make a suggestion.

Since this is a horse barn we must assume there will be a lot of dark non-reflective surfaces (bare wood, sawdust and concrete floors, etc.), which does not bode well for using only a little lighting that goes a long way (so to speak). Even though you may have some skylights we must assume you will be using the barn at night too. Also, the environment is not favorable to keeping the lighting fixtures and lamps clean where they will give maximum lighting over the lamp's lifetime. Another factor is whether the barn will be heated or not, which may cause certain lamps to be hard to start. Also, whether you want the lamps to light instantly or if you are willing to wait a minute or more for them to strike up and come up to full output. And lastly, the safety factor of whether something may strike the fixture/lamps that could causes the lamps to break and fall.

For practical purposes I have decided on a light level of approximately 50 Foot Candles, which should be more than plenty in a horse barn. This light level is equal to many low-level business offices however the design I am offering will produce more than that initially when the lamps are new and clean but less than the designed level after the lamps have aged a few years and gotten dirty. The dirt factor will be your biggest deterrent to overcome, therefore cleaning the lamps of dust and dirt should be a once yearly chore.

With all of that having been said, I propose using a lighting layout using a quanity of twelve (12) 8 foot 2-lamp F96T12HO (high-output) strip type lighting fixtures. These fixtures hold two (2) 8 foot flourescent lamps and each fixture housing has a ballast that will start the two lamps, almost immediately, down to -20 degrees F.

Your layout in the 40' x 40' barn will be four (4) rows of three (3) fixtures totalling twelve (12) fixtures. The spacing will begin 4' in from the wall with 4' spacing between the ends of each of the three 8' fixtures in each row, which equals 40'. The spacing of the rows will be 5' off the side wall with 10' spacing between each of the four rows of fixtures, side to side, which equals 40'.

This should give you more than ample lighting in your barn that can withstand low temperatures, start quickly, be fairly energy conservative, long-lasting, easily cleaned and produce even lighting. I suggest putting each of the four rows (of three fixtures) on a separate light switch, which will allow you to use less than all the fixtures if you wish and would be appropriate to break up the electrical load also.

For the lighting gurus, I used 8,000 lumens per lamp with a combined MF and CU of .40 based on 11' mounting height and a work plane of 4' with 20/20/20 (ceiling, wall and floor) reflectance.

I hope this helps!

Kooter