orientation of lights

[crewchief437]

are lights output evenly distributed or omnidirectional in displacement of light. basically i am building a 30wx40l shop and trying to cover it with two runs of four lights should they be oriented with the long axis or wide axis. this might be going to a level of cold fusion with minor difference but just trying to get best bang for the buck.

 

[Steevo]

30w x 40 L x how high?
Two runs of four lights doesn't tell much
What kind if fixtures are you using, with what kind of bulbs/tubes?

 

[Ray916MN]

Assuming you're talking about fluorescent tubes they are predominantly radially directional around the length of the tube. Strip fixtures essentially throw half their light at the ceiling which significantly reduces the amount of illumination they provide unless you use the ceiling as a work surface or have mirrored ceilings. You also want to be careful about mounting with respect to where your garage doors sit when open. The closer they are to the door when open the more light lost between the ceiling and the side of the garage door facing the ceiling. The higher a strip fixture is mounted, the more output that is used to light the ceiling and walls, as opposed to horizontal work surfaces.

Mounting height to surfaces to be lighted is critical to consider to avoid shadows. With 8' ceilings, whenever the fixtures are behind you, you cast a shadow. The further the behind you the fixture is the bigger the shadow. In general, the lower the ceiling the more fixtures you want to use to get even shadow free lighting. The higher the ceilings the more you want fixtures with reflectors and/or higher output bulbs and/or more fixtures to get more output to compensate for the amount of light going to light the walls.

The optimal placement of your lights depends on what you want lit, your ceiling height and things like your garage door placement.

 

[Falcon67]

Gonna be real dark in places. Longways with regular 8' fixtures you're going to have two strips of light with a lot of shadow.

 

[Charles (in GA)]

With the lights the length of the building, (assuming fluorescent strips) you would have two rows, 15 ft apart, thus 7½ ft from each wall. If the lights are high enough, say 10 to 12 ft, this might give you enough spread of light to not leave any dark areas. If the ceiling is say, 8 ft, then it probably won't work.

 

[crewchief437]

not 100% decided on ceiling height but it will be either 10' or 12'. I am looking at going LED with http://www.homedepot.com/p/Lithonia...ERCH=RV-_-rv_homepage_rr-_-NA-_-203820958-_-N which is a 4000 lumen light. if i need to add another row i will at 120 a fixture it aint cheap though. i asked for a quote on lighting and they sent me a diagram of the lighting with lumen calcs for every sqft. is there a free software out there that will plot your lighting system?