More planning:
# Step 4: How will lighting be provided?
AKA: The lighting plan.
The lighting plan encompasses area lighting, task lighting, and exterior lighting.
Area lighting:
The first thing to consider was the overall level of illumination inside the building, at floor level. According to the Illuminating Engineering Society (IES), the standard for a garage is 50 foot candles (fc). My understanding is that foot candles is a measure of illumination at the surface being illuminated.
Lumen (lm), on the other hand, is a measure of brightness of the source, at the lamp itself.
Frankly, I find the discussion of foot candles and lumens and the relationship of them hard to wrap my mind around. As I understand it, the number of lumens from a light source needed to achieve a number of foot candles on the floor depends upon several variables, including the design of the fixture and the distance from the fixture to the surface.
But 50 foot candles is a minimum, and would probably work. It was suggested earlier that 100 fc is preferable, as it gets into truly well-lit territory.
When figuring up the number of 4’ 5000-lumen fixtures needed to get close to 100 fc, I came up with 24. Hanging and wiring that many fixtures seemed to be a bit excessive.
I also considered UFO high bay fixtures, as they are much brighter and therefore would require fewer fixtures. However, they’re designed for ceilings significantly higher than mine. And they cast shadows.
Then I started looking 4’ shop lights with higher output. One company sells US-made three-tube, 8550 lumen led shop lights that would get me to 91 fc using 12 fixtures, according to their calculations. They seem like excellent fixtures.
Unfortunately they’re quite expensive; those 12 fixtures would set me back almost $1,000. That said, they’re made out of steel, have a five year warranty, have replaceable tubes, and are made in the USA. But still, $1000 for interior lights...
So I went back to amazon to see just how close I could come to 100 fc without breaking the bank. And found some 10,000 lumen 4’ fixtures that would seem to do the job for about $25 each.
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Taking the differences of the fixtures into account, twelve of these
should provide around 100 foot candles. But if they’re close to that, and they last, they’re a bargain. FWIW, they have a 4.8 star amazon rating.
The disadvantages of these are that they’re made in China and don’t have replaceable parts. The whole fixture has to be replaced in the event of a failure.
If I were still drawing a salary instead of my current retired status, I just might buy the US made lights. But that’s not my reality, so it’s off to amazon I go. I ordered 12 for area lighting.
Task Lighting:
Since the workbench, tool table, tool chest, and parts washer will be along the back wall, task lighting will simply be a row of the same 4’ fixtures placed 18” off the wall. A drafting lamp on the workbench or tool table could be added for those times when they’re wheeled out from under the fixed lights. Task lighting will be the easiest of the three to change if it comes to that. I’ll try it out and see how it goes.
Exterior lighting:
I have mixed feelings on this, as we live in the country and I really don’t like light pollution or light trespass. However, some exterior lighting is necessary.
Pole mounted sodium vapor lamps, for example, are popular as yard lights out here; we have one. It’s arguably the most practical and economical solution for security lighting in a rural area. Someone suggested to me that it helps keep coyotes away, but that seems like a stretch. But they contribute to light pollution and trespass.
Most commercial buildings around here have box type fixtures that project as much light outward as they do downward.
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My preference is to use cutoff type fixtures so that most of the light shines down, rather than in our eyes when approaching the building.
This is an example of a Dark Sky compliant cutoff fixture:
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The plan is to place a fixture above each bay door, and one on the side by the man door.
And here’s what the lighting plan looks like:
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The area and task lights are ordered. Next will be to figure out how to provide and distribute electrical power.
More to follow.