I am defending a lawsuit, and need a source for calculating the area that would have been illuminated by the 400 watt halogen bulb they had in place when the plaintiff fell into a stairwell.
2006-12-07 03:58:17 · 4 answers · asked by Patrick F 1 in Science & Mathematics ➔ Engineering
You need the photometrics for the light fixture itself, not just the light bulb. A 400 watt quartz lamp in a pendant downlight is going to give a totally different light distribution than a 400 watt quartz lamp in, say, a desk light. It's the design of the refractors in the fixture that determine the footcandle illumination spread. It also depends on how the light fixture itself is placed -- if it's a floodlight it would have to be aimed correctly. In fact, if a light that strong was aimed wrong it could make it harder to see a safety hazard because it was blinding the person.
Really the only valid legal evidence would be to take a light meter reading directly in the area that the accident occurred (meters are cheap -- you can get a Greenlee model at any electrical supply house for around $20).
2006-12-08 04:53:59 · answer #1 · answered by c_kayak_fun 7 · 0⤊ 0⤋
You haven't defined your question very well. You really need to say how illuminated the stairwell had to have been. Also, the 'area' illuminated is very ambiguous. What was the solid angle of illumination for the bulb? From that, we could work out the luminous flux and work out how bright the light would be at a certain distance. From that, we could work out what area would be illuminated at a certain intensity.
Personally, I wouldn't take this case. A 400 watt bulb is very strong and a stair-well is usually very narrow, so the chances are they could see perfectly well.
2006-12-07 04:02:36 · answer #2 · answered by Mawkish 4 · 0⤊ 0⤋
It would depend on a lot of things. How far the light source is from the steps. What type of halogen lamp is it? What color are the walls and ceilings? Usually software is used to calculate the illuminance. Your best bet is to get a hold of a light meter and go measure how many foot candles are the top and bottom step. I think 20 ft-cd is more than enough for steps. You would have to check with IES. Illumination Engineering Society.
Good Luck.
2006-12-07 04:34:34 · answer #3 · answered by scubamasterme 3 · 0⤊ 0⤋
You need to get an isolux diagram for the wattage and light mounting type. If you are defending this lawsuit, you may want to check with DPW (Electrical Division) or their standard plans for such a diagram.
IMHO, 400 watts is pretty bright. The highest that we use around here is 310 with 200 being the most common.
2006-12-07 04:51:48 · answer #4 · answered by Stan the Rocker 5 · 0⤊ 0⤋