Re: Light Output

"Roger Breton" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> > "Roger Breton" <[EMAIL PROTECTED]> wrote in message
> > news:[EMAIL PROTECTED]
> >> I have setup two Phillips ColorTone F40C50 40W Fluorescents above my
work
> >> area, at a distance of approximately 36 inches -- I know that's not a
huge
> >> distance. I have measured the illuminance on my work area to be 400
Lux.
> > If
> >> I want the illuminance to reach 2000 Lux on my work area what course of
> >> acton would you recommend: add more of the same lamps or switch to
higher
> >> Lumen lamps?
> >
> > Yes, one of those two should work.  Once you calculate what you need
going
> > either way, you can look at the aesthetics and costs of the two
solutions
> > and chose the one that meets your needs the best.
> >
> Is there a mathematical relationship one can use to determine, given a
> certain illuminance level on a given surface at a given distance from the
> source which Lumen power lamp is required?
>
> In the case of illuminating my work area, if I know I am going to place
the
> lamps at a distance of 6 feet aove it, and I want to obtain an
illumination
> of say 1000 Lux, is there any equation that I can use to figure
> theoretically how much Lumen is needed from the lamps?
> Is there a mathematical relationship one can use to determine, given a
> certain illuminance level on a given surface at a given distance from the
> source which Lumen power lamp is required?
>
> In the case of illuminating my work area, if I know I am going to place
the
> lamps at a distance of 6 feet aove it, and I want to obtain an
illumination
> of say 1000 Lux, is there any equation that I can use to figure
> theoretically how much Lumen is needed from the lamps?

I misunderstood your original post.  I thought you were looking for an
opinion for the two solutions.  Try
http://www.thornlighting.com/light/radiance6.html where the basic equation
for the inverse square law is given.


Sincerely,


Donald L. Phillips, Jr., P.E.
Worthington Engineering, Inc.
145 Greenglade Avenue
Worthington, OH  43085-2264

[EMAIL PROTECTED]
(remove NS to use the address)
614.937.0463 voice
208.975.1011 fax

http://worthingtonengineering.com