Warwick Silvester w.silvester at WAIKATO.AC.NZ
Mon May 18 19:01:45 EST 1998

Can someone help me compare apples and oranges?

I made some light intensity measurements in my lab using a quantum sensor
for PAR (400-700 nm), so the units are umoles photons per m2 per sec.  My
purpose was to help our operations folks design better room lighting.  I
realize that architects are used to measuring light in units such as lumens
or foot-candles.  My problem is to try to convert.  I know it can't be done
exactly, because one is measuring different things.  But assuming the
spectral distribution of a typical fluorescent light bulb, does anyone have
a rough approximation of a conversion?

Carl S. Pike                             (717) 291-3958
Department of Biology                    FAX (717) 399-4548
Franklin and Marshall College            Internet  C_PIKE at ACAD.FANDM.EDU
P.O. Box 3003
Lancaster, PA  17604-3003  USA

PAR measurement under cool white fluorescent of 27 micro moles is equal to
c. 200 lux ie 200 lumens per m2 or c. 2000 foot cadles (lumens per ft2).
This ratio only holds for the particular light source but will be generally
OK for  most fluorescents

Warwick Silvester                      Ph. +64-7-838 4613  and voicemail
Dept of Biological Sciences          Fax +64-7-838 4324
University of Waikato                  Email w.silvester at waikato.ac.nz
Hamilton, New Zealand

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