[Radiance-general] Help - Radiance / LEED

[Guglielmetti, Robert]

There are a whole bunch of people on this list that I'm thankful for knowing; it's truly a great bunch, and I have learned a lot from these people, both on- and off-list. To answer your question, yes, it sounds like the "illumimance image" option is what you want, since it gives you a result in SI illuminance units (lux) -- which you can convert to footcandles with that multiplier so that the LEED reviewers are happy. Sorry for adding confusion by botching the units in my previous post. For the record: one footcandle is equal to one lumen in a square foot!

- Rob


From: Ignacio Fajardo <primiark at gmail.com<mailto:primiark at gmail.com>>
Reply-To: Radiance general discussion <radiance-general at radiance-online.org<mailto:radiance-general at radiance-online.org>>
Date: Sun, 24 Apr 2011 15:14:59 -0600
To: Radiance general discussion <radiance-general at radiance-online.org<mailto:radiance-general at radiance-online.org>>
Subject: Re: [Radiance-general] Help - Radiance / LEED


Dear Rob and Lars

Searching on internet I realize that I´m very lucky to be in the same mail list with both of you. Let me show me respect and gratitude.

I still have a question in units to use for LEED calculations and I write below some important data to remember:

 Robert told us to use for LEED :

 Illuminance lm/m2 (lumens/m2)

Radiance web site :

Radiance / Luminance (W/sr.m2, cd/m2)

Irradiance / Iluminance (W/m,lux)

Ecotect options:

Luminance Image (cd/m2)

Iluminance Image (lux/m2)    may be, must mean  lm/m2

 LEED requeriements :

25 footcandle min

500 footcandle max

So, Rob and Lars I´m going to use Iluminance image Options on Ecotect to have result in lux (lumens/m^2), then multiplying those values by 0.0929030436 will convert the grid values to footcandles (1lm/m2 = 0.09 foot-candle)    http://www.convertworld.com/en/illuminance/
LEED mentions that 75% of the zone must be between 25 and 500 footcandle, So If I do the conversion (Lumens/m2) x (0.09)   that  value in the grid point can be use to complete the % of area for LEED.

Lars you correct Rob about a mistake in theunits…
ROB: “So, assuming you are indeed calculating illuminance, in lux (lumens/m^2), then multiplying those values by 0.0929030436 will convert the values to footcandles (lumens/m^2).”
LARS: Actually lm/ft2. You see what a mess the mixing of metric and imperial system leads to if these typos appear even in Rob's explanation.

… But the units still  footcandles right?  The confusion was that Rob meant lumens/ ft2.


Guys…please confirm the information above is correct and have a look to the website if you have time.

I will gladly take any comments.
Cheers!!


2011/4/22 Rob Guglielmetti <rob.guglielmetti at gmail.com<mailto:rob.guglielmetti at gmail.com>>
OK, I won't kill myself. Instead, I will open up a unit salad bar. Should make a killing.

Man, that was funny, even if only to me.

- Rob


On Fri, Apr 22, 2011 at 2:54 AM, Lars O. Grobe <grobe at gmx.net<mailto:grobe at gmx.net>> wrote:
Thank you Lars; I will now kill myself.

I think that I can ask you to review this decision on behalf of this mailing list's subscribers who would really miss your insight :-)

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