Here in Minnesota, where I live and work, there is a requirement that all publicly funded projects comply with the B3 program, which is similar to USGBC's LEED program. One of those requirements relates to Daylight Factor. We use ElumTools to run a simulation to derive this value. This post will touch on this more, and a challenge the ElumTools developers helped us overcome!
Read on to learn more...
Daylight Factor defined (Wikipedia): Daylight Factor
Related Minnesota B3 Requirement from section I.9(A):
Solar Tube Challenge
In some cases, we have employed solar tubes to increase natural daylight in a space to achieve DF compliance. Solar tube manufactures often provide an IES file which approximates lighting through their apparatus for multiple site locations. However, originally, ElumTools did not allow photometry (i.e. IES files) be used in a Daylight Factor calculation.
The “formal” definition of Daylight Factor says an overcast sky type must be used, and no electric lighting can be considered. *.IES files are typically for electric light. But solar tubes are a notable exception, of course.
At point point, about two years ago, the developers gave us a special build of ElumTools so we could utilize IES files for solar tubes within a calculation. Now, as shown in the ElumTools Settings dialog above, this is possible when needed.
This new setting simply ignores those rules! Which allows you use any sky type, and consider *.IES files, for Daylight Factor calculations.
Related post:
Licaso Has Arrived! Annual daylight simulation software for AGi32 and ElumTools
Tally - Life Cycle Assessment - By KieranTimberlake
For BIM Chapters updates, follow @DanStine_MN on Twitter or connect on LinkedIn
I also write blog posts for Enscape - a new paradigm in rendering, animation and VR for AEC.
Read on to learn more...
Daylight Factor defined (Wikipedia): Daylight Factor
"the ratio of the light level inside a structure to the light level outside the structure"
Also, the building orientation does not matter and the sky is always overcast.
Related Minnesota B3 Requirement from section I.9(A):
"In New Buildings, at least 75% of the floor area of continuously occupied spaces in the building shall have a minimum daylight factor of 1% when measured without furniture and at 2'6" above the floor. This may be demonstrated using the Daylight Factor Calculator provided in the guidelines, through daylight simulation, or physical daylight modeling. (This is recommended for Major Renovations where applicable.)"
Click here is see the full section.
Solar Tube Challenge
In some cases, we have employed solar tubes to increase natural daylight in a space to achieve DF compliance. Solar tube manufactures often provide an IES file which approximates lighting through their apparatus for multiple site locations. However, originally, ElumTools did not allow photometry (i.e. IES files) be used in a Daylight Factor calculation.
For example, the manufacture, Solartube provides photometric data files for all their products at 130 site locations. Click here for more on that.
The “formal” definition of Daylight Factor says an overcast sky type must be used, and no electric lighting can be considered. *.IES files are typically for electric light. But solar tubes are a notable exception, of course.
At point point, about two years ago, the developers gave us a special build of ElumTools so we could utilize IES files for solar tubes within a calculation. Now, as shown in the ElumTools Settings dialog above, this is possible when needed.
This new setting simply ignores those rules! Which allows you use any sky type, and consider *.IES files, for Daylight Factor calculations.
Thanks ElumTools!
Licaso Has Arrived! Annual daylight simulation software for AGi32 and ElumTools
Tally - Life Cycle Assessment - By KieranTimberlake
For BIM Chapters updates, follow @DanStine_MN on Twitter or connect on LinkedIn
I also write blog posts for Enscape - a new paradigm in rendering, animation and VR for AEC.