The MLO says that in order to establish the Total Initial Site Lumens one must use Table D, adding together the Allowed Lumens Per Square Foot and the Allowed Base Lumens Per Site. Could someone please explain what exactly the Allowed "Base" Lumens Per Site are? Is this referring to existing lighting or to the area outside of the zone's perimeter? What is the "base"?
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Bill Swanson
Sr. Electrical EngineerIntegrated Design Solutions
LEEDuser Expert
731 thumbs up
June 25, 2018 - 2:16 pm
Per the MLO guide,
Table D establishes the basic total initial site lumens allowed. These lumen allowances are added together for a total initial site lumen allowance. Allowances include:
1) Initial lumen allowance per site
2) Per area (SF) of hardscape
As an example, Project with 20,000 sf of hardscape located in LZ2 will look like this.
1) LZ2 = 7,000 lumens
2) 20,000 sf of hardscape is 2.5 * 20,000 = 50,000 lumens
Total initial site lumen allowance = 7,000 + 50,000 = 57,000 lumens.
"Base" just means the first line of this equation. If you are in lighting zone LZ2 your base lumens is 7,000 lumens. If LZ3, your base lumens is 14,000 lumens.
The reason for having "base" in this calculation is that they recognize that smaller sites use more lumens per sf. Having this base values helps smaller projects show compliance, and as project area increases, the base lumens help less and less.
For LZ2, the second line allows 2.5 lumens per sf of hardscape. Compare this with total site lumen averages.
A project with 2,000 sf gets 6 lumens per sf
A project with 20,000 sf gets 2.85 lumens per sf
A project with 200,000 sf gets 2.535 lumens per sf.
Candace Cohen
June 26, 2018 - 5:23 am
Got it! Thank you so much!