We have a project pursuing LEED v4/4.1 that is surrounded by large existing pecan trees. Should we be including modeled trees in our daylight study? The challenge is that these are deciduous trees and therefore are fairly dynamic and changing throughout the seasons so it is not an accurate reflection to have them "on" as an annual influence on the building. Does anyone have guidance on if they should be included, and if so, the best way to model them and the material type? We use Climate Studio which has various leaf and similar materials that could be used.
Thanks!
Daniel Glaser
PrincipalLightStanza
LEEDuser Expert
18 thumbs up
February 4, 2022 - 12:17 am
Hi Kate,
Technically there is no technical reference anymore for LEED 4.0/4.1. It used to be IES LM-83 2012, but it has been deprecated by the IES. In the 2012 document it stated:
"Model trees as appropriately sized cones, spheres, or cylinders with 20% reflective component. More accurate shapes are allowable."
The document is being revised/republished, but in the meantime you may use its guidance for volumes or something equivalent.
Yes, given seasonal variation you can say average best and worst case. Or run it with full volume for worst case sDA and best ASE and slender for best case sDA and worst case ASE. As you know LEED does not penalize for ASE/glare.
The fact that you are modeling for trees at all is commendable. There are other factors that I'm sure you know about like modeling the ground plane an appropriate dimension (for light to bounce off of), assigning interior finishes, glazing VT, etc.
Kristen Vachon Vogel
USGBC/GBCINovember 26, 2024 - 8:45 am
In case others are referencing this forum for information, please note that LEED guidance has not removed the technical reference in v4/v4.1. LM-83-12 is still the referenced standard and modeling per that standard is required for Options 1 and 2. Section 2.2.8 describes the methodology for modeling all exterior obstructions (buildings, trees, ground surfaces, etc.) within 100 feet.
Elliot Glassman
Building Performance Group Leader and Vice PresidentCannonDesign
4 thumbs up
November 26, 2024 - 9:01 am
Also, Climate Studio's latest release now allows you to model deciduous trees to take into account their dynamic nature when running annual simulations.