We are working on a Healthcare project and are looking to pursue IEQc5. We have several questions regarding the documentation and the requirements related to the mathematical modeling option:
1.What type of support documentation is required to upload to Leedonline if we pursue the mathematical modeling route to show compliance?
2.On page 268 of LEED Reference Guide - Healthcare Supplement NCv2009 Edition, under Outdoor Air Intake it states “examples of mathematical modeling include analytical models and computational fluid dynamics.” What are analytical models as they refer to in the above quote?
Kim Shinn
Executive Principal and Senior WizardTLC Engineering Solutions
80 thumbs up
February 11, 2014 - 8:16 pm
The requirements for the documentation are fairly qualitative. If you look at the LEED Online form, you will see that you are to "provide a narrative describing which sources of exterior contamination the team chose to model, reasoning behind selection, and modeling techniques including how the worst case meteorological scenario was identified, assumptions about compositions, assumptions about dilution ratios, and software used". Then you are to "provide [the] calculations based upon physical or mathematical models that demonstrate outside air intake concentrations do not exceed applicable exposure limits". We take this to mean that you should, like for an energy model, make a list of the inputs and assumptions, provide a "map" showing the locations of the sources and areas of concern, and a table listing the concentration ratios at the areas of concern.
As far as the "analytical models" phrase goes, this is just a catch-all to cover any computational model that can demonstrate the contaminant concentrations. There are several different computational fluid dynamic (CFD) modeling programs that can be used to do the analysis - there isn't one proscribed modeling program to be used. The credit also allows the team to do physical modeling (like a "wind-tunnel" test) in lieu of doing the computational or analytical modeling.
Generally speaking, you need to engage the services of a specialized CFD modeler. This is not a common skill set, so be sure that you get someone with experience to look at the project and give you an idea of the amount of work required. There is a continuum of complexity and rigor. For instance, multi-building campuses with many point sources (exhausts) and target areas (outdoor air intakes, places of respite, operable windows and doors, etc) can be very difficult to model. On the other end of things, if you have a simple building on a wide open site, the modeling can be less difficult. CFD models are very sensitive to "mesh size" - the density of calculation nodes, and converging on a stable model can be hard to achieve.
Finally, be aware that there is a link between SSc9.2 and IEQc5. If you are pursuing SSc9.2, you will need to provide the same documentation as for IEQc5.
Susan Walter
HDRLEEDuser Expert
1296 thumbs up
February 12, 2014 - 9:40 am
Thanks, Kim for the very considered response.
Susan