[BLDG-SIM] Appendix G, Window wall ratio for the baseline

[Dana Troy]

Hello All, 
 
 I have a question that pertains to ASHRAE 90.1-2004, Appendix G, Table G3.1, No.5, which details modeling requirements for calculating proposed and baseline building performance for the building envelope.  I'd appreciate any thoughts you all might have on this LEED modeling.  
 
 We are currently working with a client on a building with a window-wall ratio of 27%. The WWR was reduced from 40% by the architect in order to obtain higher energy cost savings. When building the baseline model, Appendix G states: 
 
 "Vertical fenestration areas for new building and additions shall equal that in the proposed design or 40% of gross above-grade wall area, which ever is smaller..." 
 
 Our client believes that since in the schematic design, the WWR was over 40% and was then reduced to below 27% for energy efficiency reasons, the baseline building should be modeled with a 40% WWR to show these savings due to architectural design. 
 
 I understand that the proposed design stated in Appendix G refers to the building that is going to be built, or the 100% CD drawings. However, our client wants to see the definition of "proposed design" from ASHRAE that explicitly states what the proposed design is. After researching for a while, I found Addendum A, which states on page 4 of the Addendum: 
 
 G3.1 Proposed Design Model. The simulation model o f   
 the proposed design shall be consistent with the design documents, 
 including proper accounting of fenestration and 
 opaque envelope types and areas; 
 
 and: 
 
 G3.6 Building Envelope. All components of the building 
 envelope in the proposed design shall be modeled as shown on 
 architectural drawings or as built for existing building envelopes. 
 
 This still is not enough to accurately define the proposed design. I am sure that you might  all agree with me on the interpretation of Appendix G, but does anyone know where I can find a solid definition of what the proposed design is? I have searched the CIRs on the USGBC website and came up empty handed and don't know where else to go. ASHRAE said a formal interpretation request could take upwards of 6 months, so that is also out of the question .  
 
 Any help would be greatly appreciated.  
 
 Thanks, 
 Dana Troy


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