Rating System

LEED BD+C: New Construction

Rating System Version

v2 - LEED 2.2

Inquiry

This CIR is a follow-up to the 2/26/2007 ruling for our 120,000 sq. ft. laboratory project. The EAc1 ruling dated 2/26/2007 indicates "the ASHRAE 90.1-2004 Standard Appendix G modeling protocol is not a compliance method but rather a method of comparing the proposed design\'s energy performance to a building that would have been typically built." The prescriptive requirements in 6.5.7.2 of ASHRAE 90.1-2004 indicate fume hood systems having a total exhaust rate greater than 15,000 cfm shall include either VAV exhaust and room supply, direct make-up, or heat recovery systems. Based on these prescriptive requirements, a lab similar to ours would that would have been typically built would not include both VAV and energy recovery. It would only include one of these strategies. But based on the 2/26/2007 ruling, it seems the baseline in Appendix G will require both VAV and energy recovery, which is above the typical based on the prescriptive requirements noted above. The 2/26/2007 EAc1 ruling indicates "the baseline should be modeled as system 5", meaning we should ignore G3.1.1(c) (which tells us to model our baseline in the lab only as constant volume) and we should model the baseline lab as a VAV system. G3.1.2.10 requires us to have energy recovery in the baseline since we also have it in the proposed design. By having us ignore G3.1.1(c), the 2/26/2007 ruling has created a baseline that is above the typical. This ruling does not award labs for providing both VAV and energy recovery even though having both is not typical. Can we instead match the prescriptive requirements and typical lab building design by not including energy recovery in the baseline with VAV when we do have energy recovery in the proposed design?