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?
"The applicant is requesting an allowance to match the prescriptive requirements of Standard 90.1 in their baseline building model. This request is allowed. Section 6.6.7.2 of Standard 90.1-2004 requires the proposed laboratory system to include either VAV controls that are capable of reducing exhaust and makeup air volume by 50% of design values or heat recovery meeting the requirements of Section 6.5.6.1. This is consistent with the applicants request to not include heat recovery in the baseline building model. In addition, the baseline VAV system serving the laboratory should only reduce the exhaust and makeup air volume to 50% of design values during unoccupied periods instead of the minimum volume setpoint of 0.4 cfm/ft2 of floor area as required by Section G3.1.3.13."