I am not clear about explanation from ASHRAE 90.1-2007 User’s Manual:
1. For laboratory spaces with a min. exhaust of 5000 cfm, the HVAC system type should be 5 or 7 and reducethe exhaust and makeup airvolume to 50 % of design values during unoccupied periods.
2. For larger nonresidential buildings (more than 5 stories), the baseline building HVAC system is system 8, if the heating source in the proposed building is all electric.
For a lager laboratory building (more than 5 stories) the HVAC system type in the baseline building should be 7 or 8, when the proposed building has only electric heat?
Thank you in advance!
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Yu Wang
Mechanical EngineerSCHOLZE Consulting GmbH
13 thumbs up
July 19, 2012 - 3:52 am
Dear Yu,
Thank you for contacting the Green Building Certification Institute. Based upon the description given, we are assuming that your laboratory building is more than 5 stories, only uses electric heating within the building, and has more than 5,000 CFM of exhaust. In this case, the Baseline Case system type should be system #7, with electric heating at the VAV box in lieu of hot water reheat.
Please note that this issue isn’t entirely clear within Appendix G, and the project team may want to consider submitting a Credit Interpretation Ruling (CIR) for an official decision. The CIR will receive an official ruling whether the approach is acceptable and meets the intent of the credit, and would be applicable to this project only. For more information about CIRs refer to this link: http://www.gbci.org/Certification/Resources/cirs.aspx.