Project background: The project owner has purchased an unconditioned warehouse with the intent to convert it 100% into a school. Approximately 92% of the existing walls will be thermally modified to improve energy performance.
According to Table G3.1(5)(Baseline Building Performance)(f.) Existing Buildings: "For existing building envelopes, the baseline building design shall reflect existing conditions prior to any revisions that are part of the scope of work being evaluated."
However, in the 90.1 User's Manual of this section (page G-17) it indicates this requirement is only applicable to existing buildings where an addition is being evaluated by the PRM.
Should the baseline building walls be modeled as the existing building construction or as steel framed according to Tables 5.5-1 through 5.5-8 of 90.1-2007?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
February 9, 2014 - 4:06 pm
In my opinion the baseline should be the Table 5.5-X values. While Table G3.1-5 (Baseline)(f) states that you should use the existing envelope, if you read the definitions a building envelope it separates conditioned spaces (or semi-conditioned) and the exterior (or unconditioned spaces). Since the warehouse was not conditioned in its "existing" state it is not technically a building envelope.
Matt Humphreys
February 10, 2014 - 5:23 pm
Thank you.