ID#2346 made on
EAp2 - Minimum energy performance
LEED BD+C: New Construction, LEED BD+C: Core and Shell, LEED BD+C: Schools
The prerequisites requirements are to design the building project to comply with both- the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) of ASHRAE/IESNA Standard 90.1-2004 (without...
The prerequisites requirements are to design the building project to comply with both- the mandatory provisions (Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4) of ASHRAE/IESNA Standard 90.1-2004 (without amendments); and the prescriptive requirements (Sections 5.5, 6.5, 7.5 and 9.5) or performance requirements (Section 11) of ASHRAE/IESNA Standard 90.1-2004 (without amendments). The project consists on installations for a public park, they are: an exterior amphitheater, one administrative office, exhibition space and a refreshment stand. The project is designed 100% "off-grid" with Photovoltaic (PV) renewable energy source completely, that means that there will be no electrical consumption from fossil fuels. A battery bank will provide the back up power. The project is 100% naturally ventilated. There is no mechanical ventilation and it will be operated accordingly. The ASHRAE's Mandatory provisions in Section 5: Building Envelope will not be met completely, outside air infiltration will be promoted, all windows will be opened during operation hours. The walls are designed to be permanently permeable to outside air. Accordingly, thermal transmission will not be possible to achieve in some of the spaces. Section 6: HVAC, will not be contemplated for being outside of the project's scope. Section 7: Water heating for service water will be designed with solar thermal water heaters. Therefore water heating in this project is contemplated as no electrical consumption. Section 8, 9 and 10 will be completely contemplated. Because of project's scope, complete compliance with ASHRAE would be incoherent. But being a 100% renewable energy, 'off grid' project, its design is streamlined for energy efficiency, and obliged to operate as intended, as it will be demonstrated. Therefore we think we will meet outstandingly the EA Prerequisite 2 and EA Credit 1 intents, even if deviating from ASHRAE's provisions and requirements. Is our assumption correct?
The project team is requesting variance on meeting the mandatory and prescriptive requirements of ASHRAE 90.1-2004, given that this project is a public park with some structures, all of which will be naturally ventilated. Section 5.2.1 - Compliance, of the ASHRAE 90.1-2004 states: "For the appropriate climate, space-conditioning category, and class of construction, the building envelope shall comply with 5.1, General; 5.4, Mandatory Provisions; 5.7, Submittals; and 5.8, Product Information and Installation Requirements; and either..." (It goes on to state Section 5.5 (Prescriptive Building Envelope Option) or Section 5.6 (Building Envelope Trade-Off option) as the compliance paths - however LEED only allows for Section 5.5 as the compliance path). Section 5.1.2 - Space-Conditioning Categories, Sub-Section 18.104.22.168, of ASHRAE 90.1-2004 provides further guidance on this, stating that: "In climate zones 3 through 8, a space may be designated as either semiheated or unconditioned only if approved by the building official." (See definitions in ASHRAE 90.1-2004 for italicized terms, including "building official".) (Note that it is not clear from the request, as to whether this project is indeed in climate zones 3 through 8.) On the prescriptive building envelope requirements, assuming that this designation will be approved, given this situation; the project team can follow Section 5.5.2 of the ASHRAE 90.1-2004 which states: "If a building contains any semiheated space or unconditioned space, then the semi-exterior building envelope shall comply with the requirements for semiheated space in Tables 5.5-1 through 5.5-8 for the appropriate climate." The project team may interpret this requirement to apply only to parts of the building envelope that are not designed to be permeable to outside air, as long as supporting documentation to this effect is provided. On the mandatory provisions (Section 5.4), subject to the space-conditioning category designation being approved by the building official; and provided ALL of the structures are indeed naturally ventilated/conditioned (including the administrative office, exhibition space and refreshment stand); it is acceptable to exclude requirements for Section 5.4.3 - Air Leakage for this project. Please provide sufficient documentation to demonstrate that this is indeed the case, when submitting for certification/review. Sections 5.4.1 and 5.4.2 would fall under the purview of Section 5.5.2 as quoted above. Furthermore, this should be accompanied by a letter of undertaking by the responsible party that in the event that alterations are made to the structures under the scope of this certification that would affect it's energy performance in the future, these alterations will comply with the requirements of this prerequisite. The project must also include occupied interior space in order to be eligible for certification. Applicable Internationally.
Related Addenda (Corrections & Interpretations)