The project is a high-rise residential building that is being applied under LEED-CS certification. Living units are being designed without air-conditioning system, since generally the people use natural ventilation during summer. Building spaces with regular occupation, such as bedrooms and living rooms, will be furnished with operable windows only, without mechanical systems. Therefore, under ASHRAE Standard 90.1 the entire building would be defined as unconditioned space, and the envelope does not need to comply with mandatory provisions of that Standard. Following this interpretation, the scope of work for this project would be limited to sections 7, 8, 9 and 10 of ASHRAE Standard 90.1, as the building will be provided with: service water heating; power distribution systems; lighting systems for common areas; and electric motors (stairs ventilators, water pumps and sewage pumps). In order to achieve the minimum energy performance prerequisite needed for LEED certification, only the lighting system for common areas and the service water heating were identified by the design team as the scope of work to be treated under ASHRAE Standard 90.1 and modeling rules of appendix G. This CIR is to clarify three questions: 1. Is this building eligible to certification under LEED, even without HVAC system? 2. If affirmative, the minimum energy performance has to be achieved only for those systems that will be provided by the owner, i. e., lighting system for common areas and service water heating? 3. Can natural ventilation be used as an energy efficiency strategy to achieve the minimum energy performance, in similar way as discussed in a CIR posted in 03/22/2007 (through an Exceptional Calculation Methodology)?
1) Yes, the project is eligible for LEED certification. 2) Yes, the minimum energy performance and energy savings only applies to systems supplied by the owner. PLEASE NOTE that this project must comply with the mandatory provisions (Sections 5.4, 6.4 (when applicable), 7.4, 8.4, 9.4, and 10.4) of ASHRAE 90.1-2004, which includes the Building Envelope. Section 5.1.2.2 of ASHRAE 90.1-2004 clearly states that "spaces shall be assumed to be conditioned space and shall comply with the requirements for conditioned space at the time of construction, regardless of whether mechanical or electrical equipment is included in the building permit application or installed at that time." 3) Yes, natural ventilation can be used as an energy efficiency strategy to achieve minimum energy performance through the Exceptional Calculations Methodology approach outlined in CIR Ruling 3/22/2007. Credit achievement is contingent on the submittal documentation and compliance with the stated method to the satisfaction of the certification reviewer. Please be sure to submit the documentation outlined in the CIR in order to determine compliance during LEED certification. Applicable Internationally.