IGCC CODE CHANGE PROPOSAL FORM (See instructions on page 2)

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1 IGCC CODE CHANGE PROPOSAL FORM (See instructions on page 2) Code: GC 11(to be filled in by ICC) Code Sections/Tables/Figures Proposed for Revision (3.3.2); Note: , , , 603.3, Proponent: Dave Hewitt & Sean Denniston / New Buildings Institute Address: sean@newbuildings.org Revise as follows: Modify the following text to read: Minimum performance. The building shall be designed and constructed to deliver a zero energy performance index (zepi) not greater than the value shown in Table The zepi shall be calculated in accordance with Section Buildings complying with the 2006 International Energy Conservation Code ANSI/ASHRAE/IESNA Standard shall be deemed to have a zepi of zepi determination. Building zero energy performance index (zepi) shall be determined in accordance with Section and Equation 6-3. zepi = x (PD-RE-WE)/RD (Equation 6-3) Where: PD = Total annual energy delivered to the proposed design and consumed on site, as determined in accordance with Section 603. RE = Total annual energy savings from renewable energy derived on site RD = Total annual energy used by a standard reference design, determined in accordance with Section 603 WE = Total annual energy savings from waste energy recovery PD, RE, RD and WE shall all be expressed in consistent units of energy in accordance with Section Design. For the purposes of plan review and approval to construct the building, compliance shall be based on submission of calculations and supporting data by a registered design professional indicating that the building as designed will comply with the provisions of Section after construction and commissioning. Calculation software tools and procedures used to document compliance shall include the capabilities identified in accordance with Section of the International Energy Conservation Code comply with the requirements of the COMNET Modeling Guidelines and Procedures. i

2 603.3 Calculation procedures. Calculation software tools and procedures used to comply with Section 603 shall include the capabilities identified in accordance with Section of the International Energy Conservation Code. The COMNET Modeling Guidelines and Procedures shall be used to calculate the energy performance of the proposed design (PD) and standard reference design (RD) from Equation 6-3. The standard reference design shall be based on ANSI/ASHRAE/IESNA Standard as documented in the COMNET Modeling Guidelines and Procedures. Table (1) of the International Energy Conservation Code shall be modified as follows: 1. Replace the glazing row in the table with the following: TABLE 603.3(1) MODIFICATIONS TO IECC TABLE (1) SPECIFICATION FOR THE STANDARD REFERENCE AND PROPOSED DESIGNS BUILDING COMPONENT CHARACTERISTICS STANDARD REFERENCE DESIGN PROPOSED DESIGN Area: (a) The proposed glazing area; where the proposed glazing area is less than 40 percent of above-grade wall area. (b) 40 percent of above-grade wall area; where the proposed glazing area is 40 percent or more of the above-grade wall area. Glazing U-factor: from Table SHGC: from Table except that for climates with no requirement (NR) SHGC = 0.40 shall be used Shading is provided on the south, east, and west walls as required by For Greenfield sites, window wall ratio on the north and south walls is two times greater than on the east and west walls. For Greenfield sites, window wall ratio on the north and south walls is two times greater than on the east and west walls. 2. Add the following rows to the Table: TABLE 603.3(2) MODIFICATIONS TO IECC TABLE (1) SPECIFICATION FOR THE STANDARD REFERENCE AND PROPOSED DESIGNS BUILDING COMPONENT CHARACTERISTICS STANDARD REFERENCE DESIGN PROPOSED DESIGN Orientation For Greenfield sites, twice as long on the eastwest axis as on the north-south axis. For non- Greenfield sites, as proposed. ii

3 Electrical Power Voltage drop in branch circuits: 1.5% at design load Voltage drop in feeders: 1.5% at design load Distribution transformer efficiency, in accordance with Tables ,1 (1), (2), and (3) Voltage drop in branch circuits: 1.5% at design load As Proposed Qualified software for determinations of annual energy use. Calculation software tools and procedures used to comply with Section 603 shall include the capabilities identified in accordance with Section of the International Energy Conservation Code comply with the requirements of the COMNET Modeling Guidelines and Procedures. Reason: The IECC currently does not have a comprehensive protocol governing the modeling of either proposed or reference models such as is found in ANSI/ASHRAE/IESNA Standard 90.1 Appendix G, ANSI/ASHRAE/IESNA Standard Appendix D, California Title 24 s Alternative Calculation Method Manual or COMNET Modeling Guidelines and Procedures. The basic building description offered in IECC 2012 Section 507 leaves the door open for the manipulation of non-specified modeling inputs in order to affect the apparent performance of either the proposed or reference model. The significant push for greater efficiency in both the 2012 IECC and IgCC, provides much greater motivation to game the system through the manipulation of these non-specified inputs in order to make the proposed design model perform more favorably relative to the reference model. The COMNET Modeling Guidelines and Procedures (MGP) are a well-developed and detailed set of modeling rules and guidelines. Such detailed guidelines are missing from the IgCC and the IECC. The MGP uses ASHRAE Standard as the baseline for tax credits and ASHRAE Standard as the basis for green building ratings. By referencing zepi to ASHRAE Standard instead of the IECC, the consensus MGP may be directly used to provide a more replicable modeling process and more confidence in the results. Additionally, the COMNET Modeling Guidelines and Procedures provide guidance to software programmers to automate the generation of a standard reference design based on ASHRAE Standard When software implements this capability, it will reduce the cost of modeling and increase the reliability and consistency of the models for standard reference designs. Examples of how modeling assumptions that are clearly specified in COMNET, but not defined in the IgCC or the IECC: The HVAC systems to be used in the reference design. Part load performance of HVAC and other equipment. Energy use for plug loads, commercial refrigeration, elevators, and other energy end-uses not directly addressed by IgCC/IECC. Credit for naturally ventilated and hybrid proposed designs. Modeling guidelines and limits for determining daylighting credit. It was previously determined that minimum compliance with the IECC 2006 (ASHRAE Standard ) achieved a zepi score of 73. The USDOE determination for ASHRAE Standard shows that this standard is 4.4% more stringent than ASHRAE Standard , thus, a 4.4% reduction of 73 results in the recommended value of 70. The DOE determination can be reviewed at: The 57 in Equation 6-3 was based on the assumption that the IECC 2012 was 22 better than IECC 2006, e.g. a 22% reduction of 73 results in 57. The overall zepi goal was to get 30% better energy performance than the IECC 2006 so the zepi target is set to 51 (73 less 30%). Changing the 57 to 70 enables ASHRAE Standard to be used as the baseline instead of IECC This change enables the COMNET Modeling Guidelines and Procedures to be used for calculations without affecting the stringency of the performance approach. The COMNET MGP fully documents ASHRAE Standard as a baseline, which eliminates the need for Tables (1) and (2). iii

4 COMNET Modeling Guidelines and Procedures was developed through a consensus process that involved two public reviews and resolution of over 70 comments. COMNET is undergoing the process of becoming an ANSI certified Standard. Cost Impact: Public Hearing: Committee: AS AM D Assembly: ASF AMF DF iv

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