Date
Inquiry

Project is an undergraduate teaching Science Center consisting of physics, chemistry and biology laboratories, class rooms and faculty offices. Project is to be designed to meet the standards and guidelines of US Army Corps of Engineers (USACE). Army requires EPACT compliance to be measured as a percentage reduction in energy use. Per USACE Army LEED Implementation (January 2008): Performance improvement is based on EPACT energy use reduction percentage (measured in Btu/SF) instead of energy cost reduction percentage (measured in kBtu/year, $/year). Percentage improvement (energy reduction percentage) is calculated as follows: oPercentage improvement = 100* (Base building consumption - Proposed building consumption) / (Base building consumption - Receptacle and Process loads) -USACE equation is different than the one used per LEED-NC v2.2. Per USACE compliance, Receptacle and Process loads are subtracted from the Base building energy consumption denominator. Receptacle and Process loads are included in the numerator. -Building consumption is based on kBtu/year. Compliance Path: Project uses Whole Building Energy Simulation (Option 1) method in conjunction with USACE EPACT energy use reduction percentage calculation to determine energy reduction for EAc1: Performance Rating Method-Alternative Compliance Points. Option 1-Whole Building Energy Simulation requires a percentage improvement in the proposed building performance rating compared to the baseline building performance rating per ASHRAE/IESNA Standard 90.1-2004 (without amendment) by a whole building project simulation using the Building Performance Rating Method in Appendix G of the Standard. From ASHRAE 90.1 Standard and Reference Guide for LEED-NC v2.2, the following items are related to this CIR request: Building performance is to include Receptacle and Process loads in both the numerator and the denominator for the Base Building Performance Performance improvement is based on energy cost savings in $/year Percentage improvement (energy cost reduction percentage) is calculated as follows: o Percentage improvement = 100 * (Baseline Building Performance - Proposed Building Performance) /(Baseline Building Performance) -Building performance is based on annual energy cost in $/year. Clarification requested: Please confirm that government project can be rated in accordance with USACE Army LEED Implementation (January 2008) guidelines and criteria for EAc1 credit - Performance Rating Method-Alternative Compliance Points based on the following: 1.Use energy consumption kBtu/year, not energy cost in $/year, to determine the Performance Improvement. 2.Use the USACE equation to calculate the percentage improvement and use this percentage improvement to determine the number of points for EAc1 - Alternate Compliance.

Ruling

The project team requested an alternative compliance path for demonstrating energy savings that conforms to the US Army Corps of Engineers (USACE) LEED Implementation (January 2008) guidelines, in lieu of ASHRAE 90.1-2004 Appendix G - Performance Rating Method. Based on the description of the alternative compliance methodology, the approach is not an equivalent method for determining energy savings and is not acceptable. For consistency, projects pursuing compliance Option 1 must comply with ASHRAE 90.1-2004 section G1.1. Appendix G is a modified Energy Cost Budget method and energy savings must be accounted as a percentage of energy cost savings, as dictated in ASHRAE 90.1 Section G1.2. Applicable Internationally.

Internationally Applicable
On
Campus Applicable
Off
Credits