D.C. Mun. Regs. tit. 12, 12-I-Z1
Appendix Z is intended to be an optional alternative compliance path for building projects to comply with the Energy Conservation Code-Commercial Provisions.
The design of a net-zero energy building shall be achieved through the use of three complementary approaches, to be employed to the maximum extent feasible, in the following order:
Reducing building energy demand for heating, cooling, lighting and ventilation through the use of passive design and improved envelope performance techniques.
Reducing total building energy demand through the installation of high-efficiency mechanical systems, hot water systems, power systems, lighting, and process equipment.
Supplying remaining building energy needs from renewable sources of energy.
Appendix Z draws on existing requirements outlined in the Energy Conservation Code-Commercial Provisions. Additional minimum performance requirements for building thermal energy performance and airtightness testing have been set to ensure new construction achieves a high degree of energy conservation.
In addition to definitions contained in Chapter 2 of the Building Code and in Section 3.2 of the Energy Conservation Code-Commercial Provisions , the following definitions shall apply to building projects opting to use Appendix Z:
Airtightness.
The rate of air leakage through the building envelope, measured in cubic feet per minute per square foot of building envelope (cfm/ft2env), at 0.0109 psig (75 Pa) of pressure differential.
Annual cooling demand. The total amount of thermal energy required to cool a building over the course of a year, measured in thousands of British thermal units per square foot of interior conditioned floor area, per year (kBtu/ft2iCFA/yr).
Annual heating demand. The total amount of thermal energy required to heat a building over the course of a year, measured in thousands of British thermal units per square foot of interior conditioned floor area, per year (kBtu/sf iCFA/yr).
Building Code. See 12-A DCMR §101.2.
Energy Use Intensity (EUI). The annual energy use of the building expressed in kBtu divided by square feet (kbtu/ ft2).
Low-car bon neighborhood thermal energy system. A district-scale energy system that uses acceptable sources of renewable energy per section Z3.2 to produce steam, hot water, or chilled water for the purposes of providing for building heating, cooling, and/or domestic hot water needs.
Net-zero energy building. A highly energy-efficient building that produces on-site, or procures through the construction of new renewable energy generation, enough energy to meet or exceed the annual energy consumption of its operations.
Renewable energy microgrid. (As defined by the U.S. Department of Energy) A group of interconnected loads and distributed renewable energy resources within clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid.
Zero Energy Performance Index (zEPI). A scale representing the ratio of the energy performance of a proposed design or an existing building compared to the mean energy performance of the building stock from the benchmark year of 2000 (Commercial Buildings Energy Consumption Survey, US Department of Energy, 2003 Average).
The provisions of Appendix Z regulate the design, construction, commissioning and operation of buildings and their associated building sites for compliance with the Energy Conservation Code-Commercial Provisions . The intent of this Appendix is the reduction of energy use to achieve net-zero performance.
Administration and enforcement of Appendix Z shall be governed by Chapter 1 of the Building Code , 12-A DCMR.
The provisions of Appendix Z shall apply to each building project that is new construction, or classified as a Level 3 alteration under the Existing Building Code , and for which this compliance path option has been chosen.
Compliance with Appendix Z requires that the building and its site comply with the provisions of Sections Z2, Z3, Z4, and Z5.
D.C. Mun. Regs. tit. 12, 12-I-Z1