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City of San Mateo Municipal Code.

23.24.050 Local Amendment Regarding All-Electric or Energy Efficiency Standards for High-Rise Multifamily Residential Buildings with 100% Affordable Units.

(a) All-electric high-rise multifamily buildings that consist of 100% affordable units are required to meet the established energy efficiency standards in Subchapter 5, "Nonresidential, High-rise Residential, and Hotel/Motel Occupancies – Performance and Prescriptive Compliance Approaches for Achieving Energy Efficiency," of the 2019 state Energy Code.

(b) Mixed-fuel high-rise multifamily buildings that consist of 100% affordable units shall comply with increased energy efficiency standards. Subchapter 5, "Nonresidential, High-rise Residential, and Hotel/Motel Occupancies – Performance and Prescriptive Compliance Approaches for Achieving Energy Efficiency," of the 2019 state Energy Code is amended to require increased energy efficiency standards in the performance or prescriptive compliance approaches as follows:

(1) Performance Approach: Energy Code Section 140.1 "Performance Approach: Energy Budgets" is amended to include the following performance standards for mixed-fuel high-rise multifamily building that consists of 100% affordable units: A newly constructed mixed-fuel high-rise multifamily building that consists of 100% affordable units complies with the performance approach if the energy budget calculated for the Proposed Design Building under Subsection (b) has a compliance margin exceeding the energy budget calculated for the Standard Design Building under Subsection (a) of at least 5%.

(2) Prescriptive Approach: Energy Code Section 140.2 "Prescriptive Approach" is amended to include the following prescriptive standards for newly constructed mixed-fuel high-rise multifamily buildings that consist of 100% affordable units:

(A) Install fenestration with a solar heat gain coefficient no greater than 0.22.

(B) Design Variable Air Volume (VAV) box minimum airflows to be equal to the zone ventilation minimums.

(C) Include economizers and staged fan control in air handlers with a mechanical cooling capacity ≥ 33,000 Btu/h

(D) Reduce the total lighting power density (Watts/ft2) by ten percent (10%) from that required from Table 140.6-C in the 2019 state Energy Code.

(E) Improve lighting without claiming any Power Adjustment Factor credits:

(i) Control to daylight dimming plus off per 2019 state Energy Code Section 140.6(a)2H, and

(ii) Perform Institutional Tuning per 2019 state Energy Code Section 140.6(a)2J.

(F) For all ducted central forced air heating systems and central fan integrated ventilation systems the duct distribution system shall be designed to reduce external static pressure to meet a maximum fan efficacy equal to 0.25 Watts per cfm according to the procedures outlined in the 2019 state Energy Code Reference Appendices RA3.3.

(G) Hot water pipe insulation shall be verified by a HERS inspector, in accordance with the 2019 state Energy Code Reference Appendices Section RA3.6.3.