It is the intent of this Article 22.000 to promote environmentally sustainable and energy-efficient design and development practices in new construction and renovation of buildings in the city. Some of the regulations in this Article include design standards that shall be applied to new construction and renovation projects of a significant size. Other regulations in this Article modify regulations found elsewhere in this Zoning Ordinance in order to encourage the incorporation of specific design features that will improve the sustainability and energy-efficiency of buildings.

22.21

Statement of Purpose. This Section 22.20 is adopted to ensure that major new projects and substantially rehabilitated buildings in the City of Cambridge are planned, designed and constructed in a sustainable way so as to minimize adverse environmental impacts as they are initially constructed and as they are occupied and operated over the course of their useful lives. It is the purpose of this Section 22.20 to encourage the reuse of existing buildings and materials; to encourage the conservation of natural resources and reduction of toxins in new construction and substantial rehabilitation of existing buildings through selection of recycled and otherwise environmentally appropriate building materials and methods; to ensure a reduction in the use of energy in both the initial construction of the project and in its daily operation; and to encourage an arrangement of buildings and mix of uses, on individual lots and within the city as a whole, that will foster renewable energy generation and pedestrian, bicycle, and public transit use in the city. While the provisions of this section apply to projects of 25,000 square feet or larger, developments of all sizes are encouraged to incorporate sustainable design principles. Notwithstanding the provisions of this Article 22.00, the requirements of all local, state and/or federal regulations applicable to a project must be met, particularly the State Building Code, including its energy components.

22.22

The provisions of these Sections 22.20 through 22.25 shall apply to a Green Building Project as defined in Article 2.000 of this Zoning Ordinance.

22.23

Authorized Green Building Rating Programs and Green Building Rating Systems.

22.23.1

Authorized Green Building Rating Programs. Any of the following Green Building Rating Programs may be used for the application of these Sections 22.20 through 22.25:

(a)

the Leadership in Energy and Environmental Design (" LEED" ) Green Building Rating Program developed and overseen by the United States Green Building Council;

(b)

the Passive House Green Building Rating Program developed and overseen by either Passive House Institute US, Inc. or the Passive House Institute; or

(c)

the Enterprise Green Communities Green Building Rating Program developed and overseen by Enterprise Community Partners, Inc.

22.23.2

Applicability of Rating Systems.

(a)

If a Green Building Rating Program offers different Green Building Rating Systems, a Green Building Project shall use the rating system that is most directly applicable to that Green Building Project or building type, subject to the following limitations:

(1)

the applicable Green Building Rating System must address design and construction of buildings rather than building operations or neighborhood development; and

(2)

Green Building Rating Systems that only address interior design may be used for rehabilitation projects subject to the requirements of Sections 22.20 through 22.25 only if another rating system cannot be reasonably applied.

(b)

A Green Building Project shall use the most current version of the applicable Green Building Rating System at the time an application for a special permit is filed or, if a special permit is not required, the time an application for a building permit is filed; however, within twelve (12) months after the time of adoption of a new version of a Green Building Rating System, a Green Building Project shall have the option to apply using either the most current version or the preceding version.

(c)

The Green Building Rating System, including the applicable version, shall be specified at the initial stage of administrative review set forth in Section 22.25.

22.24

Requirements

22.24.1

Rating. A Green Building Project shall be designed to meet the standards of one of the authorized Green Building Rating Systems listed in Section 22.23 above. Compliance shall be demonstrated to the Community Development Department ("CDD") pursuant to the administrative review procedures in Section 22.25.

(a)

If the LEED Green Building Rating Program is being used, the Green Building Project shall be designed such that it would achieve a minimum " Gold" level standard, except if the Green Building Project contains less than 50,000 square feet of GFA in which case the Green Building Project shall be designed such that it would achieve a minimum " Silver" level standard.

(b)

If the Passive House Green Building Rating Program is being used, the Green Building Project shall be designed such that it would achieve the minimum criteria for certification from the applicable Passive House Green Building Program, whether it be the Green Building Rating Program developed and overseen by either Passive House Institute US, Inc. or the Passive House Institute.

(c)

If the Enterprise Green Communities Green Building Rating Program is being used, the Green Building Project shall be designed such that it would achieve the minimum criteria for certification from the Enterprise Green Communities Green Building Program.

Certification by the Green Building Rating Program shall not be required.

22.24.2

Green Commissioning. The Owner of property on which a Green Building Project is proposed shall engage a Green Commissioning Authority as defined in Article 2.000 of this Zoning Ordinance to verify and document that all building systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the applicable Green Building Project requirements. Compliance shall be demonstrated to CDD pursuant to the administrative review procedures in Section 22.25.

(a)

The Green Commissioning Authority shall complete the following activities for mechanical, electrical, plumbing, and renewable energy systems:

(1)

review contractor submittals;

(2)

verify inclusion of systems manual requirements in construction documents;

(3)

verify inclusion of operator and occupant training requirements in construction documents;

(4)

verify systems manual updates and delivery;

(5)

verify operator and occupant training delivery and effectiveness;

(6)

verify seasonal testing;

(7)

review building operations ten (10) months after substantial completion; and

(8)

develop an ongoing commissioning plan that outlines the organization, schedule, allocation of resources, and documentation requirements of the commissioning process prior to the start of commissioning activities.

(b)

The Green Commissioning Authority shall report results, findings, and recommendations directly to the Owner of the property on which the Green Building Project is located.

(c)

If the Green Building Project is using a Green Building Rating System that includes an optional standard for enhanced commissioning, that standard must be met.

22.24.3

Verification.

(a)

The Owner of the property on which the Green Building Project is located or developer of a Green Building Project shall designate a Green Building Professional to be engaged throughout the design and development of the Green Building Project to ensure and verify that the Green Building Project is designed to meet the applicable requirements. The designated Green Building Professional, in addition to meeting the requirements set forth in the definition of Green Building Professional in Article 2.000 of this Zoning Ordinance, shall hold a credential from a Green Building Rating Program indicating advanced knowledge in the specific Green Building Rating System being applied to the Green Building Project. Examples include a LEED accredited professional or Certified Passive House Consultant. The credentials of the designated Green Building Professional shall be provided to CDD at the initial stage of administrative review pursuant to the procedures set forth in Section 22.25.

(b)

An Energy Simulation Tool shall be used by the Green Building Professional to demonstrate compliance with the requirements of the applicable Green Building Rating System. The Energy Simulation Tool that is being used by the Green Building Professional shall be provided to CDD at the initial stage of administrative review pursuant to the procedures set forth in Section 22.25.

(c)

Green Building Projects using the Passive House Green Building Rating Program shall employ on-site quality assurance testing performed by a Passive House rater/verifier who is trained and certified by Passive House Institute US, Inc. or the Passive House Institute to perform such testing for the type of Green Building Project being designed.

22.24.4

Reserved.

22.24.5

Flood Resilience. A Green Building Project shall meet the Flood Resilience standards set forth in Section 22.80.

22.24.6

Green Factor. A Green Building Project shall meet the Green Factor standards set forth in Section 22.90.

22.25

Administrative Review Procedures.

22.25.1

Before applying for any special permit from the Planning Board or any development review procedure under Article 19.000 of the Zoning Ordinance, the documentation listed below shall be submitted to CDD for review. Within thirty (30) days after receiving a complete set of documentation, CDD shall provide written notice that the documentation sufficiently demonstrates compliance with the requirements of Section 22.24, or shall provide a written explanation of deficiencies to be corrected in a revised submission.

(a)

Rating System Checklist: The document that enumerates the criteria set forth in the applicable Green Building Rating System, indicates which technical and design requirements will be met in the Green Building Project design, and indicates the intended rating level of the Green Building Project.

(b)

Rating System Narrative: A written description of the technical and design requirements utilized to meet each of the criteria that the Green Building Project intends to achieve under the applicable Green Building Rating System.

(c)

Net Zero Narrative: A written description of how the Green Building Project is being designed in response to the City's Net Zero Action Plan, which seeks to neutralize greenhouse gas emissions resulting from buildings by reducing their energy use intensity and promoting renewable sources of energy. This information is provided for advisory review by CDD staff, and CDD may provide a questionnaire template to the developer for completing this narrative. At a minimum, this narrative shall include the following information:

1.

Anticipated building envelope performance, including roof, foundation, walls and window assemblies, and window-to-wall ratio;

2.

Anticipated energy loads, baseline energy simulation tool assumptions, and proposed energy targets, expressed in terms of site energy use intensity ("EUI"), source EUI (expressed as British Thermal Unit (BTU) per square foot per year), and annual greenhouse gas emissions projected until 2050, expressed as Metric Tons of Carbon Dioxide Equivalents (MTCO2e), and calculated in accordance with the standards and requirements established in Chapter 8.67 of the Municipal Code ("Building Energy Use") and associated regulations. If anticipated tenant plug loads (EUI and emissions) are provided, they shall be separately broken out and clearly identified as such;

3.

A description of ways in which building energy performance has been integrated into aspects of the Green Building Project's planning, design, and engineering, including building use(s), orientation, massing, envelope systems, building mechanical systems, on-site and off-site renewable energy systems, and district-wide energy systems;

4.

A description of the technical framework by which the Green Building Project can be transitioned to net zero emissions prior to 2050 (acknowledging that such a transition might not be economically feasible at first), including future net zero emissions options for building envelope, HVAC systems, domestic hot water, interior lighting, and on- and off-site renewable energy sources;

5.

A description of programs provided by local utility companies, government agencies, and other organizations that provide technical assistance, rebates, grants, and incentives that can assist in achieving higher levels of building performance, summarizing which entities have been contacted and which programs could be utilized in the Green Building Project; and

6.

An assessment of the technical and financial feasibility to meet the projected HVAC and domestic hot water demands of the building (as set forth in Paragraph (2) above) using energy systems that do not consume carbon-based fuels on-site (to include solar photovoltaics and hot water, ground source, water source or air source heat pumps, district energy, geothermal systems, and/or similar systems) compared to code-compliant energy systems that consume carbon-based fuels on-site (including, where applicable, the construction or expansion of energy plants controlled by the developer that may be necessary to produce energy for that specific building), which shall include the cost of installation, maintenance and upkeep of the energy system and its components (incorporating programs and incentives as set forth in Paragraph (5) above). This paragraph will become effective on February 23, 2021.

7.

Embodied Emissions: A whole building lifecycle analysis of the estimated emissions generated by the construction of the Green Building Project. The Assistant City Manager for Community Development shall promulgate regulations for how these estimated emissions are to be reported. Such regulations shall include at minimum the required reporting of estimated lifecycle emissions generated by the use of major building materials, including but not limited to wood, concrete, steel, aluminum and glass, using embodied emissions modeling software and industry standards acceptable to CDD staff. This paragraph will become effective on the date of final promulgation of the regulations for Green Building Projects that have not yet completed the initial stage of administrative review by such date, and shall not impose a requirement on any building project that does not meet the standard threshold for project review special permit of 50,000 square feet or includes housing units.

(d)

Credentials of the Green Building Project's designated Green Building Professional and affidavit signed by that professional stating that he/she has reviewed all relevant documents and that to the best of his/her knowledge, the documents provided indicate that the Green Building Project is being designed to achieve the requirements of Section 22.24.

22.25.2

Before applying for a building permit for a Green Building Project, the documentation listed in Subsection 22.25.1 above, updated from any previous version (if applicable) to reflect the current Green Building Project design, and the additional documentation listed below shall be submitted to CDD for review. Within thirty (30) days after receiving a complete set of documentation, CDD shall provide written notice to the developer of the Green Building Project that the documentation sufficiently demonstrates compliance with the requirements in Section 22.24 and that said developer may apply for a building permit from the Superintendent of Buildings, or CDD shall provide a written explanation of deficiencies to be corrected in a revised submission.

(a)

Energy Simulation Tool results demonstrating compliance with the selected Green Building Rating System.

(b)

For a Green Building Project using the Passive House Green Building Rating Program, the following set of documents is required:

(1)

credentials of the Passive House rater/verifier who will perform testing and verification and letter of intent stating he/she has been hired to complete the on- site verification process;

(2)

credentials of the Certified Passive House Consultant who has provided design, planning, or consulting services;

(3)

construction drawings and specifications, including building envelope assemblies, all mechanical systems, and appliance specifications; and

(4)

Energy Simulation Tool results using "WUFI Passive" software, developed by Fraunhofer IBP in partnership with Passive House Institute US, Inc. and Owens Corning, or Passive House Planning Package software developed by the Passive House Institute, or a comparable software tool that is authorized for use by the Passive House Green Building Rating Program.

(c)

Credentials of the Green Building Project's designated Green Building Professional and an affidavit signed by that professional stating that he/she has reviewed all relevant documents and that to the best of his/her knowledge, the documents provided indicate that the Green Building Project is being designed to achieve the requirements of Section 22.24.

(d)

Credentials of the Green Building Project's Green Commissioning Authority or a copy of an executed contract with the developer of the Green Building Project if the Green Commissioning Authority is an independent consultant or subcontractor.

22.25.3

Before applying for a certificate of occupancy for a Green Building Project, the documentation listed in Subsections 22.25.1 and 22.25.2 above, updated from any previous version to reflect the current Green Building Project design, and the additional documentation listed below shall be submitted to CDD for review. Within thirty (30) days after receiving a complete set of documentation, CDD shall provide written notice to the developer of the Green Building Project that the documentation sufficiently demonstrates compliance with the requirements in Section 22.24 and that said developer may submit an application for a certificate of occupancy from the Superintendent of Buildings, or CDD shall provide a written explanation of deficiencies to be corrected in a revised submission.

(a)

For Green Building Projects using the Passive House Green Building Rating Program, the final testing and verification report completed by the Passive House rater/verifier.

(b)

Credentials of the Green Building Project's accredited Green Building Professional and an affidavit signed by that professional stating that he/she has reviewed all relevant documents and that to the best of his/her knowledge, the documents provided indicate that the Green Building Project was built to achieve the requirements of Section 22.24.

(c)

An affidavit in a form created and approved by CDD, signed by the Green Commissioning Authority, certifying that the pre-construction commissioning process requirements of this Section were included in the scope of work for the Green Building Project and have been met and that the post-construction commissioning process requirements of this Section were included in the scope of work and will be met, including a schedule of when each commissioning requirement was or will be met.

22.26

This Ordinance shall take effect ninety (90) days from the date of its enactment.

(Ord. No. 1412, 12-9-2019; Ord. No. 2020-10, 11-23-2020; Ord. No. 2022-9, 2-24-2023; Ord. No. 2022-20, 3-6-2023)

22.31

Purpose. The purpose of this Section is to establish standards for the development of green roof systems on new and existing buildings for the purpose of stormwater management, heat mitigation, and access and enjoyment by occupants of a building, and to require new buildings of substantial size to include vegetation and/or solar energy roofing systems on much or most of the available roof area.

22.32

Access. Green Roof Area as defined in Article 2.000 of this Zoning Ordinance may be accessible by means of a roof entrance either for maintenance or for recreational use by building occupants or the general public. If Green Roof Area is intended for recreational use, it shall be designed and maintained to ensure that the vegetation will endure the anticipated use throughout the Green Roof Area's lifetime.

22.33

Types. Green Roof Area shall be classified as one of the three following types:

(a)

Non-Intensive Green Roof Area shall have a minimum 4-inch layer of growing substrate that requires minimal maintenance, using small, low-growing plant species, particularly succulents.

(b)

Short Intensive Green Roof Area shall have a minimum 18-inch layer of growing substrate that supports a wider variety of plant types, such as herbaceous and woody plants that are less than two (2) feet tall at maturity.

(c)

Intensive Green Roof Area shall have a minimum 24-inch layer of growing substrate that supports a wider variety of plant types, such as herbaceous and woody plants that are greater than two (2) feet tall at maturity, and requiring more structural support, irrigation, and maintenance than Short Intensive Green Roof Area.

22.34

Operation and Maintenance Plan. Wherever Green Roof Area is proposed, a long-term operation and maintenance plan shall be created and implemented to ensure that the Green Roof Area functions as designed. The level of detail in these plans should reflect the type of Green Roof Area being proposed, the complexity of the project, and the nature and extent of the impacts that may arise both during and after construction. The owner shall submit the operation and maintenance plan to the Department of Public Works (DPW) for approval before applying for a building permit for any building containing Green Roof Area. DPW shall certify to the Superintendent of Buildings that the operation and maintenance plan has been provided to DPW and approved prior to issuance of a building permit for any Green Roof Area. The Commissioner of Public Works shall have the authority to promulgate regulations for the implementation of this Section.

22.35

Green Roofs Requirement.

22.35.1

Applicability. This Section 22.35, et. seq., shall apply to any new building or structure of twenty-five thousand (25,000) gross square feet or more, except it shall not apply to affordable housing buildings that either are developed under the Affordable Housing Overlay (AHO) as defined in Section 11.207 or have a majority of their units permanently reserved for households at or below 100% of AMI.

22.35.2

Requirement.

(a)

At least 80% of the roof area of the building as measured in plan view, excluding those portions of the roof listed below, shall be devoted to Green Roof Area, Biosolar Green Roof Area, or Solar Energy Systems.

1.

Areas having a slope greater than 3 in 12 or twenty-five percent (25%).

2.

Areas designed and managed for use by building occupants or the general public.

3.

Vehicular parking decks.

4.

Chimneys, water towers, air conditioning equipment, elevator bulkheads, skylights, ventilators and other necessary features appurtenant to buildings which are usually carried above roofs and are not used for human occupancy, in addition to conduit, visual and acoustical screening, access routes for maintenance and service, and other areas that must be clear of obstruction to comply with applicable building and safety codes.

(b)

In the case of non-residential or mixed-use buildings in which at least half of the Gross Floor Area is devoted to one or more of the non-residential uses listed below (with reference to the Table of Use Regulations, Section 4.30 of this Zoning Ordinance), excluding any municipal buildings, at least 80% of the roof area of the building as measured in plan view, excluding those portions of the roof listed above at 22.35.2(a)(1)-(4), shall be devoted to Green Roof Area or Biosolar Green Roof Area:

1.

Transportation, Communication & Utility Uses (Section 4.32);

2.

Educational Purposes (Section 4.33-b.);

3.

Noncommercial Research Facilities (Section 4.33-c.);

4.

Other Institutional Uses (Section 4.33-h.);

5.

Office and Laboratory Use (Section 4.34);

6.

Retail Business and Consumer Service Establishments (Section 4.35);

7.

Open Air or Drive In Retail & Service (Section 4.36);

8.

Light Industry, Wholesale Business and Storage (Section 4.37); or

9.

Heavy Industry (Section 4.38).

22.35.3

Exemption. The Planning Board may grant a special permit to reduce the required Green Roof Area, Biosolar Green Roof Area, or Solar Energy System below the area required by Section 22.35.2, provided that each square foot so reduced be compensated by a unit price contribution to the Cambridge Affordable Housing Trust. This unit price shall be determined based on the average costs to design, install, and maintain green roofs and rooftop solar energy systems in Cambridge using actual cost figures to the extent possible, shall be subject to annual adjustment based on standard construction cost indices, and shall be calculated, and recalculated approximately every three years, by the Cambridge Community Development Department. All such funds contributed to the Trust shall be dedicated to the design and incorporation of Green Roof Area, Biosolar Green Roof Area, or Solar Energy Systems into new or existing affordable housing developments.

22.35.4

Effective Date. The provisions of this Section 22.35, as adopted on June 1, 2021, shall not apply to structures lawfully in existence or lawfully begun before June 1, 2021, or to a building or special permit issued before June 1, 2021, and shall take effect on June 1, 2021.

(Ord. No. 2020-25, 5-3-2021; Ord. No. 2022-9, 2-24-2023)

Editor's note— Ord. No. 2022-9, adopted Feb. 24, 2023, repealed § 22.40, which pertained to exterior walls and insulation and derived from Ord. No. 1413, adopted Dec. 9, 2019. Provisions for exterior walls and insulation are currently found in Articles 2.000 and 5.000 of the Zoning Ordinance.

Editor's note— Ord. No. 2022-9, adopted Feb. 24, 2023, repealed § 22.50, which pertained to overhangs and sun-shading devices and derived from Ord. No. 1333, adopted August 2, 2010. Provisions for overhangs and sun-shading devices are currently found in Articles 2.000 and 5.000 of the Zoning Ordinance.

22.61

Purpose. The purpose of this Section is to define solar energy systems within the zoning ordinance, to provide a mechanism for publicly registering such systems so that nearby developers can be aware of their existence, and to provide limited zoning protections for such systems in some instances where developers of neighboring properties are seeking a special permit or variance.

22.62.1

Solar energy systems are viewed as potentially valuable contributors to meeting the City's objective of encouraging sustainable development and energy conservation. However, the complex nature of urban development in the city limits the extent to which the city's zoning regulations can be employed to guarantee long-term access to sunlight on a wide geographic basis. Therefore, the following provisions are intended to provide limited support for such systems and to raise awareness of their contribution to the objectives of this Article 22.000 on the part of the general public and property owners.

22.62

A Solar Energy System shall be defined as a device or combination of equipment that converts radiant energy from the sun into heat or electricity that can be used for the purpose of heating indoor spaces, producing hot water, or powering electrical devices.

22.63

A Registered Solar Energy System shall be defined as a Solar Energy System for which a building permit has been issued, provided that at least one year has passed since the issuance of such permit, and whose sun-exposed elements are at a height no lower than five (5) feet below the maximum height allowed within the base zoning district in which it is located. Such systems shall be recorded on a public registry of Solar Energy Systems that shall be maintained by the City's Inspectional Services Department and made available to property owners by request.

22.64

Protection of Registered Solar Energy Systems. The impacts of a proposed development seeking a special permit or variance on a Registered Solar Energy System shall be considered by the Board of Zoning Appeal or the Planning Board, whichever is applicable, in making its determination, as described in Article 10, Subsection 10.32 and Article 19, Subsection 19.33 of this Zoning Ordinance. No protection shall be provided by this Zoning Ordinance to a Solar Energy System that does not meet the definition of a Registered Solar Energy System.

22.71

Purpose. It is the intent of this Section 22.70 to permit the limited use of wind turbines throughout the city (a) for the purpose of small scale generation of electricity for on-site consumption as an accessory use to other activities located on the same lot, (b) for the purpose of researching, testing, evaluating, or demonstration of the efficacy in an urban setting of such instruments as a means by which renewable sources of energy might be employed to generate electricity at a larger scale for both a domestic and commercial purposes, and (c) in appropriate locations in non residential districts for the generation of electricity for commercial sale as a principal use. These provisions are intended to ensure that such facilities are well designed, carefully sited, and operated in a manner that will not pose a nuisance or hazard to the general public or nearby neighbors.

22.72

Wind Turbine Systems Permitted by Special Permit. A Wind Turbine System may generally be permitted anywhere in the city after the granting of a special permit from the Planning Board, subject to the conditions and limitations described in this Subsection 22.72. In special cases, there is a limited provision for the permitting of Wind Turbine Systems as-of-right, without the granting of a special permit, as described in Subsection 22.73 below.

22.72.1

Dimensional Limitations.

1.

Height. There shall be no maximum height limit for a Wind Turbine, but the permitted height of a Wind Turbine shall be specifically approved by the Planning Board.

2.

Setbacks. There shall be no required minimum yard setbacks for a Wind Turbine, but the permitted placement of a Wind Turbine with respect to public street lines and adjacent lot lines shall be specifically approved by the Planning Board. All equipment and structures accessory to the Wind Turbine shall be subject to the yard requirements of the applicable zoning district unless waived by the Planning Board.

22.72.2

Application Material. At a minimum the special permit application shall contain the following material:

1.

Plans of the site showing the location of the Wind Turbine System and its relationship to other uses and buildings on the site, including elevations of Wind Turbines and other features on the site; plans, descriptions, illustrations and/or photographs describing the surrounding uses and physical context in sufficient detail to allow an assessment of the proposal on those surrounding activities; illustration of the laydown options for maintenance of the equipment; any proposed screening and landscaping.

2.

A detailed description of the Wind Turbine System including number, size, materials, noise rating, operational plan, maintenance schedule.

3.

A narrative discussion of the extent to which the operation of the proposed Wind Turbine System will generate continuous shadows, intermittent shadows (a.k.a. flicker), and/or noise that may be detected from adjacent properties and from the public street.

4.

Photo simulations or other representations, from at least two vantage points (one of which should be from a public street), illustrating the proposal in its physical context.

5.

A detailed estimate of the cost of removal of the Wind Turbine System.

22.72.3

Standards for Granting of the Special Permit. In addition to the limitations requirements described in Section 22.74 below and the criteria established in Section 10.43 of the Zoning Ordinance for the granting of a special permit, the Planning Board shall consider the following specific criteria.

1.

The visual impact of the Wind Turbine System on the abutting properties and the neighborhood. In recognition of the fact that a Wind Turbine of any significant size will introduce a physical structure and form not typical of most residential and commercial neighborhoods in the city, the Planning Board shall consider the following when assessing whether a proposal has any unreasonable negative impacts on neighborhood character or adjacent uses:

a.

the size, scale and bulk of the proposed Wind Turbine System in relationship to the scale of typical buildings and other elements in the neighborhood;

b.

the visibility and impact of the proposed Wind Turbine System from important view corridors and viewsheds, with the understanding that reasonable efforts should be made to make the system visually unobtrusive, although in many cases a system may not be reasonably expected to be screened from public view;

c.

the nature of adjacent uses, including the historical and architectural quality of surrounding buildings, the consistency of that architectural character over an extended area, and the extent to which the proposed Wind Turbine System is visually integrated with that character and with the larger urban landscape; and

d.

in the case of building-mounted Wind Turbine Systems, the visual relationship between the system and the architecture of the building upon which it is installed.

2.

The extent, frequency and duration of continuous and intermittent shadows and their relationship to interior spaces and places people will regularly occupy. Such impacts should be minimized and directed away from sensitive spaces in residential environments. It shall be the burden of the applicant to demonstrate that there shall be no significant adverse impact on adjacent properties.

3.

The extent of detectable noise and vibration impact on neighboring uses.

4.

Where a Wind Turbine System is proposed in an Open Space District or near an open space facility, particularly one with a significant natural aspect, the system's impact on any conservation, historic, or recreational value should be carefully analyzed.

5.

Other factors with regard to the operational and visual impacts of the Wind Turbine System that may suggest that a time limitation should be imposed on the special permit.

22.73

Wind Turbine Systems Permitted As-of-right. A Wind Turbine System shall be permitted as-of-right, without the granting of a special permit, only if the conditions and limitations of this Subsection 22.73 and the requirements of Subsection 22.74 below are met. Any proposed Wind Turbine System not meeting all of the conditions and limitations of this Subsection 22.73 may be permitted only after the granting of a special permit by the Planning Board, as described in Subsection 22.72 above.

22.73.1

District Limitations. The Wind Turbine System and all associated monitoring and testing equipment must be located in a Residence C-3, C-3A, C-3B or Special District 6 zoning district.

22.73.2

Use Limitations.

1.

The Wind Turbine System must be accessory to an educational use, Section 4.56 c, Paragraphs 4-6, dormitory use accessory to such educational use, Section 4.56 c, Paragraph 8, or museum use, Section 4.56 i, Paragraph 2 where such museum has as its core mission the display, exploration and dissemination of knowledge, scientific principles, and natural phenomena to the general public.

2.

The Wind Turbine System shall only be installed for the purpose of advancing the educational and instructional purposes of the institution to which it is accessory and shall not be installed for the specific and principal purpose of generating electricity for sale. However, energy generated by the Wind Turbine System may be used in the operation of the physical plant of the institution to which it is accessory.

22.73.3

Dimensional Limitations.

1.

The Wind Turbine must be installed on a building and may not be a freestanding structure.

2.

Height: The Wind Turbine Height may not extend more than forty (40) feet above the existing height of the portion of the building upon which it is mounted. Such limitation shall apply even if the height of the building is non-conforming and already exceeds the height of structures permitted in the zoning district. The height shall be measured to the highest point of the turbine, including the height of blades when in the vertical position.

3.

Setbacks. The Wind Turbine shall be subject to the following minimum setbacks, which shall apply regardless of the location of the building upon which the turbine is installed.

a.

No portion of the Wind Turbine may be located nearer than two hundred (200) feet to any structure containing a residential use (exclusive of transient accommodations, Section 4.31.1) that is neither owned nor under the control of the institution erecting the turbine.

b.

The minimum setback of the Wind Turbine from any public street line or from a lot line of a lot not in the ownership of the institution to which the Wind Turbine is accessory shall be a distance equal to the Wind Turbine Height. However, a Wind Turbine with a height of ten (10) feet or less shall have no required minimum setback.

22.73.4

Time Limitations. A building permit authorizing the installation of a Wind Turbine System under the provisions of this Subsection 22.73 shall limit said use to a period not to exceed two years unless, prior to expiration of said two years, a request in writing is submitted to the Inspectional Services Department for an extension of the permit for an additional two years. Such extension shall not be unreasonably withheld and may be granted if the conditions and requirements of this Subsection 22.73 and Subsection 22.74 below continue to be met by the Wind Turbine System and no nuisance or hazard has been identified during the previous two years of operation. Such building permit may be extended for additional two year intervals in the same manner.

22.74

General Limitations and Requirements for Wind Turbine Systems.

22.74.1

In all cases, a Wind Turbine System shall be subject to the following limitations and requirements:

1.

The Wind Turbine System shall be free from any appurtenances with the exception of equipment necessary to monitor, regulate, secure, and maintain the system and the electricity it may produce. No sign may be attached to the system with the exception of unobtrusive manufacturer identification and operational guidance informational signs. No cellular or mobile phone equipment may be attached to the system.

2.

The Wind Turbine System shall not be independently lighted except as may be required by any local, state or federal regulation.

3.

The Wind Turbine System shall be painted in subdued tones of white, black, silver, grey, dark green, brown, blue or similarly subdued, non-reflective color unless otherwise required by local, state and/or federal regulations or allowed by the Planning Board.

4.

In operation the Wind Turbine System shall meet the requirements of the Cambridge Noise Ordinance, cumulatively for all equipment installed at a single location. All equipment shall be rated for noise generation so that it can be evaluated prior to installation.

5.

The site shall be capable of accommodating the laydown of the Wind Turbine without trespass onto city streets or adjacent lots held in a different ownership.

6.

The Wind Turbine System shall be designed and located so as to prevent unauthorized access and otherwise be maintained in a safe operating condition.

7.

Abandonment. Given the unique safety considerations associated with Wind Turbines, the owner shall be obligated to remove the Wind Turbine System if any one of the following occurs:

a.

Abandonment of the Wind Turbine System through disuse for a period of one year;

b.

Non-functioning of the Wind Turbine System for more than 100 days, where substantial steps have not been initiated to make necessary repairs; or

c.

Failure to request an extension of a building permit as required in Subsection 22.73.4 above, or a special permit authorized under Subsection 22.72 above, where that special permit may have been time-limited by the Planning Board.

Upon failure to remove the Wind Turbine System 150 days after any one of these threshold events occurs, the City of Cambridge shall have the authority to enter the property and remove the system at the expense of the owner/operator where it finds that the equipment constitutes a hazard to the general public. At or before issuance of a building permit for the system, the Permittee shall post a bond or other surety in a form and in an amount acceptable to the City that shall cover the cost of removal of the system by the City should that be necessary, such bond amount to be consistent with estimates for removal prepared at the Permittee's expense by a qualified engineer. The surety mechanism shall account for cost of living adjustments over the expected life of the system.

8.

A Wind Turbine System principally used for the express purpose of the commercial selling of the energy generated shall be permitted only in non-residential zoning districts. In residential districts, such commercial use shall not be permitted. However, it is understood that in those residential districts a portion of the energy generated by the system that is not immediately consumed on-site may at times be sold back or credited to the local-serving power utility, consistent with any applicable state or federal law or regulation. Furthermore, a cooperative system serving multiple adjacent properties shall be permitted in residential districts and may share the output of the system without being considered a commercial use.

22.74.2

Waiver of Requirements. When granting a special permit for a Wind Turbine System, the Planning Board may grant a waiver from the general requirement to accommodate laydown of a Wind Turbine without trespass onto city streets or adjacent lots as described in Subsection 22.74.1, Paragraph 5 above. The Planning Board may also grant a waiver of the requirement to post a bond or other surety that shall cover the cost of removal of the Wind Turbine System by the City, as described in Subsection 22.74.1, Paragraph 7 above. The Planning Board may grant such a waiver if the Board finds the requirement to be unnecessary in a given case.

22.75

Definitions.

22.75.1

Wind Turbine. A device that converts wind energy to rotational energy that then drives an electrical generator. A conventional turbine generally consists of a tower or pole, a nacelle body, and a rotor with multiple blades. Variations may include vertical axis turbines and structural elements housing and encapsulating the rotating elements of the turbine. It is anticipated that as testing and experimentation continues the physical form of turbines may become much more varied.

22.75.2

Wind Turbine System. A combination of equipment designed to be permanently mounted on a building or freestanding, including Wind Turbines and associated and accessory equipment and structures, necessary to convert wind energy to electricity.

22.75.3

Wind Turbine Height. The vertical dimension of a Wind Turbine as measured from ground level in the case of a freestanding turbine, or from the height of the portion of the building upon which it is mounted in the case of a building-mounted turbine, to the highest point of the Wind Turbine, including the height of blades when in the vertical position.

(Ord. No. 2024-2, 6-24-2024)

22.81

Statement of Purpose. The purpose of this Section is to promote building designs that are resilient to the impacts of flood events that are likely to become more frequent and intense due to the effects of climate change. These standards are informed by future projections, based on up-to-date scientific research, rather than historical occurrences of flooding. These standards are intended to account for the differing needs of buildings and sites and provide flexibility to use different measures to promote resilience. They are also intended to work in tandem with environmental standards promulgated by the Department of Public Works (DPW).

22.82

Applicability. This Section shall apply to development subject to Section 22.20 Green Building Requirements, and to other development as set forth elsewhere in this Zoning Ordinance.

22.83

Flood Elevation Standards.

22.83.1

Promulgation.

(a)

The City Engineer shall promulgate, and shall revise from time to time, the projected elevations of future flood risk due to certain types and probabilities of flood events for every lot in the City of Cambridge. The resulting projected elevations are referred to herein as Long-Term Flood Elevations ("LTFEs").

(b)

LTFEs shall be determined for flood risk due to precipitation based on piped infrastructure using the City's hydraulic model, and for flood risk due to sea level rise and storm surge based on climate modeling performed by or endorsed by the Commonwealth of Massachusetts's agencies and determined by the City Engineer to represent the most reliable and up-to-date scientific analysis of future climate conditions. Whenever promulgating new LTFEs, the City Engineer shall document the source data used to determine the LTFEs and shall provide an explanation of why such data was selected.

(c)

LTFEs shall be based on an approximately 50-year projection from the time of promulgation. For example, LTFEs promulgated in or around the year 2020 shall anticipate flood risks in or around the year 2070. The City Engineer shall identify the projected timeframe when promulgating LTFEs.

(d)

LTFEs shall be represented in vertical feet relative to the Cambridge City Base (CCB) datum.

(e)

LTFEs shall be presented in the form of data tables that provide the numerical LTFEs for each parcel identified on the Cambridge Assessing Map and may also be presented in the form of a physical or digital map (for example, the Cambridge "FloodViewer" or any successor map) illustrating the LTFEs for different probabilities of flood risk for different types of flooding (i.e., precipitation, sea level rise, and storm surge) across the City. Such a map may be presented and/or illustrated in relation to ground elevation data collected by the City of Cambridge through light detection and ranging (LIDAR) or other technology; however, if a property owner provides a property survey performed by a licensed surveyor, such survey shall be considered more accurate than ground elevation data collected by the City of Cambridge. Property surveys shall not alter the LTFEs but may affect the relative difference between the LTFE and the Grade on a given parcel.

(f)

New or revised LTFEs shall be made available to the public for comment no less than 90 days prior to final promulgation.

22.83.2

Application in Zoning.

(a)

For the purpose of this Section, the following LTFE standards promulgated by the City Engineer as set forth above shall be applicable to development on a lot or development parcel:

(1)

The 1%-Probability Long-Term Flood Elevation standard, or "1%-LTFE standard," shall refer to the projected elevation of floodwater that has a one percent annual chance of occurrence due to either sea level rise and storm surge or due to precipitation, whichever is higher.

(2)

The 10%-Probability Long-Term Flood Elevation standard, or "10%-LTFE standard," shall refer to the projected elevation of floodwater that has a ten percent annual chance of occurrence due to either sea level rise and storm surge or due to precipitation, whichever is higher.

(b)

For the purpose of this Section, then current LTFE standards shall be applicable to a lot or development parcel beginning on the date of final promulgation. However, a development proposal that has already submitted a LTFE plan that has been approved in writing by DPW, in accordance with Section 22.85 below, shall not be subject to LTFE standards promulgated after the date of such written approval, provided that the proposal receives all necessary permits including but not limited to a building or special permit and proceeds thereafter continuously and expeditiously to completion.

22.84

Development Standards.

22.84.1

Protection. A Story Above Grade or portion thereof shall be considered protected from flooding to a specified LTFE standard if its finished floor is higher in elevation than the LTFE standard, or if its finished floor is lower than the LTFE standard, there are permanent or passively deployable barriers in place at the height of the LTFE standard adequate to fully prevent the entry of floodwater into the building's interior. A Story Below Grade or any portion thereof shall be considered a finished floor protected from flooding to a specified LTFE standard if the LTFE standard is below the Grade adjoining the building, or if the LTFE standard is above the Grade adjoining the building, there are permanent or passively deployable barriers in place at the height of the LTFE standard adequate to fully prevent the entry of floodwater into the interior of the Story Below Grade. The following standards shall apply:

(a)

All occupiable spaces within the building, as defined in the State Building Code, shall be protected to the 10%-LTFE standard, except that small entryways, vestibules, or lobbies with a finished floor below the 10%-LTFE standard are allowed to not be protected if they contain stairs, ramps, or lifts that allow occupants to travel to portions of the building that are protected, and if they meet the standards for "Recovery" set forth in Section 22.84.2 below.

(b)

Habitable spaces for residential use, as defined in the State Building Code, shall be protected to the 1%-LTFE standard.

(c)

The following critical building equipment within the building or on the site shall be protected to the 1%-LTFE standard: mechanical heating and cooling systems including fuel storage tanks, supply meters, shut-off switches and building management system controls; electrical power supply, transformers, panels, switchgear, and safety equipment including electrical shut-off equipment, backup generators and their fuel sources; water heaters and water supply related equipment; telecommunications equipment; elevator and lift equipment.

22.84.2

Flood Recovery. A portion of a building shall be considered recoverable from the impact of flooding if floodwater is able to enter and leave the space without causing damage that cannot be readily repaired. This can be achieved through various strategies, including using permanent or contingent measures that prevent or provide resistance to flood damage, or that can be easily repaired or replaced if damaged. Portions of a building located at or below the 10%-LTFE standard that are not required to be protected in Section 22.84.1 above shall be designed to be recoverable.

22.84.3

Modifications. Upon granting a special permit, the Planning Board may approve modifications to the development standards set forth in Section 22.84.1 and 22.84.2 above after finding that a proposed development is designed to meet the intent of the standards in a manner that is more suitable to the unique conditions of the development or the site. No such modification may be approved under this section unless it has been reviewed and approved in writing by the City Engineer.

22.85

Administrative Review Procedures. Before applying for any special permit from the Planning Board, any development review procedure under Article 19.000 of the Zoning Ordinance, or a Building Permit, whichever occurs sooner, the documentation listed below shall be submitted to the Department of Public Works (DPW) for review. Within forty-five (45) days after receiving a complete set of documentation, DPW shall provide written notice that the documentation sufficiently demonstrates compliance with the requirements of this Section or shall provide a written explanation of deficiencies to be corrected in a revised submission. To verify continued compliance, revised documentation incorporating any design modifications shall be reviewed and approved by DPW in accordance with the aforementioned procedures before application for any Building Permit or Certificate of Occupancy sought after the initial submission is accepted.

(a)

Identification of the LTFE standards employed in the development proposal and their date of promulgation. The applicant's initial submission shall employ the LTFE standards that have been promulgated most recently prior to the applicant's submission of the required documentation. If new LTFE standards have been made available to the public for possible promulgation, such LTFE standards shall be identified in the applicant's submission and shall be applicable to the application if new LTFE standards are promulgated before DPW completes its review of the application. For a specific lot or Development Parcel for which the owner has provided a topographical survey, the City Engineer may approve LTFEs that are adjusted for the unique topography of the lot or Development Parcel.

(b)

Elevations and vertical cross-sections of the building and site indicating the 1%-LTFE standard and 10%-LTFE standard, the elevation of the Grade, and the elevation of all finished floors of the building, as well as the uses of all interior sections of the building and the locations of all openings in the building envelope that are below the 1%-LTFE standard and 10%-LTFE standard including pedestrian and vehicular entrances/exits and windows. All drawings shall be drawn to scale and shall include a graphic scale symbol on each drawing sheet.

(c)

A written summary of the technical approaches to meeting the "Protection" and "Recovery" development standards set forth in this Section for any portions of the building located at or below the 1%-LTFE standard or 10%-LTFE standard, including but not limited to the types of flood barriers to be employed and the types of construction materials to be used within such portions of the building.

(d)

A narrative describing any proposed alternative approaches to meeting the intent of the development standards set forth in this Section, if the proposal is seeking approval of any modifications to such standards.

22.86

Implementation.

(a)

The DPW Commissioner shall have the authority to promulgate regulations for the implementation of the provisions of this Section. There shall be a ninety (90) day review period to receive public comments on draft regulations before final promulgation.

(b)

The Department of Public Works may develop standards and procedures appropriate to and consistent with the provisions of this Section.

(c)

These Flood Resilience Standards shall become effective on September 1, 2023, or on the date of final promulgation of regulations promulgated by the DPW Commissioner, whichever is first.

(Ord. No. 2022-9, 2-27-2023)

22.91

Purpose and Intent. The purpose of this Section is to promote the inclusion of features that have a demonstrable cooling effect on buildings and sites to mitigate urban heat island effect. The performance-based "Green Factor," as defined in Article 2.000, approach is intended to be flexible and provide options that can be tailored to different building and site conditions. It is also intended to work in tandem with other regulations, including existing zoning requirements for open space and permeable area, Green Building Requirements (Section 22.20 of this Zoning Ordinance), stormwater control regulations promulgated by the Department of Public Works (DPW), and other standards.

22.92

Applicability. This Section shall apply to development subject to Section 22.20 Green Building Requirements, and as set forth elsewhere in this Zoning Ordinance.

22.93

Prerequisites. The following requirements shall be met for any development that is required to achieve a minimum Cool Score, as defined in Article 2.000:

22.93.1

High Solar Reflectance Index (SRI) Roof. Where the development involves the construction of a new building roof or replacement of more than 50% of an existing roof, the surface of such roof shall have a minimum initial SRI of 82, with the following exceptions:

(a)

Roofs with a slope of 2:12 or steeper shall not be subject to a minimum SRI requirement.

(b)

Components of a Solar Energy System or Green Roof Area, as defined in this Zoning Ordinance, shall not be subject to a minimum SRI requirement.

(c)

In the case of a locally-designated historic structure, the minimum SRI may be reduced or waived to the extent necessary to comply with the conditions of any Certificate of Appropriateness issued by the Cambridge Historical Commission or by a Neighborhood Conservation District Commission. In the case of a state-designated or federally-designated historic structure, the minimum SRI may be reduced or waived to the extent necessary to comply with a determination of adverse effect by the Executive Director of the Cambridge Historical Commission.

22.94

Calculation.

22.94.1

Cool Target. The Cool Target shall be determined by multiplying the total lot area of the lot or Development Parcel by the total Open Space requirement applicable in the zoning district, or by 20%, whichever is greater (see formula below). The Cool Target shall be expressed in square feet.

Total Lot Area x Open Space Requirement (min. 20%) = Cool Target

22.94.2

Cool Area. The Cool Area shall be determined by multiplying the building and site design features listed in the table below (as defined in Article 2.000 of this Zoning Ordinance) by the corresponding weighted values in the table. Features that are located within 20 feet of a street shall use the weighted values in the rightmost column; all other areas shall use the weighted values in the column to the left. The Cool Area for a lot or Development Parcel shall be the sum of the weighted values for all such features located on the lot or Development Parcel, expressed in square feet.

22.94.3

Cool Score. The Cool Score shall be the Cool Area divided by the Cool Target. It shall be expressed as a numerical value that is less than, equal to, or greater than 1.0.

(a)

A Cool Score of 1.0 or greater shall be considered to meet the Green Factor standard, except as set forth elsewhere in this Zoning Ordinance.

(b)

Where a development proposal involves the preservation and/or rehabilitation of a pre-existing building on the site, but does not result in an enlargement of the building footprint or expansion of the existing building on the site, then a Cool Score of less than 1.0 shall be considered to meet the Green Factor standard if it is equal to or greater than the Cool Score attributable to the existing conditions on the site.

22.95

Modifications. Upon granting a special permit, the Planning Board may approve modifications to the development standards set forth above after finding that a proposed development is designed to meet the intent of the standards in a manner that is more appropriate to the unique conditions of the development or the site.

22.96

Administrative Review Procedures. Before applying for any special permit from the Planning Board, any development review procedure under Article 19.000 of the Zoning Ordinance, or a Building Permit, whichever occurs sooner, the documentation listed below shall be submitted to the Community Development Department (CDD) for review. Within thirty (30) days after receiving a complete set of documentation, CDD shall provide written notice that the documentation sufficiently demonstrates compliance with the requirements of this Section or shall provide a written explanation of deficiencies to be corrected in a revised submission. To verify continued compliance, revised documentation incorporating any design modifications shall be submitted to CDD and reviewed in accordance with the aforementioned procedures before applying for any Building Permit or Certificate of Occupancy that is sought after the initial submission.

(a)

Green Factor Score Sheet. A tabulation of the Cool Score of a lot, to be submitted on a form provided by CDD and updated by CDD from time to time.

(b)

Site and Roof Plans. A set of plans that depict the location and extent of all building and site features identified as contributing to the Cool Score, and also delineate which portions of the lot are within 20 feet of a street.

22.97

Implementation of Green Factor Standard.

(a)

The Assistant City Manager for Community Development in consultation with the City Engineer may develop standards and procedures appropriate to and consistent with the provisions of this Section.

(b)

All features used in calculation of the Cool Score shall be designed, installed, and maintained in accordance with such guidelines promulgated by the City.

(c)

This Green Factor Standard shall become effective ninety (90) days after the date of adoption by the City Council.

(Ord. No. 2022-9, 2-27-2023)