C401.2 Replace Section C401.2 as follows:
C401.2Application. Commercial buildings shall comply with either Section C401.2.1 or C401.2.2. When constructed for the first time, all requirements imposed on the building housing a tenant space fit out zone shall also apply to the tenant space fit out zone. Commercial buildings containing multiple use type classifications (mixed-use buildings) shall comply with C401.2.4C401.2.1Prescriptive and Performance Compliance. Commercial buildings shall comply with one of the following:1.Prescriptive Compliance: This pathway may only be used for any nonresidential building, or portions thereof when following C401.2.4, up to 20,000-sf. The Prescriptive Compliance pathway requires compliance with Sections C401.3, C402 through C406, and Section C408.2.Targeted Performance Compliance: This pathway shall be used for dormitory, fire station, library, office, school, police station, post office, and town hall buildings, or portions thereof when following C401.2.4, over 20,000-sf which have average ventilation at full occupancy of 0.5 cfm/sf or less. This pathway can also be used for any building of any size. After 1 July 2024, this pathway shall be used for residential buildings, or portions thereof when following C401.2.4, over 12,000-sf, or the building may comply with Section C401.2.2. The Targeted Performance Compliance pathway requires compliance with Section C401.3, Sections C402 through C406, Section C407.1, Section 408, and select sections of ANSI/ASHRAE/IESNA 90.1-2019 Appendix G as described in Section 407.1.3.Relative Performance Compliance: This pathway may be used by buildings not required to use Option 2. The Relative Performance Compliance pathway requires that the Proposed building complies with Sections C401.3, C402.1.5, C402.2.8, C402.3, C402.4, C402.5, C402.6, C402.7, C403.5, C403.7, C405, C406, C407.2, C408, and ANSI/ASHRAE/IESNA 90.1-2019 using the Appendix G compliance pathway as modified in Section C407.2. Exception: Additions, alterations, repairs and changes of occupancy to existing buildings complying with Chapter 5. This exception does not include tenant space fit out zones when constructed for the first time.
C401.2.2Certified Performance Standard Compliance. Commercial buildings or portions thereof when following C401.2.4 shall comply with one of the following certified performance standard 1.Passivehouse Compliance: This pathway can be used for any building of any size. The Passive House Compliance pathway requires compliance with Sections C401.3, C402.3, C405, C407.3 and C408.2.HERS Compliance: This pathway can be used for any Group R building with multiple individual dwelling units. The HERS pathway requires compliance with Section C401.3, C402.3, C405, C407.4 and C408.C401.2.4 Add Section C401.2.4 Mixed Use Buildings
C401.2.4Mixed Use Buildings. Where different building use types within a new building require different Section C401.2 Compliance Pathways, each use type shall separately and individually show compliance with C401.2.1 or C401.2.2 for that respective use type.C401.4 Add Section C401.4 as follows:
C401.4Building electrification. Building projects which utilize Section C407.2.1 shall conform with C401.4.1. Building projects which utilize Section C402.1.5.2 shall conform with C401.4.2 except for buildings using the Relative Performance pathway because average ventilation at full occupancy is greater than 0.5 cfm/sf which shall comply with C401.4.1 rather than C401.4.2. Building projects which utilize Section CC104.1, Part 1 shall conform with C401.4.3. C401.4.1Partial Space Heating Electrification. Electric air source, exhaust source, or ground source heat pump systems shall supply 25% of the building's peak space heating and ventilation air heating load at the ASHRAE 99.6% winter climatic design condition. Heat pumps used for space and ventilation air heating shall comply with C401.4.4.C401.4.1.1Heat Pump Primary Operation. Heat pump systems shall be controlled to prioritize their primary operation, prior to operation of supplemental fossil-fuel equipment, during non-emergency conditions.C401.4.2Full Space Heating Electrification. Electric air source, exhaust source, or ground source heat pump systems shall supply 100% of the building's peak space heating and ventilation air heating load at the ASHRAE 99.6% winter climatic design condition. No fossil fuel heating equipment shall be used for space heating or ventilation air heating. Heat pumps used for space and ventilation air heating shall comply with C401.4.4.C401.4.3Full Space and Water Heating Electrification. Electric air source, exhaust source, or ground source heat pump systems shall supply 100% of the building's peak space heating and ventilation air heating load at the ASHRAE 99.6% winter climatic design condition. Electric air source, ground source, electric resistance, or solar thermal systems shall supply 100% of the building's service water. No fossil fuel equipment shall be used for space heating, ventilation air heating, or service water heating. Heat pumps used for space and ventilation air heating shall comply with C401.4.4. Heat pump service water heating shall conform to the applicable efficiencies in Section C404.2. Solar thermal service water shall have a solar fraction of 0.4 or larger.
C401.4.4Heat Pump Requirements. Heat pumps used for space heating and ventilation air heating shall comply with C401.4.4.1 through C401.4.4.3. C401.4.4.1Equipment Efficiencies. Heat pump equipment shall conform to the applicable efficiencies in Section C403.3.2.C401.4.4.2Multiple Systems. For buildings with multiple heat pump systems, compliance shall be based on the combined capacity of all heat pump systems serving the building. For purposes of this calculation, the heating capacity of a heat pump system shall not exceed the heating load of that system and the portion of the building served by that system.C401.4.4.3 Exhaust Source Heat Pumps. For purposes of this calculation, the capacity of exhaust source heat pumps shall only include the heating capacity that exceeds the energy recovered by the minimum ventilation heat recovery required by C403.7.4. In addition, for purposes of this calculation, the capacity of the exhaust source heat pumps shall not exceed the heat pump capacity when the exhaust airflow is at 50% of design airflow.C402.1.3 Delete Subsection C402.1.3 and Table C402.1.3 and mark as Reserved.
C402.1.5 Replace Section C402.1.5 with the following:
C402.1.5Component Performance Alternative. Above grade wall and fenestration values and areas determined in accordance with C402.1.5.1 or C402.1.5.2 shall be an alternative to compliance with the above grade wall U- factors in Tables C402.1.4 and vertical fenestration U- factors in Table C402.4 and the maximum allowable fenestration areas in Section C402.4.1. Fenestration shall meet the applicable SHGC requirements of Section C402.4.3. Buildings following ANSI/ASHRAE/IESNA 90.1-2019 Appendix G shall comply with this section. Roofs, below grade walls, floors, slab-on-grade floors, and opaque doors shall comply with the values in Table C402.1.4. C402.1.5.1Low Glazed Wall System Buildings. Buildings in which less than or equal to 50% of the total, above-grade wall area of the building thermal envelope is a glazed wall system shall comply with Equation 4-2a and vision glass used in the glazed wall system shall have a maximum whole assembly U factor of U-0.25. Area-weighted U proposed <= 0.1285 (Equation 4-2a)
where:
Area-weighted U proposed = U value for each distinct assembly type of the above grade wall portion of the building thermal envelope weighted by vertical area for each distinct assembly type.
C402.1.5.2High Glazed Wall System Buildings. Buildings in which more than 50% of the total, above-grade wall area of the building thermal envelope is a glazed wall system shall comply with Equation 4-2b and vision glass used in the glazed wall system shall have a maximum whole assembly U factor of U-0.25 and the building complies with Section C401.4.2. Area-weighted U proposed <= 0.1600 (Equation 4-2b)
where:
Area-weighted U proposed = U value for each distinct assembly type of the above grade wall portion of the building thermal envelope weighted by vertical area for each distinct assembly type.
Exception: Buildings using the Relative Performance pathway because average ventilation at full occupancy is greater than 0.5 cfm/sf shall comply with C401.4.1 rather than C401.4.2.
C402.2.4.1Delete the exception in Subsection C402.2.4.1:C402.2.8 Add Subsection C402.2.8 as follows:
C402.2.8Fireplaces. New combustion fireplaces shall have tight-fitting flue dampers or doors, and outdoor combustion air as required by the fireplace construction provisions of MA Construction Codes, as applicable. Where using tight-fitting doors on factory-built fireplaces listed and labeled in accordance with UL 127, the doors shall be tested and listed for the fireplace.C402.3 Replace Section C402.3 with the following:
C402.3Rooftop Solar Readiness (Mandatory). Follow Appendix CB: Solar-ready zone -Commercial.C402.4Modify Vertical fenestration U-factors in TABLE C402.4 as follows: CLIMATE ZONE 5 AND MARINE 4
Vertical fenestration U-factor
Fixed fenestration | 0.30 |
Operable fenestration | 0.32 |
Add Subsection C402.4.6:
C402.4.6Fenestration Documentation. In accordance with Section 303.1.3 fenestration performance shall be documented according to C402.4.6.1 or C402.4.6.2. C402.4.6.1Labeled Performance. The thermal transmittance of glazed fenestration products within the scope of NFRC shall be indicated by labels applied to the products at the manufacturing location or by a label certificate produced by an NFRC Approved Calculation Entity.C402.4.6.2 Calculated Performance. Fenestration products outside the scope of NFRC may demonstrate compliance by submitting a thermal simulation report prepared by a registered design professional for each product as defined by NFRC 100. Thermal simulations shall be performed in accordance with the NFRC 100-2020 simulation procedures at the size and configuration defined in NFRC 100 Table 4-3.C402.5 Replace Section C402.5 with the following:
C402.5Air Leakage - Thermal Envelope. The building thermal envelope shall comply with Sections C402.5.1 through Section C402.5.10.1. C402.5.1 Replace Section C402.5.1 with the following and delete the exception:
C402.5.1Air Barriers. A continuous air barrier shall be provided throughout the building thermal envelope. The continuous air barrier is permitted to be any combination of inside, outside, or within the building thermal envelope. The air barrier shall comply with Sections C402.5.1.1, and C402.5.1.2. The air leakage performance of the air barrier shall be verified in accordance with Section C402.5.2. 402.5.1.1 Replace Section C402.5.1.1 with the following:
C402.5.1.1Air Barrier Design and Documentation Requirements. Design of the continuous air barrier shall be documented in the following manner: 1. Materials, assemblies, and systems comprising the continuous air barrier and their position within each building thermal envelope assembly shall be identified.2. Joints, interconnections, and penetrations of the continuous air barrier materials, assemblies, and systems shall be detailed.3. The continuity of the air barrier at building element assemblies that enclose conditioned space or provide a boundary between conditioned space and unconditioned space shall be identified.4. Documentation of the continuous air barrier shall detail methods of sealing the air barrier such as wrapping, caulking, gasketing, taping or other approved methods at the following locations:i. Joints around fenestration and door frames.ii. Joints between walls and floors, between walls at building corners, between walls and roofs including parapets and copings, where above-grade walls meet foundations and similar intersections.iii. Penetrations or attachments through the continuous air barrier in building envelope roofs, walls, and floors.iv. Building assemblies used as ducts or plenums.v. Changes in continuous air barrier materials and assemblies.vi. Transition from one wall or roof assembly type to another such as, but not limited to, transition between opaque wall system and glazed wall system, and transition between a curtain wall glazed wall system and a storefront glazed wall system.5. Identify where testing will or will not be performed in accordance with Section C402.5.2. Where testing will not be performed, a plan for field inspections required by C402.5.2.3 shall be provided that includes the following:i. Schedule for periodic inspection(s),ii. Continuous air barrier scope of work,iii. List of critical inspection items,iv. Inspection documentation requirements, andv. Provisions for corrective actions where needed.C402.5.1.2Renumber Section C402.5.1.1 as Section C402.5.1.2 and make the following changes: In Part 3, delete "Joints and seams associated with penetrations shall be sealed in the same manner or taped"
In Part 3, replace "from wind stack effect and mechanical ventilation" with "pressure".
In Part 4, replace "C402.5.10" with "C402.5.1.2.1".
C402.5.1.2.1 Add Section C402.5.1.2.1 as follows:
C402.5.1.2.1Electrical and Communication Boxes. Electrical and communication boxes that penetrate the air barrier of the building thermal envelope, and that do not comply with C402.5.1.2.1.1, shall be caulked, taped, gasketed, or otherwise sealed to the air barrier element being penetrated. All openings on the concealed portion of the box shall be sealed. Where present, insulation shall rest against all concealed portions of the box. C402.5.1.2.1.1 Add Section C402.5.1.2.1.1 as follows:
C402.5.1.2.1.1Air-sealed Boxes. Where air-sealed boxes are installed, they shall be marked in accordance with NEMA OS 4. Air-sealed boxes shall be installed in accordance with the manufacturer's instructions.C402.5.1.3Delete Section C402.5.1.3C402.5.1.4Delete Section C402.5.1.4C402.5.1.5Delete Section C402.5.1.5C402.5.2 Replace Section C402.5.2 with the following:
C402.5.2Air Leakage Compliance. Air leakage of the building thermal envelope shall be tested by an approved third party in accordance with C402.5.2.1. The measured air leakage shall not be greater than 0.35 cfm/ft2 (1.8 L/s x m2) of the building thermal envelope area at a pressure differential of 0.3 inch water gauge (75 Pa) with the calculated building thermal envelope surface area being the sum of the above- and below-grade building thermal envelope. Exceptions:
1. Where the measured air leakage rate is greater than 0.35 cfm/ft2 (1.8 L/s x m2) but is not greater than 0.45 cfm/ft2 (2.3 L/s x m2), the approved third party shall perform a diagnostic evaluation in accordance with ASTM E1186. All identified leaks shall be sealed where such sealing can be made without damaging existing building components. A report specifying the corrective actions taken to seal leaks shall be deemed to establish compliance with the requirements of this section where submitted to the code official and the building owner. Where the measured air leakage rate is greater than 0.45 cfm/ft2 (2.3 L/s x m2), corrective actions must be made to the building and an additional test completed for which the results are 0.45 cfm/ft2 (2.3 L/s x m2), or less.2. As an alternative, buildings or portions of buildings, containing Group R and I occupancies, shall be permitted to be tested by an approved third party in accordance with C402.5.2.2. The reported air leakage of the building thermal envelope shall not be greater than 0.27 cfm/ft2 (1.4 L/s x m2) of the testing unit enclosure area at a pressure differential of 0.2 inch water gauge (50 Pa).C402.5.2.1 Add Section C402.5.2.1 as follows:
C402.5.2.1 Whole Building Test Method and Reporting. The building thermal envelope shall be tested for air leakage in accordance with ASTM E3158 or an equivalent approved method. A report that includes the tested surface area, floor area, air by volume, stories above grade, and leakage rates shall be submitted to the code official and the building owner. Exceptions:
1. For buildings less than 10,000 ft2 (1000 m2), the entire building thermal envelope shall be permitted to be tested in accordance with ASTM E779, ASTM E3158 or ASTM E1827 or an equivalent approved method.2. For buildings greater than 50,000 ft2 (4645 m2), portions of the building shall be permitted to be tested and the measured air leakage shall be area-weighted by the surface areas of the building thermal envelope in each portion. The weighted average tested air leakage shall not be greater than the whole building leakage limit. The following portions of the building shall be tested: i. The entire building thermal envelope area of stories that have any conditioned spaces directly under a roof.ii. The entire building thermal envelope area of stories that have a building entrance, a floor over unconditioned space, a loading dock, or that are below grade.iii. Representative above-grade portions of the building totaling not less than 25% of the wall area enclosing the remaining conditioned space.C402.5.2.2Renumber Section C402.5.2 as new Section C402.5.2.2 and make the following changes: Add "ASTM E3158," after "ASTM E1827"
Replace "Units shall be tested separately with an unguarded blower door test as follows:" with "Units shall be tested without simultaneously pressurizing adjacent units and shall be separately tested as follows".
In part 2, add "a middle floor unit" between "including a top floor unit" and "a ground floor unit"
In part 2, replace "two units shall be tested" with "three units shall be tested"
Add new Part 3 as follows: "Enclosed spaces with not less than one exterior wall in the building thermal envelope shall be tested in accordance with C402.5.3."
Add the following exception: "Exception: Corridors, stairwells, and enclosed spaces having a conditioned floor area not greater than 1,500 ft2 shall be permitted to comply with Section C402.5.1.5 and either Section C402.5.1.3 or C402.5.1.4."
C402.5.2.3Renumber Section C402.5.1.5 as Section C402.5.2.3 and make the following changes: Add "In addition to the requirements of Sections C402.5.2.1 and C402.5.2.2" after "verification criteria" and before "the installation of the continuous air barrier".
In part 2, replace "components and assemblies" with "materials, assemblies, and systems"
In part 2, delete "while the air barrier is still accessible for inspection"
In part 2, replace "Sections C402.5.1.3 and C402.5.1.4" with "Sections C402.5.2.3.1 or C402.5.2.3.2" and add "The air barrier shall remain accessible for inspection and repair"
C402.5.2.3.1Renumber Section C402.5.1.3 as new Section C402.5.2.3.1.C402.5.2.3.2Renumber Section C402.5.1.4 as new Section C402.5.2.3.2.C402.5.3Renumber Section C402.5.4 as Section C402.5.3 and make the following changes: Replace "shall meet the provisions of Table C402.5.4" with "shall comply with Table C402.5.3".
Add "conducted by an accredited, independent testing laboratory" between "Testing shall be" and "in accordance with"
Replace "reference test standard in C402.5.4 by an accredited, independent testing laboratory" with "reference test standard in Table C402.5.3".
In Exception 1, replace "C402.5.1" with "C402.5.1.2"
In Exception 2, replace "comply with the testing alternative of Section C402.5," with "are tested for air leakage in accordance with Section C402.5.2"
In Exception 2, replace "Table C402.5.4" with "Table C402.5.3"
Relabel "Table C402.5.4" to "Table C402.5.3"
C402.5.4Renumber Section C402.5.5 as Section C402.5.4 and make the following changes: In Part 2.1, delete "Table C402.1.3 or".
In Part 2.2, replace "Section C402.5.1.1" I "Section C402.5.1.2".
In Part 2.4, replace "Water lines" with "Piping serving as part of a heating or cooling system".
C402.5.5Renumber Section C402.5.6 as Section C402.5.5 and make the following changes: Replace "Section C402.5.4" with "Section C402.5.3".
C402.5.6Renumber Section C402.5.7 as Section C402.5.6.C402.5.7Renumber Section C402.5.8 as C402.5.7 and make the following changes: Replace "infiltration" with "air leakage".
C402.5.8Renumber Section C402.5.9 as Section C402.5.8 and make the following changes:C402.5.9Renumber Section C402.5.10 as Section C402.5.9. In part 2 replace "more" with "greater"
In part 2 replace "when" with "where"
C402.5.10Renumber Section C402.5.11 as Section C402.5.10 and make the following changes: Replace "and lower the heating setpoint to 55°F (13°C)" with "and lower the heating setpoint to 50°F (10°C)"
In Exception 1, add "operable openings into " before "separately-zoned areas "
In Exception 2, replace "warehouses " with "storage occupancies "
In Exception 3, revise to read: "Doors located in the exterior wall that are part of a vestibule system".
Add new Exception 4, "Operable openings used as part of a designed system for natural ventilation."
C402.5.10.1Renumber Section C402.5.11.1 as Section C402.5.10.1C402.6 Add Section C402.6 as follows:
C402.6 Approved Calculation Software Tools. The following software tools are sufficient to demonstrate compliance with Sections C401.2.1 Prescriptive Compliance and C402.7.C402.7 Add Section C402.7 and subsections as follows:
C402.7Derating and Thermal BridgesC402.7.1General. In addition to pre-calculated assembly U-factors, C-factors, or F-factors outlined in Appendix A of ASHRAE 90.1 2019, vertical envelope performance shall also take into account the effect of thermal bridges according to both C402.7.2 and C402.7.3. In addition, the thermal resistance of spandrel sections within glazed wall systems shall be according to C402.7.4. Together with Appendix A of ASHRAE 90.1 2019, these derated values and spandrel section values shall be used when showing compliance with Section C402.1.4 or Section C402.1.5, as applicable.C402.7.2 Continuous Insulation for Vertical Walls. Installed vertical wall continuous insulation shall be derated using either C402.7.2.1, C402.7.2.2 or C402.7.2.3 to account for the effect of fasteners through the continuous insulation.C402.7.2.1Prescriptive Derating. Derate vertical wall continuous insulation using Equation C402.7.2.1 and a derating Factor from C402.7.2.1.1 for portions of wall having brick veneer systems and a derating factor from C402.7.2.1.2 or C402.7.2.1.3 for portions of wall having cladding systems. (Equation C402.7.2.1)
Rderated = Ro x Derating Factor
Where
Rderated: R value after derating, to be used when showing compliance R402.7.2
Ro: R value of the continuous insulation prior to derating
Derating Factor: Derating factor From C402.7.2.1.1, C402.7.2.1.2, or C402.7.2.1.3
C402.7.2.1.1Brick Veneer Systems. Wall systems comprised of brick veneer anchored to the building with fasteners shall use a Derating Factor of 0.7 to account for the clear field thermal bridge derating effect of the fasteners. In addition, brick shelf angles shall be derated according to Section C402.7.3 to account for the linear thermal bridge derating effect of any brick shelf angles.C402.7.2.1.2Cladding Systems. Wall systems comprised of cladding systems shall use a derating factor per Table 402.7.2.1.2 Table 402.7.2.1.2 Cladding System Derating Factors
Thickness of Ro | Derating Factor |
Ro is less than or equal to R-15 | Derating Factor = 0.74 - 0.021 x Ro |
Ro is greater than R-15 | Derating Factor = 0.55 - 0.007 x Ro |
C402.7.2.1.3Cladding Systems with Qualifying Thermal Breaks. If plastic or fiberglass fasteners entirely comprised of material having thermal conductivity of 3 Btu-in/hr-ft2-F or less are used to support external cladding; or, if fasteners having thermal breaks which have a conductivity of 3 Btu-in/hr-ft2-F or less on both ends of the fastener are used to support external cladding, use Derating Factor of 0.8.C402.7.2.2.Reference Derating. Use pre-solved, derated continuous insulation values contained in Building Envelope Thermal Bridging Guide, version 1.6 or higher, published by BC Hydro Power Smart at https://www.bchydro.comC402.7.2.3.Modelled Derating. Use two or three-dimensional finite element analysis heat transfer model to calculate derated value. A three-dimensional model shall be used when there are point thermal bridges or thermal bridging in multiple planes.C402.7.3.Linear Thermal Bridges. In addition to derating per Section C402.7.2, installed vertical wall insulation U values shall be further derated for linear thermal bridges where the vertical wall intersects the following: brick shelf angles, balconies, vertical interior walls, horizontal interior walls, windows, roof, other vertical walls on different plane, and grade using Equation C402.7.3. (Equation C402.7.3)
Click to view image
Where
Uderated Derated wall U value (Btu/hr-ft2-F)
PSI Value from Section C402.7.3.1, C402.7.3.2, or C402.7.3.3 (Btu/hr-ft-F) Length Length of linear thermal bridge (ft)
Atotal Area of derated wall (ft2)
Uo Wall or roof U value prior to linear thermal bridge derating
C402.7.3.1Prescriptive PSI Values. Use PSI values from Table C402.7.3.1 Table C402.7.3.1 Linear Thermal Bridge Prescriptive PSI values.
Type of Linear Thermal Bridge | PSI-value (Btu/hr - ft - F) |
Balcony to exterior vertical wall intersection | 1.00 |
Intermediate floor to exterior vertical wall intersection | 0.60 |
Interior vertical wall to exterior vertical wall intersection | 0.50 |
Fenestration to exterior vertical wall intersection | 0.32 |
Parapet (vertical wall to roof intersection) | 0.60 |
Brick shelf angle | 0.35 |
Vertical wall to grade intersection | 0.52 |
Vertical wall plane transition (building corners and other changes in vertical wall plane) | 0.25 |
C402.7.3.2Reference PSI Values. Use pre-solved PSI values contained in Building Envelope Thermal Bridging Guide, version 1.6 or higher, published by BC Hydro Power Smart.C402.7.3.3Modelled PSI Values. Use a two or three-dimensional finite element analysis to calculate PSI values. A three-dimensional model shall be used when there are point thermal bridges or thermal bridging in multiple planes.C402.7.4Thermal Resistance of Spandrel Sections. R-factor of opaque spandrel sections within curtain wall systems shall be accordance with C402.7.4.1, C402.7.4.2, or C402.7.4.3. C402.7.4.1Prescriptive R Value. Opaque spandrel sections within glazed wall systems shall have at least R-12 insulation. For the purpose of calculating weighted U value in accordance with Section C402.1.5, spandrel sections shall use values in Table C402.7.4.1. Table C402.7.4.1 Spandrel Section Default R values
Type | Default R-Value |
Thermally broken | 3.5 |
Non-thermally broken | 2 |
C402.7.4.2Reference R Values. Use pre-solved opaque spandrel sections R values contained in Building Envelope Thermal Bridging Guide, version 1.6 or higher, published by BC Hydro Power Smart.C402.7.4.3.Modelled R values. Use a two or three-dimensional finite element analysis to calculate R value of opaque spandrel section. A three-dimensional model shall be used when there are point thermal bridges or thermal bridging in multiple planes.C403.5Modify Section C403.5 as follows: Add "Dedicated outside air systems " as Item 4 of the list of where air or water economizers shall be provided.
Delete exception 5 and renumber subsequent exceptions to reflect deletion
Table C403.5(1). Show only Climate Zone 5A.
Table C403.5(2). Delete this table
C403.7.4 Replace Subsection C403.7.4 with the following:
C403.7.4Energy Recovery Systems. Energy recovery ventilation systems shall be provided as specified in Section C403.7.4.1, as applicable and C403.7.4.2. C403.7.4.1Modify Section C403.7.4.1 as follows: Replace "not less than 60 percent at heating design condition." with "not less than 75 percent at heating design condition. Outdoor air must be delivered directly to the dwelling unit. The building weighted average sensible energy recovery effectiveness must meet the requirements of C403.7.4.2."
Delete all the exceptions (exceptions 1 through 4).
C403.7.4.2Modify Section C403.7.4.2 as follows:Replace "The energy recovery system shall provide an enthalpy recovery ratio of not less than 50% at design conditions" with "The energy recovery system shall result in either 1 or 2, as applicable"
Add 1 and 2 as follows
1. A sensible recovery ratio of at least 50% at heating design conditions for systems that provide makeup for Class 3 or 4 exhaust. The requirement can be satisfied either for each fan system individually or based on a weighted average of the ventilation air flow for all applicable fan systems in the entire building per Equation C403.7.4.2(1). Equation C403.7.4.2(1)
Weighted average sensible energy recovery ratio = [sensible energy recovery ratio for fan system 1 x outside air flow for system 1 + sensible energy recovery ratio for fan system 2 x outside air flow for system 2 + ... ]/[outside air flow for system 1 + outside air flow for system 2 + ...]
2. An enthalpy recovery ratio of not less than 70% at heating and cooling design conditions for all other systems. The requirement can be satisfied either for each fan system individually or based on a weighted average of the ventilation air flow for all applicable fan systems in the entire building per Equation C403.7.4.2(2). Equation C403.7.4.2(2)
Weighted average enthalpy energy recovery ratio = [enthalpy recovery ratio for fan system 1 x outside air flow for system 1 + enthalpy recovery ratio for fan system 2 x outside air flow for system 2 + ... ]/[outside air flow for system 1 + outside air flow for system 2 + ...]
Delete exceptions 2 (including 2.1 and 2.2), 4, 5, 6, 7, and 8
Renumber exception 3 as exception 2
Renumber exception 9 as exception 3 and change from "20 hours per week" to "10 hours per week
Renumber exception 10 as exception 4
Renumber exception 11 as exception 5
Revise Tables C403.7.4.2(1) and C403.7.4.2(2) and show only Climate Zone 5A row, as follows:
Table C403.7.4.2(1) ENERGY RECOVERY REQUIREMENT (Ventilation systems operating less than 8,000 hours per year)
Climate Zone | PERCENT (%) OUTDOOR AIR AT FULL DESIGN AIRFLOW RATE |
>=10% and <20% | >=20% and < 30% | >=30% and < 40% | >=40% and <50% | >=50% and <60% | >=60% and <70% | >=70 % and <80% | >=80% |
Design Supply Fan Airflow Rate (cfm) |
5A | 10,000 | 8,000 | 2,750 | 0 | 0 | 0 | 0 | 0 |
Table C403.7.4.2(2) ENERGY RECOVERY REQUIREMENT (Ventilation systems operating note less than 8,000 hours per year)
Climate Zone | PERCENT (%) OUTDOOR AIR AT FULL DESIGN AIRFLOW RATE |
>=10% and < 20% | >=20% and < 30% | >=30% and < 40% | >=40% and <50% | >=50% and <60% | >=60% and <70% | >=70% and<80% | >=80% |
Design Supply Fan Airflow Rate (cfm) |
5A | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
C405.2.4Modify Section C405.2.4 as followsIn item 1, replace "150 watts" with "100 watts"
In item 3, replace "150 watts" with "100 watts"
C405.13 Add Section C405.13 as follows:
C405.13Electric Vehicle Ready Parking Spaces ("EV Ready Spaces") (Mandatory). New parking spaces shall provide EV Ready Spaces in accordance with Table C405.13. Installed wiring suitable for 6.6kW or higher SAE J1772-2017 AC Level II EVSE shall be connected to the service panel and run to within 6 feet (1828mm) of any qualifying parking space. Conductors and outlets for EVSE shall be sized and installed in accordance with the MA electrical code. TABLE C405.13 EV-READY SPACE REQUIREMENTS
Occupancy Classification | Minimum percentage of EV-Ready Spaces | EV Charging Performance Requirements |
Group R and Group B | 20% | 40-amp dedicated branch circuit or larger branch circuit with ALMS in accordance with Table C405.13.1 |
All Other Occupancies | 10% | 40-amp dedicated branch circuit or larger branch circuit with ALMS in accordance with Table C405.13.1 |
Exceptions:
1. Parking spaces and garage spaces intended exclusively for storage of vehicles for retail sale or vehicle service are excluded from the EV-ready space percentage calculation.2. Any parking facility with 4 or more spaces providing installed Direct Current fast charging EVSE with a minimum charging speed of 150 kW to each space.3. One or more AC Level II spaces may be substituted with multiple AC Level I spaces provided with wiring for a minimum 20amp, 120-volt EVSE, with a ratio of at least 3 AC Level I spaces for each AC Level II space required.4. Parking spaces specifically designated for medium or heavy-duty vehicles are excluded from the EV-ready space percentage calculation.C405.13.1 Add Section C405.13.1 as follows:
C405.13.1Minimum Charging Performance Requirements. Automatic Load Management System (ALMS) may be used to control electric vehicle loads for EV-Ready or EVSE-Installed Spaces with AC Level II or Level I charging, subject to the performance requirements in Table C405.13.1. The maximum number of parking spaces that may share a single branch circuit varies based on the percentage of all parking spaces to be provided with EVSE.TABLE C405.13.1 EV-READY PERFORMANCE REQUIREMENTS
Circuit Breaker Amperage | Maximum Parking Spaces that May Share a Branch Circuit with 10%-60% EV Ready spaces | Maximum Parking Spaces that May Share a Branch Circuit with 61100% EV Ready spaces |
40A | 1 | 2 |
50A | 1 | 2 |
60A | 2 | 4 |
70A | 3 | 6 |
80A | 4 | 8 |
90A | 5 | 9 |
100A | 6 | 10 |
C405.13.2 Add Section C405.13.2 as follows:
C405.13.2 Identification. Construction documents shall indicate the branch circuit termination point and proposed location of future EVSE. Construction documents shall also provide information on amperage of future EVSE, wiring schematics, Automatic Load Management Systems, and electrical load calculations to verify that the electrical panel service capacity and electrical system, including any on-site distribution transformers, have sufficient capacity to simultaneously charge all EVs at all required EV ready spaces.C406.1Modify Section C406.1 as follows:Replace "shall achieve a total of 10 credits" with "shall achieve a total of 15 credits"
Table C406.1(1)Modify Table C406.1(1) as follows:
Delete rows for C406.2.1: 5% heating efficiency improvement and C406.7.3: Efficient fossil fuel water heater
Replace row for option C406.2.3:10% heating efficiency improvement with the following:
Section | Climate Zone 5A |
C406.2.3 Renewable space heating | 15 |
Add the following row for option C406.13:
Section | Climate Zone 5A |
C406.13 Heavy Timber Construction | 8 |
Table C406.1(2), Modify Table C406.1(2) as follows:
Delete rows for C406.2.1:5% heating efficiency improvement and C406.7.3: Efficient fossil fuel water heater
Replace row for option C406.2.3:10% heating efficiency improvement with the following:
Section | Climate Zone 5A |
C406.2.3 Renewable space heating | 15 |
Add the following row for option C406.13:
Section | Climate Zone 5A |
C406.13 Heavy Timber Construction | 8 |
Table C406.1(3) Modify Table C406.1(3) as follows:
Delete rows for C406.2.1:5% heating efficiency improvement and C406.7.3: Efficient fossil fuel water heater
Replace row for option C406.2.3:10% heating efficiency improvement with the following:
Section | Climate Zone 5A |
C406.2.3 Renewable space heating | 15 |
Add the following row for option C406.13:
Section | Climate Zone 5A |
C406.13 Heavy Timber Construction | 8 |
Table C406.1(4) Modify Table C406.1(4) as follows:
Delete rows for C406.2.1:5% heating efficiency improvement and C406.7.3: Efficient fossil fuel water heater
Replace row for option C406.2.3:10% heating efficiency improvement with the following:
Section | Climate Zone 5A |
C406.2.3 Renewable space heating | 15 |
Add the following row for option C406.13:
Section | Climate Zone 5A |
C406.13 Heavy Timber Construction | 8 |
Table C406.1(5) Modify Table C406.1(5) as follows:
Delete rows for C406.2.1:5% heating efficiency improvement and C406.7.3: Efficient fossil fuel water heater
Replace row for option C406.2.3:10% heating efficiency improvement with the following:
Section | Climate Zone 5A |
C406.2.3 Renewable space heating | 15 |
Add the following row for option C406.13:
Section | Climate Zone 5A |
C406.12 Heavy Timber Construction | 8 |
C406.1.1Modify Section C406.1.1 as follows: Replace "minimum number of 5 credits" with "minimum number of 10 credits"
C406.2.1Delete this sectionC406.2.3 Replace Section C406.2.3 with the following:
C406.2.3.Renewable space heating. All space heating shall be provided with cold-climate air source heat pumps having rated coefficient of performance (COP) of at least 1.75 at 5 degrees Fahrenheit source air, or ground source heat pumps.C406.7.3Delete this sectionC406.9 Replace Section C406.9 with the following:
C406.9Reduced air leakage. Air leakage of the building thermal envelope shall be tested by an approved third party in accordance with Section C402.5.2.1. The measured air leakage shall not exceed 0.20 cfm/ft2 (1.1 L/s x m2) of the building thermal envelope at a pressure differential of 0.3 inches water gauge (75 Pa), with the calculated surface area being the sum of the above-and below-grade building thermal envelope.C406.13 Add Section C406.13 as follows:
C406.13Heavy Timber construction. For buildings with 4 stories or more of Type IV heavy timber construction either above grade, or above a podium. C407 Replace Section C407 in its entirety with the following:
C407.1Targeted PerformanceThis option requires compliance with Sections C407.1.1 through C407.1.2.
C407.1.1Compliance. Buildings shall comply with Sections C407.1.1.1 through C407.1.1.6. C407.1.1.1Building performance modelingBuilding performance modeling shall be used to show compliance with C407.1.1.5. The simulation program shall be a computer-based program for the analysis of energy consumption in buildings. The simulation shall include calculation methodologies for the building components being modeled and meet the requirements in ANSEASHRAE/IESNA 90.1-2019 Appendix G Section G2.2.1(a)-(d) and Section G2.2.4.
C407.1.1.2Climatic ConditionsThe simulation program shall perform the simulation using hourly values of climatic data using representative weather files prescribed by the Massachusetts Department of Energy Resources.
C407.1.1.3Modeling Building Envelope Infiltration. The air leakage rate of the building envelope shall be modeled following ANSI/ASHRAE/IESNA 90.1-2019 Section G3.1.1.4.C407.1.1.4Internal loads, scheduling, and other modeling assumptionsPerformance modeling shall use the internal load, scheduling, and other assumptions as prescribed by the Massachusetts Department of Energy Resources.
C407.1.1.5 Thermal energy demand intensity (TEDI) limitsPerformance modeling shall show that the building's heating thermal energy demand intensity and cooling thermal energy demand intensity are less than or equal to the values in Table C407.1.1.5
Table C407.1.1.5 Thermal Energy Demand Intensity (TEDI) Limits
Use Type | Heating TEDI (kBtu/sf-yr) | Cooling TEDI (kBtu/sf-yr) |
Office, fire station, library, police station, post office, town hall >= 125,000-sf | 1.5 | 23 |
Office, fire station, library, police station, post office, town hall between 75,000 and 125,000-sf-sf | 4 - 0.00002 * Area (sf) | 18 + 0.00004 * Area (sf) |
Office, fire station, library, police station, post office, town hall <= 75,000-sf | 2.5 | 21 |
K-12 School >= 125,000-sf | 2.2 | 12 |
K-12 School between 75,000 and 125,000-sf | 2.7 - 0.000004 * Area (sf) | 32 - 0.00016 * Area (sf) |
K-12 School <= 75,000-sf | 2.4 | 20 |
Residential multifamily and dormitory >= 125,000-sf | 2.8 | 22 |
Residential multifamily and dormitory between 75,000 and 125,000-sf | 3.8 - 0.000008 * Area (sf) | 4.5 + 0.00014 * Area (sf) |
Residential multifamily and dormitory <= 75,000-sf | 3.2 | 15 |
All other >= 125,000-sf | 1.5 | 23 |
All other between 75,000 and 125,0000-sf | 4 - 0.00002 * Area (sf) | 18 + 0.00004 * Area (sf) |
All other <= 75,000-sf | 2.5 | 21 |
C407.1.1.6Mixed use buildingsFor buildings having more than one use type where any use type is more than 10% of the total space conditioned area, each separate use type having more than 10% of the total space conditioned area shall separately and individually show compliance with C407.1.1.5 for that respective use type. Use types having less than or equal to 10% of the total space conditioned area do not have to show separate, individual compliance with C407.1.1.5 but can be incorporated into and treated as the majority use type.
C407.1.2Documentation. Simulated performance shall be documented, and documentation shall be submitted to the rating authority. Documentation shall include all the assumptions used in the performance modeling such that the documentation can be used as a specification checklist for implementation during design and construction. The information shall be submitted in a report and shall include the items described in ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Section G1.3.2 Parts b, g, h, i, j, k, l, n, o, and q, and Section G1.3.3.C407.2Relative Performance. This option requires compliance with Section C407.2.1 and C407.2.2C407.2.1Electrification and Documentation of Highly Ventilated Buildings. Buildings using the Relative Performance Pathway (C407.2) because average ventilation at full occupancy is greater than 0.5 cfm/sf shall have space heating electrified in accordance with Section C401.4.1 and shall submit design documents showing ventilation system design and air flow rates as required by Section C103.2 part 16.C407.2.2Compliance. Building shall comply with ANSI/ASHRAE/IESNA 90.1-2019 Section 4.2 using the Appendix G pathway as modified by C407.2.2.1 and C407.2.2.2.C407.2.2.1Modification to ANSI/ASHRAE/IESNA 90.1-2019 Section 4.2.ANSI/ASHRAE/IESNA 90.1-2019 Section 4.2 Replace 4.2.1.1 with the following:
New buildings shall comply with 4.2.2 through 4.2.5 and normative Appendix G. When using Normative Appendix G, the Performance Energy Index (PEI) of new buildings, additions to existing buildings, and alterations to existing buildings shall be less than or equal to the Performance Energy Index Target (PEIt) when calculated in accordance with the following:
PEIt = [BBUE + (BPF x BBRE)]/BBSE
PEI = Performance Energy Index calculated in accordance with Section G1.2
BBUE = Baseline building unregulated site energy
BBRE = Baseline building regulated site energy
BPF = Building performance factor from Table 4.2.1.1 For building area types not listed in Table 4.2.1.1 use "All others". Where a building has multiple area types, the required BPF shall be equal to the area-weighted average of the building area types.
BBSE = Baseline building site energy (sum of BBUE and BBRE)
ANSI/ASHRAE/IESNA 90.1-2019 Section 4.2 Revise Table 4.2.1.1 to show only Climate Zone 5A; remove multifamily, office, and school; and adjust the BPFs as follows:
TABLE 4.2.1.1 BUILDING PERFORMANCE FACTOR (BPF)
Building Area Type | Climate Zone 5A |
Health care/hospital | 0.59 |
Hotel/motel | 0.57 |
Restaurant | 0.62 |
Retail | 0.47 |
Warehouse | 0.41 |
All others | 0.51 |
C407.2.2.2Modification to ANSI/ASHRAE/IESNA 90.1-2019 Appendix GANSI/ASHRAE/IESNA 90.1-2019 Appendix G In all Sections of Appendix G, replace references to "baseline building performance" with "baseline building site energy", replace "proposed building performance " with "proposed building site energy ", replace "energy cost savings " with "site energy savings "
ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Replace G1.2.2 with following, keeping the exception unchanged:
The site energy of the proposed design is calculated in accordance with the provisions of this appendix using the followin
g formula:
Performance energy index (PEI) = Proposed building site energy / baseline building site energy (BBSE)
Both the proposed building site energy and the baseline building site energy shall include all end use load components within and associated with the building when calculating the performance energy index.
ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Delete G1.3.2 Part m and Part p
ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Delete G2.1 Part c
ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Revise G2.4.1 as follows
Site recovered energy shall be subtracted from the proposed building site energy when calculating performance. Energy used to recharge vehicles that are used for on-road and off-site transportation purposes, or energy losses from use of behind-the-meter energy storage, should not be included when calculating performance. On-site renewable energy shall not be subtracted from the proposed building site energy when calculating performance.
ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Delete G2.4.2
ANSI/ASHRAE/IESNA 90.1-2019 Appendix G Add the following row to Section G Table G3.1.1-1.
TABLE G3.1.1-1 BASELINE BUILDING VERTICAL FENESTRATION PERCENTAGE OF GROSS ABOVE-GRADE-WALL AREA
Building Area Types | Baseline Building Gross Above-Grade-Wall Area |
Multifamily | 24% |
Section C407.3 Add Section C407.3 as follows:
C407.3Passive House. This option requires compliance with Section C407.3.1 and C407.3.2. C407.3.1Compliance. Buildings shall be pre-certified as meeting the Phius CORE 2021 or Phius ZERO 2021 Passive Building Standard - North America, or newer, demonstrated using Phius approved software, where Phius Design-Certification is demonstrated by Phius and a Certified Passive House Consultant (CPHC); or, Projects pre-certified as meeting the Certified Passive House standard using the current software and program criteria by the Passive House Institute (PHI), where PHI certification is demonstrated by a Certified Passive House Designer and a Certified Passive House Certifier.C407.3.2Documentation. Compliance with Phius or PHI shall be in accordance with C407.3.3.1 or C407.3.3.2C407.3.2.1Phius Documentation. When using WUFI Passive or other Phius-approved software: 1. Prior to the issuance of a building permit, the following item(s) must be provided to the Building Official: a. A Phius 2021 (or newer) Verification Report which demonstrates project compliance with Phius 2021 (or newer) performance requirements.b. A statement from the CPHC that the verification report results accurately reflect the plans submitted.c. Evidence of project registration from Phius. OR
a. A Design Certification Letter from Phius.2. Prior to the issuance of a certificate of occupancy, the following items must be provided to the building official: a. Design Certification Letter from Phius.b. An updated Verification Report by the CPHC which reflects "as-built" conditions and test results that demonstrate project compliance with Phius (blower door and ventilation results).c. A statement from the CPHC that the envelope meets the Phius hygrothermal requirements found in Appendix B of the Phius 2021 Certification guidebookd. A statement from the Phius Certified Verifier or Rater that the project test results and other Phius verification requirements are met.e. A copy of the Phius workbook listing all testing results and as-built conditions. OR
a. A Project Certificate demonstrating final certification awarded by Phius. AND
f. A statement from the Phius Verifier or Rater of compliance with C405.13: EV ready, and Appendix CB: Solar Ready Provisions.C407.3.2.2Passive House International (PHI) Documentation.1. If using PHI Passive House software, prior to the issuance of a building permit, the following item(s) must be provided to the Building Official: a. A PHPP compliance report which demonstrates project compliance with current PHI performance requirements;b. A statement from the Certified Passive House Consultant/Designer (CPHC/D) that the PHPP results and compliance report accurately reflect the plans submitted;c. Evidence of project registration from a Certified Passive House Certifier. OR
a. A Design Certification Letter from a Certified Passive House Certifier.2. Prior to the issuance of a certificate of occupancy, the following items must be provided to the building official:a. A Design Certification Letter from a Certified Passive House Certifier.b. An updated PHPP compliance report which reflects "as-built" conditions and test results (blower door and ventilation results) that demonstrates project compliance with PHI performance requirements;c. A copy of the Passive House Verifier's or Rater's test results;d. A statement from the CPHD that the project test results meet the model performance requirements, all the mandatory limits and any other mandatory requirements. OR
a. A Final Certification Letter from a Certified Passive House Certifier AND
e. A statement from the Passive House Verifier or Rater of compliance with C405.13: EV ready, and Appendix CB: Solar Ready Provisions.Section C407.4 Add Section C407.4 as follows:
C407.4HERS Index (HERS) for multi-family buildings. This option requires compliance with Section C407.4.1, C407.4.2, C407.4.3 C407.4.1Compliance. Each dwelling unit shall have a certified HERS Index (HERS) rating less than or equal to the appropriate value indicated in Table C407.4 when compared to the HERS index reference design for each dwelling unit prior to credit for onsite renewable electric generation. Buildings shall meet or exceed ENERGY STAR Multifamily New Construction (MFNC) program requirements. The Home Energy Rating Index (HERS) shall be determined in accordance with RESNET/ICC Standard 301-2019. Software tools used for determining HERS Index shall be Approved Software Rating Tools in accordance with RESNET/ICC 301. Where calculations require input values not specified by Sections R402, R403, R404 and R405, those input values shall be taken from RESNET/ ICC 301. TABLE C407.4 MAXIMUM ENERGY RATING INDEX
Building Energy Sources | Maximum HERS Index scorea, |
New construction permits until June 30, 2024 | New construction permits after July 1, 2024 | Major alterations, additions, or Change of useb |
Mixed-fuel building | 52 | 42 | 52 |
Solar Electric Generation | 55 | 42 | 55 |
All-Electric building | 55 | 45 | 55 |
Solar Electric & All-Electric building | 58 | 45 | 58 |
a Maximum HERS rating prior to onsite renewable electric generation in accordance with Section C407.4
b Alterations, Additions or Change of use covered by Section R503.1.5 are subject to this maximum HERS rating.
C407.4.2Documentation. Documentation verifying that the methods and accuracy of compliance software tools conform to the provisions of this section shall be provided to the building official in accordance with C407.4.3.1 and C407.4.3.2: C407.4.2.1Prior to issuance of building permit. Prior to the issuance if a building permit, the following items must be provided to the Building Official: 1. Building street address, or other building site identification.2. Declare the HERS Index on title page and building plans.3. The name of the individual performing the analysis and generating the compliance report.4. The name and version of the compliance software tool.5. Documentation of all inputs entered into the software used to produce the results for the reference design and/or the rated home.6. A certificate indicating that the proposed design has a HERS Index less than or equal to the appropriate score indicated in Table C407.4 when compared to the ERI reference design. The certificate shall document the building component energy specifications that are included in the calculation, including: component level insulation R-values or U-factors; assumed duct system and building envelope air leakage testing results; and the type and rated efficiencies of proposed heating, cooling, mechanical ventilation, and service water-heating equipment to be installed. If on-site renewable energy systems will be installed, the certificate shall report the type and production size of the proposed system.7. When a site-specific report is not generated, the proposed design shall be based on the worst-case orientation and configuration of the rated home.C407.4.2.2Prior to issuance of certificate of occupancy. Prior to the issuance of a certificate of occupancy, the following items must be provided to the Building Official: 1. Building street address or other building site identification.2. Declaration of the Final HERS Index on title page and on building plans.3. The name of the individual performing the analysis and generating the report.4. The name and version of the compliance software tool.5. Documentation of all inputs entered into the software used to produce the results for the reference design and/or the rated home.6. A final confirmed certificate indicating that the confirmed rated design of the built home complies with Sections C407.4. The certificate shall report the energy features that were confirmed to be in the home, including: component-level insulation R-values or U-factors; results from any required duct system and building envelope air leakage testing; and the type and rated efficiencies of the heating, cooling, mechanical ventilation, and service water-heating equipment installed.7. Documentation that each unit meets or exceeds ENERGY STAR Multifamily New Construction (MFNC) program requirements.8. Where on-site renewable energy systems have been installed on or in the home, the certificate shall report the type and production size of the installed system.9. Compliance with C405.13, and either Appendix CB or Appendix CC as applicableC407.4.3Verification by approved agency. Verification of compliance shall be completed by a certified HERS rater.Adopted by Mass Register Issue 1485, eff. 12/23/2022.