510-RICR-00-00-8. RISBC-8 Rhode Island Energy Conservation Code (version Amendment, 08/01/2019 to 01/04/2022)

8.1 Authority The Building Code Standards Committee, in accordance with the rule making authority of R.I. Gen. Laws §§ 23-27.3-109.1(a) through (c) inclusive, has formally adopted and promulgated as the Rhode Island State Building Code, the provisions of the International Energy Conservation Code, 2015 edition, as published by the International Code Council, Inc. (I.C.C.), together with amendments thereto hereinafter set forth to the articles and sections of this code. 8.2 Incorporated Materials A. The provisions of R.I. Gen. Laws Chapter 23-27.3 establishing administration and enforcement are hereby incorporated by reference. § 8.3 of this Part (Chapter 1) immediately follows and is supplemental to the General Laws. Editorial Note: Code users please note: 1. When purchasing or using the International Energy Conservation Code 2015 code, please take note of the particular printing edition. Errata to that printing edition is available on-line directly at no charge at www.iccsafe.org/cs/codes/pages/errata.aspx or call the office of the State Building Code Commissioner at 401-889-5550 for further information. 2. Printed copies of the administrative and enforcement provisions of R.I. Gen. Laws Chapter 23-27.3 are available at the Office of the State Building Code Commission or on-line at http://www.rilin.state.ri.us/Statutes/TITLE23/23-27.3/INDEX.HTM . 3. The International Energy Conservation Code, 2015 Edition, is protected by the copyright that has been issued to the ICC. As a result, the State Building Code is not available in complete form to the public in an electronic format. The State Energy Conservation Code 2019 edition that is referred to within is contained in a printed volume and is also in an electronic format that have been published by the ICC under an exclusive license. B. Format: These code changes follow numbering sequence and topics of the INTERNATIONAL ENERGY CONSERVATION CODE 2015 (first printing). All Provisions of IECC 2015 are retained unless indicated as deleted or revised. Published errata are available from the ICC website dependent on the printing issue number and date. 8.3 Chapter 1[CE] ADMINISTRATION Revise IECC section C101.1, Title, to read as follows: C101.1 Title: This part shall be known as the State Energy Conservation Code SBC-8-2019 hereafter referred to as "this code”. Add the following new section C101.1.1 referenced codes. C101.1.1 Referenced Codes. The other codes listed in Sections C101.4.1 through C101.4.6 and referenced elsewhere in this code shall be considered part of the requirements of this code to the prescribed extent of each such reference. (1) Electrical. The provisions of Rhode Island State Electrical Code SBC-5-2019 ( Part 5 of this Subchapter ) shall apply wherever referenced in this code as the ICC Electrical Code, and shall apply to the installation of electrical systems, including alterations, repairs, replacement, equipment, appliances, fixtures, fittings, and appurtenances thereto. (2) Gas. The provisions of the Rhode Island State Fuel Gas Code SBC-19-2019 ( Part 19 of this Subchapter ) shall apply wherever referenced in this code as the International Fuel Gas Code, and shall apply to the installation of gas piping from the point of delivery, gas appliances and related accessories as covered in this code. These requirements apply to gas piping systems extending from the point of delivery to the inlet connections of appliances and the installation and operation of residential and commercial gas appliances and related accessories. (3) Mechanical. The provisions of the Rhode Island State Mechanical Code SBC-4-2019 ( Part 4 of this Subchapter ) shall apply wherever referenced in this code as the International Mechanical Code and shall apply to the installation, alterations, repairs and replacement of the mechanical systems, including equipment, appliances, fixtures, fittings and/or appurtenances, including ventilating, heating, cooling, air-conditioning and refrigeration systems, incinerators and other energy-related systems. (4) Plumbing. The provisions of Rhode Island State Plumbing Code SBC-3-2019 ( Part 3 of this Subchapter ) shall apply wherever referenced in this code as the International Plumbing Code, and shall apply to the installation, alteration, repair and replacement of plumbing systems, including equipment, appliances, fixtures, fittings and appurtenances, and where connected to a water or sewage system and all aspects of a medical gas system. (5) Property Maintenance. The provisions of the Rhode Island State Property Maintenance Code SBC-6-2019 ( Part 6 of this Subchapter ) Provides requirements for continued use and maintenance buildings and property, and of related plumbing, mechanical, electrical and fire protection systems in existing residential nonresidential structures. (6) Fire Prevention Code. Wherever and whenever provisions of the International Fire Code 2019 editions are referenced, the appropriate Rhode Island Fire Safety Code ( 450-RICR-00-00-1 through 10 ) requirements shall apply. (7) Building Code. The provisions of the Rhode Island State Building Code SBC-1-2019 ( Part 1 of this Subchapter ) shall apply wherever referenced in this code as the International Building Code, and shall apply to all matters governing the design and construction of buildings. (8) Existing Building Code. The provisions of the State Building Codes SBC-1-2019 ( Part 1 of this Subchapter ) in conjunction with the State Rehabilitation Code SRC-1 ( Part 20 of this Subchapter ) and the Rhode Island Fire Safety Code ( 450-RICR-00-00-1 through 10 ) shall apply wherever referenced in this code as the International Existing Building Code. (9) Any and all such references to the various International Code Council family of code shall be substituted for the appropriate state code as indicated above. 8.4 Chapter 3[CE] Climate Zones Delete section C301 in its entirety and substitute the following. Section C301 Climate Zones C301.1 General Rhode Island shall be considered as climate zone 5 with the following design conditions. Table C301.1 Delete and substitute the following: Table 301.1 Exterior Design Conditions. Value Value Climate zone Providence County All others Winter, design dry-bulb (degree F) 0 5 Summer, design dry-bulb 87 89 Summer design wet-bulb 71 73 Degree days heating 6831 5950 Degree days cooling 371 811 Delete Figure C301.1 and Substitute the following: Figure C301.1 Delete without substitution section C301.2 and C301.3 Delete without substitution Table C301.3(1) Delete table C301.3(2) and substitute the following TABLE C301.3(2) RHODE ISLAND CLIMATE ZONE DEFINITION Zone Number THERMAL CRITERIA IP UNITS SI UNITS 5 5400, HDD650F≤ 7200 3000 < HDD180C ≤ 4000 Delete C302.1 and substitute the following: C302.1 Interior design conditions. The interior design temperature used for energy load calculations shall be a maximum of 72°F (22°C) for heating and minimum of 75°F (24°C) for cooling. 8.5 Chapter 4[CE] Delete C401.2 Application. And add the following: C401.2 Application. Commercial buildings projects shall comply with the requirements in sections C403 (Building Envelope Requirements), C403 (Building Mechanical Systems), C404 (Service Water Heating), C405 (Electrical Power and Lighting Systems) and C406 (Tenant Spaces, including C406.1.1) in its entirety. As an alternative, commercial buildings projects shall comply with the energy cost budget method in ASHRAE/IESNA 90.1. Delete without substitute C401.2.1 Application to existing building. Delete Table C402.1.4 and substitute the following TABLE C402.1.4 OPAQUE THERMAL ENVELOPE ASSEMBLY REQUIREMENTS CLIMATE ZONE 5 All other Group R Roofs Insulation entirely above deck U-0.039 U-0.039 Metal buildings U-0.035 U-0.035 Attic and other U-0.027 U-00021 Walls, Above Grade Mass U-0.078 U-0.78 Metal building U-0.052 U-0.052 Metal framed U-0.064 U-0.064 Wood framed and other U-0.064 U-0.064 Walls, Below Grade Below-grade walls C-0.119 C-0.119 Floors Mass U-0.074 U-0.064 Joist/Framing U-0.033 U-0.033 Slab-on Grade Floors Unheated slabs F-0.54 F-0.54 Heated slabs F-0.58 F0.58 a. Use opaque assembly U-factors, C-factors, and F-factors from ANSI/ASHRAE/IESNA 90.1 Appendix A shall be permitted, provided the construction complies with the applicable construction details from ANSI/ASHRAE/IESNA 90.1 Appendix A. b. When heated slabs are placed below-grade, below grade walls must meet the F-factor requirements for heated slabs. Delete Table C402.1.3 and substitute the following TABLE C402.1.3 OPAQUE THERMAL ENVELOPE REQUIREMENTS CLIMATE ZONE 5 ALL OTHERS GROUP R Roofs Insulation entirely Above deck R-25ci R-25ci Metal buildings (with R-5 thermal blocks a,b ) (Assembly descriptions can be found in ANSI/ASHRAE/IESNA Appendix A.) (When using R-value compliance method, a thermal spacer block shall be provided, otherwise use the U-factor compliance method in Table C402.1.2.) R-19 + R-11LS R-19 R-11LS Attic and other R-38 R-49 Walls, Above Grade Mass R-11.4ci R-13.3 ci Metal building c (When using R-value compliance method, a thermal spacer block shall be provided, otherwise use the U-factor compliance method in Table C402.1.2.) R-13 + R-13ci R-13 + R-13ci Metal framed R-13 + R-7.5ci R-13 + R-7.5ci Wood framed and other R-13 + R-3.8ci or R-20 R-13 + R-7.5ci or R-20 + R-3.8ci Walls, Below Grade Below grade wall c (R-5.7ci is allowed to be substituted with concrete block walls complying with ASTM C 90, un-grouted or partially grouted at 32 inches or less on center vertically and 48 inches or less on center horizontally, with un-grouted cores filled with materials having a maximum thermal conductivity of 0.44 Btu-in/h-f2 F.) R-7.5ci R-7.5ci Floors Mass R-10ci R-12.5ci Joist/framing Steel/(wood) R-30 R-30 Slab-on-Grade Floors Unheated Slabs R-10 for 24” below R-10 for 24” below Heated slabs R-15 for 36” below R-15 for 36” below Opaque doors Swinging U –0.37 U –0.37 Roll-up or sliding R -4.75 R -4.75 For SI: 1 inch = 25.4mm. Ci = Continuous insulation. NR = No requirement. a. Assembly descriptions can be found in ANSI/ASHRAE/IESNA Appendix A. b. When using R-value compliance method, a thermal spacer block shall be provided, otherwise use the U-factor compliance method in Table C402.1.2. c. R-5.7ci is allowed to be substituted with concrete block walls complying with ASTM C 90, ungrouted or partially grouted at 32 inches or less on center vertically and 48 inches or less on center horizontally, with ungrouted cores filled with materials having a maximum thermal conductivity of 0.44 Btu-in/h-f2 F. d. Where heated slabs are below grade, below-grade walls shall comply with the exterior insulation requirements for heated slabs. e. Steel floor joist systems shall be insulated to R-38. Delete Table C402.4 and substitute the following TABLE C402.4 BUILDING ENVELOPE REQUIREMENTS: FENESTRATION CLIMATE ZONE 5 Vertical fenestration U-factor Fixed fenestration 0.38 Operable fenestration 0.45 Entrance door 0.77 SHGC SHGC 0.40 Skylights U-factor 0.50 SHGC 0.40 Add Exception: #8 C402.5.7: Exception: #8 Where a compliant main entrance is already required such as patio doors intended for seasonal use. C403.2.1 Delete and Substitute C403.2.1 Calculation of heating and cooling loads. Design loads shall be determined in accordance with the procedures described in the ANSI/ASHRAE/ACCA Standard 183. The design loads shall account for the building envelope, lighting, ventilation and occupancy loads based on the projected design. Heating and cooling loads shall be adjusted to account for load reductions that are achieved when energy recovery systems are utilized in the HVAC system. Alternatively, design loads shall be determined by an approved equivalent computation procedure, using the design parameters specified in Chapter 3. C403.2.4.3 Delete and substitute the following exceptions. 1. Gravity exhaust dampers shall be permitted in buildings less than three stories in height. 2. Gravity dampers shall be permitted for exhaust airflows of 300 CFM (.14 m 3 /s) when serving a single space. C403.2.4.5 Delete and substitute C403.2.4.5 Snow melt system controls. Snow and ice-melting system are allowed only when there is no increase in supplied energy consumption above a base code compliant level. As certified by Registered Design Professional. Snow- and ice- melting systems, supplied through energy service to the building, shall include automatic controls capable of shutting off the system when the pavement temperature is above 50°F (10°C) and no precipitation is falling and an automatic or manual control that will allow shutoff when the outdoor temperature is above 40°F (4°C) so that the potential for snow or ice accumulation is negligible. C403.2.6.1 Demand controlled ventilation. Demand control ventilation (DCV) shall be provided for spaces larger than 500 square feet (46.5 m2) and with an average occupant load of 25 or more people per 1,000 square feet (93 m2) of floor area and served by systems with one or more of the following: TABLE C403.2.7 ENERGY RECOVERY REQUIREMENT CLIMATE ZONE PERCENT (%) OUTDOOR AIR AT FULL DESIGN AIRFLOW RATE >30% AND <40% >40% AND <50% >50% AND <60% >60% AND <70% >70% AND <80% > 80% DESIGN SUPPLY FAN AIRFLOW RATE (cfm) 5 > 5500 >4500 > 3500 > 2000 > 1000 > 0 C403.2.9 Delete and substitute C403.2.9 Duct and plenum insulation and sealing. All supply and return air ducts and plenums shall be insulated with a minimum of R-8 insulation when located in unconditioned spaces and a minimum of R-12 insulation when located outside the building. When located within a building envelope assembly, the duct or plenum shall be separated from the building exterior or unconditioned or exempt spaces by a minimum of R-8 insulation. Exceptions: 1. When located within equipment. 2. When the design temperature difference between the interior and exterior of the duct or plenum does not exceed 15°F (8°C). All ducts, air handlers and filter boxes shall be sealed. Joints and seams shall comply with section 603.9 of the International Mechanical Code. Delete Table C403.3.3.3 and replace with the following Table C403.3.3.3 High-Limit Shutoff Control Setting for Air Economizers b Device Type Climate Zone Required High Limit (Economizer Off When): Equation Description Fixed dry bulb T OA >70°F Outdoor air temperature exceeds 70°F 5A, 6A Differential dry bulb 1B, 2B, 3B, 3C, 4B, 4C, 5A, 5B, 5C, 6A, 6B, 7, 8 T OA > T RA Outdoor air temperature exceeds return air temperature Fixed enthalpy with fixed dry-bulb temperatures All h OA >28Btu/lb a or T OA >75°F Outdoor air temperature exceeds 28 Btu/lb of dry air a or Outdoor air temperature exceeds 75°F Differential enthalpy with fixed dry-bulb temperature All h OA > h RA or T OA >75°F Outdoor air temperature exceeds return air enthalpy or Outdoor air temperature exceeds 75°F For SI: 1 foot = 305mm, °C = (°F – 32)/1.8, 1 Btu/lb = 2.33 kJ/kg. a. At altitudes substantially different than sea level, the fixed enthalpy limit shall be set to the enthalpy value at 75°F and 50-percent relative humidity. As an example, at approximately 6,000 feet elevation, the fixed enthalpy limit is approximately 30.7 Btu/lb. b. Devices with selectable setpoints shall be capable of being set to within 2°F and 2 Btu/lb of the setpoint listed. Deleted without substitute Section C407 8.6 Chapter 5[CE] Reference Standards Delete without substitute ASHRAE – 2012 ASHRAE HVAC Systems and Equipment Hand Book –2012. 8.7 Chapter 1[RE] 8.7.1 ADMINISTRATION Revise IECC section R101.1, Title, to read as follows: R101.1 Title: These regulations shall be known as the State Energy Conservation Code Regulation SBC-8-2019 hereafter referred to as "this code”. Add the following new section R101.1.1 referenced codes. R101.1.1 Referenced Codes. The other codes listed in Sections R101.4.1 through R101.4.7 and referenced elsewhere in this code shall be considered part of the requirements of this code to the prescribed extent of each such reference. (1) Electrical. The provisions of Rhode Island State Electrical Code SBC-5-2019 ( Part 5 of this Subchapter ) shall apply wherever referenced in this code as the ICC Electrical Code, and shall apply to the installation of electrical systems, including alterations, repairs, replacement, equipment, appliances, fixtures, fittings, and appurtenances thereto. (2) Gas. The provisions of the Rhode Island State Fuel Gas Code SBC-19-2019 ( Part 19 of this Subchapter ) shall apply wherever referenced in this code as the International Fuel Gas Code, and shall apply to the installation of gas piping from the point of delivery, gas appliances and related accessories as covered in this code. These requirements apply to gas piping systems extending from the point of delivery to the inlet connections of appliances and the installation and operation of residential and commercial gas appliances and related accessories. (3) Mechanical. The provisions of the Rhode Island State Mechanical Code SBC-4-2019 ( Part 4 of this Subchapter ) shall apply wherever referenced in this code as the International Mechanical Code and shall apply to the installation, alterations, repairs and replacement of the mechanical systems, including equipment, appliances, fixtures, fittings and/or appurtenances, including ventilating, heating, cooling, air-conditioning and refrigeration systems, incinerators and other energy-related systems. (4) Plumbing. The provisions of Rhode Island State Plumbing Code SBC-3-2019 ( Part 3 of this Subchapter ) shall apply wherever referenced in this code as the International Plumbing Code, and shall apply to the installation, alteration, repair and replacement of plumbing systems, including equipment, appliances, fixtures, fittings and appurtenances, and where connected to a water or sewage system and all aspects of a medical gas system. (5) Property Maintenance. The provisions of the Rhode Island State Property Maintenance Code SBC-6-2019 ( Part 6 of this Subchapter ) Provides requirements for continued use and maintenance buildings and property, and of related plumbing, mechanical, electrical and fire protection systems in existing residential nonresidential structures. (6) Fire Prevention Code. Wherever and whenever provisions of the International Fire Code 2019 editions are referenced, the appropriate Rhode Island Fire Safety Code ( 450-RICR-00-00-1 through 10 ) requirements shall apply. (7) Building Code. The provisions of the Rhode Island State Building Code SBC-1-2019 ( Part 1 of this Subchapter ) shall apply wherever referenced in this code as the International Building Code, and shall apply to all matters governing the design and construction of buildings. (8) Existing Building Code. The provisions of the State Building Codes SBC-1-2019 ( Part 1 of this Subchapter ) in conjunction with the State Rehabilitation Code SRC-1 ( Part 20 of this Subchapter ) and the Rhode Island Fire Safety Code ( 450-RICR-00-00-1 through 10 ) shall apply wherever referenced in this code as the International Existing Building Code. (9) Any and all such references to the various International Code Council family of code shall be substituted for the appropriate state code as indicated above. 8.8 Chapter 3[RE] Climate Zones Delete section R301 in its entirety and substitute the following. Section C301 Climate Zones R301.1 General Rhode Island shall be considered as climate zone 5 with the following design conditions. Table R301.1 Delete and substitute the following: Table R301.1 Exterior Design Conditions. Value Value Climate zone Providence County All others Winter, design dry-bulb (degree F) 0 5 Summer, design dry-bulb 87 89 Summer design wet-bulb 71 73 Degree days heating 6831 5950 Degree days cooling 371 811 Delete without substitute section R301.2 and R301.3 Delete Table R301.3(1) without substitute Delete Table R301.3(2) without substitute Delete Figure R301.1 and Substitute the following: Figure R301.1 8.9 Chapter 4 [RE] R401.2 Delete R401.2 and substitute the following: R401.2 Compliance Methods Compliance shall be demonstrated by either: 1. Meeting the requirements of the Rhode Island Energy Conservation Code SBC-8-2019 (this Part). 2. Meeting the requirements of this chapter using the criteria for climate zone 5 from Figure N 1102A or table 1102.1.2. 3. Compliance submission of Res-Check for Zone 5 & R.I. Energy Conservation Code Residential Provisions. Add the following to R401.3 Certificate: Figure R401.3 A certificate similar to this shall be attached to or near the electrical panel board ENERGY CERTIFICATE Street Address City / Town Predominant Values R-Value Ceiling / Roof R- Value Walls R- Value Ducts (outside conditioned space) U Factor Fenestration SHGC Fenestration Gas Fired Un-Vented Room Heater Baseboard Electric Heater Electric Furnace U Factor Skylight / SHGC AFUE Value Boiler / Furnace Efficiency and type of heating equipment Efficiency and type of cooling equipment Efficiency and type of service water heater Contractor or Design Professional Address Registration Signature Delete and substitute Table R402.1.2 TABLE R402.1.2 INSULATION AND FENESTRATION REQUIREMENTS BY COMPONENT a CLIMATE ZONE FENESTRATION U-FACTOR b SKYLIGHT b U-FACTOR GLAZED FERNESTRATION SHGC b CEILING R-VALUE i WOOD FRAME WALL R-VALUE g MASS WALL R-VALUE FLOOR R-VALUE BASEMENT C WALL R-VALUE SLAB d R-VALUE & DEPTH CRAWL SPACE c WALL R-VALUE 5 0.35 0.60 NR 38 20 or 13+5 f 13/17 30 e 10/13 R-10 for 2 ft. 10/13 For SI: 1 foot = 304.8 mm. a. R-values are minimums U-factors and SHGC are maximums. R-19 batts compressed into a nominal 2 × 6 framing cavity such that the R- value is reduced by R-1 or more shall be marked with the compressed batt R-value in addition to the full thickness R-value. b. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. c. “10/13” means R-10 continuous insulated sheathing on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall. d. R-5 shall be added to the entire slab and the required slab edge R-values for heated slabs e. Or insulation sufficient to fill the framing cavity, R-19 minimum. f. “13+5” means R-13 cavity insulation plus R-5 insulated sheathing. If structural sheathing covers 25 percent or less of the exterior, insulating sheathing is not required where structural sheathing is used. If structural sheathing covers more than 25 percent of exterior, structural sheathing shall be supplemented with insulated sheathing of at least R-2. g. The second R-value applies when more than half the insulation is on the interior of the mass wall. TABLE R402.1.4 EQUIVALENT U-FACTORS, a CLIMATE ZONE FENESTRATION U-FACTOR SKYLIGHT U-FACTOR CEILING U-FACTOR FRAME WALL U-FACTOR MASS WALL U-FACTORb FLOOR U-FACTOR BASEMENT WALL U-FACTOR CRAWL SPACE WALL U-FACTOR 5 0.32 0.55 0.026 0.057 0.082 0.033 0.050 0.055 R402.1.5 Total UA alternative Delete and substitute R402.1.5 Total UA alternative. If the total building thermal envelope UA (sum of U-factor times assembly area) is less than or equal to the total UA resulting from using the U-factors in Table R402.1.3 (multiplied by the same assembly area as in the proposed building), the building shall be considered in compliance with Table R402.1.1. The UA calculation shall include the thermal bridge effects of framing materials. The UA calculation shall include the thermal bridging effects of framing materials. The SHGC requirements shall be met in addition to UA compliance R402.4.1.2 Delete and substitute the following R402.4.1.2 Testing. The building or dwelling unit shall be tested, and the air leakage rate shall be verified. Testing shall be conducted with a blower door at a pressure of 0.2 inches (50 Pascals). Maximum air change rates per hour: in 2019 = 8; in 2020 = 7; in 2021 = 6; and in 2022 and subsequent years = 5. Testing shall be conducted by an approved third party, where required by the building official. A written report of the results of the test shall be signed by the party conducting the test and provided to the building official. Testing shall be performed at any time after creation of all penetrations of the building thermal envelope. During testing: 1. Exterior windows and doors, fireplace and stove doors shall be closed, but not sealed, beyond the intended weather-stripping or other infiltration control measures; 2. Dampers including exhaust, intake, makeup air, backdraft and flue dampers shall be closed, but not sealed beyond intended infiltration control measures; 3. Interior doors, if installed at the time of the test, shall be open. 4. Exterior doors for continuous ventilation systems and heat recovery ventilators shall be closed and sealed; 5. Heating and cooling systems, if installed at the time of the test, shall be turned off; and 6. Supply and return registers, if installed at the time of the test, shall be fully open. R403.3.3 Sealing (Mandatory) Delete From sections 403.3.3 1) Post construction test 2) Rough-in test Substitute the following: 1. Post construction test: Total leakage shall be less than or equal to 8 cfm (113.3 L/min) per 100 square feet (9.29 m 2 ) of conditioned floor area when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the entire system, including the manufacturer’s air handler enclosure. All register boots shall be taped or otherwise sealed during the test. 2. Rough-in test: Total leakage shall be less than or equal to 6 cfm (113.3 L/min) per 100 square feet (9.29 m 2 ) of conditioned floor area when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the system, including the manufacturer air handler enclosure. All registers shall be taped or otherwise sealed during the test. If the air handler is not installed at the time of the test, total leakage shall be less than or equal to 4 cfm (85 L/min) per 100 square feet (9.29 m 2 ) of conditioned floor area. Delete R403.3.5 and substitute the following: R403.3.5 Building cavities (Mandatory). Interior building framing cavities shall be permitted to be used as return ducts or plenums. (BP) 8.10 Chapter 5[RE] Reference Standards Delete without substitute ASHRAE – 2013 ASHRAE Handbook of Fundamentals.