Recommended Amendments to the 2012 International Residential Code (IRC)

Transcription

1 Issue: Insulation Requirements by Components- Basement Wall R-value and U-value 2012 IECC Section: Table N and Table N Modify the Tables as shown below: (Delete data, add new data) CLIMATE ZONE U-FACTOR b TABLE N INSULATION AND REQUIREMENTS BY COMPONENT a SKYLIGHT b U-FACTOR GLAZED SHGC b, e CEILING WOOD FRAME MASS i FLOOR BASEMENT c SLAB d & DEPTH 1 NR / / or 13+5 h 8/ /13 f 0 5/13 except and 8 CRAWL SPACE c or 13+5 h 8/ /13 10, 2ft 10/ NR 9 20 or 13+5 h 13/17 30 g 10/13 10, 2ft 15/ All footnotes shall remain NR 9 NR 9 15/ h 15/20 30g 10/13 10, ft 15/19 15/ h 19/21 38g 10/13 10, ft 15/19 Climate Zone Fenestratio n All Footnotes remain unchanged Skylight TABLE N EQUIVALENT U-FACTORS a Ceiling Frame Wall Mass Wall b Floor Basement Wall Crawl Space Wall c except and

2 Issue: Ceilings without Attic Spaces 2012 IRC Section: N Modify the Section as shown below (Delete text): N Ceilings without attic spaces. Where Section N would require insulation levels above R-30 and the design of the roof/ceiling assembly does not allow sufficient space for the required insulation, the minimum required insulation for such roof/ceiling assemblies shall be R-30. This reduction of insulation from the requirements of Section N shall be limited to 500 square feet (6 m2) or 20% of the total insulated ceiling area, which ever is less. This reduction shall not apply to the U-factor alternative approach in Section N and the total UA alternative in Section N

3 Issue: Solar Heat Gain Requirements in Southern Climates 2012 IRC Section: Table N Modify the Tables as shown below: (Delete data, add new data) CLIMATE ZONE U-FACTOR b TABLE N INSULATION AND REQUIREMENTS BY COMPONENT a SKYLIGHT b U-FACTOR 1 NR except GLAZED SHGC b, e CEILING WOOD FRAME MASS i FLOOR BASEMENT c SLAB d & DEPTH CRAWL SPACE c / / or 13+5 h 8/ /13 f 0 5/ or 13+5 h 8/ /13 10, 2ft 10/ NR 9 20 or 13+5 h 13/17 30 g 15/19 10, 2ft 15/19 7 and All Footnotes remain unchanged NR 9 NR h 15/20 30g 15/19 10, ft 15/ h 19/21 38g 15/19 10, ft 15/19

4 Issue: Wood Frame Wall Insulation 2012 IRC Section: Table N and Table N Modify the Tables as shown below: (Delete data, add new data) CLIMATE ZONE U-FACTOR b TABLE N INSULATION AND REQUIREMENTS BY COMPONENT a SKYLIGHT b U-FACTOR GLAZED SHGC b, e CEILING WOOD FRAME MASS i FLOOR BASEMENT c SLAB d & DEPTH 1 NR / / except and All footnotes shall remain NR 9 NR 9 NR 9 20 or 13+5 h or 13+5 h 13 CRAWL SPACE c 8/ /13 f 0 5/13 8/ /13 10, 2ft 10/ or 13+5 h 13/17 30g 15/19 10, 2ft 15/ or 13+5 h 15/20 30g 15/19 10, ft 15/ or h 19/21 38g 15/19 10, ft 15/19 Climate Zone Fenestratio n All Footnotes remain unchanged Skylight TABLE N EQUIVALENT U-FACTORS a Ceiling Frame Wall Mass Wall b Floor Basement Wall Crawl Space Wall c except and

5 Issue: Restoring Equipment Trade-offs 2012 IRC Section: Table N (1) Modify the Table as shown below (Delete text, add New Text) TABLE N (1) SPECIFICATIONS FOR THE STANDARD REFERENCE AND PROPOSED DESIGNS BUILDING COMPONENT Heating systems f, g, Cooling system g, i, Service Water As g, i, j, k Heating STANDARD REFERENCE DESIGN for other than electric heating without a heat pump, Where the proposed design utilizes electric heating without a heat pump the standard reference design shall be an air source heat pump meeting the requirements of Section R03 of the IECC- Commercial Provisions. Fuel type: same as proposed design Efficiencies: Electric: air-source heat pump with prevailing federal minimum efficiency Nonelectric furnaces: natural gas furnace with prevailing federal minimum efficiency Nonelectric boilers: natural gas boiler with prevailing federal minimum efficiency Capacity: sized in accordance with Section R03,6 Fuel type: Electric Efficiency: in accordance with prevailing federal minimum standards Capacity: sized in accordance with Section R03,6 proposed Fuel type: same as proposed design Efficiency: in accordance with prevailing Federal minimum standards Use: gal/day = Nbr Tank temperature: 120 F Use: same as proposed design (Remainder of Table remains unchanged) PROPOSED DESIGN Same as standard reference gal/day = Nbr

6 Issue: Duct Sealing 2012 IRC Section: N Modify the Section as shown below (Delete text): N (R03.2.2) Sealing (Mandatory). Ducts, air handlers, and filter boxes shall be sealed. Joints and seams shall comply with Section M of this code. Exceptions: 1. Air-impermeable spray foam products shall be permitted to be applied without additional joint seals. 2. Where a duct connection is made that is partially inaccessible, three screws or rivets shall be equally spaced on the exposed portion of the joint so as to prevent a hinge effect. 3. Continuously welded and locking-type longitudinal joints and seams in ducts operating at static pressures less than 2 inches of water column (500 Pa) pressure classification shall not require additional closure systems. Duct tightness shall be verified by either of the following: 1. Postconstruction test: Total leakage shall be less than or equal to cfm (113.3 L/min) per 100 square feet (9.29 m2) 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 Rough-in test: Total leakage shall be less than or equal to cfm (113.3 L/min) per 100 ft2 (9.29 m2) of conditioned floor area when tested at a pressure differential of 0.1 inches w.g. (25 Pa) across the system, including the manufacturer s 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 3 cfm (85 L/min) per 100 square feet (9.29 m2) of conditioned floor area. Exception: The total leakage test is not required for ducts and air handlers located entirely within the building thermal envelope.

7 Issue: Building Cavities 2012 IRC Section: N Modify the Section as shown below (Delete text): N (R03.2.3) Building cavities (Mandatory). Building framing cavities shall not be used as supply ducts or plenums. Building cavities used as plenums shall be durably sealed to limit infiltration. The sealing methods between dissimilar materials shall allow for differential expansion and contraction and shall be caulked, gasketed, weatherstripped or otherwise sealed with an air barrier material, suitable film or solid material.