Recommended Amendments to the 2015 International Energy Conservation Code (IECC)

Transcription

1 BACKGOUNDE OCTOBE 2014 ecommended Amendments to the 2015 International Energy Conservation Code (IECC) The 2015 International Code Council (ICC) model buildg codes were completed June 2014 and are now available for adoption at the state and local level. For the first time, the National Multifamily Housg Council (NMHC, National Apartment Association (NAA), Buildg Owners and Managers Association (BOMA) and National Association of Home Builders (NAHB) generally recommend the ICC codes be adopted without amendments, with two exceptions. The first is the International Green Construction Code (IgCC) which has not been published. The second is the International Energy Conservation Code (IECC), which we suggest be amended some key areas. This document provides the suggested amendments developers and builders should make when the IECC is adopted at the local level. National Multifamily Housg Council 1850 M Street, NW, Suite 540 Washgton, DC Phone This document may not be reproduced or retransmitted electronically, whole or part, without permission from the National Multifamily Housg Council.

2 02 Overview This Backgrounder This document outles the key changes between the 2012 and 2015 International Energy Conservation Code (IECC). It also documents the changes that NMHC/NAA, NAHB and BOMA recommend be made when the IECC is adopted by local jurisdictions. We identify five specific amendments. Specifically, we recommend that the value and U-factor tables from the Commercial and esidential portions of the 2015 IECC be replaced by the 2009 IECC versions of those tables. The value and U-factor tables the 2012 IECC were based on an analysis completed when ASHAE 90.1 was updated that was later shown to not be cost effective. This resulted higher values and lower U-factors beg corporated to the 2012 IECC. The 2015 IECC uses the same flawed tables as the 2012 IECC that, based on the revised analysis by ASHAE, are not cost effective. Therefore, when local jurisdictions are adoptg the 2015 IECC, developers and builders should advocate that the 2015 tables be replaced with the earlier 2009 versions. The 2009 IECC tables are considered cost effective based on calculations supportg the values when they were corporated to the code. We also propose a change to allow apartments construction under the residential portion (three stories or less height) to use the air-barrier requirements contaed the commercial portion of the code. The 2015 IECC requires apartments conduct the blower-door, air-barrier testg that is standard one- and two-family dwellgs. No such standard procedure exists for multifamily construction. Our proposed change does not elimate the requirement for an air-barrier, it simply cross references to the commercial provisions which require the air-barrier, but set the testg requirement as an option. ECOMMENDED AMENDMENTS TO THE 2015 IECC

3 IECC Proposed Changes Section(s) & Issue(s) Type of Change Cost Implication Comment IECC Tables C , C , and values and U- values IECC Thermal Envelope Air Barrier Testg Delete these Tables the 2015 IECC and replace with the correspondg Tables from the 2009 IECC which are considered to be cost effective. (See Proposed Local Amendments #1 - #4 on pages 2-5.) Section should be revised to allow air barrier compliance with Section C402.5 from the commercial section which requires an air barrier but allows pressure testg as an option. There is no test procedure for blower door testg of 2 occupancies (See Proposed Local Amendment #5 on page 5 addg an Exception to Section ) Savgs if locally amended as shown. Savgs if locally amended as shown. The value and correspondg U-value tables for the commercial and residential requirements have not been changed and are the same as those the 2012 versions of the IECC which are not cost effective IECC Section requires that the air barrier be pressure tested accordance with a test method for one- and two-family dwellgs that is not appropriate for 2 occupancies. E COMMENDED AMENDMENTS TO THE 2015 IECC

4 04 Proposed Local Amendment #1: eplace 2015 IECC value Table C with this 2009 IECC value Table 502.2(1) and renumber it Table C Climate Zone Table 502.2(1) BUILDING ENVELOPE EQUIEMENTS--OPAQUE ASSEMBLIES 4 EXCEPT MAINE 5 AND MAINE oofs Insulation entirely above deck 15CI 20CI 20CI 20CI 20CI 20CI 20CI 20CI 20CI 20CI 20CI 20CI 25CI 25CI 25CI 25CI Metal buildgs (with 6 thermal blocks a,b ) Attic and Mass N 5.7ci c 5.7ci c 7.6ci 7.6ci 9.5ci 9.5ci Walls, Above Grade 11.4ci Metal buildg b Metal framed Wood framed and ci 3.8ci 7.5ci 7.5ci ci 3.8ci Walls, Below Grade 11.4ci 5.6ci 7.5ci 13.3ci 5.6ci 7.5ci 13.3ci 5.6ci 7.5ci 15.2ci 5.6ci 7.5ci 15.2ci ci 7.5ci 15.2ci 25ci 25ci d Below grade wall N N N N N N N 7.5ci 7.5ci 7.5ci 7.5ci 7.5ci 7.5ci 10ci 7.5ci 12.5ci Mass Joist/Framg (steel/wood) N N 6.3ci 8.3ci 6.3ci 8.3ci 10ci Floors 10.4ci 3.8ci 10ci 3.8ci 12.5ci 7.5ci 12.5ci 7.5ci 14.6ci 7.5ci ci 15.6ci 7.5ci ci 7.5ci 15.6ci ci 18.8ci 15.6ci 15ci 16.7ci 15ci 16.7ci N N e e 30 e 30 E COMMENDED AMENDMENTS TO THE 2015 IECC

5 05 Table 502.2(1) (contued) BUILDING ENVELOPE EQUIEMENTS--OPAQUE ASSEMBLIES Climate Zone EXCEPT MAINE 5 EXCEPT MAINE Unheated slabs Heated slabs Slab-on-Grade Floors 10 N N N N N N N N 7.5 for for for for a. When usg value compliance method, a thermal spacer block is required; wise, use the U-factor compliance method. b. Assembly descriptions can be found ANSI/ASHAE/IESA Appendix A. c. 5.7 is allowed to be substituted with concrete block walls complyg with ASTM C90, ungrouted or partially grouted at 32 ches or less on center vertically and 48 ches or less on center horizontally, with ungrouted cores filled with material havg a maximum thermal conductivity of 0.44 Btu-/hf2F. d. When heated slabs are placed grade, -grade walls must meet the exterior sulation requirements for perimeter sulation accordg to the heated-slab-on-grade construction. e. Steel floor joist systems shall be Opaque Doors Swgg U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.70 U-0.50 U-0.50 U-0.50 U-0.50 U-0.50 oll-up or slidg U-1.45 U-1.45 U-1.45 U-1.45 U-1.45 U-1.45 U-0.50 U-0.50 U-0.50 U-0.50 U-0.50 U-0.50 U-0.50 U-0.50 U-0.50 U for for for for for for for for 48 E COMMENDED AMENDMENTS TO THE 2015 IECC

6 06 Proposed Local Amendment #2 eplace 2015 IECC U-value Table C with this 2009 IECC U-value Table and renumber it Table C Table BUILDING ENVELOPE EQUIEMENTS OPAQUE ELEMENT, MAXIMUM FACTOS Climate Zone Insulation entirely above deck Metal buildgs Attic and Mass Metal buildg Metal framed Wood framed and EXCEPT MA INE oofs Walls, Above Grade AND MAINE E COMMENDED AMENDMENTS TO THE 2015 IECC

7 . 07 Below grade wall a Mass Table (Contued) BUILDING ENVELOPE EQUIEMENTS OPAQUE ELEMENT, MAXIMUM FACTOS 4 EXCEPT MA 5 AND MAINE INE Walls, Below Grade Floors Joist/Framg Slab on Grade Floors F F F F F F F F F F F F F F Unheated slabs F F F F F F F F F F F F F F F F Heated slabs F F a. When heated slabs are placed grade, grade walls must meet the F factor requirements for perimeter sulation accordg to the heated slab on grade construction E COMMENDED AMENDMENTS TO THE 2015 IECC

8 08 Proposed Local Amendment #3: eplace 2015 IECC value Table with this 2009 IECC value Table the residential section of the 2015 IECC and renumber it Table CLIMATE ZONE FENESTA- TION U-FACTO b TABLE INSULATION AND FENESTATION EQUIEMENTS BY COMPONENT a SKY- LIGHT b U-FACTO GLAZED FENES- TATION SHGC b, e CEIL- ING VALUE WOOD- FAME WALL VALUE MASS WALL VALUE i FLOO VALUE BASE- MENT c WALL VALUE SLAB d VALUE & DEPTH / j / CAWL SPACE c WALL VALUE j / /13 f 0 5/13 4 except Mare N / /13 10, 2ft 10/13 5 and or N 38 Mare h 13 / g 10/13 10, 2ft 10/ or N h 15 / g 15/19 10, 4ft 10/13 7 and N / g 15/19 10, 4ft 10/13 a. values are mimums. U-factor and SHGC are maximums. 19 batts compressed to a nomal 2x6 framg cavity such that the value is reduced by 1 or more shall be marked with the compressed batt value addition to the full thickness value. b. The fenestration U-factor column excludes skylights. The SHGC column applies to all glazed fenestration. c. 15/19 means 15 contuous sulated sheathg on the terior or exterior of the home or 19 cavity sulation at the terior of the basement wall. 15/19 shall be permitted to be met with 13 cavity sulation on the terior of the basement wall plus 13 cavity sulation at the terior of the basement wall. d. 5 shall be added to the required slab edge values for heated slab. Insulation depth shall be the depth of the footg or 2 feet, whichever is less Zones 1 through 3 for heated slabs. e. There are no SHGC requirements Mare Zone. f. Basement wall sulation is not required warm-humid locations. g. Or sulation sufficient to fill the framg cavity, 19. E COMMENDED AMENDMENTS TO THE 2015 IECC

9 09 h means 13 cavity sulation plus 5 sulation sheathg. If structural sheathg covers 25 percent or less of the exterior, structural sheathg shall be supplemented with sulated sheathg of at least 2. i. The second value applies when more than half the sulation is on the terior of the mass wall. j. For impact rated fenestration complyg with Section of the International esidential Code or Section of the International Buildg Code, the maximum U-factor shall be 0.75 Zone 2 and 0.65 Zone 3. Proposed Local Amendment #4: eplace 2015 IECC U-value Table with this 2009 IECC U-value Table the residential section of the 2015 IECC and renumber it Table Climate Zone Fenestration U-Factor Skylight U- Factor TABLE EQUIVALENT U-FACTOS a Ceilg U- Factor Frame Wall U-Factor Mass Wall Floor U- U-Factor b Factor Basement Wall U-Factor Crawl Space Wall U-Factor except Mare and Mare and a. Nonfenestration U-factor shall be obtaed from measurement, calculation or an approved source. b. When more than half the sulation is on the terior, the mass wall U-factors shall be a maximum of 0.17 Zone 1, 0.14 Zone 2, 0.12 Zone 3, 9.10 Zone 4 except Mare, and the same as the frame wall U-factor Mare 4 and Zones 5 through 8. Proposed Local Amendment #5: Add the followg Exception to , Testg, the residential section of the 2015 IEEC as follows: Exception: 2 Occupancies that comply with Section C E COMMENDED AMENDMENTS TO THE 2015 IECC