Page 61 - Green Builder July-August 2019 Issue

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CODE ARENA Down to business. Revisions to
CREDIT: KWANGMOOZAA ISTOCK International Energy Conservation
insulation, heating and cooling
The Latest Rules, Regulations and Codes Impacting Sustainable Construction regulations were among the key
discussions at this year’s
Code (IECC) Committee Action
Hearings for Group B Codes.

Table R402.1.2 (IRC N1102.1.2) of prescriptive options and show the full range of equivalent
Insulation and Fenestration insulation options (e.g., cavity only, hybrid cavity + continuous,
and continuous only).
Requirements by Component 4. Address concerns that the prescriptive table favors certain options
over others by excluding viable options in some climate zones.
Climate Zone Wood-Frame Wall R-Value 5. Provides more exibility to coordinate insulation options with
vapor retarder provisions in the building code, which vary by
1 13 or 0+10 h climate as well as insulation strategy. The proposed exibility
gives users more choice between insulation options that provide
2 13 or 0+10 h equivalent assembly U-factor (as a minimum requirement of

3 20 or 13+5 or 0+15 h the energy code), yet have di­erent capabilities and functions
h
with respect to comfort, air tightness, moisture control, thermal
4 except Marine 20 or 13+5 or 0+15 h
h
bridging mitigation, and other factors that are important to an
5 and Marine 4 20 or 13+5 or 0+15 h overall code-compliant wall assembly.
h
6 30 or 20+5 or 13+10 or 0+20 h The reason statement for this proposal also contains a number of
h
h
calculation spreadsheets for the di­erent insulation levels/respective
7 and 8 30 or 20+5 or 13+10 or 0+20 h climate zones.
h
h
COMMITTEE ACTION: Approved as Submitted: “This provides
h. The first value is cavity insulation, the second value is continuous
insulation. For example, “13+5” means R-13 cavity insulation plus additional options for compliance. It simpli†es code language and
R-5 continuous insulation. encourages users to look at all the associated issues (Vote: 8-3).”
COMMENTARY: If for no other reason than the 8-3 committee vote,
insulation, because in the 2018 IECC, an equivalent cavity this will probably have comments †led. However, it seems to have
insulation-only option is missing in Climate Zones 6-8. positive momentum heading into October’s hearing.
2. Provide for equivalent continuous insulation-only options, which
are also are missing. RE223-19 (APPENDIX RB)
3. Provide the table with a simple-yet-complete set of insulation PROPOSAL: This proposal would create a new appendix for zero-
options for location of insulation on wood-frame wall assemblies energy residential buildings. This section, if adopted, would require
for each climate zone, which would improve the usefulness the rated design to have a score less than or equal to the values
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