© Copyright CalCERTS, Inc. 2019
Code Cycle: 2016 & 2019 Standards
Reference: RCM 126.96.36.199
Reference: CalCERTS New Construction Training Manual Chapter 6, Section 3
Diagnostic Duct Location, Surface Area, and R-value
In order to claim these compliance credits, the system must first meet the HERS Verified Duct System Design criteria per RA188.8.131.52.1.4, See article titled "Duct System Design Verification and Form."
To claim this credit, the duct system design must be documented on plans that are submitted to the enforcement agency and available at the construction site for use by the installers, the enforcement agency field inspector, and the HERS Rater. The duct system must be installed in accordance with the approved duct system plans, and the duct system installation must be certified by the installer on the CF2R form and verified by a HERS Rater on the CF3R form. Details of this compliance option are described in the Residential Alternative Calculation Method (ACM) Reference Manual, and verification procedures are described in RA3.1 of the Reference Residential Appendix.
Although not HERS verified, the compliance software calculates a Performance credit if all of the ducts are insulated to a level higher than required by the Prescriptive Package. If ducts with multiple R-values are installed, when calculating the compliance margin, the compliance software assumes the lowest duct R-value for the entire duct system. As an alternative, when there is a mix of duct insulation R-values, credit is available through the method described in the next section which does require HERS verification.
HERS Verification of Duct Surface Area Reduction
Compliance with Verified Duct System Design procedures specified in RA184.108.40.206.1 are prerequisite for compliance with the Duct Surface Area Reduction compliance credit. A visual inspection shall confirm that the installed duct system layout conforms to the Duct Design Layout.
This verification must be performed when the ducts are all accessible, typically prior to the ducts being covered with cavity insulation, and/or before drywall if the ducts will be concealed.