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C304.3.2 Assembly U -Factor, C -Factor and F -Factor Calculation
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The U-factors, C-factors, F-factors, and heat capacities for typical construction assemblies from ASHRAE 90.1 Normative Appendix A shall be used for all calculations unless otherwise allowed by applicant-determined assembly U-factors, C-factors, F-factors or heat capacities. Interpolation between values for rated R-values of insulation, including insulated, sheathing is allowed; extrapolation beyond values in the ASHRAE 90.1 Normative Appendix A tables is not.
If the building official determines that the proposed construction assembly is not adequately represented in the appropriate table of ASHRAE 90.1 Normative Appendix A, the applicant shall determine appropriate values for the assembly using the assumptions in ASHRAE 90.1 Normative Appendix A. An assembly is deemed to be adequately represented if:
- the interior structure, hereafter referred to as the base assembly, for the class of construction is the same as described in Normative Appendix A and
- changes in exterior or interior surface building materials added to the base assembly do not increase or decrease the R-value by more than 2 from that indicated in the descriptions in ASHRAE 90.1 Normative Appendix A.
Insulation, including insulated sheathing, is not considered a building material.
Related Code Sections
C304.3.2 [CE] General Requirements, Assembly U -Factor, C -Factor and F -Factor Calculation
be used for all calculations unless otherwise allowed by applicant-determined assembly U -factors, C -factors, F -factors or heat capacities ...
2020 FBC - Energy Conservation, 7th edition > 3 [CE] General Requirements > C304 Materials Testing and Thermal Properties > C304.3 Calculation Procedures and Assumptions > C304.3.2 Assembly U -Factor, C -Factor and F -Factor Calculation
C304.3.2 [CE] General Requirements, Assembly U -Factor, C -Factor and F -Factor Calculation
be used for all calculations unless otherwise allowed by applicant-determined assembly U -factors, C -factors, F -factors or heat capacities ...
2017 FBC - Energy Conservation, 6th edition > 3 [CE] General Requirements > C304 Materials Testing and Thermal Properties > C304.3 Calculation Procedures and Assumptions > C304.3.2 Assembly U -Factor, C -Factor and F -Factor Calculation
C304.3.2 [CE] General Requirements, Assembly U-factor, C-Factor and F-Factor Calculation
for all calculations unless otherwise allowed by applicant-determined assembly U -factors, C -factors, F -factors, or heat capacities ...
2014 FBC - Energy Conservation, 5th edition > 3 [CE] General Requirements > C304 Materials Testing and Thermal Properties > C304.3 Calculation Procedures and Assumptions > C304.3.2 Assembly U-factor, C-Factor and F-Factor Calculation
C304.3.2.2 [CE] General Requirements, Applicant-Determined Assembly U-Factors, C-Factors, F-Factors, or Heat Capacities
If the building official determines that the proposed construction assembly is not adequately represented in the appropriate table of ASHRAE 90.1 ...
2014 FBC - Energy Conservation, 5th edition > 3 [CE] General Requirements > C304 Materials Testing and Thermal Properties > C304.3 Calculation Procedures and Assumptions > C304.3.2 Assembly U-factor, C-Factor and F-Factor Calculation > C304.3.2.2 Applicant-Determined Assembly U-Factors, C-Factors, F-Factors, or Heat Capacities
C304.3 [CE] General Requirements, Calculation Procedures and Assumptions
90.1 Normative Appendix A shall be used for all calculations unless otherwise allowed by applicant-determined assembly U -factors, C -factors, F ...
2014 FBC - Energy Conservation, 5th edition > 3 [CE] General Requirements > C304 Materials Testing and Thermal Properties > C304.3 Calculation Procedures and Assumptions