What you should know about 90.1 and Insulated Metal Panels.
Most of us know ASHRAE 90.1 as the World’s most adopted building energy code and the basis for the International Energy Conservation Code (IECC) as a compliance option in IECC Minimum energy code standards. ASHRAE 90.1 is also the basis of the ASHRAE green building codified Standard 189.1 that is an optional compliance for the IGCC – International Green Construction Code.
Currently 38 states have energy code requirements ≥ IECC-2009 (ASHRAE 90.1-2007); (1) state (Maryland) has adopted the latest code/standard (ASHRAE 90.1-2010/IECC-2012); (4) states (Texas, Illinois, Minnesota, and Virginia) are projected to require 2012 IECC or equivalent by the end of 2015.
U-Value requirements (i.e. Insulation values) increase significantly for most climate
zones (Comparing IECC 2006, IECC 2009, and IECC 2012).
ASHRAE/IECC Paths to Compliance
The 90.1 Prescriptive Tables provide energy compliance criteria based on:
Maximum U-Value of the envelope component Assembly OR Minimum R-Value of Insulation Material
“Materials” vs. “Assemblies”
“Materials” refer to the individual parts (i.e. 2X4s, Fiberglass Insulation, Gypsum board) that make up a wall, roof, etc..
“Assemblies” refer to the in-place construction of an envelope component.
In the Codes, the difference between U-Values and R-Values is the difference between Assemblies and Materials
Material vs. Assembly U-Values and R-Values
U-Value = 1/”Effective” R-Value
“Effective” R-Value < Material R-Value 1,2
1 This is caused by less resistant materials (thermal “bridges”) in the assembly’s
2 “continuous insulation” is the exception.
The difference in performance between Materials and Assemblies is captured within the ASHRAE 90.1 Prescriptive Table U-Values.
IMP panels, typically have better “Material-to-Assembly” performance than the wall
systems described by the construction type definition.
The Material R-Values listed in the table do not reflect the assembly and materials
of an IMP assembly.
The Maximum U-Value criteria should be used for compliance when evaluating IMP Assembly performance.
Through “Design Support”, Kingspan can ensure that the desired performance, beyond aesthetics, is designed into the project from step one. Kingspan’s in house technical team and energy modeling services evaluate the many different architectural profiles and reveals to make certain the thermal continuity of the project is optimized.