The default R-values for roof (assembly) are referred from:
- ASHRAE table 5.5 when respective ASHRAE code version (2007, 2010, 2013, 2016) is selected.
- Table 140.3-B when respective California Title 24 code version (2016, 2019) is selected.
- Division B-Part 3 when respective NECB cove version (2011, 2015) is selected.
Since there are different types of material assemblies for roof which would affect what value would be used to determine the automated value, cove.tool makes that assumption for the users based on Pacific Northwest National Laboratory (PNNL) building prototypes.
- Roof Area: Total roof area of the building. This area can be imported using different plugins (Revit, Rhino/Grasshopper, SketchUp) that cove.tool supports or can be entered manually.
- Roof R-Value: This measures how effective is your roof material as in insulator. The default R-values for roof (assembly) are referred from ASHRAE table 5.5. Cove.tool will automatically populate the R-values based on location of the project assuming the Insulation Entirely above Deck roof type for all commercial building types except small office (Attic and Other).
For example, if your project (Hospital) is in Atlanta, GA (ASHRAE Climate Zone 3A) and the energy code selected is ASHRAE 90.1 2013, the automated roof R-value (Insulation Entirely above Deck) can be seen highlighted in the image attached below: