What Changed in ASCE 7-22 Snow Loads
ASCE 7-22 reworked how ground snow load is determined and added reliability-targeted values. Here is what designers need to know.
ASCE 7-22 is the 2022 edition of Minimum Design Loads and is being adopted through the 2024 IBC/IRC cycle. Its snow chapter (Chapter 7) kept the familiar equations but changed how the ground snow load is determined.
Reliability-targeted ground snow loads
The biggest change is that ground snow loads are now reliability-targeted and delivered through the ASCE Hazard Tool database rather than a single printed map with case-study regions. The result is more site-specific values and, in some places, different numbers than ASCE 7-16 produced.
The equations are familiar
The flat-roof equation Pf = 0.7 Ce Ct Is Pg, the slope factor Cs, the minimum-load rules and the drift formulas are all still here and broadly unchanged in form. If you know the 7-16 method, the 7-22 calculation will feel the same; it is mostly the Pg source that moved.
What to do
Always pull the ground snow load from the Hazard Tool for the correct code edition your jurisdiction has adopted, and confirm which edition that is. Then run the standard calculation, which is exactly what RoofHelm implements.
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