The building code and commercial energy code each state enforces, the statute or rule that adopts it, where the adopted code can be read, and the plan-review and permit checklists the state or its cities publish.
Check before you rely on it. Many states have no statewide building code, and cities in the others often adopt a different edition or amend it. This is a research reference, not legal advice. Confirm the edition and any amendments with the authority having jurisdiction before filing. Model-code text (ICC, ASHRAE) is copyrighted and is linked, not reproduced.