Codes - As enacted, requires the statewide building construction safety standards to allow a local government to amend the adopted building code for three-family dwellings and four-family dwellings in accordance with the standards; provides that, in amending the rules, the state fire marshal must not mandate automatic fire sprinkler systems for three-family dwellings and four-family dwellings where structures are under 5,000 square feet in area and meet other criteria; authorizes local governments to mandate sprinklers if certain conditions are met. - Amends TCA Title 68, Chapter 120.