National Plumbing Code, 607.3 THERMAL EXPANSION CONTROL, [PDF] (1996 - 2009) as adopted by Mecklenburg County North Carolina Building Department, retrieved 2018/02/15, original source: https://www.mecknc.gov/LUESA/CodeEnforcement/Tools/CodeInterpretations/CodeInterpretations/Thermal%20Expansion%20Contr...