From NSF:
ANN ARBOR, Mich. – NSF International is taking steps to make recreational splash parks and water venues safer. A new section of NSF/ANSI 50: Equipment and Chemicals for Swimming Pools, Spas, Hot Tubs and Other Recreational Water Facilitiesestablishes minimum criteria for safety flooring at interactive water play venues. Considered the premier pool and spa safety standard, NSF/ANSI 50 is required by most commercial swimming pool codes.