As Eric has stated API RP53, a recommended practice became a standard, S53 with the latest edition being the 5th released December 2018.
The only stipulated requirement now appears at the bottom of the tables, for example Table C.4 for Surface Stacks. It states: "*Pressure test evaluation periods shall be a minimum of five minutes. No visible leaks. Pressure to remain stable during the evaluation period. The pressure shall not decrease below the intended test pressure."
Hope that helps.