Each tube shall be tested by the manufacturer and shall
withstand a hydraulic pressure to one and half times the
subject to a minimum of 1.00 kgf/mm2, but
not greater than pressure calculated by the following formula.
P = test pressure
D = specified outside diameter of the tube
= specified wall thickness of the tube
S = stress which shall be taken as 40% of the minimum
tensile strength at room temperature.
Notwithstanding any thing contained in the above
clause, the hydraulic test at the makerís works may be
dispensed with, provided that the tubes are subject to non
destructive testing by an appropriate method like Ultrasonic
or Eddy Current or Stray Flux testing.