Document ID: chunk:federal_register_of_legislation:F2023L01530:body:0:p40
Version: federal_register_of_legislation:F2023L01530
Segment Type: other
Provision Reference: 
Character Range: 113584–116441

5 per cent NWP (+0/-2 MPa) and 150 per cent NWP (+2/-0 MPa) ;
              (c) Low temperature: condition the unit at -40 °C or lower; test at 5 per cent NWP (+0/-2 MPa) and 100 per cent NWP (+2/-0 MPa).
         Additional units undergo leak testing as specified in other tests in Annex 4, paragraph 2. with uninterrupted exposure at the temperatures specified in those tests.
         The outlet opening is plugged with the appropriate mating connection and pressurized hydrogen is applied to the inlet. At all specified test temperatures, the unit is conditioned for one minute by immersion in a temperature controlled fluid (or equivalent method). If no bubbles are observed for the specified time period, the sample passes the test. If bubbles are detected, the leak rate is measured by an appropriate method. The leak rate shall not exceed 10 Nml/hr of hydrogen gas.
         2.3. Extreme temperature pressure cycling test
              (a) The total number of operational cycles is 11,000 for the check valve and 50,000 for the shut-off valve. The valve unit are installed in a test fixture corresponding to the manufacturer's specifications for installation. The operation of the unit is continuously repeated using hydrogen gas at all specified pressures.
              An operational cycle shall be defined as follows:
                  (i) A check valve is connected to a test fixture and 100 per cent NWP (+2/-0 MPa) is applied in six step pulses to the check valve inlet with the outlet closed. The pressure is then vented from the check valve inlet. The pressure is lowered on the check valve outlet side to less than 60 per cent NWP prior to the next cycle;
                  (ii) A shut-off valve is connected to a test fixture and pressure is applied continuously to the both the inlet and outlet sides.
              An operational cycle consists of one full operation and reset.
              (b) Testing is performed on a unit stabilized at the following temperatures:
                  (i) Ambient temperature cycling. The unit undergoes operational (open/closed) cycles at 125 per cent NWP (+2/-0 MPa) through 90 per cent of the total cycles with the part stabilized at
                  20 (±5) °C. At the completion of the ambient temperature operational cycles, the unit shall comply with the ambient temperature leak test specified in Annex 4, paragraph 2.2.;
                  (ii) High temperature cycling. The unit then undergoes operational cycles at 125 per cent NWP (+2/-0 MPa) through 5 per cent of the total operational cycles with the part stabilized at 85 °C or higher. At the completion of the 85 oC cycles, the unit shall comply with the high temperature (85 °C) leak test specified in Annex 4, paragraph 2.2.;
                  (iii) Low temperature cycling. The unit then undergoes operational cycles at 100 per cent