Document ID: chunk:federal_register_of_legislation:F2023L01530:body:0:p43
Version: federal_register_of_legislation:F2023L01530
Segment Type: other
Provision Reference: 
Character Range: 121616–124441

conductor and the component casing for at least two seconds. The minimum allowable resistance for that component is 240 kΩ.
         2.8. Vibration test
         The valve unit is pressurized to its 100 per cent NWP (+2/-0 MPa) with hydrogen, sealed at both ends, and vibrated for 30 minutes along each of the three orthogonal axes (vertical, lateral and longitudinal) at the most severe resonant frequencies. The most severe resonant frequencies are determined by acceleration of 1.5 g with a sweep time of 10 minutes within a sinusoidal frequency range of 10 to 40 Hz. If the resonance frequency is not found in this range the test is conducted at 40Hz. Following this test, each sample shall not show visible exterior damage that indicates that the performance of the part is compromised. At the completion of the test, the unit shall comply with the requirements of the ambient temperature leak test specified in Annex 4, paragraph 2.2.
         2.9. Stress corrosion cracking test
         For the valve units containing components made of a copper-based alloy (e.g. brass), one valve unit is tested. The valve unit is disassembled, all copper-based alloy components are degreased and then the valve unit is reassembled before it is continuously exposed for ten days to a moist ammonia-air mixture maintained in a glass chamber having a glass cover.
         Aqueous ammonia having a specific gravity of 0.94 is maintained at the bottom of the glass chamber below the sample at a concentration of at least 20 ml per litre of chamber volume. The sample is positioned 35 (±5) mm above the aqueous ammonia solution and supported in an inert tray. The moist ammonia-air mixture is maintained at atmospheric pressure at
         35 (±5) ºC. Copper-based alloy components shall not exhibit cracking or delaminating due to this test.
         2.10. Pre-cooled hydrogen exposure test
         The valve unit is subjected to pre-cooled hydrogen gas at -40 ºC or lower at a flow rate of 30 g/sec at external temperature of 20 (±5) ºC for a minimum of three minutes. The unit is de-pressurized and re-pressurized after a two minute hold period. This test is repeated ten times. This test procedure is then repeated for an additional ten cycles, except that the hold period is increased to 15 minutes. The unit shall then comply with the requirements of the ambient temperature leak test specified in Annex 4, paragraph 2.2.

Annex 5

Test procedures for a vehicle fuel system incorporating the compressed hydrogen storage system
         1. Post-crash compressed hydrogen storage system leak test
         The crash tests used to evaluate post-crash hydrogen leakage are those set out in paragraph 7.2. of this Regulation.
         Prior to conducting the crash test, instrumentation is installed in the hydrogen storage system to