Document ID: chunk:federal_register_of_legislation:F2023L01530:body:0:p48
Version: federal_register_of_legislation:F2023L01530
Segment Type: other
Provision Reference: 
Character Range: 134200–137264

valve or of the sound of the shut-off valve activation may be used to confirm the operation of the main shut-off valve of the hydrogen supply.
         3.2. Test procedure for integrity of enclosed spaces and detection systems.
         3.2.1. Preparation:
         3.2.1.1. The test is conducted without any influence of wind.
         3.2.1.2. Special attention is paid to the test environment as during the test, flammable mixtures of hydrogen and air may occur.
         3.2.1.3. Prior to the test the vehicle is prepared to allow remotely controllable hydrogen releases from the hydrogen system. The number, location and flow capacity of the release points downstream of the main hydrogen shut-off valve are defined by the vehicle manufacturer taking worst case leakage scenarios under single failure condition into account. As a minimum, the total flow of all remotely controlled releases shall be adequate to trigger demonstration of the automatic "warning" and hydrogen shut-off functions.
         3.2.1.4. For the purpose of the test, a hydrogen concentration detector is installed where hydrogen gas may accumulate most in the passenger compartment (e.g. near the headliner) when testing for compliance with paragraph 7.1.4.2. of this Regulation and hydrogen concentration detectors are installed in enclosed or semi enclosed volumes on the vehicle where hydrogen can accumulate from the simulated hydrogen releases when testing for compliance with paragraph 7.1.4.3. of this Regulation (see Annex 5, paragraph 3.2.1.3.).
         3.2.2. Procedure:
         3.2.2.1. Vehicle doors, windows and other covers are closed.
         3.2.2.2. The propulsion system is started, allowed to warm up to its normal operating temperature and left operating at idle for the test duration.
         3.2.2.3. A leak is simulated using the remote controllable function.
         3.2.2.4. The hydrogen concentration is measured continuously until the concentration does not rise for 3 minutes. When testing for compliance with paragraph 7.1.4.3 of this Regulation, the simulated leak is then increased using the remote controllable function until the main hydrogen shut-off valve is closed and the tell-tale warning signal is activated. The monitoring of the electric power to the shut-off valve or of the sound of the shut-off valve activation may be used to confirm the operation of the main shut-off valve of the hydrogen supply.
         3.2.2.5. When testing for compliance with paragraph 7.1.4.2. of this Regulation, the test is successfully completed if the hydrogen concentration in the passenger compartment does not exceed 1.0 per cent. When testing for compliance with paragraph 7.1.4.3. of this Regulation, the test is successfully completed if the tell-tale warning and shut-off function are executed at (or below) the levels specified in paragraph 7.1.4.3. of this Regulation; otherwise, the test is failed and the system is not qualified for vehicle service.
         4. Compliance test for the vehicle exhaust system
         4.1. The power system of the