Document ID: chunk:federal_register_of_legislation:F2023L01530:body:0:p36
Version: federal_register_of_legislation:F2023L01530
Segment Type: other
Provision Reference: 
Character Range: 103377–106227

except that in the test of one unit, the pH of the salt solution shall be adjusted to 4.0 ± 0.2 by the addition of sulphuric acid and nitric acid in a 2:1 ratio, and in the test of the other unit, the pH of the salt solution shall be adjusted to 10.0 ± 0.2 by the addition of sodium hydroxide. The temperature within the fog chamber is maintained at 30-35 °C).
         Following these tests, each pressure relief device shall comply with the requirements of Leak test (Annex 3, paragraph 6.1.8.), Flow rate test (Annex 3, paragraph 6.1.10.) and Bench top activation test (Annex 3, paragraph 6.1.9.).
         1.5. Vehicle environment test
         Resistance to degradation by external exposure to automotive fluids is determined by the following test:
              (a) The inlet and outlet connections of the TPRD are connected or capped in accordance with the manufacturers installation instructions. The external surfaces of the TPRD are exposed for 24 hours at 20 (±5) C to each of the following fluids:
              (i) Sulphuric acid (19 per cent solution by volume in water);
              (ii) Sodium hydroxide (25 per cent solution by weight in water);
              (iii) Ammonium nitrate (28 per cent by weight in water); and
                  (iv) Windshield washer fluid (50 per cent by volume methyl alcohol and water).
                  The fluids are replenished as needed to ensure complete exposure for the duration of the test. A distinct test is performed with each of the fluids. One component may be used for exposure to all of the fluids in sequence.
              (b) After exposure to each fluid, the component is wiped off and rinsed with water;
              (c) The component shall not show signs of physical degradation that could impair the function of the component, specifically: cracking, softening, or swelling. Cosmetic changes such as pitting or staining are not failures. At the conclusion of all exposures, the unit(s) shall comply with the requirements of Leak test (Annex 4, paragraph 1.8.), Flow rate test (Annex 4, paragraph 1.10.) and Bench top activation test (Annex 4, paragraph 1.9.).
         1.6. Stress corrosion cracking test.
         For TPRDs containing components made of a copper-based alloy (e.g. brass), one TPRD unit is tested. All copper alloy components exposed to the atmosphere shall be degreased and then 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