Division 4.2.4.2 Procedure

Special consideration shall be given to safety when conducting this test.

The container shall be pressurised to nominal working pressure with hydrogen or a gas with a higher thermal pressure build up. The pressurised container shall be tested as follows:

1. (a)

   Place the container in a horizontal position approximately 100 mm above a uniform fire source with a length of 1,65 m. The arrangement of the fire shall be recorded in sufficient detail to ensure the rate of heat input to the container is reproducible. Any failure or inconsistency of the fire source during a test shall invalidate the result;

2. (b)

   If the container is ≤ 1,65 m, it shall be positioned centrically above the fire source;

3. (c)

   If the container is > 1,65 m and it is fitted with a pressure relief device at only one end, the fire source shall commence at the opposite end;

4. (d)

   If the container is > 1,65 m and it is fitted with pressure relief devices at more than one location along its length, the centre of the fire source shall be centred midway between those pressure relief devices that are separated by the greatest horizontal distance;

5. (e)

   If the container is > 1,65 m and it is additionally protected by thermal insulation, 2 fire tests shall be performed at nominal working pressure. The container shall be positioned centrically above the fire source in one test, while the fire shall commence at one of the container ends in the other;

6. (f)

   Metallic shielding shall be used to prevent direct flame impingement on container valves, fittings, or pressure relief devices. The metallic shielding shall not be in direct contact with the pressure relief devices. Any failure during the test of a valve, fitting or tubing that is not part of the intended protection system for the design shall invalidate the result;

7. (g)

   Surface temperatures shall be monitored by at least three thermocouples located along the bottom of the container and spaced not more than 0,75 m apart. Metallic shielding shall be used to prevent direct flame impingement on the thermocouples. Alternatively, thermocouples may be inserted into blocks of metal measuring less than 25 mm × 25 mm × 25 mm;

8. (h)

   The fire source shall provide direct flame impingement on the container surface across its entire diameter immediately following ignition;

9. (i)

   Thermocouple temperatures and the container pressure shall be recorded at intervals of ≤ 10 seconds during the test;

10. (j)

    Within 5 minutes of ignition and for the remaining duration of the test the temperature of at least one thermocouple shall indicate at least 590 °C.