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Division 4.2.2.2.5 Pressure relief devices

Original text. Later amendments are not shown.

  1. (a)

    Creep test

    Pressure relief devices shall be hydrostatically pressurised to 1,25 times nominal working pressure and held for 500 hours at a temperature (TL) calculated from the following equation:

    TL = T (0,057) (0,34 log(T/Tf))

    where

    TL

  2. Test temperature, °C

    3. Tf

  3. Activation temperature of the pressure relief device, °C

    4. T

  4. 82 °C

    5. Log is base 10.

    Pressure relief devices shall not show signs of deformation caused by creep and shall fulfil the requirements of the internal leakage test (section 4.2.4.) after being subjected to the above test;

  • (b)

    Activation temperature

    Following the creep test in a) above, the pressure relief devices shall be pressurised with dry air, nitrogen, helium or hydrogen to nominal working pressure. Subsequently the pressure relief devices shall be exposed to an increasing temperature cycle starting from ambient temperature with a rate not exceeding 10 °C per minute until the specified activation temperature minus 10 °C is reached and then with a rate of not exceeding 2 °C per minute until the pressure relief devices activate. The activation temperature shall be within a range of ± 5 per cent of the manufacturer’s specified activation temperature. After activation the pressure relief devices shall show no evidence of fragmentation.