3.13 Liquid-filled pressure/vacuum breakers
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Specifications and Manuals - Inert Gas Systems - 3 Function and Design Considerations - 3.13 Liquid-filled pressure/vacuum breakers

3.13 Liquid-filled pressure/vacuum breakers

  3.13.1 One or more liquid-filled pressure/vacuum breakers should be fitted, unless pressure/vacuum valves having the capacity to prevent excessive pressure or vacuum in accordance with requirements of regulation 62.14 are fitted.

  3.13.2 These devices require little maintenance, but will only operate at the required pressure if they are filled to the correct level with liquid of the correct density. Either a suitable oil or a freshwater/glycol mixture should be used to prevent freezing in cold weather. Evaporation, ingress of seawater, condensation and corrosion should be taken into consideration and adequately compensated for. In heavy weather, the pressure surge caused by the motion of liquid in the cargo tanks may cause the liquid of the pressure/vacuum breaker to be blown out (see figure 16).

  3.13.3 The designer should ensure that the characteristics of the deck water seal, pressure/vacuum breakers and pressure/vacuum valves and the pressure settings of the high and low inert gas deck pressure alarms are compatible. It is also desirable to check that all pressure/vacuum devices are operating at their designed pressure settings.


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