In order to ensure the correct functioning of PV valves the following should always be complied with:
- PV valves should be serviced and calibrated according to classification society requirements;
- Prior to loading and discharging, PV valves should be checked to ensure they function as designed;
- During cargo operations the correct functioning of PV valves should be monitored; and
- Pressure sensors fitted as the secondary system as a back up to the primary vent system should be checked to ensure that they function as designed and, where provided, that the alarms are correctly set.
Setting PV alarms
High pressure alarms and low pressure alarms must be set to:
- Activate additional safety or other alarm systems;
- Support maintenance of correct positive inert gas pressure in tanks;
- Prevent air intake to tanks; and
- Comply with regulations.