Ventilation and gas-freeing

Ventilation and gas-freeing

• Where the venting arrangements of more than one tank are connected to a vent header system, a shut-off device is to be provided at each tank.
• Where stop valves are used, they shall be provided with locking arrangements.
• When shut-off devices according are provided, cargo tanks are to be protected against excessive positive and negative pressures caused by thermal variations by means of Pressure/vacuum relief devices.
• Venting arrangements are to be connected to the top of each cargo tank in such a way that, under normal conditions of trim and list, they are self-draining into the cargo tanks.
• Where a self-draining arrangement is impossible, permanently installed means for draining the vent lines to a cargo tank shall be provided.