Ventilation and gas-freeing

Ventilation and gas-freeing

• In the design of pressure and vacuum valves and the determination of their opening pressures attention is to be paid to:
• the maximum loading and unloading rate
• the gas evolution factor
• the flow resistance in the venting system and
• the permissible tank pressures
• Where static flame arresters, e.g. Flame screens and detonation arresters, are used, due attention is to be paid to the fouling caused by the cargo.
• Vent headers may be used as vapour return lines.
• Vapour return line connections are to be fitted with shut-off valves and blind flanges.