On A Chemical Tanker - Various precautions need to be adhered to with regard to Safe Operation in Preparying of Cargo Tanks ensuring Safe Operation n strictly sticking to its Safety Procedure: 

Prior Arrival at Loadport Various stringent Ship Checks to be carried out as per laid down Check List:

When approaching a Loadport or Disport, following important pre-arrival checks should be carried out by the ship staff in order to play safe and avoid any delays.

1. On tanks in which cargo is to be transferred, In-Tank Instrumentation such as Level Gauges, Level Alarms and Thermometers should be Tested and Tried out for safe operation, accuracy in gauging of cargo in tanks and Remote Control System should be tested where appropriate. High Level Alarms and Tank Overflow Control Alarms are safety critical components of the cargo transfer system, and loading should not be commenced if pre-transfer checks are found deficient & faulty. 

2. Hatches, lids and openings to cargo tanks that are not required to be open for a specific reason should be firmly closed.

3. Cargo pipelines and crossover valves should be checked, and all drains closed and secured.

4. All ship's cargo and bunker pipelines not in use should be securely blanked and fully bolted at the manifold. Unless it is to be used, the stern cargo pipeline should be isolated from the tanker's main pipeline system at a point forward of the aft accommodation, by blanking or the removal of a spool piece.

5. Where loading or discharging is to be via a cargo pump-room, the pump-room ventilation system should be checked to ensure readiness for operation throughout the cargo operations.

6. Cargo area deck lighting should be checked and confirmed as being in full working order, with special attention given to the area of the ship to shore cargo connection and hose handling equipment.

Ship checks after arrival but prior to cargo operations

Before any cargo transfer starts, the responsible officer should be satisfied that the applicable precautions are being observed. The use of safety checklists, appropriately adapted for the specific ship, is strongly recommended. The following important checks should be made by the ship at this stage:

1. Information should be sought on any forecast of adverse weather conditions which may require operations to be stopped or transfer rates reduced.

2. Certain cargoes require the vapour that is displaced by incoming cargo to be returned to the shore facility. The responsible officer should ensure that the ship and the shore vapour system are compatible, and that the system will operate in compliance with local and terminal regulations.

3. The characteristics of the product must be known, usually in the form of a cargo information form or data sheet indicating, among other things, health hazards, specific gravity, temperature, vapour pressure, reactivity with other materials or cargoes, heat sensitivity, risk of exothermic self-reaction, toxicity and general safe handling practices. It is desirable that initial response to emergencies is clearly shown. 

4. If a cargo liable to self-reaction is to be loaded, correct arrangements should be made for conditions and limitations in the inhibitor certificate to be met with for the duration of the voyage. 

5. Normally tanks to be loaded are pre-inspected for cleanliness by an independent surveyor. This can vary from a superficial visual inspection from the deck, to a very detailed inspection inside the cargo tank in which bulkheads are wall-washed and thoroughly checked. The responsible officer should satisfy himself that the tanks to be so inspected are well ventilated and safe to enter, and are marked as being safe to enter. Tank entry procedures should be complied with. When a tank is entered for inspection the surveyor should be accompanied by the responsible officer or a person delegated by him.

6. Tanks passed for loading should be tightly secured with all cargo openings closed.

7. All sighting ports and ullage plugs should be closed and secured, unless expected to be used during handling of the cargo about to be loaded. If openings are required to be open for venting purposes, each opening should be protected by a flame screen designed for that opening and kept clean.

8. When not in use, sea suction and overboard discharge valves connected to cargo and ballast systems must be securely closed and lashed, and may be sealed by shore authorities. In-line blanks should be inserted where these are provided. When lashing is not practicable, valves should be suitably marked to indicate clearly that they are to remain closed.

9. Before cargo handling is started, all deck scuppers and any open drains onto the jetty must be effectively plugged to prevent spilled cargo escaping into the water around the tanker or onto the terminal. Accumulations of rainwater should be drained periodically and scupper plugs replaced immediately afterwards. Contaminated water should be transferred to a slop tank or other suitable receptacle.

10. Cargo manifolds should be ready for connection to shore hoses, but with blank flanges removed only on those lines to be used, and only on the connecting side of the ship.

11. Where loading is via a cargo pump-room, the pump-room ventilation system should be working throughout the operation, and all drains and non-essential valves in the pump-room must be closed and secured.

12. Accommodation doors and portholes overlooking the cargo area should be shut. If stern loading is to be undertaken, it may be necessary to provide special advice to the crew.

13. The cargo venting system should be appropriate for the cargo operation.

14. Intakes for central air conditioning and mechanical ventilation systems should be checked for correct setting.

15. Means should be provided for the prompt removal of any spillage on deck.

16. Fire fighting equipment should be inspected, and ready for immediate use.

17. Correct personal protective clothing and breathing apparatus, appropriate to the cargo, should be immediately available, and should be worn as necessary.

Just prior to commencing cargo transfer, the responsible officer should check that the cargo pipeline system is set correctly, that correct valves are open and that pipeline valves not being used (including drop valves) are closed.

Joint ship anti shore liaison, and checks prior to cargo operations

A liaison meeting should be held with the responsible terminal staff, at which the operational plan for the order of cargo handling can be agreed. The following joint ship and shore checks in co-operation with a terminal representative are recommended:

1. That the Ship/Shore Safety Checklist has been completed satisfactorily.

2. That Local and Terminal Regulations have been ascertained and are being observed.

3. That agreement has been reached with the responsible terminal representative about signals to indicate stand-by, start operation, slow down and stop operation.

4. That when shore-supplied nitrogen is to be used for inerting cargo tanks, the procedure for handling it has been agreed.

5. That the sequence of cargoes and pumping rates has been agreed.

6. Whether ship or shore will order pumps to be stopped on completion.

7. That emergency shutdown procedures, and action to be taken in case of fire or other emergency, have been agreed.

8. That if an insulating flange is used in the hose connection, its insulation has not been impaired.