The main problems with cement cargo arise when holds are not initially dry, clean and watertight. The majority of claims arising from cement cargo are caused by the following factors:
- Solidification when wet
- Contamination by residues of previous cargoes
- Retention of heat when loaded warm
Solidification:
- It is crucial to ensure all holds and bilges are completely dry prior to loading.
- It is also of paramount importance that all valves in the drain and bilge systems are thoroughly checked and confirmed to be operational. Dysfunctional valves can allow water to seep into holds through the bilge line system causing the cement in the holds to solidify.
Contamination:
- Cargo holds must be clean and odour-free.
- It must be clarified in the charterparty what level of cleanliness is required on delivery and an independent surveyor can be employed to make sure the vessel is ready to load cement.
- Cargo residues such as sugar and fertilizers may result in the contamination of cement cargoes. Raw sugar reacts with cement and even small amounts seriously affect the setting and hardening performance of cement. As little as 0.001% of sugar, if mixed with cement, renders it worthless. Some cement companies do not allow cement to be carried on vessels which have carried previous sugar cargoes.
Temperature:
- It is important to check the temperature of cement before loading, as its temperature can be as high as 110C when leaving the production site. This should especially be considered when loading takes place alongside the factory and cargo is loaded as soon as it is passed through the kilns.
- Loading cement at high temperatures (over 100C), not only damages hold coatings, but also leads to the production of water vapour within the holds.
- Conducting pre-loading surveys to ensure all cargo is below 100 C can prevent cargo and vessel damage.
Points to pounder for cement loading:
- HAZARD: It may shift when aerated. This cargo is non-combustible or has a low fire-risk.
- STOWAGE & SEGREGATION: No special requirements. Clean and dry as relevant to the hazards of the cargo.
- WEATHER PRECAUTIONS: This cargo shall be kept as dry as practicable. This cargo shall not be handled during precipitation. During handling of this cargo all non-working hatches of the cargo spaces into which this cargo is loaded or to be loaded shall be closed.
- LOADING: The ship shall be kept upright during loading of this cargo. This cargo shall be so trimmed to the boundaries of the cargo space that the angle of the surface of the cargo with the horizontal plane does not exceed 25 degrees. Both the specific gravity and the flow characteristics of this cargo are dependent on the volume of air in the cargo. The volume of air in this cargo may be up to 12%. This cargo shows fluid state prior to settlement. The ship carrying this cargo shall not depart until the cargo has settled. After the settlement, shifting of the cargo is not liable to occur unless the angle of the surface with the horizontal plane exceeds 30 degrees.
- PRECAUTIONS: Appropriate precautions shall be taken to protect machinery and accommodation spaces from the dust of the cargo. Bilge wells of the cargo spaces shall be protected from ingress of the cargo. Due consideration shall be paid to protect equipment from the dust of the cargo. Persons, who may be exposed to the dust of the cargo, shall wear protective clothing, goggles or other equivalent dust eye-protection and dust filter masks, as necessary. Bilge wells shall be clean, dry and covered as appropriate, to prevent ingress of the cargo.
- VENTILATION: The cargo spaces carrying this cargo shall not be ventilated during voyage.
- CARRIAGE: After the completion of loading of this cargo, the hatches of the cargo spaces shall be sealed, as necessary. All vents and access ways to the cargo spaces shall be shut during the voyage. Bilges in the cargo spaces carrying this cargo shall not be pumped unless special precautions are taken.
- CLEAN-UP: In the case that the residues of this cargo are to be washed out, the cargo spaces and the other structures and equipment which may have been in contact with this cargo or its dust shall be thoroughly swept prior to washing out. Particular attention shall be paid to bilge wells and framework in the cargo spaces. The fixed bilge pumps shall not be used to pump the cargo spaces, because this cargo may make the bilge systems inoperative.
