What are risk of carrying Cement cargo and how it is managed ?
Transportation of Cement
Cement cargoes, which account for about 5% of the dry bulk trade, can prove to be extremely problematic when carried in conventional bulk carriers as opposed to specialized cement carriers.
Loss Prevention:
-Before Loading.
-During Loading.
-After Loading but before departure.
BEFORE LOADING
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.
-An ultrasonic test before loading must be conducted in order to ensure the hatch covers are weather tight. The ultrasonic test saves a lot of trouble in comparison with other conventional methods (hose test, chalk test) of checking weather-tight ness and has become the international standard in recent years. If seawater leaks though the hatch covers, the cement can harden and result in damage to the vessel, unloading equipment, loss of cargo, additional removal work and possible damages to the terminal.
Contamination
-Cargo holds must be clean and odour-free.
-It must be clarified in the charter party 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 110°C 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 100°C), 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
DURING LOADING
If it is warm and humid at the port of loading, hatch covers should be closed as soon as loading has been completed to retain dry air inside the holds.
Hatch covers should also be kept closed during intervals in loading, especially if there is a possibility of rain.
-Closed loading systems
Closed loading systems entail pumping cargo under high pressure into the holds through a loading chute, while the hold covers remain closed.
When loading cement in this manner it could result in a large amount of cement dust sticking to the hatch cover undersides, hatch trackways, hatch coamings, drain holes and drain channels. Incorrect loading equipment could worsen the situation. If this cement dust is not cleaned, it would harden and result in the blockage of the drain holes and channels on coming into contact with rainwater or seawater during the vessel’s journey.
AFTER LOADING, BUT BEFORE DEPARTURE
-The main deck, hatch covers, hatch coamings, drain holes and draining channels should be swept and washed down before departure of the vessel.
-If not forbidden by the port due to anti-pollution regulations, these areas should be cleaned with compressed air.
-This prevents any loose cement in these areas from hardening if exposed to water.
During discharge
-Discharge should not be undertaken during periods of bad weather.
-Charterers may be asked for a LOI if they insist on discharge. This would usually serve to place all liability and damage risks on charterers.
-´´If charterers have CLH cover, that could be prejudiced by the terms of the LOI.
After discharge
-After discharge, dry residue and pockets of cement remain loosely adhered to exposed surfaces in the hold, including bilge wells, cargo hold bulkheads, hatch cover undersides and hatch coamings.
-The cement dust in these areas should be cleaned using brooms, brushes and air guns with the help of Cherry Pickers. When all cement dust has been swept away, all areas should be washed with seawater using high pressure hoses (2,500 psi).
-If there is semi-hardened cement visible on the hold surfaces, a more aggressive approach should be employed from the start. Stiff bristle brushes and hand scrapers should be used to remove as much as the cement as possible. If hardened, pressure hoses will not successfully remove the cement and only worsen the situation. Water will aid in the hardening process of the cement, causing more damage and further delaying the cleaning process
-If manually sweeping and scraping the surface does not remove the hardened cement, additional equipment such as very high pressure washers (20,000 psi) may have to be loaded on board. These are expensive, extremely heavy and cause delay.
CREW SAFETY
Crew involved during the loading, discharging and cleaning process must always be provided with appropriate personal protective equipment (“PPE”) and trained on using it properly. Appropriate PPE will include chemical gloves, chemical body suits, eye goggles, breathing masks and boots. All crew must be trained in how to use them properly. Whereas dry cement dust can cause severe eye and respiratory irritation when it comes in contact with mucous membranes, wet cement can also cause severe skin burns if not washed off properly.
Packaging
Cement, if not carried in bulk, is usually shipped in 50 kg paper bags or one/two tonne polypropylene bags.
These must be further packaged in water-proof material as absorption of moisture or carbon dioxide from the air can significantly deteriorate cement over time.
Precaution to be taken(cement cargo)
-Make sure the holds are clean and dry before loading.
-´´Be extremely careful if the vessel has previously carried a cargo of sugar.
-´´Conduct an ultrasonic test before loading to ensure hatch covers are weather tight.
´´-Discourage loading and unloading during periods of bad weather.
´´-Discourage loading cargo at very high temperatures as this could produce water vapor in the holds.
-´´After loading, ensure all cement dust is swept away from all exposed surfaces to prevent it from hardening on contact with rainwater or seawater.
-´´Always ensure crew dealing with cement are provided and trained in using the appropriate PPE.
-´´Consider carefully the cleaning method to be employed from the very start in the event of hardened cement on the hold surface. A wrong approach can exacerbate the situation, increase cleaning costs and cause significant delays.
-´´Aim to include extremely specific clauses regarding delivery, re-delivery and cleaning obligations in the charterparty.
-´´Know your obligations and liabilities under the charterparty.
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