How To Clean The Cargo Hold of A Bulk Carrier

In determining the level of cleanliness that needs to be met for the next cargo to be loaded in the hold of a bulk carrier, the International Maritime Solid Bulk Cargoes Code (IMSBC) cargo hold cleanliness requirements for the specific type of cargo to be loaded must be taken into account.

Many cargoes are specified as "no special requirements" or "keep clean and dry according to the hazardous nature of the cargo", although some cargoes may have specific instructions. Sulphur (UN No. 1350) is an example, and the IMSBC Code states that the hold shall be "kept clean and dry according to the hazardous nature of the cargo and shall be thoroughly cleaned and washed with fresh water".

Whether or not the next cargo is secured, preparations for cargo hold cleaning should begin as soon as the unloading of the previous cargo has been completed. It is vital that the entire chain of command, from the chartering and technical management teams ashore to the ship's master and crew, understands what needs to be done and has the appropriate tools, materials and manpower to achieve the right level of cleaning. Practices that are acceptable for one type of cargo, such as sweeping and washing, may not be for another, so all parties must be aware of the specific requirements.

Cargo Hold of Bulk Carrier Cleaning Level

1. Hospital cleaning: All cargo residues, loose rust and scale, and paint must be removed, and the cargo hold should be cleaned, dried and ventilated. In addition, all surfaces, including ladders, piping, the underside of hatch covers, and the tops of fuel tanks must have a full coat of paint. This cleaning requirement is most commonly used for high-grade cargo, materials intended for end-use, or cargo intended for direct human consumption.

2. Grain cleaning: Grain cleaning is the most common standard required for tank washing. If the next cargo has not been identified after the discharge has been completed, then grain cleaning is the default standard to which most ships will wash their holds while waiting for instructions. Grain cleaning is required when ships load most bulk cargoes such as all grain cargoes, cement, sulphur, alumina and fertilizers.

Requirements for grain include the removal of all previous cargo residue and lashing material, bedding, etc. from the cargo hold. All loose rust scale and paint must be removed. Cargo holds are usually cleaned with sea water and dried. It is worth noting that most cargoes require the cargo hold to be washed/flushed with fresh water to remove all chloride residues (e.g. cleaning for transportation of sulphur). Finally, the cargo hold must be ventilated to ensure that it is free of odors and gases.

According to U.S. Department of Agriculture (USDA) requirements for grain loading, cargo stowage areas on bulk carriers must be clean, dry, free of pests, rodents, toxic substances and odors. The USDA's conformity standards also detail requirements for rust and scale, dryness, and insect infestation or contamination. For example, the standards allow for no more than 10 square feet (2.32 square meters) of loose paint or loose rust scale on a single piece, or a total of 100 square feet (9.26 square meters) for several pieces combined. In practice, however, since each inspector may have his or her own interpretation of the required "standard", it is desirable that the hold be completely free of loose rust.

3.General cleaning: When not specified in the charter, cargo residues should be removed and the hold should be swept twice, washed with salt water, then rinsed with fresh water and dried. This standard of cleanliness is usually used for loading cargoes similar or comparable to those previously carried, and is a typical level of cleanliness for cargoes such as coal, bauxite, salt and iron ore.

4. Sweeping or shoveling: The standard for sweeping or shoveling means removing all previous cargo residue with a backhoe or rough sweeper and cleaning with a shovel. Before such cleaning operations are carried out, the master must define the specific requirements.

If the cargo hold is required to be swept clean, then the stevedore should sweep the hold before unloading is completed to minimize cargo residue. If the cargo hold is required to be shoveled clean, then the stevedore is only required to remove cargo residue that can be easily removed by a mechanical shovel or excavator.

5. Top loading: Although top loading does not require specialized cleaning of the cargo hold, it is recommended that consideration be given to the fact that cargo residue can prevent a thorough inspection of the structure of the hold for any damage. If multiple loads continue to be top-loaded over a period of time, subsequent cleaning to any higher standard of cleanliness will take longer. Therefore, if time permits, it is recommended that the cargo hold of a bulk carrier be cleaned regularly, or at least that residue be removed from one side, to allow inspection of the structure.

Other Requirements

It should be noted that the IMSBC Code also details specific requirements for cleaning after discharge. Many cargoes are "no special requirements", but some (e.g. sulphur) have detailed instructions, such as: "Cargo spaces and other structures which may have come into contact with the cargo or its dust shall not be cleaned. After unloading such cargo, the cargo space and other necessary structures shall be cleaned with fresh water to remove all residues of the cargo. The cargo space shall then be thoroughly dried. Wet dust or residue may form highly corrosive sulphite, which is extremely dangerous to personnel and corrosive to steel. Personnel involved in the cleanup should be equipped with protective clothing, goggles and face shields."

It is therefore important that the master and crew receive the correct cargo information in order to be prepared for the specific cleaning requirements of each type of cargo.