Section 7 Cargoes which may liquefy
In how many ways a bulk cargo may shift?
A ship’s motion may cause a cargo to shift sufficiently to capsize the vessel. Cargo shift can be divided into two types, namely,
1. sliding failure; or
2. liquefaction consequence.
Trimming the cargo in accordance with section 5 (3 categories of angle of repose), can prevent sliding failure.
How is the liquefaction related to reduction of shear strength of cargo?
Group A cargoes contain a certain proportion of small particles and a certain amount of moisture. Group A cargoes may liquefy during a voyage even when they are cohesive and trimmed level. Liquefaction can result in cargo shift. This phenomenon may be described as follows:
1 the volume of the spaces between the particles reduces as the cargo is compacted owing to the ship’s motion, etc.;
2 the reduction in space between cargo particles causes an increase in water pressure in the space; and
3 the increase in water pressure reduces the friction between cargo particles, resulting in a reduction in the shear strength of the cargo.
A cargo shift caused by liquefaction may occur when the moisture content exceeds the TML.
Why the liquefaction does not occur when cargo is large particles or lumps?
Liquefaction does not occur when the cargo consists of large particles or lumps and water passes through the spaces between the particles and there is no increase in the water pressure.
Can the cargo shift even if moisture content is less than TML?
Some cargoes are susceptible to moisture migration and may develop a dangerous wet base even if the average moisture content is less than the TML.
Shift can occur when the cargo is shallow and vessel is subject to large heel angles.
How can a liquid shift cause the ship to capsize?
In the resulting viscous fluid state cargo may flow to one side of the ship with a roll but not completely return with a roll the other way. Consequently the ship may progressively reach a dangerous heel and capsize quite suddenly.
Is there a provision to load cargoes having moisture content more than TML, on some ships?
Cargoes having moisture content in excess of the TML may be carried on a specially constructed or fitted cargo ship for confining cargo shift.
Section 8 Test procedures for cargoes which may liquefy
What are the different laboratory methods for determining transportable moisture limit?
The various methods for determining transportable moisture limit are given in appendix 2. Six methods of testing for the transportable moisture limit are currently in general use:
.1 flow table test;
.2 penetration test; and
.3 Proctor/Fagerberg test.
As each method has its advantages, the selection of the test method should be determined by local practices or by the appropriate authorities.
.4 Modified Proctor/Fagerberg test procedure for iron ore fines;
.5 Modified Proctor/Fagerberg test procedure for coal; and
.6 Modified Proctor/Fagerberg test procedure for bauxite.
What is complementary test procedure for determining the possibility of liquefaction on ship?
A ship’s Master may carry out a check test for approximately determining the possibility of flow on board ship or at the dockside by the following auxiliary method: Half fill a cylindrical can or similar container (0.5 to 1 L capacity) with a sample of the material. Take the can in one hand and bring it down sharply to strike a hard surface such as a solid table from a height of about 0.2 m. Repeat the procedure 25 times at one- or two-second intervals. Examine the surface for free moisture or fluid conditions. If free moisture or a fluid condition appears, arrangements should be made to have additional laboratory tests conducted on the material before it is accepted for loading. If samples remain dry following a can test, the moisture content of the material may still exceed the transportable moisture limit (TML).
Specially fitted cargo ships for confining cargo shift shall be fitted with specially designed portable divisions to confine any shift of cargo to an acceptable limit. Specially fitted cargo ships shall be in compliance with the following requirements:
1 The design and positioning of such special arrangements shall adequately provide the restraint of the immense forces generated by the flow movement of high-density bulk cargoes. Divisions provided to meet these requirements shall not be constructed of wood.
.2 The elements of the ship’s structure bounding such cargo shall be strengthened, as necessary.
.3 The plan of special arrangements and details of the stability conditions on which the design has been based shall have been approved by the Administration.
For which cargoes is the flow table test procedure suitable? What can be determined?
The flow table is generally suitable for mineral concentrates or other fine material with a maximum grain size of 1 mm. It may also be applicable to materials with a maximum grain size up to 7 mm. It will not be suitable for materials coarser than this and may also not give satisfactory results for some materials with high clay content. If the flow table test is not suitable for the material in question, the procedures to be adopted should be those approved by the authority of the port State. The test provides for determination of: the moisture content; the flow moisture point (FMP); and the transportable moisture limit of the test material.
Describe the flow table test.
The quantity of material required for a flow moisture test will vary according to the specific gravity of the material to be tested. It will range from approximately 2 kg for coal to 3 kg for mineral concentrates.
The representative sample of test material is placed in the mixing bowl and thoroughly mixed. Three subsamples (A), (B) and (C) are removed from the mixing bowl as follows: about one fifth of the sample (A) should be immediately weighed and placed in the drying oven to determine the moisture content of the sample “as-received”.
Taking m1 as the exact mass of the subsample “as-received”
Taking m2 as the exact mass of the “as-received” subsample, after drying, 1. The moisture content of the concentrate “as-received” is:
2. Two further subsamples, each of about two fifths of the gross weight, should then be taken, one (B) for the preliminary FMP test and the other (C) for the main FMP determination:
The mould is placed on the centre of the flow table and filled in three stages (one third at a time after tamping) with the material from the mixing bowl. The aim of tamping is to attain a degree of compaction similar to that prevailing at the bottom of a shipboard cargo. The correct pressure to be applied is calculated from: Tamping pressure (Pa) = Bulk density of cargo (kg/m3 ) x Maximum depth of cargo (m) x Gravity acceleration (m/s2) The number of tamping actions should be about 35 for the bottom layer, 25 for the middle and 20 for the top layer.
The mould is tapped on its side until it becomes loose, leaving the sample in the shape of a truncated cone on the table. Immediately after removing the mould, the flow table is raised and dropped up to 50 times through a height of 12.5 mm at a rate of 25 times per min. If the material is below the FMP, it usually crumbles and bumps off in fragments with successive drops of the table. The flow table is stopped and the material returned to the mixing bowl, where 5-10 ml of water, or possibly more, is sprinkled over the surface and thoroughly mixed into the material. The mould is again filled and the flow table is operated for up to 50 drops. If a flow state is not developed, the process is repeated with further additions of water until a flow state has been reached.
When the sample is pushed off the table, the sample may leave tracks (stripes) of moisture on the table. If such stripes are seen, the moisture content may be above the FMP: the absence of tracks (stripes) is not necessarily an indication of being below the FMP. Increment of the base diameter is an indication of state. Required measurements are done.
Let m3 be the exact mass of the sample just above the flow state and m4 be the exact mass of the sample just above the flow state, after drying.
3. Having completed the preliminary FMP test, the sample for the main test is adjusted to the required level of moisture content (about 1% to 2%) below the flow point.
It is clearly important that the samples should be dried to a constant mass. In practice, this is ascertained after a suitable drying period at 105oC by weighing the sample successively with an interval of several hours elapsing.
Let m5 be the exact mass of the sample just below the flow state and let m6 be the exact mass of the sample just below the flow state, after drying, Then, The transportable moisture limit of the material is 90% of the FMP.
The FMP is
What is the principle of Penetration test?
The penetration test constitutes a procedure whereby a material in a cylindrical vessel is vibrated. The flow moisture point is determined on the basis of the penetration depth of an indicator. The penetration test is generally suitable for mineral concentrates, similar materials and coals up to a top size of 25 mm.
In this procedure, the sample, in a cylindrical vessel, is subjected to vertical vibration for 6 min. When the penetration depth of a bit put on the surface exceeds 50 mm, it is judged that the sample contains a moisture content greater than the flow moisture point.
What is the principle of Proctor/Fagerberg test?
Test method for both fine and relatively coarse-grained ore concentrates or similar materials up to a top size of 5 mm. This method should not be used for coal or other porous materials.
Before the Proctor/Fagerberg test is applied to coarser materials with a top size greater than 5 mm, an extensive investigation for adoption and improvement is required.
What is the principle of Modified Proctor/Fagerberg test for iron ore fines?
The test procedure specified in this section (this test) should only be used for determining transportable moisture limit (TML) of iron ore fines.
Iron ore fines is iron ore containing both:
1 10% or more of fine particles less than 1 mm; and
2 50% or more of particles less than 10 mm.
What is the principle of Modified Proctor/Fagerberg test for coal?
This procedure details the laboratory determination of transportable moisture limit (TML) for coals up to a nominal top size of 50 mm. The procedure is based on a modification of the Proctor/Fagerberg test
What is the principle of Modified Proctor/Fagerberg test for bauxite?
The test procedure specified in this section (this test) should only be used for determining transportable moisture limit (TML) of bauxite cargoes containing both:
1 more than 30% of fine particles less than 1 mm (D30 < 1 mm); and
2 more than 40% of particles less than 2.5 mm (D40 < 2.5 mm).
Section 9 Materials possessing chemical hazards
How can the cargoes under B be further classified?
General Solid bulk cargoes which may possess chemical hazards during transport, because of their chemical nature or properties, are in group B. These materials can be classified as follows:
1 dangerous goods not possessing additional chemical hazards of MHB
2 Only MHB
3 dangerous goods and are also MHB.
What are MHBs?
MHBs are materials hazardous only in bulk. These are materials which, when carried in bulk, possess chemical hazards other than the hazards covered by the classification system of the IMDG Code. These materials present a significant risk when carried in bulk and require special precautions.
How is a test sample taken and tested to confirm if it is MHB?
A material shall be classified as MHB if the material possesses one or more of the chemical hazards (excluding those hazards which are covered by the classification system of the IMDG Code) as defined below. When a test method is prescribed, representative samples of the cargo to be carried shall be used for testing. Samples shall be taken 20 to 36 cm inward from the surface at 3 m intervals over the length of a stockpile.
What are the various subcategories of MHB?
Depending on different chemical hazards they are further categorized as follows:
Describe in brief, the characteristic properties exhibited by CB, SH, WF, WT, TX & CR.
Combustible solids: MHB (CB)
These are materials which are readily combustible or easily ignitable when transported in bulk and do not meet the established criteria for inclusion in class 4.1
Self-heating solids: MHB (SH)
These are materials that self-heat when transported in bulk and do not meet the established criteria for inclusion in class 4.2
Solids that evolve flammable gas when wet: MHB (WF)
These are materials that evolve flammable gases when in contact with water when transported in bulk and do not meet established criteria for inclusion in class 4.3
Solids that evolve toxic gas when wet: MHB (WT)
These are materials that evolve toxic gases when in contact with water when transported in bulk.
Toxic solids: MHB (TX)
These are materials that have toxic hazards to humans if inhaled or with contact with skin when loaded, unloaded, or transported in bulk and do not meet the established criteria for inclusion in class 6.1
Corrosive solids: MHB (CR)
These are materials that are corrosive to skin, eye or to metal or are respiratory sensitizers and do not meet the established criteria for inclusion in class 8
How is segregation of dangerous solid bulk cargo & MHB only cargo done?
The potential hazards of the cargoes in group B and falling within the above classification entail the need for segregation of incompatible cargoes. Segregation shall also take account of any identified subsidiary hazard.
Dangerous solid bulk cargoes include:
Class 4.1, Flammable solids, Class 4.2: Substances liable to spontaneous combustion, Class 4.3, Substances which, in contact with water, emit flammable gases, Class 5.1, Oxidizing substances, Class 6.1, Toxic substances, Class 7, Radioactive material, Class 8, Corrosive substances, Class 9, Miscellaneous dangerous substances and articles
Other category is materials hazardous only in bulk (MHB).
When two or more different solid bulk cargoes of group B are to be carried, the segregation between them shall be in accordance with 9.3.4.
When solid bulk cargoes of group B and dangerous goods in packaged form are to be carried, the segregation between them shall be in accordance with 9.3.3.
What is 9.33 & 9.34?
9.3.3 is segregation between bulk materials possessing chemical hazards and dangerous goods in packaged form. 9.3.4 Segregation between solid bulk cargoes possessing chemical hazards,
How is food stuff segregated from dangerous goods carried in bulk?
To avoid contamination, all foodstuffs must be stowed as follows:
.1 “separated from” a material which is indicated as toxic;
.2 “separated by a complete compartment or hold from” all infectious materials;
.3 “separated from” radioactive materials; and
.4 “away from” corrosive materials.
What precautions are taken in respect of toxic and corrosive substances carried in bulk?
Materials which may evolve toxic gases in sufficient quantities to affect health shall not be stowed in those spaces from where such gases may penetrate into living quarters or ventilation systems connecting to living quarters.
Materials which present corrosive hazards of such intensity as to affect either human tissue or the ship’s structure shall only be loaded after adequate precautions and protective measures have been taken.
What precautions are taken when materials of classes 4.1, 4.2 and 4.3 are carried in bulk?
Materials of these classes shall be kept as cool and dry as reasonably practicable and, unless expressly provided otherwise in this Code, shall be stowed “away from” all sources of heat or ignition. Electrical fittings and cables shall be in good condition and properly safeguarded against short circuits and sparking.
What precautions are taken when materials of class 5.1 carried in bulk?
Cargoes of this class shall be kept as cool and dry as reasonably practicable and, unless expressly provided otherwise in this Code, shall be stowed “away from” all sources of heat or ignition. They shall also be stowed “separated from” other combustible materials.
As far as reasonably practicable, non-combustible securing and protecting materials shall be used and only a minimum of dry wooden dunnage shall be used.
What precautions are taken when materials of class 7 carried in bulk?
Cargo spaces used for the transport of Low Specific Activity Materials (LSA-I) and Surface Contaminated Objects (SCO-I) shall not be used for other cargoes until decontaminated by a qualified person so that the non-fixed contamination on any surface when averaged over an area of 300 cm2 does not exceed the prescribed levels
What precautions are taken when materials of class 8 or materials having similar properties are carried in bulk?
These cargoes shall be kept as dry as reasonably practicable. Prior to loading these cargoes attention shall be given to the cleaning of the cargo spaces into which they will be loaded, particularly to ensure that these spaces are dry. Penetration of these materials into other cargo spaces, bilges, wells and between the ceiling boards shall be prevented. Particular attention shall be given to the cleaning of the cargo spaces after unloading, as residues of these cargoes may be highly corrosive to the ship’s structure. Hosing down of the cargo spaces followed by careful drying shall be considered.
Explain 9.33 in brief.
9.3.3 is segregation between bulk materials possessing chemical hazards and dangerous goods in packaged form
Explain 9.34 in brief.
9.3.4 Segregation between solid bulk cargoes possessing chemical hazards.
Section 10 Carriage of solid wastes in bulk
What is waste? What is its trans-boundary movement?
The trans-boundary movement of wastes represents a threat to human health and to the environment. Wastes shall be carried in accordance with the relevant international recommendations and conventions and in particular, where it concerns transport in bulk by sea, with the provisions of this Code.
Wastes, for the purpose of this section, means solid bulk cargoes containing or contaminated with one or more constituents which are subject to the provisions of this Code applicable to cargoes of classes 4.1, 4.2, 4.3, 5.1, 6.1, 8 or 9 for which no direct use is envisaged but which are carried for dumping, incineration or other methods of disposal.
Trans-boundary movement of waste means any shipment of wastes from an area under the national jurisdiction of one country to or through an area under the national jurisdiction of another country, or to or through an area not under the national jurisdiction of any country provided at least two countries are involved in the movement. Trans-boundary movement of wastes shall be permitted to commence only when notification has been sent by the competent authority of the country of origin, or by the generator or exporter through the channel of the competent authority of the country of origin, to the country of final destination.
Section 11 Security provisions (recommendary)
What is the role of security provision? What is the mandatory revision in respect of security?
The provisions of this section address the security of bulk cargoes in transport by sea. It should be borne in mind that some substances shipped as bulk cargo may, through their intrinsic nature, or when shipped in combination with other substances, be used as constituents for, or enhance the effect of, weapons used in the commission of unlawful acts. (It should also be borne in mind that ships used to carry bulk cargoes may also be used as a means to transport unauthorized weapons, incendiary devices or explosives, irrespective of the nature of the cargo carried.) National competent authorities may apply additional security provisions, which should be considered when offering or transporting bulk cargoes.
Mandatory: The relevant provisions of chapter XI-2 of SOLAS 74, as amended, and of part A of the ISPS Code shall apply to companies, ships and port facilities both engaged in the handling and transport of solid bulk cargoes and to which chapter XI-2 of SOLAS 74, as amended, applies, taking into account the guidance given in part B of the ISPS Code.
Section 12 Stowage factor conversion tables
Section 13 References to related information and recommendations
What is contained in section 13?
This section lists the references to the IMO instruments and other international standards (such as ISO, IEC) relevant to the requirements in this Code. It should be noted that this listing is not exhaustive.
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