Maritime University of Szczecin
Akademia Morska w Szczecinie
2011, 26(98) pp. 66–74 2011, 26(98) s. 66–74
Quality determinants of solid bulk cargoes in marine transport
Determinanty jakości stałych ładunków masowych
w przewozach morskich
Ruta Leśmian-Kordas, Milena Bojanowska
Maritime University of Szczecin, Faculty of Economics and Transport Engineering
Institute of Transport Engineering, Department of Commodities Science and Quality Management Akademia Morska w Szczecinie, Wydział Inżynieryjno-Ekonomiczny Transportu
Instytut Inżynierii Transportu, Zakład Towaroznawstwa i Zarządzania Jakością 70-507 Szczecin, ul. H. Pobożnego 11, e-mail: rutana@onet.eu
Key words: solid bulk cargoes/loads, quality determinants, marine transport/shipping, BC/IMSBC Code Abstract
The paper deals with the most essential trends and types of changes in the last three editions (2001–2005– 2009) of BC/IMSBC Code concerning the shipment of specific group of loads such as solid bulk cargoes. Since the general trend of changes in the content layout has been proved advantageous due to its standardized information in relation to all types of hazardous cargoes (A, B, C groups), its continuation aimed at facilitating the use of the Code in shipping operation is justified. Examples of detailed as well as extended information concerning technological shipping quality determinants of solid bulk cargoes enabling a better choice of appropriate technology of marine transport have been presented. The essence of information relationships resulting from the knowledge of particular quality determinants with the possibility of their practical technological application has been pointed out.
Słowa kluczowe: stałe ładunki masowe, determinanty jakości, przewóz morski, Kodeks BC/IMSBC Abstrakt
W artykule przedstawiono najważniejsze kierunki i rodzaje zmian w trzech ostatnich wydaniach Kodeksu BC/IMSBC (2001–2005–2009), dotyczącego przewozu morskiego bardzo specyficznej grupy ładunków, mianowicie stałych ładunków masowych. Stwierdzono, że przy generalnie korzystnym kierunku zmian co do układu treści, ujednolicającym formę przekazu informacyjnego w odniesieniu do wszystkich ładunków, tj. stwarzających różnorodne zagrożenia (grupy A, B i C), uzasadnione jest ich kontynuowanie, celem uła-twienia wykorzystania Kodeksu w praktyce transportowej. Podano przykłady uszczegółowień i rozbudowy informacji w zakresie determinantów jakości technologiczno-transportowej ładunków sypkich przewożonych luzem, pozwalających na zwiększenie stopnia zapewnienia wyboru i zastosowania prawidłowych technologii przewozu morskiego. Wykazano istotę powiązań informacyjnych, wynikających ze znajomości określonych determinantów jakości z możliwością ich praktycznego, technologicznego wykorzystania.
Introduction
Over the last three decades the increase of shipped commodities has been steadily rising by approximately 3% per year. The growing demand for marine transport is determined mainly by increase of world exploitation of raw materials, cultivation of cereal and the relation between trade volume and fleet size. Directly stimulating, the role of trade is linked to participation in maritime
trans-port in international turnover, estimated at 80% [1]. In relation to the 70s of the previous century, the quantity of the dry cargo transported annually by bulk carriers, considered the most significant for world trade: iron ore, coal, bauxite, phosphates and apatite, grains increased fourfold, reaching the amount of 1,876 million tons in 2006 [1]. The fleet of bulk carriers in the world increased from 186 million DWT recorded in 1980 to 276 million DWT in 2000. The last decade turned out to be the
period of the most dynamic growth in tonnage to handle bulk cargoes by sea, the total capacity of bulk carriers has risen by a further 209 million DWT. Currently, the global fleet, specialized in handling bulk, amounts to 8118 units, a total ton-nage of 486 million DWT [2].
The global backlog of orders for new merchant ships at the end of 2000 reached 99 million DWT, with the largest share of oil tankers, bulk carriers and container ships [3]. The order portfolio of 2010 was dominated by bulk orders (340 units), repre-senting more than 60% of the total number of ships ordered [2], whereas for years the combined fleet of bulk carriers: (OB) oil-bulk carriers and (OBO) ore-bulk-oil carriers has been declining.
With the development of international trade in solid bulk goods by sea, not only their diversity has increased, but there are also new loads, representing a variety of goods that have been shipped for years, with very different physical and chemical proper-ties. Changing technologies of production of many bulk commodities alter the characteristics essential for their safe transport, which is reflected in sus-tained development of transport regulations and requirements, by specifying, modifying and inte-grating the latest results of theoretical and practical research.
Properties of solid bulk cargoes essential in the marine transport
Solid bulk cargoes increasingly regarded as a distinct state of matter, with their characteristics different from other solids and in some respects similar to fluids, exhibit many features which are important in marine transport. These include among others:
the capacity of transverse shift of non-cohesive bulk cargo (plastic flow) to side of the ship dur-ing maritime transport, leaddur-ing to the loss of vessel stability;
the susceptibility to consolidation and subsi-dence during carriage by sea, resulting in in-crease in the free space above the surface of the load and generating the possibility of shifting even in the case of complete filling of the hold; different, often less than the vessel stowage
factor (SFS), load stowage factor (SFL), causing the risk of overloading the vessel's structure by allowing excessive amounts of heavy cargo; the susceptibility to liquefy of the wet cargo
associated with the increase in water pressure between the lateral shift of the cargo to side, and resulting in loss of stability;
the possibility of the load chemicals reacting with other substances contained in the
environ-ment (gas, liquid vapor, dust, solid particles which constitute the previous load) or a direct adverse impact on the environment, which in the case of goods classified as hazardous, become a threat to the health and life of the crew as well as to the property located on the ship and to the cargo itself.
The listed properties are conditioned above all by: chemical composition, water content, degree of fragmentation, specific cohesion of the particles, flow rate, mass density, the presence of dust and the form of solid bulk material shaped by additional processing (pellets, granules, blocks, meal, grits, powders, beads, nodules). These characteristics are usually the most important criterion for differentiat-ing the transport requirements in relation to goods falling under the common name of Bulk Cargo
Shipping Name – BCSN [4].
IMSBC Code
The need to develop precise rules concerning bulk shipment in marine transport was first pre-sented in 1960 at the International Conference on Safety of Life at Sea (SOLAS), which resulted in the development and adoption of the first edition of
Code of Safe Practice for Solid Bulk Cargoes – BC Code in 1965 under the auspices of IMCO. So far
there have been a total of 13 improved and revised editions of the BC Code. The last amendment, adopted due to the Resolution MSC. 268 (85) from 4th December 2008, changed both the name and status of the Code, which was replaced by the In-ternational Maritime Code for Solid Bulk Cargoes (IMSBC Code). In accordance with amendments to Chapter VI and VII of the SOLAS Convention, contained in resolution MSC.269 (85), from July 2008, the IMSBC Code could be applied as binding on a voluntary basis, but since January 2011 the document has been mandatory. In Poland, after a series of accidents at sea, the BC Code was intro-duced under the Regulation of the Minister of Foreign Trade and Maritime Economy as binding as early as in 1974. The final act in the national legislation to follow the recommendations and requirements contained in the BC Code, is the
Infrastructure Minister’s Regulation of 31 January 2003 on the safe transport of bulk cargo by sea- -going vessels.
The main purpose of the IMSBC Code is to en-hance safe carriage of solid bulk cargoes by admi-nistering: essential rules of conduct during loading and unloading, trimming and sorting methods, pro-cedures in case of emergency situations (fires and spills) and special ones, which reveal the diverse properties of the cargo, including dangerous ones.
The issues raised in the Code also apply to sam-pling and methodology of determining the most important, in terms of transport, safety, physical and physical-chemical features of cargoes, transport of solid waste harmful to humans and the marine environment, the scope and methods of monitoring the atmosphere in the holds and the conditions of the crew entering the ship's enclosed spaces. The Code sets out general procedures for proceed-ings before the formal adoption of the cargo to be complied with by both the shipper and the Master of the ship.
Threats on the part of transported cargo were divided into three groups, corresponding succes-sively to liquefy of the cargo containing moisture (A), chemical hazards posed by group (B) and transverse shift to side of the ship of dry cargo (C). Dangerous solid cargo in bulk, with a broad spec-trum of properties, are a group of special cargo, identified with a number of other recommendations in a variety of IMO documents, including Chapter VII of the SOLAS Convention. In accordance with Part A-1 of Chapter VII of the SOLAS Convention, the “dangerous” bulk cargo shall be: “any material, other than a liquid or gas, consisting of a combina-tion of particles, granules or other larger pieces of material, generally uniform in composition, which is covered by the IMDG Code1 and is loaded directly into the cargo spaces of the ship without any intermediate form of containment, and includes such materials loaded in a barge on a barge- -carrying ship” [5].
Although in the SOLAS Convention the defini-tion of dangerous cargoes does not invoke the con-cept of MHB (Materials Hazardous Only in Bulk), they are defined in section 9 of the IMSBC Code:
Materials possessing chemical hazards.
Changes in the Code of BC / IMSBC in relation to the risks posed by cargoes
The procedure of updating successive versions of the BC / IMSBC Code by the initiative of IMO member states covers the amendment concerning both form and content, within which there can be distinguished:
1) content rearrangement (the order of chapters, the layout of content particulars relating to the cargo, and singling out separate additions); 2) addition of new paragraphs and chapters, which
extend the areas covered by the Code;
1 International Maritime Dangerous Goods Code, IMDG
Code – concerning the carriage of dangerous goods in packages.
3) changes in terminology, the refinement of con-cepts and terms used, attachment of explana-tions;
4) refining the criteria for eligibility of goods under the common name BCSN to different subgroups of other transport requirements and establishing new subgroups;
5) refining and extending the information about the properties of cargo and transport requirements for invidual loads;
6) changes resulting from attempts to harmonize rules concerning maritime cargo transport with the provisions for other modes of transport, in particular to standardize the naming of cargo and the corresponding UN numbers.
Examples of updates listed in the above points made over the past ten years, including three subse-quent editions of the Code (2001, 2005, 2009) [4, 6, 7] are shown in table 1.
They show considerable development and elabo-ration of requirements, especially for cargo posing threats other than chemical. The tendency is also visible to single out subsets of cargo and accurate determination of the criteria for membership by identifying the areas of chemical composition, water content, cargo form and particle size. As sub-stantial change there should be regarded the clarifi-cation of terms relating to compulsory and volun-tary requirements, preventing the misinterpretation of the rules. Another trend is the attempt to stan-dardize the wording and application of specific patterns such as consistently “this cargo shall not be ventilated,” rather than those used in previous edi-tions, the ambiguous “do not ventilate” or “should not be ventilated.”
Changes in the requirements for cargoes susceptible to liquefy (group A)
An example of cargo posing different threats depending on the water content is ilmenite (tita-nium ore, ranging from yellow to brown, containing about 45% titanium oxide), which in the latest edi-tion of the Code appears as follows:
ILMENITE CLAY: containing 10–20% of wa-ter, belongs to group (A) of cargoes susceptible to liquefy;
ILMENITE SAND: not classified as cohesive, but qualified for the risk group C, because of its high density, and only when the water content is within 1–2%. When the water content > 2% it is treated as a cargo susceptible to liquefy and subject to similar transport requirements as ilmenite CLAY (group A).
In the latest edition of the Code, the require-ments for carriage of ilmenite clay were signifi-cantly expanded. The requirement to determine the moisture content in the cargo before taking on-board to ensure that the TML2 is not exceeded, was supplemented by the need to maintain the moisture content of the load at its baseline levels throughout the duration of the voyage. The possi-bility of loading during rainfall was restricted to exceptional circumstances, when the moisture con-tent of the load is low enough not to cause the risk of its growth to a value close to TML. Discharging during precipitation was determined as possible on the condition that the total amount of cargo is unloaded in the port. The requirement to survey the surface appearance of the cargo during carriage was added with indication that in case of the presence of free water on the surface or the surface condition in the form of fluid, the captain is obliged to take ap-propriate measures to prevent the shift of cargo and loss of vessel stability. Undoubtedly, the require-ments became stricter due to incidents of accidents, including numerous cases of liquefy of the loads of ilmenite. In November 2000, the M/V Maria VG, carrying 2.662 tones of ilmenite in the form of clay, from the port Tahkoluoto (Finland) to Slite (Swe-den), had a dangerous heel on starboard beam of
2 TML – Transportable Moisture Limit
20 as a result of liquefy of cargo, which contained moisture in amounts well above the TML set for this material part (38.9–46.5% vs. TML = 22.7%). In a report on the causes of the incident the impor-tant role of reducing external sources of additional moisture was highlighted. The cargo, before load-ing, was stored for 5 days in the open air, during which heavy rainfall occurred [8].
For a better understanding of the phenomenon of liquefy, only for cargoes of specified degree of fineness and moisture content, starting from the 2005 edition of the BC Code, Chapter 7 presents an overview of the phenomenon and the reasons for the importance of interdependence between the degree of fragmentation and the water content in the process. It was noted that there is a threat of liquefy of the loads in group A also when they are cohesive and trimmed in accordance with the recommendations of the Code. There were distinguished three phases of liquefy:
1) decrease in the volume between the particles, as a result of subsidence, and consolidation of cargo during movement of the ship;
2) increase in pressure of water contained in the cargo, due to the decreasing volume between the particles;
3) decrease in the coefficient of friction between particles, due to the increase in water pressure, resulting in decrease in shear strength.
Table 1. Selected changes in the structure and general content of three consecutive editions of the BC / IMSBC Code [own study] Tabela 1. Wybrane zmiany w układzie i treści ogólnej trzech kolejnych wydań Kodeksu BC/IMSBC [opracowanie własne]
Change in BC 2005 relative to 2001 BC Change in IMSBC 2009 relative to 2005 BC Appendices A, B, C, containing a summary table of loads
(groups A and C) and individual cards (group B) have been replaced by individual cards for all goods covered by the Code, and arranged alphabetically in a single Appendix 1, with indi-cating the risk group.
Appendices 4–8 dealing respectively with: the bulk density mea-surement methods, loads with a limited requirement for a fixed gas fire-extinguishing system, the procedures for entering en-closed spaces on the ship and the use of pesticides have been transferred to the Supplement (BLU Manual)1.
Appendices, previously identified with consecutive letters of
the alphabet, have been numbered. A separate chapter – „Definitions‟ has been opted out with its contents placed in Chapter 1 – „General Provisions‟; a part of the SOLAS Convention, namely Chapter VI (Part A and B) and VII (Part A-1) have also been cited in this chapter.
Non-cohesive cargo list has been moved into a new Appendix 3 (Properties of solid bulk cargoes).
New Appendices on: (1) list of solid bulk cargo, for which there is no requirement for a fixed gas fire-extinguishing sys-tem (typically CO2) or for which the fire fighting system will
not be effective and (2) recommendations on the safe use of pesticides in ships have been placed.
There has been placed a new chapter (Chapter 11), relating to hazards resulting from terrorist actions, which may be aggravated by the direct use of the transported bulk cargo of dangerous prop-erties, or as a result of the impact of weapons on the cargo. Examples of such loads are: ammonium nitrate UN 1942 (Class 5.1) and ammonium nitrate fertilizers containing UN 2067. A new Chapter 12 has been introduced - expressing in tabular
form specified in the Code references to the other requirements of the IMO (SOLAS, IMDG Code, FSS Code1 and others).
Due to the obligatory nature of the Code, the significance of the following words in the text of the Code has been specified as: Shall – mandatory
Should – recommendatory, May – optional.
The terms static angle of repose and dynamic natural angle of repose have been replaced by angle of repose, indicating in the definition that it refers to non-cohesive cargoes.
According to the BC / IMSBC Code [4, 5], liquefy refers neither to loads of very small cles (dust) as strong cohesion between such parti-cles prevents them from moving and thereby increase the water pressure, nor cargo in the form of larger particles, between which water moves without an increase in pressure.
Changes in the requirements for cargoes possessing chemical hazards (group B)
One of the factors to ensure the safe carriage of goods that can be dangerous for their chemical hazards is the correct classification of transported cargoes. The use of cargo divisions with a common
name but different carriage conditions is due to their different characteristics:
chemical (e.g., content of hazardous component and organic pollutants in nitrogen fertilizers based on ammonium nitrate);
physical (e.g., the degree of fragmentation, or its form as in the case of sulphur);
set of physical, chemical and physical-chemical properties, due to different production techno-logies (e.g., water and fat content depending on the de-oiling process and to a certain degree on plants species the oil-cake is obtained from, par-ticle size and methods of preparation in the case of directly reduced iron).
Table 2. Selected changes in the detailed content of the cargoes contained in three consecutive editions of the BC/IMSBC Code [own study]
Tabela 2. Wybrane zmiany w treści szczegółowej dotyczącej ładunków, zawartej w trzech kolejnych wydaniach Kodeksu BC/IMSBC [opracowanie własne]
Change in BC 2005 relative to 2001 BC Change in IMSBC 2009 relative to 2005 BC For all loads the range of basic information on: the
par-ticle size, form (granules, beads, lumps, powders, etc.) and bulk density has been expanded and standardized. In case the specified feature is not translated into safety (e.g. particle size, angle of repose) or does not apply – the single phrase “not applicable” has been adopted.
Previously, these properties were given selectively or generally for a large group of similar cargoes.
Verbal description of the properties (water content, total fat content) of cargoes under the common name SEED CAKE has been supplemented with a graphic representation of these characteristics and their scope in order to avoid erroneous interpretation and correct classification of the cargo to a group of UN 1386 (a) or UN 1386 (b).
A number of detailed features have been described due to defining ranges of values for specific cargoes, which allowed separate cards for each of them.
For example, given in the 2001 edition of the stowage factor (SF) based on all ores and concentrates was 0.33– 0.57 m3/t. In the 2005 edition, its value was specified for each of the loads from the group.
Both ilmenite SAND and ilmenite CLAY are very heavy loads, but their range of stowage factors is completely different and is suitably SF = 0.31–0.42 m3/t (Sand) and SF = 0.4–0.5 m3/t (Clay).
Water content range for a load of ilmenite SAND has been supple-mented with > 2%, qualifying it as a hazard of liquefy, that is, belong-ing to group A.
In the previous classification, the extent of ilmenite SAND includes the water content of 1–2% (group C), while ilmenite CLAY 10–20% (group A).
Currently, ilmenite SAND may belong to a risk group C or A.
Other relevant information and a set of additional proper-ties for multiple loads have been added. For example, with respect to ilmenite CLAY its water content was deter-mined, the ability to pollination, non-flammability and high density indicated.
In addition to loads of sulphur SULPHUR UN 1350 (Class 4.1, Group B), a new tab for sulphur SULPHUR (former, solid) was created and classified into risk group C.
There have been created separate cards for loads of ilme-nite SAND and ilmeilme-nite CLAY, taking into account other hazards (C or A), due to their different content of water.
In addition to the existing DRI cargo cards: DIRECT REDUCED IRON (Briquettes, hot-moulded) and DIRECT REDUCED IRON (lumps, pellets, cold-moulded briquettes), there has been created a new, card for DRI (By-product Fines).
The creation of individual cards for all cargoes (also from groups A and C), has increased the amount of information concerning the individual loads, and thus the details of the transport requirements, particularly in relation to goods of non-hazardous chemical (B).
For example, for ilmenite CLAY there have been devel-oped requirements for safety precautions when loading in conjunction with very low SF.
Transport requirements for cement have been extended by more de-tailed information about the trimming of the cargo, and attention has been drawn to its characteristics (form of fluid, a variable angle of repose, subsidence, dusting), especially important if the ship is not designed for transporting cement.
Requirements for the cargo of ILMENITE CLAY concerning precau-tions when loading at the time of rainfall have been extended, and the scope of the compulsory care of cargo during transport in order to avoid liquefy of the load has been increased.
Oil cake and meal, which are residues of me-chanically expelling or extracting oil seeds, belong to a group of self-heating loads (Class 4.2, Group B), at the specified water content and residual fat. These properties, in addition to production techno-logy, are essential to distinguish four subgroups of cargo, including three dangerous ones (UN 1386, UN 1386 b, UN 2217) and a non-hazardous one. Within the subgroup classified as hazardous, there are also exemptions from the sharpened transport requirements for specific commodities (plant spe-cies) as well as load form. A seemingly insignifi-cant change in the descriptions of the cargo SEED CAKE UN 1386 (a) and SEED CAKE UN 1386 (b), definitely facilitates the correct classification of loads into one of these groups. The record repeated in subsequent editions of the Code, for UN 1386 (b), reads as follows: “solvent extractions and
ex-pelled seeds, containing NOT MORE than 10% of oil AND, when the amount of moisture is 10% higher than, not more than 20% of oil and moisture combined”, could be interpreted in two ways. The
load containing: Oil (O) < 10%, Moisture (M) < 10%, O + M < 20%, could be excluded from the requirements for UN 1386 (b) and regarded as safe for an equivalent reading of a total of three condi-tions (due to M < 10%) or as subject to the criteria, if the overriding adopted criterion was only the fat content (about < 10%).
In case of the second possible interpretation, all the cake with a fat content below 10% was attribut-able to a group of UN 1386 (b), except those con-taining M > 10% and M + O > 20%, which put them in a group of UN 1386 (a) [9]. Currently, the graphic treatment of these interdependencies, sup-plemented by a precise verbal description, provides a unique solution of the problem presented.
Especially noteworthy are changes on the sul-phur contained in the successive editions of the Code as SULPHUR UN 1350, lumps or coarse- -grained powder, classified as Class 4.1, Group B. Sulphur ignites easily, releasing toxic, very irritat-ing and chokirritat-ing sulphur dioxide. Sulphur bulk cargo is also susceptible to dust explosion, which may occur, especially during loading and unload-ing, and when cleaning the hold. Changes in the classification of sulphur and its placements in the risk group B or C, depending on its form, result from the harmonization of the Code IMSBC with the IMDG Code, where solid sulphur formed in specific shapes is excluded from the requirements of Class 4.1, by the Special Provision 242 [10]. The 2005 edition of the BC Code also contains different sizes of particles of sulphur in lumps or coarse powder, in addition, dividing them into
flakes (up to 10 mm) and pellets and lumps (up to 5 mm), while according to the IMDG Code (2008), the sulphur formed into specific shapes such as nodules, granules, pellets, pastilles or flakes, is not considered as dangerous cargo. The effect of uni-form definitions of cargo under the same name BCSN and UN number on the card is the removal for individual sulphur UN 1350 in the new edition of the IMSBC Code of the information about the dimensions and highlighting its heterogeneous shape and dimensions by adding the word “crushed” (crushed lump and coarse-grained). Separation of sulphur in the moulded form and declaring it as chemically safe cargo is the result of over 15-year successful experience in transport by sea as well as many independent laboratory tests, excluding its placement to Class 4.1, group B.
An example of distinguishing a new variation of cargo is directly reduced iron in the smallest form (Direct Reduced Iron, By-product Fines), which is a by-product formed during the production of iron pellets fused hot (DRI A Briquettes, hot-moulded) or cold-formed lumps, briquettes and pellets (DRI B Lumps, pellets, cold-moulded briquettes) included in previous editions of the BC Code. Discussion on the introduction of this variety to the IMSBC Code was launched due to a series of acci-dents involving the cargo, described in various documents by Venezuela and France [11]. In No-vember 2004, Ythan bulk carrier, carrying cargo of DRI Fines from Venezuela to China, experienced a series of catastrophic explosions in four of the five holds, which resulted in six casualties of the crew members and the ship sank 45 minutes after the event [12]. A new variant of the cargo, com-monly and similarly hazardous as the DRI (A) and DRI (B) in respect of: the possibility of self-heating and the emission of hydrogen in dangerous amounts, above the Lower Explosion Limit (4% in a mixture with air), was differentiated by the parti-cle size so that experience in the transport of the first two varieties proved inadequate. Therefore, countries with experience in shipping a new variety of directly reduced iron, which is the finest form of this cargo, were asked to provide any information about: properties, grain composition and bulk den-sity, emerging hazards during transport, the type of ships on which the cargo is transported, the use of inert gas, type of ventilation, equipment for moni-toring the cargo during transport and the tempera-ture and moistempera-ture content during transport. The result of international work and consultation is an individual card for a cargo being recognized as a DIRECT REDUCED IRON (C) (By-product Fines) in IMSBC 2009, showing in detail the risks,
requirements, including conditions during loading, transport requirements and the precautions that should be taken before the adoption of the cargo on board. The cargo was included in class MHB, group B, because of the threat of self-heating, igni-tion and explosion during transport. It was pointed out that the sources of these threats are chemical reactions with oxygen and water (fresh or sea) and even water vapour in the air, which lead to the release of hydrogen and generate heat. Despite the great similarity of other characteristics and re-quirements for the transport of DRI (A), DRI (B) and DRI (C), dimensions and particle size (from DRI in the form of briquettes – A to fine grained, with an average particle size of 6.35 mm – C) de-termine the conditions for admission to the ship because of the conditioning period required before: 0 days (DRI A), 3 days (DRI B), 30 days (DRI C). Moreover, because of the known relationship be-tween water content and degree of fragmentation of the cargo, and the rate of chemical reactions posing a risk of explosion, DRI (C), as well as DRI (B), may be transported only in an atmosphere of inert gas, a maximum oxygen content in air 5% by volume, at continuously maintained water content of less than 0.3% of the cargo at all stages of trans-port, including loading. In addition, each time be-fore loading there should be checked the water-proofness of the hatches, and a sea journey can be started only after ensuring that the holds are tight and inert, the temperature of the cargo is stable and the hydrogen concentration in the holds does not exceed 0.2% by volume. During transport, a per-manent, documented monitoring of the cargo tem-perature, water content, concentration of hydrogen and oxygen in the cargo spaces is required. Records of monitoring must be kept in the ship's records for 2 years.
Part of the cargo, under the common name, is not a hazardous cargo, if it meets certain criteria to exclude and ease the transport requirements. Exples are nitrogen-based fertilizers containing am-monium nitrate (AMMONIUM NITRATE BASED Fertilizers Non-Hazardous). Nitrogen fertilizers containing ammonium nitrate may exhibit explo-sive properties, especially in the case of the content of combustible organic pollutants such as oil. At the content of this type of contamination above 0.4%, ammonium nitrate is counted among one of the explosives. Also, mixtures of ammonium nitrate, though unclassified as explosives, may explode during incineration. Fertilizers, which are mixtures containing at least 45% of ammonium nitrate, ex-hibit oxidizing properties, if also composed of am-monium sulphate, and their total amount exceeds
70% (UN 2067, Class 5.1, Group B). In addition, fertilizers containing ammonium nitrate may be prone to spontaneous decomposition (UN 2071, Class 9, Group B). Currently, according to IMSBC 2009, fertilizers containing ammonium nitrate in quantities not exceeding the limits set for UN 2067 and UN 2071 are not included in the dangerous but only in the risk group C, because of the low value of the angle of repose 27–42. The United States, during the 11th session of the Subcommittee on the carriage of dangerous goods, solid cargoes and containers of IMO (document DSC 11/4/7) pro-posed that the cargo should be reclassified as MHB. This type of amendment, however, was not in-cluded in the new edition of the Code. A similar proposal was sent in relation to chromite ore, which is a cargo belonging now to group C, which poses a threat mainly due to high density, but generates toxic dust, and also in respect to the cargo of tapi-oca obtained from cassava – forming a dry mixture of powder and granules, with an angle of repose 32 C (group C), but also easily reacting with oxy-gen, which can lead to cargo heat and reduction of the amount of oxygen in the cargo hold. Lack of any conclusive basis for verification of an existing list of goods of MHB-class and unified criteria for assigning cargoes to the IMO class limits the intro-duction of these changes, since there are no ex-perimental data or actual threats observed in prac-tice.
Changes in the requirements for cargoes (group C) which are neither liable to liquefy (group A) nor possess chemical hazards (group B)
The threats assigning cargo to group C are usually associated with dry cargoes ranked among non-cohesive ones, characterized by low values of the angle of repose, that readily shift due to sliding during transport. Different angles of repose for individual cargoes, which are within three ranges: up to 30, 30–35 and above 35, determine dif-ferent rules of trimming and allow the classification of cargo to be high, medium or low susceptible to readily shift due to sliding during transport. Group C covers also cargoes of high specific gravity, which include mainly concentrated ore, causing a risk of exceeding the permissible loads and stresses of the hull, up to its deformation, cracking the shell, and in extremely difficult weather condi-tions, even breaking the ship in waves. Recent changes in the requirements to reduce such risks include mainly the extension of specific require-ments on the conditions under which the loading is run and how a particular shipment is trimmed.
CEMENT, one of group C loads, is character-ized by low values of the angle of repose in the aerated state. During the deposition of cement while loading which is almost immediately fol-lowed by deaeration, the load changes its character-istics, becoming relatively stable, cohesive granular material with no fixed range of values of the angle of repose. In the new edition of the Code special attention was paid to a very low angle of repose of cement in the form of fluid, actually containing more than 12% of the air occurring during loading, until the total consolidation. Although cement is not classified as non-cohesive group of cargo, with a fixed range of angle of repose, and, in respect of which there are additional requirements for the trim, detailed information appears in the IMSBC Code on how to align the cargo area. Cement must be trimmed to a level so that the angle between the surface of the cargo and the horizontal plane does not exceed 25. An important change in relation to multiple loads of Group C is supplementing the basic information about their ability to pollination, including an indication of the essential characteris-tics of these particles, mainly flammability, toxicity and harmfulness. Requirements for the precaution-ary measures in reference to the crew clothing, goggles and masks with filters, are often included as mandatory.
With regard to terminology, the concepts of cone angle (called static angle of repose) and the angle of repose (angle of repose, kinetic angle of repose), as in the Code of 2001 closely reflecting the methodology for their determination, have been replaced by a single term “angle of repose” and single definition not referring to any of the labora-tory methods. According to the IMSBC Code (as well as the BC Code of 2005): „Angle of repose
means the maximum slope angle of non-cohesive (i.e. free-flowing) granular material. It is measured as the angle between a horizontal plane and the cone slope of such material”.
Conclusions
1. The Code for the shipment of solid bulk cargo is constantly enriched with new information and more detailed determinants of the quality of these goods.
2. The introduction of these changes in the Code in relation to all groups of goods presenting a trans-port hazard (may liquefy, possess chemical hazard, readily shift to the side of the ship, the deformation of the hull) provide a significant impact on the selection and use of proper, safe techniques and transport technologies.
3. Ensuring the safety and unchanged quality of goods favours the introduction of the Code of con-duct based on individual cards for all cargoes (Groups A, B and C), containing the following: – characteristics of the determinants of quality (in the form of table headers) – arising from the character-istics transport recommendations, including the sequence of provided information about the follow-ing areas: Hazard –Stowage & Segregation – Hold cleanliness – Weather precautions – Loading – Precautions –Ventilation – Carriage – Discharge – Clean-up.
4. Adoption of the alphabetical arrangement (in reference to the technical names) of individual cards of cargo to some extent makes it difficult to quickly find the necessary information in emer-gency situations. It seems that a further stage in the development of the Code should be an alphabeti-cally arranged assortment of cargo according to the type of risks, with the information on possible si-multaneous risks enclosed in the table header of individual cards.
5. With regard to the determinants of the quality of transport – technology of solid bulk cargo, the changes made in recent editions of the Code related to: the introduction of a new definition of the angle of repose, clarification of the particle size and the various forms of structural loads, that are in direct relation with the degree of shipment risks, dividing the loads of the same kind according to different types due to the water and stowage factor, resulting in classifying risks for different groups (A, B or C), additions to the clarification of the requirements for water content, determining the dusty, consolidating, and cohesive properties and graphic representation of some of the more complex interactions between the susceptibility to self-heating and the chemical composition of cargo.
6. The selection of the examples of precise specification of the data relating to the various characteristics of loads is a proof of recognition for the significance of detailed clarification and taking into account the determinants of quality in the processes of cargo transport, especially as specific as solid bulk, which is based on long experience and its appreciation in practical use.
References
1. International Shipping and World Trade, Facts and Figures, October 2009, Maritime Knowledge Centre, IMO 2009. 2. ISL Shipping Statistics and Market Review, 2010, vol. 54,
No 8.
3. Rocznik Statystyczny Gospodarki Morskiej 2001, Instytut Morski, Gdańsk 2001.
4. International Maritime Solid Bulk Cargoes Code, 2009 Edition and Supplement, IMO, London 2009.
5. Międzynarodowa Konwencja o bezpieczeństwie życia na morzu, 1974 SOLAS, Tekst jednolity, PRS Gdańsk 2006. 6. Code of Safe Practice for Solid Bulk Cargoes 2004, 2005
Edition, IMO, London 2005.
7. Code of Safe Practice for Solid Bulk Cargoes, 2001 Edition with MSC/Circ. 908, IMO, London 2001.
8. Investigation report B 4/2000 M, Mv. Maria VG, incident at Sea of Bothnia off Pori, November 7, 2000. Edita Prima Oy, Helsinki 2002.
9. Review of the BC Code, including evaluation of properties of solid bulk cargoes. Clarification on classification of seed cake. Submitted by BIMCO, DSC/9/10, IMO 2004. 10. Review of the BC Code, including evaluation of properties
of solid bulk cargoes. Classification of formed solid sul-phur. Submitted by Germany and Canada. DSC/12/4/16, IMO, 2007.
11. Sprawozdanie z 11 sesji Podkomitetu ds. przewozu towa-rów niebezpiecznych, ładunków stałych i kontenetowa-rów (DSC) IMO Delegacji Polskiej, 02.01.2007.
12. Review of the BC Code, including evaluation of properties of solid bulk cargoes. Information needed for the definition of DRI Fines, other than DRI (A) briquettes, hot moulded. Submitted by the Republic of Marshall Islands, Malta, and INTERCARGO, DSC 12/4/14, IMO, 2007.
Recenzent: prof. dr hab. Hieronim Kubera Uniwersytet Ekonomiczny w Poznaniu
