Appendix A: Key IMSBC Code Information (Selected Cargo Schedules, Test Procedures Summary)

Part 1: Summaries of Selected IMSBC Code Schedules

This section provides simplified summaries of the key hazards and precautions for several common and challenging bulk cargoes discussed in Chapter 8.

1. IRON ORE FINES

(Always check the specific schedule; properties can vary)

• Primary Hazards:
  • Liquefaction (Group A): Primary and most critical hazard. Can lead to rapid loss of stability and capsize. This risk exists if the Moisture Content (MC) exceeds the Transportable Moisture Limit (TML).
  • High Density: Can cause excessive longitudinal stresses (Shear Force/Bending Moment) and overstressing of tank top plating if not loaded correctly.
  • Cargo Shifting (Group C aspect): Even if not liquefiable, can shift if not trimmed properly.
• Key Pre-Loading Requirements:
  • Documentation: MUST receive a valid TML certificate and MC certificate from the shipper.
  • MC vs. TML: MUST verify that MC < TML. If MC is equal to or greater than TML, the cargo MUST NOT be loaded on a conventional bulk carrier.
  • Stowage Plan: Detailed plan must be made using the loading computer, respecting tank top strength and ensuring SF/BM are within limits at all intermediate stages (alternate hold loading is common).
• Precautions During Loading:
  • Continuously monitor cargo for visual signs of excess moisture (splatter, free water).
  • Stop loading immediately if liquefaction is suspected. Perform a “Can Test” as a supplementary check if in doubt.
  • Strictly follow the pre-planned loading sequence.
  • Continuously update the loading computer to monitor stresses.
  • Trim cargo reasonably level as per IMSBC Code requirements.
• Precautions During Voyage:
  • Maintain weathertight integrity of hatches.
  • Ventilation is generally not required.
  • Monitor vessel for any unexplained list or unusual motion.
  • In heavy weather, reduce speed and alter course to minimize severe vessel motions.

2. COAL

(Always check the specific schedule; properties vary significantly by type)

• Primary Hazards:
  • Self-Heating and Spontaneous Combustion (Group B): Liable to oxidize, generate heat, and potentially ignite.
  • Methane (CH₄) Emission (Group B): Can emit flammable methane gas, creating an explosive atmosphere.
  • Oxygen (O₂) Depletion: Oxidation consumes oxygen, creating an asphyxiation hazard.
  • Toxic Gas (Carbon Monoxide – CO) Emission: CO is produced during self-heating and is a primary indicator of a developing fire. It is also toxic.
  • Dust Explosion: Fine coal dust can be explosive.
• Key Pre-Loading Requirements:
  • Documentation: Obtain shipper’s declaration specifying characteristics, particularly liability to self-heat and emit methane. Check for any weathering certificates if required.
  • Hold Preparation: Holds must be clean, dry, and free of any combustible materials or oily residues.
  • Equipment Checks: Gas monitoring equipment (CH₄, CO, O₂) must be calibrated and tested. Temperature monitoring equipment must be ready. Flame screens on vent outlets must be clean and intact.
• Precautions During Loading:
  • Do not load if cargo temperature exceeds 55°C (or as specified).
  • Strictly prohibit all ignition sources (smoking, hot work) in or near cargo areas.
  • Trim cargo reasonably level.
  • Commence gas and temperature monitoring as soon as loading starts.
• Precautions During Voyage:
  • Gas Monitoring: Regularly monitor CH₄, CO, and O₂ levels in each hold. Record all readings.
  • Temperature Monitoring: Regularly monitor temperatures at various depths. Record all readings and watch for trends.
  • Ventilation: Follow IMSBC Code schedule guidance. Typically, surface ventilation is used to remove methane. If CO levels are steadily rising or other signs of self-heating appear, ventilation should generally be stopped and holds sealed to restrict oxygen.
  • Enclosed Space Entry: NEVER enter a coal hold without strict adherence to enclosed space entry procedures, including thorough ventilation and atmosphere testing.

3. BAUXITE FINES

(Always check the specific schedule and latest IMO guidance)

• Primary Hazards:
  • Liquefaction (Group A): The overriding safety concern. Certain types of bauxite with a specific particle size distribution and moisture content are liable to liquefy.
  • Cargo Shifting (Group C aspect): Can shift if not properly trimmed.
  • Dust: Can be very dusty during handling.
• Key Pre-Loading Requirements:
  • Classification: The Master must be satisfied with the shipper’s classification of the cargo as either Group A or Group C. If declared Group C but it appears to contain fine particles, extreme caution is required.
  • Documentation: For Group A cargoes, valid TML and MC certificates are mandatory.
  • MC vs. TML: MUST verify that MC < TML. If equal or greater, the cargo MUST NOT be loaded.
  • Stowage Plan: Prepare a detailed plan respecting stress and stability limits.
• Precautions During Loading:
  • Continuously monitor cargo for visual signs of excess moisture. The “Can Test” is a vital supplementary check.
  • Stop loading immediately if liquefaction is suspected.
  • Avoid loading during heavy rain.
  • Trim cargo reasonably level.
  • Implement dust control measures.
• Precautions During Voyage:
  • Maintain weathertight integrity.
  • Ventilation is generally not required for safety.
  • Monitor for any signs of instability or unusual vessel motion.

4. AMMONIUM NITRATE BASED FERTILIZER (ANBF)

(UN 2067 or UN 2071 – Always check the specific schedule for the correct UN Number)

• Primary Hazards:
  • Self-Sustaining Decomposition (SSD) (Group B): Some types, when heated, can undergo decomposition that generates immense heat and large volumes of toxic gases (brown/yellow NOx fumes, ammonia), and can propagate even without air.
  • Fire/Explosion (Group B): AN is an oxidizing agent (Class 5.1) and can intensify fires. Contamination or involvement in a large fire can lead to an explosion.
  • Corrosivity: Can be corrosive to steel, especially when wet.
  • Hygroscopic: Absorbs moisture, leading to caking.
• Key Pre-Loading Requirements:
  • Documentation: Obtain shipper’s declaration specifying composition (especially % of AN) and, critically, the results of the test for self-sustaining decomposition. Cargoes that exhibit SSD are extremely hazardous.
  • Hold Cleanliness: Must be scrupulously clean and dry, free from ALL contaminants, especially combustible materials, oils, chlorides, sulphur, and acids.
  • Stowage: Stow away from all sources of heat (engine room bulkheads, heated bunker tanks) and ignition. Ensure strict segregation from incompatible materials.
• Precautions During Loading:
  • No Hot Work: Absolutely no hot work in the vicinity.
  • No Smoking: Strictly enforce.
  • Avoid Contamination: Ensure loading equipment is clean.
  • Do not load if cargo temperature is elevated.
• Precautions During Voyage:
  • Temperature Monitoring: If required by the schedule, monitor temperatures regularly.
  • Ventilation: Follow the specific schedule’s guidance. This can be complex; some types require ventilation, others require holds to be sealed.
  • Emergency Response for SSD:
    • Boundary Cooling with copious amounts of water is a primary response.
    • Direct application of water may be required but follow schedule guidance precisely.
    • CO₂ is generally INEFFECTIVE for SSD.
    • SCBAs are essential due to toxic fumes.

Part 2: Summary of Key Test Procedures (IMSBC Code)

This section provides a simplified overview of key test procedures referenced in the Code. This is for familiarization only; the actual tests must be conducted by competent laboratories following the detailed procedures in the Code.

1. Determination of TML & MC for Group A Cargoes (Appendix 2)

• Purpose: To determine the safe transportable moisture limit and compare it with the actual moisture content.
• Key Tests for TML:
  • Flow Table Test: A sample in a mould is subjected to jolting on a table. The moisture content at which it begins to “flow” or deform is the Flow Moisture Point (FMP). TML = 90% of FMP.
  • Penetration Test: A weighted bit is dropped on a sample. The moisture content at which penetration exceeds 50mm is the FMP. TML = 90% of FMP.
  • Proctor/Fagerberg Test: A laboratory compaction test used to determine the TML for a wider range of materials, including coal.
• Test for Moisture Content (MC): Involves weighing a sample, oven-drying it at 105°C until its weight is constant, and then re-weighing. The weight loss is the moisture content, expressed as a percentage of the original total weight.
• Critical Factor: Representative sampling of the cargo stockpile is essential for all these tests to be meaningful.

2. Shipboard Check – The “Can Test” (Section 8.4)

• Purpose: A supplementary, indicative check that can be performed by the crew if there are any doubts about a cargo’s moisture content (e.g., if it appears wetter than certified, or after heavy rain). IT IS NOT A SUBSTITUTE FOR LABORATORY CERTIFICATION.
• Procedure:
  1. Take a representative sample of the cargo.
  2. Fill a small can or similar container (e.g., 0.5 – 1.0 litre capacity) approximately half-full with the sample.
  3. Hold the can in one hand and bring it down sharply onto a hard surface (like the deck) from a height of about 0.2m. Repeat this 25 times.
• Interpretation:
  • “FAIL” (Possible Unsafe Condition): If free moisture or a “soupy” liquid appears on the surface of the cargo after the test. This is a strong warning sign. Loading should be stopped, and the Master should inform all parties and seek expert advice/re-testing.
  • “PASS” (No Free Moisture Appears): This does not necessarily mean the cargo is safe, especially if the certified MC is already very close to the TML. It is merely an absence of a clear failure indication. The certified laboratory results remain the guiding document.

Disclaimer

This summary is for guidance and quick reference only. It is not a substitute for the official, up-to-date IMSBC Code, which must always be consulted as the primary source of information for the safe stowage and carriage of any solid bulk cargo. The individual schedules contain more detailed information than can be presented here. The user must refer to the latest edition of the IMSBC Code and any subsequent amendments for full and accurate details.