Dangerous Solid Bulk Cargoes: the IMSBC Code, Liquefaction and Self-Heating
The IMSBC Code covers Groups A, A and B, B and C, excluding grain; the shipper supplies information and test certificates, while the onboard can test is only a complementary indication.
Operational Explanation
The Code covers all solid-bulk groups: A for liquefaction/dynamic separation, B for chemical hazards, A and B for both, and C for cargoes not classified A/B, excluding grain in bulk. The shipper supplies cargo information, representative sampling/testing and certificates; the Master decides whether to accept, load or continue safely.
Regulatory Reference
As of 15 September 2026, Amendment 07-23 (MSC.539(107)) has been mandatory since 1 January 2025. The IMSBC 2025 edition instead incorporates 08-25 (MSC.575(110)), available for voluntary application from 1 January 2026 with entry into force scheduled for 1 January 2027. Check the edition accepted by the flag and relevant authorities; distinguish publication year from mandatory date. IMO MSC.575(110).
The time limits concern sampling/testing relative to loading, not merely certificate issue. Also verify that the sample represents the actual cargo:
- §4.5.1 — the shipper shall ensure that a test to determine the TML is conducted within six months of the date of loading, and again whenever the composition or characteristics of the cargo have changed.
- §4.5.2 — sampling and testing for moisture content shall be conducted as near as practicable to the date of commencement of loading, and the interval shall never be more than seven days.
- §4.5.2 — if the cargo has been exposed to significant rain or snow between testing and completion of loading, the shipper is responsible for ensuring that the moisture content is still below the TML and for providing evidence of this to the master.
A TML test eight months earlier and a moisture test three weeks earlier are out of time even if the stated moisture value is below TML. Recheck material characteristics and weather exposure; a recently issued document does not cure an old test. IMO: IMSBC, section 4.5.
For unlisted cargoes follow IMSBC 1.3 with the loading-port competent authority and required agreements before carriage: do not assign Group C by analogy. For chemically hazardous cargoes, ventilation, monitoring and emergency response follow the specific schedule; indiscriminate ventilation may worsen some hazards. IMO: IMSBC Code.
Scope of Application
Groups A, A and B, B and C under the IMSBC Code; grain is excluded and governed by the International Grain Code. Identify schedule and group before acceptance.
Procedure / How to Complete It
- Obtain correct cargo information and schedule from the shipper.
- For Group A/A and B check TML and moisture-content certificates, representative sampling and applicable time limits.
- Assess rain, storage and changes that may invalidate representativeness.
- Use the can test only as a complementary indication.
- If free moisture, fluid behaviour, inconsistent certificates, recent rain or doubt exists: stop/delay and obtain competent sampling/testing before acceptance.
Practical Example
A can test shows no fluid behaviour, but the certificate conflicts with recent rain: the Master does not validate cargo from the negative test, suspends and requires representative sampling and laboratory testing under the Code.
What Typically Goes Wrong
Restricting the Code to Groups A/B, assigning test performance to the Master or using a negative can test as proof moisture is below TML.
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Doubt about the shipper's moisture-content certificate treated as resolved by a shipboard indication | Cargo with moisture above the TML loaded without the risk being detected | Stop or delay loading and obtain representative sampling and competent laboratory testing under the IMSBC Code; a can test is only a complementary indication |
| Cargo classified as Group C based on generic analogies, without checking the specific IMSBC schedule | Risk of liquefaction or self-heating not recognized and not managed | Always check the specific applicable cargo schedule, rather than relying on the classification of apparently similar cargoes |
| Cargo temperature not monitored for Group B cargoes prone to self-heating | Failure to detect a developing self-heating condition in time | Apply the temperature monitoring required by the specific IMSBC schedule for the entire voyage |
| IMSBC documentation (cargo schedule, moisture certificate) not kept on board or not immediately available | PSC deficiency and difficulty verifying compliance during the inspection | Keep the complete documentation on board for every IMSBC cargo carried, easily available for verification |
What the PSCO Checks
Operational Tips
- The Master checks and decides; the Master does not issue laboratory certificates.
- A positive can test or any doubt requires stop and further verification.
- A negative can test alone does not authorise loading.
Preparation checklist
- Group A/A+B/B/C identified
- Grain excluded from IMSBC path
- Complete shipper information
- TML/moisture certificates and sampling checked where required
- Recent conditions assessed
- Can test treated only as indication
- Stop/delay activated on doubt
FAQ
Related Topics
Last substantive revision of this page: 15 September 2026 · page fingerprint 414417272cae