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
SOLAS Chapter VI makes the IMSBC Code mandatory for the carriage of solid bulk cargoes; the 2025 edition (in force from 1 January 2025) introduces 12 new cargo schedules and amends 11 existing ones; further amendments are expected to enter into force from 1 January 2027 (voluntary application from 1 January 2026).
The two deadlines that make the certificates expire. Comparing moisture content with the TML is only meaningful if both tests are within time, and the Code sets the limits:
- §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 certificate issued eight months earlier and a moisture certificate three weeks old both pass the numerical comparison and are both outside the Code's time limits. Both paragraphs are reproduced verbatim in industry sources; the consolidated text of the Code is not freely accessible.
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 |
|---|---|---|
| Shipper's moisture content certificate accepted without independent verification in the event of doubt | Cargo with moisture above the TML loaded without the risk being detected | Always request independent verification (e.g. a can test) in the event of doubt about the documentation supplied, before authorising loading |
| 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: 31 August 2026 · page fingerprint 76c6755b4db4