Question 1

What is IMDG segregation?

Accepted Answer

Segregation is the IMDG Code's system for keeping incompatible dangerous goods apart on a ship. The general segregation table in IMDG chapter 7.2.4 assigns each pair of hazard classes a requirement from 'away from' (code 1) up to 'separated longitudinally by an intervening complete compartment or hold' (code 4).

Question 2

Can two dangerous goods classes go in the same container?

Accepted Answer

If the IMDG general segregation table shows any number (1-4) for the pair, the goods cannot be packed in the same cargo transport unit ('away from' pairs may be allowed only with competent-authority approval). If it shows X, the general table imposes no blanket rule, but the Dangerous Goods List entries for the specific UN numbers must still be checked.

Question 3

What do the IMDG segregation codes 1, 2, 3 and 4 mean?

Accepted Answer

1 = 'away from' (normally at least 3 m between cargo transport units on deck); 2 = 'separated from' (normally at least 6 m); 3 = 'separated by a complete compartment or hold from'; 4 = 'separated longitudinally by an intervening complete compartment or hold from' — the most severe requirement.

Question 4

Does the general segregation table override the Dangerous Goods List?

Accepted Answer

No — it is the other way round. The Dangerous Goods List entry for a specific UN number can impose stricter, substance-specific segregation provisions, and those take precedence over the general class-level table.

IMDG Segregation Checker

How IMDG segregation works