CDI
The Chemical Distribution Institute (CDI) is a non-profit organisation that runs an inspection and reporting scheme for the chemical shipping industry, much as OCIMF SIRE does for oil tankers. CDI inspectors examine chemical tankers, and terminals and packed-cargo operations, against a standard questionnaire, and the reports are held in a shared database.
Chemical companies and charterers use CDI (and SIRE) reports to vet ships before fixing them, so a clean CDI inspection record is essential to a ship ability to trade in the chemical market. It is a central part of the tanker vetting regime.
Major chemical shippers will not load a tanker that does not have an acceptable CDI (and SIRE) record, so passing these inspections is effectively a licence to trade in the chemical sector. A poor inspection can shut a ship out of the market, making CDI central to the commercial survival of a chemical tanker.
What is the difference between CDI and SIRE?
Both are tanker vetting inspection schemes: SIRE (run by OCIMF) focuses on oil tankers, while CDI focuses on chemical tankers and terminals. Charterers use both to assess a ship before fixing it.