All the shipping companies that come under ISM code should possess a DOC (Document of Compliance). Acquiring this certificate means that the ship is approved by the ISM and the company must abide by the rules of ISM-code. Out of all the codes, the code to develop and execute a Safety Management System (SMS) is the most important one.
DOC can be issued to a company only after the ship has been approved by a Classification Bureau. The certificate is valid for 5 years, but can be terminated in between if the results of the annual surveys by the classification society are not satisfactory.
A Safety Management Cetificate (SMC) is also provided to a ship only if the ship already has a DOC. SMC is also valid for 5 years with 2-3 inspections in between.