Classification certificates are issued for a period known as the class term or the term. The first term starts from the date of the initial classification survey. A new term is assigned to the ship after satisfactory completion of the special survey and new classification certificates are issued.
To assess the seaworthiness of a ship in service, periodical inspections are carried out, and their findings are compared with the requirements of Rules for ships in service. If conformity to Rules is noted, the certificate is renewed for a certain period of time.