Classification and certification are not the same, and fitness for purpose may or may not be determined by either. This paper compares and contrasts classification, certification, and fitness for purpose. Included are not only the general policies and definitions used by the major classification societies, but also how these services fit into the various quality certification schemes like ISO and API. As a result, when you have a need for third party verification of "quality", you will know what you should specify and the correct terminology used by those in this industry.


An "administrative" item of ongoing concern for offshore rig owners is classification of their rigs and the equipment installed on them. This is required to maintain insurance coverage, as well as compliance with various regulatory bodies governing drilling activities around the world. What this exactly covers, and the relationship between classification, certification, and fitness for purpose is not clear for many people.

Accordingly, the first step is to review definitions. From that point, it will be easier to differentiate these procedures, as well as determine what benefits you can expect when soliciting and engaging these services.


As an early initiative toward maritime loss prevention, early ship owners banded together in groups to self-insure their vessels and cargo. These groups or insurance "clubs," established in the UK, Scandinavia and elsewhere, decided to form independent technical organizations, now called classification societies, that would provide standards and inspections for ships to be sure that they were built and operated in accordance with "agreed to" safety standards. There were no existing standards so classification societies published "Rules." There are a number of international classification societies, the three major ones involved with the offshore exploration and production industry are Det Norske Veritas (DNV), American Bureau of Shipping (ABS), and Lloyd's Register of Shipping (LRS). These companies are all more than 130 years old, with Lloyd's being the oldest, dating from about 1800.

Initially, there were various levels of classification which were reflected in different insurance rates. Most vessels are today classed with a notation +1A1 which indicates that the vessel is built and maintained to the highest standards of the particular classification society. Therefore, strictly speaking, when the word classification is used today, it references a set of standards established and maintained by a specific classification society.

For example, classification based on DNV rules and the related certification imply fitness for purpose in the sense that DNV approves the completed "object" and certifies (reviews, inspects and tests) all the systems. Thus all power, safety, control, drilling, etc. systems will be certified as both safe and fit for purpose. DNV is not a designer or operator and thus will not influence operational factors such as reliability and efficiency.


Certification may be defined as steps taken to confirm that an "object" satisfies specific standards. "Object" can be a complete platform, ship, or drilling semi-submersible; it can be a system within these vessels or one component of a system. The object also could be "the most basic" part of a component, i.e. the steel, the electrical cable, etc.

Certification may or may not insure fitness for purpose, depending on a number of factors. Because of this, it is the responsibility of those designing or using an object to understand what is implied by its certification. P. 229

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