The requirements in this standard cover marine piping systems, machinery piping systems and marine machinery systems, which are defined as systems serving the marine systems on a offshore unit or installation and not primarily intended for operation in drilling or hydrocarbon production service or dedicated auxiliary systems. Interfaces between such systems and marine systems should be identified and a specification break defined.

Guidance note:

Piping and equipment for drilling and drilling related auxiliary systems are addressed in DNV-OS-E101. Piping and equipment for hydrocarbon production and production related auxiliary systems are addressed in DNVOS- E201.

Piping and equipment in connection with hydrocarbon storage (including, product piping, inert gas system, gas freeing and venting system and crude oil washing system) are addressed in the Rules for Classification of Ships (Rules for Ships) Pt.5 Ch.3. The additional requirements to class III piping in this standard shall be applied.

Reference to Rules for Ships is conditioned that there is no coincident production and tank inspection. For units subject to in-service inspection of the cargo system during production, additional requirements are given in DNV-OS-A101 Ch.2 Sec.7 or 8 as applicable.

Guidance note:

Some systems used for typical tank ship applications, (e.g. cargo piping, ballast systems, firewater systems), need to be especially considered, for example with respect to fabrication quality and support arrangement, when evaluated for use on offshore installations in view of differing operational conditions and overall safety and maintenance philosophy.

Piping and equipment in connection with LNG storage are addressed in DNV-OS-C503 "Concrete LNG Terminal Structure and Containment Systems" and Rules for Ships Pt.5 Ch.5.

Hydrocarbon loading/offloading systems are addressed in DNV-OS-E201.