DNV DNV-OS-D101 [ Revised ]

Introduction

This offshore standard provides principles, technical requirements and guidance for design, manufacturing and installation of marine and machinery systems and equipment for mobile offshore units and floating offshore installations.

The requirements of this standard are in compliance with relevant parts of SOLAS Ch. II-1 and the IMO MODU Code.

SOLAS references are as quoted in MODU Code 2009 and fulfil class requirements. Note that for compliance with flag state requirements, later amendments may be applicable.

The standard has been written for general world-wide application. Governmental regulations may include requirements in excess of the provisions by this standard depending on the size, type, location and intended service of the offshore unit or installation.

The objectives of this standard are to:

- provide an internationally acceptable standard of safety by defining minimum requirements for offshore marine and machinery systems

- serve as a contractual reference document between suppliers and purchasers

- serve as a guideline for designers, suppliers, purchasers and regulators

- specify procedures and requirements for units or installations subject to DNV certification and classification.

Application

The requirements of this standard are applicable for mobile offshore units and floating offshore installations of the ship-shaped, self-elevating and column-stabilised design types, but may also be applied to other types of floating constructions, as applicable.

The requirements in this standard apply to 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 Pt.5 Ch.3. The additional requirements to class III piping in this standard shall be applied.

Reference to Ship Rules 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 Sec. 7 or 9 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 Classification of Ships Pt.5 Ch.5.

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

The requirements of this standard may also be applied to equivalent areas of fixed offshore installations.

Units or installations with ballast water treatment systems installed in order to meet the requirements of the Ballast Water Management Convention shall follow the requirements of Ship Rules Pt.6 Ch.18 Sec.4.