ABSTRACT An introduction is given to the new revision of Det Norske Veritas (DNV) "Rules for Submarine Pipeline Systems", denoted DNV'96 in the following. The new Rules constitute a complete revision of the previous Rules from 1981 and provide a significant step forward for pipeline design and operation. The Rules adopt the latest research achievements and practical experience gained through some of the most challenging pipeline projects recently executed. The major changes compared to the old DNV"8I Rules are:*introduction of Limit State based design format with reliability based partial safety factorsnew materials
new design scenarios
new installation methods
implementation of results from major R&D projects
provide a recipe for reliability based design methods
give credit for improved materials and quality
requirements to condition assessment and re-qualification A brief introduction to the major changes is given in the following.
The paper concludes with a short example, illustrating the use of the Limit Stated concept.
1. INTRODUCTION The pipeline industry has traditionally been rather conservative. The main design requirements in codes for both land based and offshore pipelines have remained more or less as they were at the introduction of the ASME codes several decades ago. Significant technical progress has been achieved in pipeline design, materials, fabrication, installation and operation of offshore pipelines during the last ten to fifteen years without necessarily being implemented in codes. The major changes in the offshore oil and gas industry taken place recently have forced the pipeline industry to focus on cost reduction through innovative design approaches, new materials, standardisation and optimised construction and operational procedures. The industry has also been forced to implement new concepts such as safety and risk.