Based on the requirements of clients and country authorities different codes and standards may be used for designing of offshore pipelines. Pipeline design codes that are widely used are as follows:
- ASME B31.8
- BS 8010
- EN 14161
- ISO 13623
- DNV OS-F101
- API RP-1111
The main design principle of this code is that the pipeline is assessed as a pressure vessel, by limiting the hoop stress to a specific fraction of minimum specified yield strength (SMYS). ASME B31.8 is used for design of gas pipelines. For other fluids other sections of the ASME B31 should be used. For example for liquid hydrocarbons ASME B31.4 should be used instead.
BS 8010 The BS 8010 code contain three parts covering onshore and offshore oil and gas pipelines. the code has been developed over a period of more than forty years and several revisions has ensured the code is live and and the engineering practices are current.
In 2004, BSI has published PD8010 and withdraw BS 8010 to support BS EN 14161:2003.
EN 14161 The EN14161 is the European code for design of petroleum and gas transport systems. It is mainly based on ISO 13623. ISO 13623 The ISO 13623 code is the first international code prepared for liquid and gas pipeline transportation systems. It came into effect in April 2000. DNV-OS-F101
The first edition of DNV Rules for Design, Construction and Inspection of Marine Pipelines and Pipeline Risers was issued in 1976. The design section of this code was mainly based on ASME codes. A very important revision of this code issued on 1981. This version that mainly known as DNV'81 is still one of the design codes in many projects.
In 1996, DNV revised this code deeply and reconstruct it based on limit state approach. In this code, the pipeline is classified into Safety Classes based on Location Classes, Fluid Category, and potential failure consequences.
Older revision of this code can be downloaded using the following link:
Traditionally the following different limit states are considered:
- Serviceability Limit State (SLS)
- Ultimate Limit State (ULS)
- Accidental Limit State (ALS)
- Fatigue Limit State (FLS)
This recommended practice for designing offshore pipeline and risers containing hydrocarbons has been updated on limit state design concept to provide a uniform safety level. The failure mode of rupture and bursting is used as the primary design condition independent of pipe diameter, wall thickness, and material grade.
Following table gives a comparison between different pipeline codes and standards. References:
- Corrib Gas Pipeline Project: Report on Evaluation of Offshore Pipeline Design Code.
- Design and Installation of Marine Pipelines, M. W. Braestrup, et al., Blackwell Science.
- Pipeline and Risers, Y. Bai, Elsevier Ocean Engineering Book Series.
- Choosing a Standard for Natural Gas Pipelines Design and Construction, Amnon Einav.
- Offshore Pipelines, B. GUO, et al., Elsevier Publications.
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