API Std 521 for pressure relief and blowdown valves
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The consequences of an acoustic fatigue failure (also known as acoustic-induced vibration or AIV) are severe, from both a safety standpoint (gas explosion, sour gas release) and production viewpoint (loss of flare or gas compression system).
API Standard 521 (6th edition, January 2014) requires that “the potential for acoustic fatigue” be evaluated through one of several different methods, with the Energy Institute “Guidelines for the avoidance of vibration induced fatigue failure in process pipework”, in particular being widely employed. This risk-based screening methodology has been used globally for both new design and operational assets.
At the design stage, the VDN Group will work with the project team to develop a piping design sufficiently robust that the risk of an acoustic fatigue failure is minimized. The approach is a three-step methodology, based on the industry best practice Energy Institute Guidelines, which members of the VDN team co-authored.
As part of Wood Group, the VDN team also has access to other specialist engineering services such as CFD, materials and production chemistry.
Wood Group is participating in an Energy Institute joint industry project (JIP) addressing AIV. The current phase seeks to provide measurement data to give insights as to the response of different piping configurations to AIV, and quantify the effectiveness of various mitigation measures.
Test work is being undertaken at the Emerson Fisher flow labs in Marshalltown under high-pressure relief and blowdown conditions. Wood Group is providing data analysis capability of the acquired dynamic strain, acceleration and dynamic pressure data as part of our in-kind contribution to this applied research program.
BP, Chevron, ConocoPhillips and Nexen are the principal operating companies involved, with other contributors including Bechtel, Chiyoda, Emerson Process Management, KBR, Petrofac and Xodus.
Webinar: What is my risk of surge? • Examples of Piping Vibration (Video) • Pipe Support Stiffness, GMRC Project • Transient Conditions on Small-Bore Piping • Piping Vibration Design Considerations • Tips for Managing a Successful Vibration Project • Piping Vibration Examples • An Integrated Approach to Manage Vibration Risks •