Monday, April 21, 2008
Display problem ? Click HERE
Shutdown Valves (SDV) are commonly use in oil and gas production system for safe and proper isolation purpose to minimize escalation of hazardous from one system to another system.
In "12 Features required for Shutdown Valve (SDV)", one of the requirements of SDV is Fast Action.
What is the maximum allowable time from shutdown initiation to SDV fully closed ? Any code or standard can be referred ?
According to API RP 14C, 7th Edition, March 2001, "Recommended Practice for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms" Appendix C - Support Systems C.2.1.4. "The time it takes for any safety device (e.g. PSH, BSL, ESD station, etc.) to effect component or platform shutdown should not exceed 45 seconds."
Thus, the upper limit is 45 second. However, quick closing SDV would also lead to transient surge. It is recommended the closing time should be minimum 3-5 second. This is just a recommendation. For a piping which is long, low ductility, carrying incompressible fluid, etc, it increases the potential of pipe failure due to surge. A proper surge analysis may be conducted if it is deem necessary.
Related Post:
In "12 Features required for Shutdown Valve (SDV)", one of the requirements of SDV is Fast Action.
A shutdown valve shall act fast to minimize the escalation of hazards. Generally a quarter ball valve is the excellent device in quick action. As rule of thumb, shutdown valve shall be capable of begin it closing action within 10 seconds of activation, and time taken from Full open to Full Close is within 1-2 seconds per inch of shutdown valve size. However, this shall be compliant to overall safety philosophy.
What is the maximum allowable time from shutdown initiation to SDV fully closed ? Any code or standard can be referred ?
According to API RP 14C, 7th Edition, March 2001, "Recommended Practice for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms" Appendix C - Support Systems C.2.1.4. "The time it takes for any safety device (e.g. PSH, BSL, ESD station, etc.) to effect component or platform shutdown should not exceed 45 seconds."
Thus, the upper limit is 45 second. However, quick closing SDV would also lead to transient surge. It is recommended the closing time should be minimum 3-5 second. This is just a recommendation. For a piping which is long, low ductility, carrying incompressible fluid, etc, it increases the potential of pipe failure due to surge. A proper surge analysis may be conducted if it is deem necessary.
Related Post:
- A Technical Report for Partial Stroke Testing of Automated Block Valves
- Partial Stroke Testing for Emergency Shutdown Valves
- Requirements of SDV Bypass Pressurization Line
- 12 Features required for Shutdown Valve (SDV)
Labels: Emergency Shutdown, Overpressure Protection
posted by Webworm, 3:21 PM
0 Comments:
Post a Comment
Let us know your opinion !!! You can use some HTML tags, such as <b>, <i>, <a>
Subscribe to Post Comments [Atom]
Home:
<< Home