保护层分析-LayersOfProtAnalysis.ppt
《保护层分析-LayersOfProtAnalysis.ppt》由会员分享,可在线阅读,更多相关《保护层分析-LayersOfProtAnalysis.ppt(22页珍藏版)》请在三一文库上搜索。
1、Functional safety Engineering - Layers of Protection,Layers of Protection Analysis,Fault Propagation Context Event Tree Method Layers of Protection Definition LOPA Event Tree Initiating Evnents and Failure Rates Example of Layers of Protection,Fault Propagation modelling,Analyze the Chain of events
2、that leads to an accident,Control System Fails,Operator does not respond properly,Mechanical relief failed,Overpressure Event,Initiating event,Layers of Protection Analysis - LOPA,A variant of Event Tree Analysis More structures Like event tree analysis, the initiating event start the chain of event
3、s Branches are layers of protection Consider only two outcome Accident No Event,LOPA Version of Event Tree,PL2, fails,PL1, fails,PL3, fails,Accident,Quantify using multiplications; all logical ANDs,Ex, Column Rupture LOPA,Draw the LOPA diagram for following situations Consequence of the accident = f
4、ire due to distillation column rupture has a root cause of loss of cooling water Layers of protection Operator respond to alarms and stops the process Process generally designed to withstand loss of cooling water The column has a pressure relief valve Source of ignition are controlled in the process
5、 area,Ex: Column rupture LOPA,LOPA Calculations,Proceed as with event tree, but only need to calculate the frequency of accident Resulting accident frequency is initiating event frequency multiplied by PFD of all protection layers Example Cooling water failure frequency is 0,5/year Protection layers
6、 Operator response failure PFD = 0,15 Relief valve failure PFD = 0,07 Process design inadequate PFD = 0,01 Ignition source contacted PFD = 0,3,Ex: Column Rupture, LOPA,F=0,5/y * 0,15 * 0,01* 0,07 * 0,3 = 1,58E-5 per year,Failure Rate Quantification,Historical reliability data specific to your instal
7、lation is best, but often difficult to get Plant maintenance and SIS function test data by equipment type Industry average data grouped by equipment type Some expert judgment is still inevitable,Using Maintenance and Function Test Data,Companies usually keep maintenance logs IEC 61511 requires funct
8、ion testing and documentation of results Function test data used to approximate failure rate: Simple Equation for point estimate of failure rate: = # Failures / Total Unit of Operation = Failure rate,PFD from Failure Rate,PFD depends on failure rate, failure mode and test interval Failure rate is di
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 保护层 分析 LayersOfProtAnalysis
链接地址:https://www.31doc.com/p-2898692.html