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[KS2010]

Dear all,

As I understand LOPA [ Layer of Protection Analysis] is a semi-quantitative methodology for the risk assessment and to identify the SIL requirement of the plant items. I have been actively involved in FMEA and HazOp and as I understand LOPA is next step after HazOp.

Also, we can assign SIL based on the PFD [probability of failure on demand] However, I do not get my head around the actual procedure of estimating PFD for LOPA study.

What is step by step procedure for LOPA? I have referred/goggled some literature but nothing very specific and no example given.

In an old plant, which data [equipment data] do I need to collect ? How do I need to estimate PFD?

I would appreciate any pointers please.

Thanks in advance.

Edited by KS2010, 05 November 2010 - 07:27 AM.

[gvdlans]

The reference on Layer of Protection Analysis is the CCPS book on the subject, see http://www.amazon.co...t/dp/0816908117 You can find answers to most of your questions in this book.