Risk Analysis with LOPA: Layer Of Protection Analysis

The Layer Of Protection Analysis of LOPA method is a relatively recent risk analysis method that has its origin in the USA. Companies like BP and Dow use LOPA. The CCPS (Center for Chemical Process Safety) issued a LOPA "standard" book.
SSC has experience with the use of LOPE for SIL Classification.

LOPA is often used for SIL Classification. The SIL is determined by comparing the risk level with the tolerable risk level as established by the company. For example, a scenario that can cause fatal injury to a person and / or serious injuries to several persons is defined as being tolerable only once every 10,000 years (10-4/jr.).

One of the major pitfalls of LOPA is that unjustified ‘credit’ is given to those measures which are not independent. In LOPA, a measure is called an Independent Protection Layer (IPL). The figure below shows how the IPL’s will reduce the frequency of the scenario to an acceptable level.

Schema LOPA
Only 44% of Major Hazards companies apply SIL !

Column November 2010
Only 44% of Major Hazards companies apply SIL !

The Dutch Labor Inspectorate performed an inspection of 58 Major Hazards companies . This was a follow up of the BP Texas City disaster. Recently, a report with the inspection results have been p...

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