Layers Of Protection Analysis

The LOPA review is a quantitative method that enables a team to ensure that the risk level is kept below a tolerable limit. The team quantifies the initial risk associated with a given scenario and calculates risk reduction as provided by each layer of protection. When this reduction is relying on a Safety Instrumented Function (SIF), the LOPA review enables to define its associated Safety Integrity Level (SIL).


The LOPA reviews’ main objectives are twofold

  • to demonstrate that scenarios identified during the HAZOP review (or other) are at an acceptable level of risk in a quantitative approach,
  • to provide the SIL target for all SIFs within the scope of work.

When necessary the LOPA team can also propose actions to optimize the process, to investigate further scenarios, or even reduce the required SIL.


HazOptima provides high quality HAZID reviews based on very effective leaders to head up the HAZOP team.

Our chairmen are highly experienced and completely focused on HSE reviews, having both a Safety and a Process background. This ensures a broad and extensive knowledge of the given industrial context that enables us to guide the team in order to find out the optimized solution.

Our goal is to ensure the proper procedure for the relevant review at the best time.

Our services deal with LOPA reviews preparationfacilitatingreportingfollow-up and training.

We are able and experienced in working with any and all industries where HAZOP can be applied.

HazOptima provides high quality HAZOP reviews based on very effective leaders to head up the HAZOP team
Our References

“I will recommend HazOptima.”

Process Specialist
UOP A Honeywell Company

“One of the most detailed HAZOP I have ever attended.”

Process Engineer

“Adaptive, pro-active, HazOptima gives envy to go to HSE reviews. Go on!”

Project Engineer

“People from HazOptima were really efficient during the review. Planning has been respected and even challenged. Discussions with Chairman and rest of the team were constructive and no time was spent on internal meeting. Scribe was very efficient.”

Process Engineer

What is the result of a LOPA review?

LOPA review is the documented demonstration of risk acceptability. It can also define the required SIL for the analyzed Safety Instrumented Functions. The report shall include the full list of SIL targets, including the reasoning and what the analysis is based on. Moreover the report shall include a list of recommended or obligatory actions to be implemented to achieve the acceptable level of risk.

HazOptima reports include a clear and exact recording of discussions raised during the review, as well as actions list and dedicated action sheets for easier response and follow-up.

We can use the main software on the market or we can develop dedicated IT tools for your LOPA reviews.

What is the basic methodology of LOPA reviews?

In few words, the LOPA methodology is the following one:

  • each selected scenario is reviewed based on a former risk analysis (e.g. HAZOP), to define all potential initiating causes, consequences and existing safeguards,
  • the team determines the acceptable likelihood target, based on severity criteria,
  • the team calculates the expected likelihood, based on failure and reliability databases,
  • the team concludes on the scenario acceptability, and/or determines the required SIL of SIF that shall protect the scenario under review.

For more information please contact us.

What do you need to perform LOPA reviews?

LOPA reviews take place when the HAZOP review (or other) is completed. Similar documentation is required. HazOptima is here to guide you in finding the necessary documentation as per your constraints and objectives.

What is the scope of LOPA reviews?

Scope of LOPA reviews can significantly vary pending your objectives, project phase and information availability. HazOptima helps you to define the best procedure including scope of work, rules and planning.

How long do LOPA reviews take?

Depending on the number of analyzed scenarios and Safety Instrumented Functions within the scope of work, LOPA reviews can take from one day to several weeks or even months. HazOptima can help you to clearly define your planning at an early stage in the project.

For more information please contact us.


  • IEC EN 61508 (Functional safety of electrical/electronic/programmable electronic safety related systems).
  • IEC 61511 (Safety instrumented systems for the process industry sector).
  • CCPS (Layer of Protection Analysis: Simplified Process Risk Assessment).
  • Other references: do not hesitate to contact us.