Category Archives: LOPA

What is a LOPA and how can one use ETA to address it?

If you are looking for LOPA information chances are you probably already know what a LOPA is. For any of you are not familiar with a LOPA study, it could mean any number of things. However, for us a LOPA is an acronym meaning: Layer Of Protection Analysis. A LOPA can be a good and logical beginning, or addition, to your PHA (Probabilistic Hazard Analysis) studies. Which leads us to our next acronym ETA (Event Tree Analysis). Event tree analysis diagrams can be an effective approach to tackling your LOPA studies. Since this is probably easier viewed than described please take the time to watch our webinar addressing this topic:


Linking Fault Tree and Event Tree

Event Tree Analysis (ETA) complementing your Fault Tree Analysis (FTA) is like putting salt on your popcorn. Event tree diagrams provide an excellent way of showing the possible outcomes of a hazardous event (often modelled in a FTA study). An ETA diagram is a simple, logical and easy to read diagram that breaks down data to show the possible consequences of failures in an FTA study.Event trees provide an inductive approach to reliability and risk assessment and are constructed using forward logic.

FaultTree+ in Reliability Workbench includes integrated event tree analysis. The event tree model may be linked to the fault tree model by using fault tree gate results as the source of event tree probabilities. FYI, if you already have a copy of FaultTree+ the Event Tree Software is included!

Please register for this educational Webinar: Linking FaultTree+ and Event Tree Analysis on Jun 2, 2016 11:00 AM MDT at: CLICK HERE

Flow Regulator ET

We appreciate your support of Isograph. If you have any general questions or comments please feel free to contact me.


Jeremy Hynek
Isograph, Inc.
Director North American Operations
801 610 0045


Performing a LOPA using FaultTree+

On Friday April 4th at 9am PST to learn more about applications of our FaultTree+ software. During this demonstration we will introduce our fault tree analysis software FaultTree+ and as an added bonus we will be discussing how to tie a fault tree to an event tree and perform a LOPA study. Layer of Protection Analysis, or LOPA, is a study developed to identify risk. By performing a LOPA on a system you can create a method for identify the actions available to mitigate the potential consequences of a particular risk. To do this we will start with likelihood of a particular hazard occurring, analyze the system using quantitative methods, and identify the mitigation measures against the hazards that have been identified.

Once the mitigating actions have been identified the probability of those hazards occurring can be reduced by implementing safeguards that bring the hazard into an acceptable level. An event tree is an excellent way to determine the consequences of successful, or the failure of, safeguards.

Basically, a LOPA is performed to identify the weakest points of a system and evaluate the safeguards in place to mitigate the consequences of that hazard.

To join this webinar: Register Here