LOPA and IPL Credit Assignment Workshop
Where the credits come from, and which ones will not survive review
Layer of protection analysis is simple arithmetic applied to difficult judgements. This workshop concentrates on the judgements, which are whether a layer is genuinely independent, whether the operator has time to act, and whether the conditional modifiers being applied are defensible.
This course sits alongside our Layer of Protection Analysis consulting work, so what is taught is what we do.
Who should attend
Course content
Every module is taught with worked examples and exercises drawn from real plant, and adapted to your own process where the course runs in house.
What LOPA is for
- The gap between qualitative HAZOP ranking and full quantitative risk assessment
- Order of magnitude thinking and why false precision is the enemy
- Building a scenario correctly with one cause, one consequence and one enabling condition set
- Setting tolerable frequency from a corporate risk matrix
Initiating events
- Selecting initiating event frequencies and citing the source
- Control loop failure rates and what the published values assume
- Human error as an initiating event and the factors that change the rate
- Enabling conditions against conditional modifiers, and keeping them separate
What counts as an independent protection layer
- The independence, effectiveness and auditability tests applied honestly
- Why an alarm on the same transmitter as the control loop is not a separate layer
- Operator response as a layer, and the time to act that makes it credible
- Relief devices, and whether the case that was sized covers the scenario in front of you
- Layers that regularly fail review, with worked examples
Conditional modifiers and their limits
- Probability of ignition, of personnel presence and of fatality
- How stacked modifiers quietly remove orders of magnitude
- Documenting a modifier so a reviewer can agree or disagree with it
From LOPA to a SIL target
- Converting a required risk reduction factor into an integrity level
- What to do when the required reduction exceeds what a single function can deliver
- Feeding the result into a safety requirements specification
Worked scenarios and peer review
- Delegates build LOPA scenarios from a provided HAZOP output
- Each team reviews another team's credits and challenges them
- Comparing the group results against a reference solution
What you receive
- A LOPA worksheet template with an independence test built into it
- A worked scenario set with the reference solutions
- An IPL credit rules document your organisation can adopt
- Assessment result and attendance record
What changes afterwards
- Credits that would collapse under review get found in the workshop instead of at the audit
- SIL targets arrive at the functional safety team with a traceable basis
- Teams stop over crediting operator response and relief devices
- The organisation gets a consistent rule set rather than one that varies by facilitator
Standards and references
We teach LOPA and IPL Credit Assignment Workshop against IEC 61511 for the link between LOPA and safety instrumented functions and the codes listed with it, at the edition current when you run it.
Run LOPA and IPL Credit Assignment Workshop for your team
We will come back with dates, the pre-reading it needs and a cost per head. Tell us who is attending, what they already do day to day and whether you want it at your site or delivered online.
Ask about dates and cost