1. Pipeline Qra Seminar
Title slide
Title slide

2. Pipeline risk assessment
Software/tools for risk assessment

3. Software/tools for risk assessment
Different software/tools for QRA
Tools (hand calculations) versus software
Tools (hand calculations) – actually manual development of simplified software (typically Excel)
There are software/tools also for qualitative risk assessment (e.g. linked to different methods – HAZID/HAZOP)
Focus on software/tools for QRA

4. Software/tools for QRA
Advantages of tools (hand calculations)
Simple (understanding and execution)
Flexibility
Disadvantages of tools (hand calculations)
Standardization (i.e. do we always calculate in the same way?)
Size and presentation (i.e. number of documents/sheets)

5. Software/tools for QRA
Advantages of software
More advanced (often)
Accepted (e.g. could be recommended from authorities)
Disadvantages of software
Black-box (often)
Non-flexible (e.g. change of parameters)

6. Software for QRA Light blue fact box
Software/tools established by consultant companies, authorities, companies (e.g. oil and gas industry and process industry) and software companies
Method depending on the situation (e.g. complexity, stage of project and time)
Economical and technological aspects (e.g. costs for license and knowledge of the software)
No single best software/tool to solve all problems
Software: SAFETI from DNVGL QRA Open from Taylor Associates ApS Shepherd from Shell Riskcurves from TNO
Light blue fact box
Slide with light blue factbox

7. Software for QRA “Same, same. But different!”
Similarities in presentation
Differences in way of calculations/models (exact differences hard to establish, since often “black-box”)

8. Software: SAFETI Content slide Software from DNVGL
Specialized for onshore process facilities and petrochemical facilities
Used frequently in the oil- and gas industry (e.g. BP, Total, Maersk and Shell)
Connected to the PHAST software
Content slide
Content slide

9. Software: SAFETI Content slide How does it work?
- Accident scenarios (e.g. PHAST and frequencies) - Population - Weather conditions - Ignition sources - Quantification of the risk (i.e. individual risk and group risk)
Compare with presented methodology for quantitative risk assessment
Content slide
Content slide

10. Software: SAFETI Advantages of PHAST
Easy to get some quick results from (compared to others)
Interface (i.e. easy to understand and present)
Disadvantages of PHAST
Black-box (i.e. what happens in the model and change of parameters)

11. tools for QRA Light blue fact box
Tools (and guidelines/standards) established by consultant companies, organizations, authorities and companies (e.g. oil and gas industry and process industry)
General difference - two categories of tools:
- Scoring systems (i.e. simple ranking of pipeline segments) - Traditional QRA (i.e. general methodology)
Standalone versus included in larger risk management framework
Guidelines/standards: Pipeline systems - Steel pipelines on land - Guide to the application of pipeline risk assessment to proposed developments in the vicinity of major accident hazard pipelines containing flammables (BS PD :2009) (part of framework BS PD :2004) from British Standards Assessing the risks from high pressure natural gas pipelines (IGEM/TD/2) from Institution of Gas Engineers and managers
Light blue fact box
Slide with light blue factbox

12. tools for QRA Detailed difference - three categories of tools:
- Generic values for leakages - Possibility to modify values for leakage to account for special properties and situation (e.g. corrosion) - Possibility to modify values for leakage to account for special properties and situation (e.g. corrosion) as well as including of external hazards (e.g. 3rd party interference and similar)
What is best? Depending on the situation (e.g. complexity). Most important to be aware of what is included and what is not included.

13. Tools for QRA
How is a QRA carried out?

14. Example of QRA

15. Example of QRA Ringsted, Denmark
- 30’’ gas pipeline bar mm - exposed - no construction work or agricultural work allowed within 50 meters from the pipeline - shopping centre (opening hours ) at 100 meters - parking lot between shopping centre and pipeline

16. Example of QRA What could go wrong?
- Internal corrosion (expected problems with impurities) - External corrosion (noted damages to protection from installation)
As detailed as want (e.g. is the restriction on construction work followed and possible natural hazards)

17. Example of QRA What is the frequency for the different scenarios?
Where could we find information?
Riser & pipeline release frequencies from International Association of Oil- and Gas Producers (OGP)

18. Example of QRA
Riser & pipeline release frequencies from International Association of Oil- and Gas Producers (OGP)
- 8.1 x 10-5 per km-year (12 mm wall thickness) - 18% are medium holes (75 mm hole)
Frequency for specified scenario:
- 1.5 x 10-5 per km-year
Just one of several scenarios!

19. Example of QRA What is the consequence from the different scenarios?
Choice: human safety – fatalities
What do we need to consider?
- Gas cloud - flash fire (extent and radiation from) - Jet fire (radiation from)
- Pin hole - Rupture - Large hole

20. Example of QRA
As detailed as want (e.g. are there some of the combinations we can exclude?)
What do we need to consider?
- Gas cloud - flash fire (extent and radiation from) - Jet fire (radiation from) (excluded)
- Pin hole (excluded) - Rupture - Large hole
Remember – all scenarios quantified (increasing effort)!

21. Example of QRA What scenario?
- Gas cloud - flash fire (extent) - Large hole (75 mm) - LFL and ½ LFL - All inside a cloud would be fatalities (>37.5 kW/m2)
Just one of several scenarios!

22. Example of QRA
Combine the frequency for the scenario and the consequence for the scenario to get the actual risk
What do we know?
- With the frequency 1.5 x 10-5 per year there will be a release of gas from the pipeline and the cloud will enclose the parking lot

23. Example of QRA What do we not know?
- Exposure (e.g. how often are there people in the parking lot and how many people are there in the paring lot) - Ignition (i.e. what is the probability of ignition of the gas) - Weather conditions (e.g. how often wind towards the parking lot)

24. Example of QRA What do we not know?
- Exposure – in average 50 persons in the parking lot from to every day and a parking guard there 5 days a week between and Ignition – 50% probability of ignite the gas due to the cars at the parking lot and the electrical signs on the shopping centre - Weather conditions – 10% probability of wind towards the parking lot (defined as south) due to prevailing wind east

25. Example of QRA
Combine the frequency for the scenario and the consequence for the scenario to get the actual risk (considerations for the parking guard)
- Frequency x ignition x wind x exposure (individual) x 10-5 x 0.5 x 0.1 x 0.39 per year
2.9 x 10-7 per year

26. Example of QRA What does this mean?
- With the frequency 2.9 x 10-7 per year there will be a release of gas from the pipeline, the cloud will enclose the parking lot, the cloud will ignite and the parking guard will be present (fatality) - The individual risk (for the parking guard) from this scenarios is 2.9 x 10-7 per year
Just one of several scenarios!

27. Example of QRA What about the group risk?
- With the frequency 2.9 x 10-7 per year there will be a release of gas from the pipeline, the cloud will enclose the parking lot, the cloud will ignite and in average 50 persons will be present (fatalities)

28. Example of QRA Is the risk (from this scenario) acceptable?
Risk acceptance criteria for individual risk
1.0 x 10-6 (Danish legislation) – YES!
Risk acceptance criteria for group risk
- (see figure) (Danish legislation) – MAYBE! - Separate presentation on ALARP - Most likely not given contribution from other scenarios

29. Example of QRA
QRA is a tool to evaluate and support what in the end are political decisions whether to proceed with construction/design (or similar) within questionable, high-risk and/or consequence areas
Could have a high consequence and a high frequency, but anyway an acceptable risk

30. Example of QRA Even the smallest QRA has large complexity
What has been simplified in this QRA?
- Wind directions (e.g. 4 or 16?) - Wind speed (i.e. consequences different) - Ignition probabilities (e.g. models or ignition sources) - Frequency (i.e. just considered one scenario) - Consequence (i.e. just considered one scenario) - Simplified population (e.g. cars on the road and residents) - Release frequency given per kilometre (e.g. not all releases within kilometres would give consequences within 1 kilometre)

31. Example of QRA Content slide, two columns with image
How is a QRA carried out?
Content slide, two columns with image
Content slide, two columns with image. Image size: 8,46 cm x 10,76 cm or 320 x 407 pixels

32. Example of QRA What is the challenges of quantitative risk assessment?
- Uncertainty (i.e. the risk could be something that has never happened before) - Statistic (i.e. availability) - Assumptions – big effect (e.g. sensitivity analysis) - Complexity (i.e. how much could/should be included?) - Ideal model (e.g. would people move from a release?)

33. QUESTIONS?
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