Ignition frequency

Further to my last post where I made some assertions about the frequency of some failure consequences, there is particularly useful information available from European incident data.  EGIG is the European Gas pipeline Incident Group and as the name suggests they collect and report on pipeline failure incidents.  A new report is published every three years, available here.

They include information on ignition probability, which is very much less than 100%.  The latest report (2011) gives the following probabilities:

  • 4% – pinhole/crack
  • 2% – hole
  • 10% – rupture, < DN 400
  • 33% – rupture, ≥ DN 400

So for most Australian pipelines, even full bore rupture has only 10% probability of ignition.

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7 Responses to Ignition frequency

  1. Chris Hughes says:

    And those numbers haven’t changed significantly since the 2005 report where the corresponding probabilities were 3%, 2%, 9% and 30%.

    What is even more interesting is the 5 year moving average of failure frequencies which shows that failures due to external interference has been steadily dropping over the years and is now down to about 0.06 failures per 1000km per year, compared to 0.43 in 1974 and 0.1 in 2001. This suggests to me that such programs as DBYD, community education, landowner liaison, etc are being shown to be effective (I am assuming that the Europeans employ these techniques as we do).

  2. petertuft says:

    Yes, and our Australian external interference failure rate has been dropping too, although it’s a bit hard to work out a trend when it has been zero for the last 8 years 🙂
    (I’m referring to actual failures, as in loss-of-containment events, not damage incidents which continue at a low rate.)

  3. Chris Hughes says:

    We always say (well I do) that the reason we don’t apply QRA to Australian pipelines is that the statistics used for QRA are based on incident records from the USA and Europe and what little incident data we have here indicates that our incidents are an order of magnitude less. This is largely because a high percentage of our pipelines are laid in areas which are unique to Australia i.e. our central desert region. It would be interesting to look at Australian pipeline incidents which occur in those areas which are comparable to European and US areas (by which I mean the populated and agricultural regions around the eastern and southern coastlines) and see whether the incident/1000km/year count for those areas is significantly different to the overseas experience.

  4. petertuft says:

    I’ve done that just recently with the help of an overseas colleague and will be reporting it at the APIA/PRCI/EPRG Joint Technical Meeting in Sydney at the end of April, but until then I’m not going to steal my own thunder. Suffice to say that your hypothesis about low population density explaining low failure rates in Australia does not stand up. More at the end of April.

    • Chris Hughes says:

      I’m very glad to hear that Peter and will await your report with interest. My point was that for many Australian pipelines the probability of external interference is zero due to the fact that no excavation work will ever take place where they are laid (such as the MAP north of Peterborough, most of the GGT and the Carpentaria, etc) because no-one lives or works out there except for the cattle station owners.

  5. Anonymous says:

    Thanks Peter,

    As a regulator who collects such statistics as part of reporting obligations, and also publishes them in our annual compliance report, I would be very happy to reconfigure our statistics into the EGIG format for comparison purposes. Even more useful would be to see if my other fellow Australian regulatory colleagues will also be interested in sharing their statisitics so we can get a better picture on how we do comapre with overseas. Happy to co-ordinate if have any takers out there.

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