Overview

Overview developments in failure frequencies

(updated at February 2015)

An extensive analysis of data covering the period 1970 to 2013 has lead to the following overview:

Period Interval Number of
incidents
Total system
exposure ·106 km·yr
Primary failure
frequency per
1,000 km·yr
1970 - 2007 7th report
38 years
1173 3.15 0.372
1970 - 2010 8th report
41 years
1249 3.55 0.351
1970 - 2013 9th report
44 years
1309 3.98 0.329
1974 - 2013 40 years 1179 3.84 0.307
1984 - 2013 30 years 805 3.24 0.249
1994 - 2013 20 years 426 2.40 0.177
2004 - 2013 10 years 209 1.33 0.157
2009 - 2013 5 years 110 0.70 0.158

Conclusions

  • EGIG has maintained and expanded the European Gas pipeline incident database. Seventeen gas transmission system operators in Europe now collect incident data on more than 143,000 km of pipelines every year. The total exposure, which expresses the length of a pipeline and its period of operation, is 3.98 million km·yr.
     
  • In the EGIG database 1309 pipeline incidents are recorded in the period from 1970-2013.
     
  • The history of incidents collected in the database gives reliable failure frequencies. The overall incident frequency is equal to 0.33 incidents per year per 1,000 km over the period 1970-2013.
     
  • The 5-year moving average failure frequency in 2013, which represents the average incident frequency over the past 5 years, equals 0.16 per year per 1,000 km.
     
  • The five year moving average and overall failure frequency have reduced consistently over the years, although it has tended to stabilise over recent years.
     
  • Incidents caused by external interference and ground movement are characterised by potentially severe consequences which emphasises their importance to pipeline operators and authorities.
     
  • Corrosion as a primary cause has increased over the last five years and is now of the same magnitude as external interference, although consequences are much less severe.
     
  • Over the last ten years, external interference, corrosion, construction defects and ground movement, represent 35%, 24%, 16% and 13% respectively of the pipeline incidents reported.

Development Safety Performance