Pump fail­ures ahead of pipe­line leak


The pipe­line that car­ries fuel from the Mars­den Pt Oil Re­fin­ery ex­pe­ri­enced an ‘‘emer­gency shut­down’’ just two hours be­fore it broke on Septem­ber 14, trig­ger­ing the Auck­land fuel cri­sis, owner Re­fin­ing NZ has con­firmed.

Re­fin­ing NZ spokesman Greg McNeill said the emer­gency shut­down was caused by a main­te­nance worker who ac­ci­den­tally trig­gered a fire alarm at a pump­ing sta­tion part-way along the 170km pipe­line.

Two of the three pumps that were in­stalled part-way along the pipe­line failed to restart when the re­fin­ery be­gan pump­ing fuel back through the pipe­line about 20 min­utes later.

That caused a pres­sure rise at some points, in­clud­ing at Ruakaka where the al­ready-weak­ened pipe­line broke later that morn­ing, spilling 70,000 litres of jet fuel, ac­cord­ing to a re­port engi­neers Wor­leyPar­sons pro­vided to North­land Re­gional Coun­cil.

The coun­cil made no ref­er­ence to the in­ci­dent in the body of its own fi­nal re­port into the fuel leak pub­lished in Novem­ber.

The blame for the leak – which took 10 days to fix and re­sulted in more than 100 can­celled flights at Auck­land air­port – has fallen on an un­known swamp kauri log hunter.

They are be­lieved to have gouged the pipe­line with a dig­ger some time af­ter July 2014, which was when the con­di­tion of the pipe­line was last fully tested by run­ning a de­vice called a ‘‘pig’’ through the pipe.

But Re­fin­ing NZ would not say whether it thought the pump fail­ures were the ‘‘fi­nal straw’’ that trig­gered the rup­ture.

Re­fin­ing NZ had also in­creased the max­i­mum pres­sure at which the pipe was cer­ti­fied to op­er­ate from 70bar to 87bar in Au­gust so it could pump more fuel down it.

The com­pany would not say whether it be­lieved the pipe­line might have held out un­til 2019 had the Au­gust pres­sure rise or the pump fail­ures not oc­curred. That is when the next sched­uled pig run should have alerted it to the dig­ger dam­age.

McNeill ex­plained it did not want to pre-empt a gov­ern­ment in­quiry an­nounced by En­ergy and Re­sources Min­is­ter Me­gan Woods.

A spokesman for Woods said yes­ter­day that of­fi­cials were con­tin­u­ing to con­sult on the draft terms of ref­er­ence for the in­quiry.

Wor­leyPar­sons’ re­port said the events fol­low­ing the emer­gency shut­down on Septem­ber 14 in­creased pres­sure at the point where the pipe­line sub­se­quently rup­tured to about 82bar.

That was about 6bar above the nor­mal pres­sure at that point along the pipe­line, but still ‘‘sig­nif­i­cantly be­low’’ its max­i­mu­mal­low­able op­er­at­ing pres­sure of 90bar, it said.

A separate en­gi­neer­ing re­port showed Re­fin­ing NZ was an­nu­ally test­ing the ca­thodic pro­tec­tion of the pipe­line, in­clud­ing dur­ing the pe­riod between the pipe­line be­ing dam­aged and its rup­ture.

The main pur­pose of ca­thodic pro­tec­tion is to pro­tect me­tal from cor­ro­sion.

How­ever, in some ap­pli­ca­tions, rou­tine test­ing of ca­thodic pro­tec­tion to en­sure it is work­ing can also de­tect dam­age to the coat­ing of the me­tal it is pro­tect­ing.

McNeill said Re­fin­ing NZ would not an­swer fur­ther ques­tions from the me­dia about the test data and the in­ter­pre­ta­tions it had made, but in­di­cated it would pro­vide that to the gov­ern­ment in­quiry, if asked.

‘‘Should the in­quiry re­quire fur­ther in­for­ma­tion about ca­thodic pro­tec­tion on the pipe­line . . . then as the re­spon­si­ble oper- ator of that pipe­line we would gladly pro­vide that in­for­ma­tion to the in­quiry,’’ he said.

The com­pany en­gaged the coun­try’s ‘‘fore­most ex­pert’’ on ca­thodic pro­tec­tion.

North­land Re­gional Coun­cil con­cluded there was ‘‘no sug­ges­tion that Re­fin­ing NZ should or could have known that the in­ci­dent was go­ing to oc­cur’’.

Justin Tighe-Um­bers, ex­ec­u­tive di­rec­tor of the Board of Air­line Rep­re­sen­ta­tives, which rep­re­sents 29 air­lines – many of which were af­fected by the fuel cri­sis – said he had not been aware of the in­ci­dent ear­lier on the morn­ing of the pipe­line fail­ure but said it might be nei­ther ‘‘here nor there’’, if the dam­aged pipe­line was a ‘‘tick­ing time bomb any­way’’.

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