Fuel flow upped before rupture: Refining NZ
Refining NZ increased the pressure of its Auckland fuel pipeline weeks before it burst, without carrying out a fresh internal check on the pipeline’s integrity, the company has confirmed.
The Nzx-listed firm is spending more than $5 million this year upgrading the pipeline.
It had increased the volume of fuel that could be pumped through it by 5 per cent in early August, shortly before it ruptured on September 14.
However, the company said there was no evidence the pressure increase to 87 bar was the straw that broke the camel’s back.
It says the pipeline rupture – which to led to jet-fuel rationing and dozens of flight cancellations at Auckland Airport – was due to damage by a digger which it believed may have deeply scraped the pipe as early as 2014.
The company has commissioned ‘‘asset integrity expert’’ Quest Integrity to investigate.
‘‘We’re pretty confident that their findings will concur with our initial conclusions that, given the extent of mechanical damage, the pipeline would have failed regardless of the operating pressure,’’ spokesman Greg Mcneill said.
‘‘There is no evidence of a causal link between the August upgrade and the pipeline failure.’’
The pipeline was ‘‘complex’’ and an electrical glitch or an issue with a valve or pump along the pipeline could instead have been the final trigger, he indicated.
The company last ran a scanner through the pipe in 2014 and Mcneill defended its decision not to do so again before turning up the pressure.
Refining NZ was only required to test the condition of the pipe’s walls every 10 years, he said.
Lloyds Register recertified the underground pipeline was able to carry the extra fuel, based on data from the 2014 scan and visual checks, he said.
Chief executive Sjoerd Post indicated last week that Refining NZ might nevertheless review its testing policies in the wake of the leak, which it has forecast will cost it between $10m and $15m.
The company will also reduce the pressure to 70 bar until the end of the year as a precaution.