The disruption to the Refining New Zealand pipeline has horrified a Katikati welder.
The disruption to the Refining New Zealand pipeline has horrified a Katikati welder.
By Chris Steel
Katikati's Merv Gaelic was "horrified" when he heard a key part of New Zealand's gas pipeline had been ruptured by a digger, leading to jet fuel shortages and flight cancellations at Auckland Airport.
Gaelic was one of the many welders who helped build the pipeline, commissioned in the 1980s.
The 168km underground pipeline, which carries aviation fuel, petrol and diesel directly from the Marsden Pt oil refinery in Northland to holding tanks in Wiri, South Auckland, was out of action from about two weeks ago, when refinery workers noticed a drop in pressure.
Refining New Zealand believes a digger scraped pipeline at Ruakaka some time ago, leading to corrosion that caused it to fail. A 17m replacement section of pipe was delivered to the leak site last week and hydro tested before being welded into place.
Hi everyone - we were delighted to let the country know that the first batch of jet fuel arrived at Wiri at 10.09am this...
There were lots of loop lines in New Zealand for pipes carrying gas in the event that something like this happened, he said.
The disruption to the Refining New Zealand pipeline has horrified a Katikati welder.
"I find it hard to believe it took them so long to find out. The pipes have monitors, say every kilometre, to check for corrosion. The only reason it is dangerous is if someone damages it."
The pipeline is a metre below the ground. In the same trench beside the 25cm product line to Wiri, Gaelic said they laid a 12.54cm (6") pipeline carrying gas from Auckland back up to Whangarei. The pipes came in 12m lengths.
Hi everyone - here's our repair work update as at Close of Play today, Friday.
Good progress continues to be made on...
"The front end moved along as a unit, with five welders per unit. Other welders were on repairs and tie-ins. We had to do the pipe in half kilometre sections because the x-ray machine batteries couldn't do any more than that.
"Three units of welders would work on a section of pipe - beadhand, hot pass fillers and cappers. The first welder is the beadhand, so he puts in the bead. He only did one weld. The next runs the grinder around it so it's ready for the next man. Then the hot pass man would use high temperature weld to blow the weld clean blowing off excess tram tracks. Then the fillers and cappers would come in.
"It was designed so they all finished at the same time doing three welds at a time. All welds were 100 per cent x-rayed."
Gaelic said thex-ray machine travelled inside the pipe. The film was wrapped around the outside of the weld and a magnet placed on top of the weld. When the x-ray machine passed under the magnet the x-ray would be taken.
"It was pretty advanced at the time."
The pipe wall was about 8mm thick.
When crossing rivers the pipe was up to 16mm thick.
He said when working with high tensile you were not allowed to touch it anywhere with the arc welder unless you were right in the gap. No moisture was allowed as it could harden the pipe. Gaelic said it was quite intense with a lot of pressure on the welders.
"Inspectors would constantly be watching everything the welders did. We were more frightened of the inspectors but they kept you on your toes."
Gaelic's job was to do repairs.
"I'd pick up x-rays in the morning and it would be written on there, for instance, lack of penetration, slag or something in a certain place. I'd go back and repair it. You'd only get one chance and if I mucked up, I'd have to cut a metre out of the line and put a metre-long 'pup' back in.
Tough going for workers
The men worked hard from daylight to dark living in motels along the way. They got picked up before daybreak, worked all day then were dropped off at the motel at night where a meal was cooked for them.
At Ruakaka the workers came across a lot of kauri.
"We hit a big kauri stump that was right on the line. A guy was sent in to blow the stump up but in the end, he couldn't so we had to divert the pipeline around it. We welded up a side section that was fitted in later.
"Someone took a photo of the stump with the digger sitting on it and it still had a metre either side, it was that big."
Weather was a big factor during the project.
"I remember going into the Brynderwyn Hills and it rained eight days straight. The pipeline didn't stop when it rained, so there were some hair-raising rides driving in 4WD vehicles in muddy conditions. The spread boss would make the call whether we'd weld that day or not.
"You'd be in there - then he'd say go home, so we'd go back to the nearest pub."
The ground was so undulating in the Brynderwyns they used helicopters to string the pipe into position.
Sun also caused the pipe to expand and contract, Gaelic said.
"If you cut a section of pipe out in the morning, you had to go back to put the pup in at the same time the next day, providing the weather was the same. "You'd be waiting for the time to be right."
The job was also very competitive. The first crew would cut the right of way, then the digger drivers would try to catch them, then the stringing crew would try to catch the trenchers, then the welders - the teams would try to catch the team in front. If you caught the guy ahead, you stopped work or had a day off, Gaelic said.
"We got paid accordingly, but we worked hard."
Unwritten laws
Gaelic reckons there were a couple of unwritten laws - never put rod ends in the trench; never get behind the stabbing in boom - which picks up the pipe and stabs it into the next pipe - because the operator only looks forward, and never get between the pipe and the ditch, apart from welding time.
"If the pipe got bumped and got knocked into the trench, you could get knocked in with it.
"When they're working on pipe lowering and laying, once it flips in you can't stop it."
Gaelic worked on the job for a year and got to know the welders and guys in the other crews, often meeting up after work.
Merv Gaelic was one of the welders who helped build the Refining New Zealand pipeline
"I loved the camaraderie of it all. I made some good friends, and married one of their sisters. Four or five of them I still keep in touch with."
Gaelic also worked for the American Navy in Somalia refurbishing a tank farm the Russians had built and has worked on pipelines in Australia - including the gas line that went into Jupiters Casino on the Gold Coast. In New Zealand he worked on the Kapuni natural gas pipeline to Auckland city; the line over the Kaimai Ranges and the pipeline through the Waioweka Gorge to Gisborne, which he said was hard going.
"You'd be going from rock breaking to swamp within a few metres."
One of the last jobs Gaelic did on the twinline was welding pipe that was hydro tested, x-rayed and stored at Huapai, ready to be used in a rupture such as that at Ruakaka.
