Seaway 2 Pipeline Workers Test Hypertherm Plasma Cutter Prototype
Heading north out of Oklahoma City, skyscrapers give way to strip malls, strip malls to a building here and there. Finally, one sees farmland. As far as the eye can see, cows and the occasional clump of trees dot the landscape. Woven through it all are dirt roads in a seemingly perfect grid and electric fences to keep the cows from wandering too far astray.
In this spot, an hour’s drive north, one can almost imagine a tornado chaser with sophisticated storm tracking equipment zooming by. But on this day there are trucks. Not the trucks that dot suburbia, but serious full-size trucks, all heading to the right of way — a relatively narrow strip of land that stretches hundreds of miles from the largest oil storage facility in the world, just north in Cushing, Oklahoma, to the Gulf of Mexico. Eventually, the trucks find their find to the Seaway 2 — a twin to the 30-in., 500-mile Seaway pipeline in service since 1976.
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Here, dozens of men and a handful of women are tasked with laying out pipe, welding it together, then carefully moving it into a trench. The job isn’t easy. Like the original Seaway line, the Seaway 2 pipes are 30 in. in diameter with walls up to three-quarters of an inch thick. The pipe is heavy, thanks to the use of high-strength carbon steel designed to resist corrosion and provide decades of service. As when working on any line, there isn’t room for error. Hit a power line and you will lose your job. Get between the pipe and the trench and you could lose your life.
The job here is a little different than most though. The men and women working the Seaway 2 are testing a prototype of the Freedom PPA, a powerful unit designed by Hypertherm to bring plasma arc cutting and gouging onto the line. The unit being tested on the Seaway 2 contains a 28-kW, 240-volt generator, along with a built-in air compressor and a Powermax85 air plasma unit capable of cutting 1 in. thick metal at 20 in. per minute. It comes in a fairly compact 54- by 44-in. footprint, allowing it to easily fit on the small buggies that move along the line.
Alternate Method
On the Seaway 2, the unit will see action doing a number of tasks, beginning with welder testing and pipe fabrication at the yard, before moving on to line itself where the crew will use it to cut pipe to size and gouge out welds needing repair. Prior to the arrival of the unit, these crew members would have used three different processes to do that work: Oxyfuel, air carbon arc gouging and grinding.
The use of a plasma torch on a pipe cutter allows precise cuts at speeds several times faster than oxyfuel.
Oxyfuel, a process that uses a fuel gas and oxygen to burn through metal, would be used to cut the pipe. However, it has several drawbacks including the fact that it is slow. While great for cutting thicker slabs of metal, oxyfuel is not the best choice for the thinner ¾-in. thick metal on this pipe. Preheating is also required. You need to heat up the pipe before you can cut it. As a result, a dozen people — an entire crew — might spend a half hour standing and waiting for one person to make a cut to a section of pipe needed somewhere down the line, because as one pipeline worker explained, “A pipeline is like an assembly line. One slow down affects everyone on the line.”
Speeding Things Up
Another drawback of oxyfuel is that the process requires the use of fuel, whether acetylene or something else, and large pressurized containers of oxygen, which the welders need to keep close at hand. These cylinders are heavy — weighing upwards of 150 lbs apiece — so moving them isn’t the easiest job. In addition, the cylinders are hazardous. The Department of Transportation is so concerned welders are only allowed to transport one or two cylinders at a time. When the welder runs out, sure to happen in the middle of the day, he has to stop what he’s doing, hop in his truck and make the often 80- to 100-mile roundtrip trek back to the main staging yard for another couple of cylinders. In the meantime, the crew on the line just keeps waiting.
Using plasma, a welder is able to get the job done quickly.
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“It’s 100 percent faster,” said Mario Garcia, a welder charged with making engineered cuts to pipe on the line. “With oxyfuel, you’ve got to preheat the pipe, burn the coating back, then make the cut. With the Powermax, you just make the cut.”
The speed with which cuts are made is just the beginning though. The quality of the cuts also counts. The cuts need to be formed with just the right amount of bevel so a welder can come in and properly join the pipe to the line. The Powermax is making more accurate and smoother cuts prompting Dusty Syprett, a welder with about a dozen years of experience on pipelines like the Seaway, to call the Powermax the best thing since peanut butter. After less than three months with it, Syprett hopes he never has to cut pipe with an oxy torch again.
Just down the line from Syprett, Ruben Garza is tackling another job common on the pipeline: weld repair. This is perhaps the toughest job for a welder here. Garza has to fix a weld that didn’t pass inspection because it contained a small defect picked up during ultrasonic testing. He needs to remove the old weld and create a new stronger weld. He worries though that he’ll accidently burn a hole in the pipe. If that happens, Garza is done. The pipe can’t be repaired. A crew of people will need to come in and replace it completely.
Before plasma, Garza would have used air carbon arc gouging. An electric arc at the end of a carbon rod melts the metal, while a continuous blast of compressed air blows it all away. The arc is bright and intense like a small ball of fire, the compressed air violent and powerful. Garza straddles the pipe trying to see past the molten metal flying at him to the defect he’s trying to fix. Fumes and an extremely loud noise fill the air. Even with ear plugs — mandatory if Garza wants to keep his hearing—and a mask, he is still exposed.
Fortunately for Garza, he’s using the Powermax today. The plasma unit pushes the molten metal out of the groove less violently than with air carbon arc gouging. Less molten metal vaporizes and fewer sparks fly though the air. Garza can actually see what he’s doing.
“You can see every defect real clearly and keep on gouging until it goes away,” he says. “I have so much more control this way.”
More control means the chances of Garza accidently melting a hole in the pipe are much lower. Fewer sparks flying through the air means there’s less risk of a fire breaking out. Air carbon arc gouging will shoot flames at least 15 feet away from the source. If it’s windy, even further. One spark on dry Oklahoma brush is all it’ll take for this crew to have a big problem on its hands.
Gouge Away
One hour on a plane and 45 minutes in an SUV, the southernmost end of the Seaway comes into view. MPG Pipeline is responsible for this roughly 150-mile stretch of pipe. Levi Rodriquez is doing weld repairs down here. He too is using the Powermax system and he too marvels at the control he has.
Based on feedback from the fields tests on the Seaway 2 pipeline, Hypertherm has tweaked the design and released the product as the Freedom 38 PPA.
“The best advantage of plasma over conventional carbon arc gouging is that you can thread a needle with that thing,” Rodriquez says. “You can take out as little or as much of the weld as you want.”
As with plasma cutting, plasma gouging is much faster than the air carbon arc process he is used to. It’s also much quieter. Pointing at the unit sitting on a buggy next to him, Rodriquez is animated.
“That thing right there is jam-up.” Levi’s way of saying he likes the Freedom unit. “It takes the work right out of the repair. It’s two times faster. It don’t throw the fire. There’s no snap. It’s quiet, just a little whistle.
“I was 12 repairs in the hole when I got here. It took me three days to catch up and that was with more repairs being added. I was so fast, they had to put another welder behind me.”
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Rodriguez admits he had some not so nice words for the welding superintendent who first told him he had a “new tool” for Levi to use on the Seaway job. He was understandingly hesitant to move away from a method that, in his opinion, was tried and true. Looking back now though Rodriguez says the Powermax was easy to master.
“It took a day and I was smiling,” he says. “If I get back on a job where I have to use a grinder or air carbon arc, I’ll feel like I went back to the stone ages.”
Endorsements like that have prompted Hypertherm to move forward with production of a unit like the one used on the Seaway 2. The company made a couple of changes though. Instead of a 28-kW generator, the company increased the generator size to 38 kW and coupled it with a 125-amp Powermax versus the 85 amp unit used on the Seaway 2. The combined system is now called the Freedom 38 PPA. The changes mean workers have the ability to cut slightly thicker 1-in. walled pipe without sacrificing cut speed or quality.
Tags: Hypertherm, Plasma Cutter, Seaway 2, WeldingMichelle Avila is a public relations specialist for Hypertherm.
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