[Michele Norris:] From NPR News, this is ALL THINGS CONSIDERED. I'm Michele Norris.
[Melissa Block:] And I'm Melissa Block. Energy Secretary Samuel Bodman said today that there are adequate supplies of oil to keep refineries on the West Coast running, even without supplies from BP's Prudhoe Bay field in Alaska. BP has shut down a major pipeline. It needs to repair at least 16 miles of severely corroded pipes. That corrosion was discovered by a pig. Not a barnyard pig. NPR's Nell Boyce tells us about the pigs that roam through pipelines. NELL BOYCE reporting When it comes to pipelines, there's two kinds of pigs dumb pigs and smart pigs. Al Crouch says that dumb pigs came along first, decades ago, to clean out the pipes.
[Mr. Al Crouch:] They were often made of bales of straw, maybe with barbed wire wrapped around them, and they would pump them through the line to do a cleaning job. This made a squealing sound and that's where the name pig came from.
[Boyce:] Crouch is an engineer at Southwest Research Institute in San Antonio, Texas. He says dumb pigs are no longer made out of straw, but companies still send modern versions through their pipes to scrape out junk. Then there are your smart pigs. Crouch says a smart pig is a machine that has a power supply, a data storage device and a sensor that looks for flaws.
[Mr. Al Crouch:] And since it had intelligence, they say, to it, it was called a smart pig.
[Boyce:] The first smart pig came along in the 1960s. Today's versions are multimillion-dollar machines that look like torpedoes. Some use magnetic fields, some use ultrasound. They weigh several tons and can be 15 to 20 feet long. Instead of squealing, they rumble like a freight train. Crouch says they can travel for hundreds of miles.
[Mr. Al Crouch:] What some people don't realize is that the amount of data recorded by one of these smart pigs is enormous. It's every square inch of a pipe for 100 miles or more, and all of that has to be stored on board the pig.
[Boyce:] Each pig only looks for a particular kind of damage, usually corrosion or cracking. BP has been criticized for not using pigs to maintain its Alaska pipelines. The lines shut down now hadn't seen a pig since 1992. But after an oil spill earlier this year, federal regulators ordered the company to send in the pigs, and they found corrosion. BP says it hasn't used pigs because the lines were above ground and could be inspected by workers. But Ronnie Chappell, a company spokesperson, says that will change.
[Mr. Ronnie Chappell:] You know, in the future, smart pigging is going to be a much bigger part of our corrosion inspection program.
[Boyce:] But pipeline experts say that smart pigs are no panacea. They can't detect all kinds of damage like a scrape from a backhoe that's working above a pipeline. Pigs have other problems. For example, they can't go around sharp curves.
[Mr. Richard Kuprewicz:] There are pipes who can't, for various reasons, can't take smart pigs, and can't even take cleaning pigs.
[Boyce:] Richard Kuprewicz is a pipeline consultant with a company called Accufacts. He says there have been cases where a pig said a pipe was okay, then it later ruptured.
[Mr. Richard Kuprewicz:] There's lots of ways to screw up pardon my French to mess up a smart pig. You know, you can choose the wrong pig for the type of problem you have. The vendor could be overstating the capabilities of the pig.
[Boyce:] Or someone might misinterpret the pig's data. To help improve things, last year the American Petroleum Institute released some new guidelines on how to best use pigs. And the pigs just keep getting smarter, though Kuprewicz says no one has built the dream pig, a single pig smart enough to detect every possible kind of flaw in a pipe.
[Mr. Richard Kuprewicz:] That's kind of like the Holy Grail. That's like getting the space shuttle launched, okay. It's easier said than done. There's a lot of technical hurdles there.
[Boyce:] It's a tall order for a small community. Just a handful of companies and a few hundred people work on pigs. Nell Boyce, NPR News.