Gas pipe corrosion and home explosions

Framing case for why the polyethylene pipe was developed — sixty-year-old steel pipe corroding through, century-old cast iron pipe failing.

[Tom holds up a piece of polyethylene pipe.] This is a piece of polyethylene pipe. The gas industry was tired of all the steel pipe corroding in the ground after fifty, sixty years and having to replace everything. Plus they didn't like it when houses blew up. So they wanted something that was corrosion resistant, and polyethylene will be around for millennia. There aren't a lot of bugs that eat it. But how do you put it together? They weld it. It's hot pressure welding. They take the two ends of the pipes, machine them flat, put a heater in between, pull the heater out when it's hot, and squeeze it together. You extrude out the contaminated surface, because it is still a contaminated polyethylene surface. Polyethylene has a very low surface energy, so it doesn't want to attract very many things. If it's got a lower surface energy to begin with, it's not going to get contaminated.