Maintaining and prolonging the life of existing assets is important. Here's a video of what engineers at our company do to maintain aging pipelines:
http://www.youtube.com/watch?v=tdt2-St7l7I&feature=PlayList&p=33A8BD03465A4121&playnext=1&playnext_from=PL&index=9Another part of the job, which isn't shown and actually done first, is conducting risk assessments. What are the likelihoods and consequences of pipelines failing? What needs to be inspected and in what order?