Drain lines in a potato chip processing plant in Orlando, Fla., were running slowly or not at all. The facility, built in 1976, operates nonstop.Herrell Plumbing in Orlando responded to the numerous service calls, cutting through the 6-inch-thick concrete floors to replace the worst of the cast-iron pipes. Three lines, however, were under a floor holding ovens and fryers weighing many tons.Moving the equipment to open-cut, then rerouting the lines to accommodate the machines needing drainage, would have been extremely expensive. Chris Peterson of Herrell called Rusty McFall, owner of TNT Sewer LLC, a certified provider of Perma-Liner products in
