The construction of a large-scale interstate pipeline can take 18 months, while smaller, local distribution lines can take as few as six months. Each project typically is divided up into several smaller lengths called "spreads," which creates a construction assembly line that can span up to 100 miles at a time.
After each spread is cleared and graded, sections of pipe are laid on the ground along the pipeline's right-of-way. Usually between 40 ft and 80 ft long, the pipe segments have 20-in. to 40-in. diameters for interstate and gathering lines and 6-in. to 16-in. diameters for lateral distribution lines. Larger lines, which operate at between 600 and 1,000 pounds per sq in. (psi) of pressure, are made of high-strength steel pipe that has a 0.25-in. to 0.75-in. thickness.