Spiral welded pipe is manufactured from steel coil. The coil is unwound and then welded while it is being turned into the shape of the pipe. Changing the angle of the spiral and the thickness of the coil is all that is needed to change from one pipe size to another. The two sides of the double submerged arc weld penetrate the full thickness of the steel to ensure the strength of the finished pipe. Full scale tests have shown that high quality spiral welded pipe is as strong as API pipe. The strength and flexible manufacturing of spiral welded pipe make it the product of choice for a variety of applications.