Hercules Industries spiral pipe is formed from a coil of metal into a rigid steel tube with a 4-ply spiral lockseam. Our Spiral Pipe has a smooth interior for low friction loss with the grooved seam entirely on the outside. This pipe has a resistance to crushing approximately 2 1/2 times that of longitudinal lockseam pipe. Spiral Pipe sections can be joined together by duraflange rings, standard spiral pipe connector, or companion angle rings.