Characteristics and standard classification of spiral steel pipes: Spiral seam double-sided submerged arc welded steel pipes for low-pressure fluid transportation (SY/T5037-2018). There should be a certain channel between the stacks of double-sided submerged arc welded pipes, and the width of the inspection channel is generally around 0.5m. The width of the entry and exit channels depends on the material size and transportation machinery, generally ranging from 1.5 to 2m.