Drained straight seam steel pipe

 Drainage straight seam steel pipes, sewage pipes, and drainage pipes are systems consisting of pipe channels that collect and discharge sewage, wastewater, and rainwater, and their ancillary facilities. Including the main pipe, the branch pipe and the pipe leading to the treatment plant, whether it is built on the street or anywhere else, as long as it is a drainage pipe, it should be counted as a drainage pipe. The length of the drainage pipe is calculated according to the length and calculation of all the drainage main pipes, main pipes, branch pipes and inspection wells, and the connection of the inlet and outlet of the well. It does not include the connecting pipe, the inlet pipe and the open channel between the gully and the drainage pipe. The calculation should be based on a single pipe, that is, if there are two or more side-by-side drainage pipes on the same street, the length of the sum of each drainage pipe should be calculated.