In order to ensure the quality of the project and the simplicity of installation, specific segment marks should be marked on the pipeline, and a reasonable selection of free pipe sections and closed pipe sections should be made. The adjustment length of the on-site connection pipeline should maintain a margin of 50mm, and the corresponding number and welding seam should be marked on the preform. Ensure that the prefabrication direction of the pipeline is consistent with the installation direction on site, so as to prevent the inconsistency between the installation and the icon. The welding group of the pipe fittings shall be flush with the inner wall, and the misalignment of the inner wall shall not exceed 10% of the wall thickness and shall not exceed 2mm.
