Can low-pressure steel pipes be directly welded to branch pipes?
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Can a DN200 low-pressure carbon steel pipe be directly perforated and welded to a DN80 pipe, without the need for a tee or any reinforcement? Are there any regulatory requirements for this?
I think it’s fine; the opening is less than half of the pipe diameter
Yes, if the thickness of the main wall is not large, reinforcement calculations can be carried out for verification.
Generally, it is possible, provided that the stress displacement of the pipeline is not significant
This is related to the medium and pressure of pipeline transportation. Low-pressure, non-toxic, non-flammable media can be directly connected via tapped fittings. For some pipes with low pressure that transport flammable, explosive, or toxic substances, it is necessary to ensure complete weld penetration, and corresponding inspections must be carried out; they can only be used after passing these inspections. Reference can be made to GB 50236-2011 Code for Construction of Welding Works of Field Equipment and Industrial Pipelines, and GB 50683-2011 Code for Acceptance of Construction Quality of Welding Works of Field Equipment and Industrial Pipelines