【Common Issues in Haichuan Pipeline Design】--Installation of vent and drain ports in pipeline design

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Installation of vent and drain ports in pipeline design △ Venting and draining at high and low points In pipeline design, corresponding vent and drain ports must be installed at the high or low points that arise as a result of the layout. Specifically, the minimum pipe diameter for the high-point exhaust outlet should be DN15, while the minimum pipe diameter for the low-point drain outlet is DN20 (when the main pipe is DN15, the drain outlet also uses DN15). For high-viscosity media, the minimum pipe diameter for the exhaust and drain ports must be increased to DN25. △ High-point exhaust vents on gas pipelines: In the design of gas pipelines, valves are generally not required for high-point exhaust vents; these vents can be sealed using threaded pipe caps or flange covers. Furthermore, apart from the pipes in the pipe tray, pipes with a DN of 25 or less do not necessarily require high-point vents. △ Representation and specifications for exhaust and drain outlets: For non-process-related high-point exhaust and low-point drain outlets, it is not necessary to indicate them on the PID (Piping and Instrumentation Diagram). According to the indications on the PID (Piping and Instrumentation Diagram), the exhaust and drainage ports required for the process should be installed strictly, including the interfaces connected to the equipment. The height of the exhaust outlet must comply with the relevant provisions of the **current standard, the Code for Fire Protection Design of Petrochemical Enterprises (GB50160)**. △ Discharge requirements for pipelines with special media: For pipelines carrying toxic or flammable and explosive liquids, their discharge points must not be connected to the sewer system; instead, they should be fed into a closed system for treatment. At the same time, if the pipeline transports gases that are heavier than air, the design of the venting points must take into account the effects of the operating environment as well as measures to ensure personnel safety.