Selection of pipeline grade
Thread Content
1. The design pressure of the pipeline is 1.5 MPa. 2. The hydrostatic test pressure for the pipeline should be 1.5 times the design pressure, which equals 2.25 MPa. 3. Question: If American standards are to be followed for determining the pipeline grade, should 2.0 MPa or 5.0 MPa be chosen?
The determination of the pipeline grade is unrelated to the hydraulic test pressure of the pipeline; it can only be determined based on the design pressure. Therefore, the pipeline grade for your case should be set at 2.0 MPa
Agree with the person above; a pipeline pressure rating of 2.0 MPa should be selected.
Temperature and pressure cannot be considered separately; temperature correction must also be taken into account for hydrostatic test pressures! The nominal pressure of the flange to be selected should be determined by referring to the flange’s temperature and pressure class, taking into account the material of the flange, the design temperature, the design pressure, and the required design margin. No parameters can be determined based solely on pressure.
What was said on the 4th floor is very accurate; the pipe grade is determined based on the design temperature, design pressure, and corrosion allowance. Using these parameters, it is possible to find the required pipe grade in the relevant standards. (For example, Sinopec’s standard: SEPM 0101.1-2002 Specifications for Pipeline Material Grades (Refining))
The operating temperature is room temperature, so I forgot to mention it. I will definitely develop the habit of speaking at the same time from now on. :P Last edited by pdms0009 on 2009-4-2 10:12 ]
2.0 Mpa will suffice.
Temperature correction must also be considered for the hydrostatic test pressure! For carbon steel, when the temperature is above 200 degrees, it’s no longer a simple 1.5-fold relationship. For stainless steel, the temperature exceeding 150 degrees does not follow a 1.5-fold relationship either. When selecting a grade, the design temperature also needs to be taken into account; relying solely on pressure cannot determine any parameters. Of course, it also depends on the materials and standards. For example, the material pressure stabilization curves specified in ASME B16.5 and SH/T3406 are not exactly the same.