Minor issues with the vacuum system pipes
Thread Content
For a certain project, the system pressure fluctuates repeatedly between vacuum and atmospheric pressure. The design pressure is set at 0.1 MPa, while the nominal pressure is 1.6 MPa. The wall thickness of the pipes was not determined considering the vacuum condition; instead, it was selected using the \"Table for selecting pipe wall thicknesses under common nominal pressures\" from a certain manual. This results in a wall thickness that is even thinner than that specified for SCH20. D1221 wound gaskets were chosen as the sealing elements. Is there any problem with this? The project has been in operation for several years, and the owner has not reported any issues.
Taizu said that practice is the only means to test truth. Since there have been no problems for several years and the work pressure is so low, nothing serious will happen. But I think the term “a bit” used by the original poster to describe something thinner than SCH20 is a bit imprecise.
The table below shows the standard values. Nominal diameter DN 20 25 32 40 50 65 80 100 125 150 200 250 300 350 400 450 500 550 600 Sch20s SH3405 2.5 3.0 3.0 3.0 3.5 3.5 4.0 4.0 5.0 5.0 6.5 6.5 6.5 Sch20 ASME 6.4 6.4 6.4 7.9 7.9 7.9 9.5 9.5 SH3405 3.5 4.5 4.5 5.0 5.0 5.5 6.5 6.5 6.5 8.0 8.0 8.0 9.5 9.5 9.5 The table below shows the materials used for these items; they are relatively thin. (1) Wall thickness of seamless carbon steel pipe, in mm; Material, PN, DN, in MPa: 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 150, 200, 250, 300, 350, 400, 450, 500, 600. 20 ≤1.6, 2.5, 3, 3, 3, 3, 3.5, 3.5, 4, 4, 4, 4, 4.5, 5, 6, 7, 7, 8, 8, 8, 9
The leader said it’s necessary to take engineering experience into account, :(
Is your leader planning to cross the river by feeling the stones, relying on experience? If there’s no written documentation, say “It doesn’t meet the standards and won’t pass inspection; it’s recommended to follow the specifications”: lol