Design pressure of the equipment
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I’ve seen that the design pressure for some equipment is specified as full vacuum, for example 1.2 MPa(G)/FV. I would like to ask: what difference does it make for the equipment whether FV is included or not?
I seem to remember that according to 20570, whenever there is a vacuum level involved, the equipment should be treated as if it were in a full-vacuum environment.
What I actually meant to ask is what is the difference between a device with a design pressure of 0.1 Mpag and one with a design pressure of 0.1 Mpag/FV
This post was last edited by Grizzly on 2016-2-23 21:14. I don’t have any practical experience; I’m just making guesses. Let’s discuss it together. For a device with a pressure of simply 0.1 MPa (G), the stress condition is that the internal pressure exceeds the external pressure by 0.1 MPa. For a device with 0.1MPa (G)/FV, the stress condition may be such that the internal pressure exceeds the external pressure by 0.1MPa, or it may be the other way around, with the external pressure exceeding the internal pressure by 0.1MPa. Perhaps in terms of structural support, supports under compression at both ends differ from those under compression at only one end, but given that these pressures are actually quite small, this difference can be ignored. I remember that there is another method specified, which is based on the pressure difference between the inside and outside. For example, container A is inside container B. Container A is a vacuum container, while Container B is a container with internal pressure. This time, it resulted in a large pressure difference inside and outside container A; this is exactly the situation that requires specialized design.