The significance of the maximum impact-free operating pressure for flange selection
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When selecting flanges, when determining the pressure rating of the flange, should the maximum shock-free operating pressure be based on the design pressure and design temperature, or on the operating pressure and temperature? For example, the operating pressure is 8.8 Mpa, the operating temperature is 88°C; the design pressure is 9.5 Mpa, and the design temperature is 100°C. The flange material is 16Mn. Should the pressure rating of the flange be 600LB or 900LB?
When selecting a flange, the maximum impact energy must not exceed that specified for the flange at its design temperature. At 100 degrees, the maximum impact energy capacity of 600lb flanges for 16Mn is only 9.02 MPa; since the design pressure for low-pressure applications is 9.5 MPa, 900lb flanges need to be used. The maximum impact energy of the 900lb flange at 100 degrees is 13.53 MPa, which fully meets the design requirements, allowing it to be used with confidence.
I think the same, but the manufacturer believes that 9.02 Mpa is sufficient for the operation of the equipment. They won’t let us replace it.
This depends on how the design firm decides it, because it is the party that will be held responsible in case of any problems later on; it cannot be determined by the equipment manufacturer.