Design Pressure

X

You gotta give more info, my crystal ball is in for a service

In the absence of specifications, you (and we as well) are working a bit in the dark. Can you come up with a required pressure rating by examining some gauges, asking plant operators, and applying a reasonable multiplier or safety factor? If this can be done, the stress calculations should not be difficult.

At least check the schedules - assuming the system is well designed, that may provide at least some semblem of sanity.

Hope you found minimum thickness from the UT.Based on thickness and material data, you can calculate allowable working pressure based on ANSI B31.1 or B31.3 depending on service. You have apply proper corrosion and other allowances

Good morning inspectorjoe,

Could you pls let us know what is a UT gauging? Did it give you Minimum Yield Strength of the piping material? Wall thickness? Outside Diameter? Construction of Pipe? Temperature of carried material?

Usually, the design pressure comes from a process engineer or someone familiar with the process (an operator that has run this process for many years). Someone should have the designed the pipe that you tested.

Usually, the design pressure is regulated by a relief device. For example, if your system is pump, relief valve, then pipe that you tested, then the design pressure would be the same as the relief valve set pressure.

Be careful whatever you do though because as an inspector you should not be the one choosing a design pressure. I would urge the owner to provide a pressure for you.