2 replies to this topic

[Rick Mtz.]

Hello, i have a question about the calculation of pressure design in asme b31.3 for process piping. Generally the client provides us the pressure test for the job, buy in case i need to calculated this value, the norm asme b31.3 in numeral 345.4.2 saids that the test pressure is 1.5 times the design presssure. So i want to know where can i find that design pressure or how to calculated.

 

I expect that you can help me with this question, i will be so greatful.

[astro]

Where I come from (hydrocarbon processing industry), definition of design conditions is fundamental to the discipline and goes hand-in-hand with process flow and mass & energy balance development.

 

That's why the data on the left hand side of a line list or line designation table is "owned" by the process engineer.

 

To arrive at the key data, the determination of the design pressure / temperature needs to be developed. I'm not about to set out such basic principles long hand here. However, you would do well to review chapter 4 of this reference:

https://www.pdhonlin...esign P-001.pdf

that I found by web search.

 

If you're lucky, you can find the data in a line list or project basis of design. If not, it's possibly a case of get down to basics, understand the mechanical limitations and operating potential of the equipment involved in your process (e.g. pumps, compressors, heaters, reactors) and marry that detail together with piping standards to arrive at a sensible end point. Another port of call for guidance is API STD 521 - take a look at (7th Edition) B.3 Procedure to Calculate the Design Pressure or MAWP of Equipment Components for guidance. This could be a substantial piece of work. Difficult to offer better guidance over the web.

 

If anyone can offer better guidance, I'd appreciate an alternate perspective.

Edited by astro, 26 October 2020 - 04:02 AM.

[fallah]

Hello, i have a question about the calculation of pressure design in asme b31.3 for process piping. Generally the client provides us the pressure test for the job, buy in case i need to calculated this value, the norm asme b31.3 in numeral 345.4.2 saids that the test pressure is 1.5 times the design presssure. So i want to know where can i find that design pressure or how to calculated.

 

I expect that you can help me with this question, i will be so greatful.

 

Hi,

 

A simple method of Hydro Test Pressure calculation is 1.5 times of total of maximum operating pressure plus a reasonable margin; but you should preferably refer to the relevant project design criteria to evaluate the design pressure and then multiply it to 1.5 to calculate the hydro test pressure based on ASME B31.3.