HELP

Are you under ASME codes ? For that you may refer the ASME standards say B31 series as applicable

From ASME B 31.3 I COULD NOT FOUND ANY FORMULA FOR HYDROTEST CALCULATION.

PL. HELP.

This is a link currently available with me, for DN 450 (you are DN 457.2 but the values are almost matching)

the pressure rating at different temp is given

http://www.matthewdavis.com.au/downloads/pds_Pipe_Pressure-Temp_Data_Sheet_Pg2.pdf

check the standards, the hydrotest (if I remember, is 1.5 times the rated pressure if not covered specifically). But not in business for this area (Pressure vessels) for a long long time

It depends on what code the piping system was designed and built to.

For instance, with the popular ASME B31.3 (2008) paragraph 345.4.2

When the design temperature is greater than the test temperature -

P_T = 1.5(P)(R_r)

Where:

• P = internal design gage pressure
• P_T = minimum test gage pressure
• R_r = ratio of S_T/S for pipe or components without established ratings, but shall not exceed 6.5 OR = ratio of the component pressure rating at the test temperature to the component pressure rating at the component design temperature for components with established ratings, but shall not exceed 6.5
• S = allowable stress value at component design
  temperature (see Table A-1)
• S_T = allowable stress value at test temperature