D.Poulios
Petroleum
- Oct 21, 2024
- 4
Hello Everyone,
I have a question regarding the Hydrotest procedure of some piping lines connected to a compressor. The compressor has 8 stages and the Suction design data of those stages are the following:
Stage 1: Temperature: 80 deg. C Pressure: 2 bar Hydrotest Pressure: 3 bar
Stage 2: Temperature: 80 deg. C Pressure: 8 bar Hydrotest Pressure: 12 bar
Stage 3: Temperature: 80 deg. C Pressure: 14 bar Hydrotest Pressure: 21 bar
Stage 4: Temperature: 80 deg. C Pressure: 32 bar Hydrotest Pressure: 48 bar
Stage 5: Temperature: 80 deg. C Pressure: 65 bar Hydrotest Pressure: 97.5 bar
.
.
.
Reaching all the way to
Stage 8: Temperature: 157 deg. C Pressure: 162 bar Hydrotest Pressure: 243 bar.
Now, the questions are the following:
1) Is the thickness of the piping defined only by the design pressure and temperature as ASME B31.3 suggests (304.1.2) or at some point the hydrotest pressure governs in the thickness calculation?
In the fifth stage for example I have a 14" pipe (SS316L) 1 mm C.A. with a defined thickness 14.27mm ( ASME B16.10). For this thickness the maximum allowable working pressure is *88.6 bar which is significant lower than my Hydrotest pressure.
Should I increase the thickness so the pipe can withstand the hydrotest pressure?
*To calculate the 88.6 bar I solved the ASME B31.3 (304.1.2) equation and found P.
2) This very high Hydrotest pressure (of again let's only mention 5th stage) also concerns me in regards to flanges. Based on the design data, and as per ASME B16.5 tables the flanges are selected to be Class 600** (material group 2.3).
For 600 rating the maximum allowable working pressure is 82.7 bar which is again significantly lower than 97.5 bar which is the hydrotest pressure. Should I consider 900 lbs flanges to withstand the hydro pressure or should I leave it as is considering that these flanges (600lbs) have been tested up until 1,5*P@38 degrees [bar]?
** ( Pmax@ 80 degrees = 74 bar > 65 bar = Pdesign. )
Thank you everyone in advance!!
I have a question regarding the Hydrotest procedure of some piping lines connected to a compressor. The compressor has 8 stages and the Suction design data of those stages are the following:
Stage 1: Temperature: 80 deg. C Pressure: 2 bar Hydrotest Pressure: 3 bar
Stage 2: Temperature: 80 deg. C Pressure: 8 bar Hydrotest Pressure: 12 bar
Stage 3: Temperature: 80 deg. C Pressure: 14 bar Hydrotest Pressure: 21 bar
Stage 4: Temperature: 80 deg. C Pressure: 32 bar Hydrotest Pressure: 48 bar
Stage 5: Temperature: 80 deg. C Pressure: 65 bar Hydrotest Pressure: 97.5 bar
.
.
.
Reaching all the way to
Stage 8: Temperature: 157 deg. C Pressure: 162 bar Hydrotest Pressure: 243 bar.
Now, the questions are the following:
1) Is the thickness of the piping defined only by the design pressure and temperature as ASME B31.3 suggests (304.1.2) or at some point the hydrotest pressure governs in the thickness calculation?
In the fifth stage for example I have a 14" pipe (SS316L) 1 mm C.A. with a defined thickness 14.27mm ( ASME B16.10). For this thickness the maximum allowable working pressure is *88.6 bar which is significant lower than my Hydrotest pressure.
Should I increase the thickness so the pipe can withstand the hydrotest pressure?
*To calculate the 88.6 bar I solved the ASME B31.3 (304.1.2) equation and found P.
2) This very high Hydrotest pressure (of again let's only mention 5th stage) also concerns me in regards to flanges. Based on the design data, and as per ASME B16.5 tables the flanges are selected to be Class 600** (material group 2.3).
For 600 rating the maximum allowable working pressure is 82.7 bar which is again significantly lower than 97.5 bar which is the hydrotest pressure. Should I consider 900 lbs flanges to withstand the hydro pressure or should I leave it as is considering that these flanges (600lbs) have been tested up until 1,5*P@38 degrees [bar]?
** ( Pmax@ 80 degrees = 74 bar > 65 bar = Pdesign. )
Thank you everyone in advance!!