We rate the pipe for internal pressure first and come
out with safe adopted or rated thickness. The pipe so
sized is then checked if the thickness opted is safe
for the external pressure as evaluated in case of
underground pipes or the design external pressure as
for jacketted pipes ( even for pipes under vacuum).
The earlier rating is done using the relevant Piping
Code like ASME B31.3, 31.4 or 31.8 as the case may be.
The external pressure evaluation is done using the
methods guided by ASME PV Code Sec VIII Div 1.
Hope it clarifies.
Narendra K. Roy
Charisma Global, NZ
Camp: India
www.charismaglobal.com
- cckla <cckla@pd.jaring.my> wrote:
> Dear all piping specialists,
>
>
>
> We usually talk about pressure of the pipe, such 10
> bar, 20 bar and so forth, which marked on the pipe
> itself. Is this pressure valid only for the pressure
> acting from internal only ? Or it also involve the
> external pressure ? When internal and external
> pressure exist together in the system (such as in
> underground piping), should we look at them
> individually or together during the determination of
> the selected pipe pressure ?
>
>
>
> Please guide me.
>
>
>
> Thanks.
>
>
>
> Regards,
>
> cckla
>
>
>
> [Non-text portions of this message have been
> removed]
>
>
>
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Received on Thu Jun 10 23:01:00 2004