[MW:3147] Re: hot-oil traced line

Augustin,

thanks

I read before that ...the client due the complexity of 1" traced oil hot line....is worry if the water will not realise completely from system will happen an incident so ...they propose to substitute hydrostatic with pneumatic ....maximum operation pressure is 2 bars ...so we wants to do the pneumatic test at 6 or 8 bars ...means 300-400% over the max operat. pressure....and also in the same time ...soup test ....bubble test....

i am just confused about the restriction for pneumatic test ...i know that for pressure vessels are completely avoid .....

daniel

On Tue, Sep 8, 2009 at 4:14 PM, AGUSTIN JIMENEZ <agumarca@yahoo.com> wrote:

Hi Daniel.

ASME B31.4

-Piping systems that at some point will operate in an effort
circumferential greater than 20% of minimum yield strength
specified, shall be subjected to a hydrostatic test of 1.25 times the
design internal pressure of the pipe at that point, considering the
external pressure of the water column at that point (foot of water / 2.31
lbs/pul2). The minimum duration is 4 hours. 
- At no time efforts that are induced during the test
hydrostatic exceed the effort for 90% of point
minimum yield strength of material. If this occurs, the pressure
test should be reduced to the maximum pressure to which the effort
produced by hydrostatic testing does not exceed 90% of the yield strength
of pipe to the test temperature.
- The maximum test pressure to which the effort produced by the test
Hydrostatic not exceed 90% of yield stress of pipe material
can be calculated with the following equation:
Pm = Sy x 1.8 t/D + Pe
Where:
Pm = Maximum test pressure
Sy = specified minimum yield limit
t = thickness of the pipe
D = Outside diameter of pipe
Pe = Pressure of the water column (foot of water / 2.31 lbs/pulg2)
- A hydrostatic or pneumatic test can be used for systems
pipeline that will operate at a circumferential stress of 20% or less of
specified minimum yield strength. The test pressure shall not be less
1.25 times the design internal pressure (considering the external pressure
by effects of water column). If a pneumatic test, it
will be 0.689 MPa (100 Lbs/pulg2) or that an effort to produce
circumferential equal to 25% of specified minimum yield strength of the
pipe, whichever is the lesser. Test time will be longer
specified above.

 

Excuse if my English is not good

 

Agustin Jimenez

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De: daniel iordache <daniel.iordache@gmail.com>
Para: materials-welding@googlegroups.com
Enviado: martes, 8 de septiembre, 2009 2:26:52
Asunto: [MW:3137] hot-oil traced line

hello Friends

 

we have in project 10-12" bitumen line .......these lines are accompanied by hot-oil traced line 1" sch 40....maximum pressure for those line are 30 psi.....due the complexity of network ....i want to test line instead of hydrostatic ...pneumatic at 90 psi ... ....there is any restriction..? Most of people said is avoid to do pneumatic test ...by code ....i did not find any ....

 

please advice

--
Daniel Iordache
Bureau Veritas - Angola
Mechanical& Welding Surveyor
Mobile Ao: +244921544583
Mobile Ro:   +40721731728
E-Mail: daniel.iordache@gmail.com
          daniel_iordache@yahoo.com

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--
Daniel Iordache
Bureau Veritas - Angola
Mechanical& Welding Surveyor
Mobile Ao: +244921544583
Mobile Ro:   +40721731728
E-Mail: daniel.iordache@gmail.com
          daniel_iordache@yahoo.com

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