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1055 views
00:16 May-21-2006
daniel
inspection methodes for pipe line has been working over pressure

hello
i need information how to inspect a line that was subject for short period by over pressure around 3500 psi - 6" schedule 80 -flange rate 600
thanks



    
 
08:10 May-22-2006

Rich Roberts (Quest TruTec)

Engineering, Executive Managment
Quest Integrity Group,
USA,
Joined Nov 1998
78
Re: inspection methodes for pipe line has been working over pressure Good Day,

You may want to consider applying the "ultrasonic" based FTIS Intelligent Pigging technology. The FTIS system can clearly detect and quantify damages such as: Bulging, Swelling, Ovality in addition to Corrosion, Erosion & Pitting.

Regards, Rich Roberts
Quest TruTec





    
 
01:14 May-23-2006

John O'Brien

Consultant, -
Chevron ETC ,
USA,
Joined Jan 2000
278
Re: inspection methodes for pipe line has been working over pressure On a rough calculation you have exceeded maximum allowable pressures on both pipe and flanges by a factor of 2.

You do not indicate how long the over pressurisation was for or what the current working pressure is. You also do not indicate temperature and fluid service and whether the pipe is aboveground or buried.

You need to consider a risk assessment looking at all these factors plus was this a one time deal or have you been cycling the piping system.

Consider likelihood and consequences of failure, impact on operations, environment etc.

First is a visual to look for visible signs of damage, leaking flanges, loose bolts, deformation, misalignment, stressed pipe supports etc. API RP 574 can be used for guidance.

If this first go around looks good then you may have mitigated your risk of an immediate release.

Then consider long term operation, how long, what pressure, fluid service, future pressure excursions.

If there remains a high concern then you may need to proceed to the approach suggested by Rich Roberts or it may be more cost eefective to schedule a replacement.





    
 
08:46 May-29-2006
Robert Davis
Re: inspection methodes for pipe line has been working over pressure Please be clear, is this a design pressure or operating pressure. Even if design let's back out of the analysis and look at the uncertianty with the stress. Then look at the actual design numbers, generally you will find that you never went above yeild. OK once this has been looked at, now find a reference for the creep properties. Using the NDE results for maximum flaw size apply the flaw diameter and determine the Kic.

RBD



    
 


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