Re: [MW:12254] DSS spools 6" sch 40 x 2mtr.lg.hydro test

Dear Mr. RK vichare

 

I think you have misunderstood my reply.

 

I did not suggest HT can be replaced by doing RT.

 

I said "If weld is passed the RT test there would not be weld flaws/defect from where failure can initiate in doing repeated Hydro test at such high pressures"

 

Murugesan

 

On Wed, Aug 17, 2011 at 6:45 PM, Ramchandra vichare <vicharerke@indiatimes.com> wrote:

Dear Friend,
 As far as my experience in Piping & Pr.Vessel, Hydro test for Piping should not be 1-1/2times of design pressor (Pl. ref. ASME B31.3 Page 85 (Para 345.4.2). Hydro test & Radiography is totally different, RT will not give proper result of Hydrotest so go for hydro test only where necessary by solving all techanical probles. It will help to give good result for process piping.


Regards,

RK Vichare


----- Original Message -----

From: murugesan jeyaraman

To: materials-welding@googlegroups.com

Sent: Thu, 11 Aug 2011 18:51:21 +0530 (IST)

Subject: Re: [MW:12197] DSS spools 6" sch 40 x 2mtr.lg.hydro test

Hi

 

I presume that the test failed due to flange leakage, or pr drop due to enviorment or any other reason except weld leakage.

 

I am also sure that for such a High pressure, it is 100% RT joint and assume all your joints are of qood quality,

 

No codes and standards specify about  about howmany times  we can do hydro test and intervals between tests.  I am not sure whether any specs limit the repetition of testing on a spool.

 

Test pressure is arrived at by considering yield strength of the materials. so we can safely say materials and joints would not be stressed upto Yield point.

 

so, if you do one or two more time, it would not be a problem.

 

But as a suggestion, and as being DSS, i would say you first do the testing at Design pressure and hold it for 15 minutes, observe for any leakages, then you can raise the pressure to Test pressure.

 

After pressure test, you may want to do 100% PT to detect any surfaces flaws.

 

Thanks

 

Murugesan

 

 

On Thu, Aug 11, 2011 at 7:15 PM, prashant pansare <prashantpan_99@yahoo.co.in> wrote:

Dear All, I' ve inspected DSS spools 6" sch 40 x 2mtr.lg.hydro test at a press. of 230 kg. Test failed two times. Pl. guide me-- How many times I can do the hydro testing of such a spool? If there is no limit, what should be the time interval between two tests? Thanx & Regds, psp

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