Re:Pneumatic Leak test required for Reinforcement Pad covering Pressure containing welds

[Saravanan Murugappan]

Dear Friends,

1.As the above stated subject;can anyone explain me Briefly When it is required??

2.Contractor Saying that they wont do Pneumatic Leak test  for Branch connections consists of RF Pads.They are objecting Because "They do leak test whenever the longitudinal or circumference weld seams covering the RF pads.(That means "Weld seams " when it comes under RF pads.)

3.Is this Contractor Query about this valid?...and Plz guide me  to follow the exact requirements.

[ajay pathak]

Dear Sir,

 

Please note that Leak test of reinforcing pads shall be performed in accordance with the ASME Code Section V. Each reinforcing pad shall have one test hole, tapped for 1/4 inch NPT, and located at least 45 degrees off the longitudinal axis of the vessel. This applies to each pad or segment of a multiple piece pad. The welds of each pad or segment shall be given an air and bubble solution pressure test before the test of the vessel. The test pressure shall be at least 1.0 bar (g) but shall not exceed 1.4bar (g). The test holes shall be left open for use as telltale holes. 

 

Regards,

Ajay Pathak

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[Saravanan Murugappan]

MrAjay,

My query is different.Whether ITP(Inspection Test Plan) Mentioning :

"Pneumatic Leak test required for Reinforcement Pad covering Pressure containing welds"

My question is RF Pad covering pressuring containing weld means what????? 1.Whether weld seams under RF Pads?or 2. Branch connections  contains RF pad?

Which is correct?

[Karthi Keyan]

Dear Saravanan,

 

          Which means that, Shell with RF Pad welds and Pad with Nozzle Welds. that is to be pneumatically tested at a pressure of 1.5 bar(g).

 

 

Regards,

 

Karthikeyan

Thanks & Regards,

 

Karthikeyan. P,

Surveyor.

 

BUREAU VERITAS (INDIA) PRIVATE LIMITED,

30/6, 3rd Floor, Aparna Tower, New Dhamu Nagar,

Puliakulam Road, Pappanaiken Palayam,

Coimbatore - 641 037, India.

 

Mobile No.: 9994999503

[Saravanan Murugappan]

Dear Karthikeyan,

It's For Piping Branch connection.No any shell or Nozzles 

Please Clarify me:

"Pneumatic Leak test required for Reinforcement Pad covering Pressure containing welds"......??

Contractor Saying that they wont do Pneumatic Leak test  for Branch connections consists of RF Pads.They are objecting Because "They do leak test whenever the longitudinal or circumference weld seams covering the RF pads.(That means "Weld seams " when it comes under RF pads.)

Is this Contractor Query about this valid?...and Plz guide me  to follow the exact requirements.

[HAREESH K V]

For some clients there will be a requirement for Reinforcement Pneumatic pad test. Eg: M/s.EIL.

Its all, the specification which governs. If you have given the specification to the contractor he is obliged to do so[ as per your contract terms.]

The pneumatic tests are done to ensure that there is no leak [ no puncture] due to the welding of Reinforcement pad [ mostly it is done very carelessly...]

It ensures [ in general terms..]

1.No puncture has happened to mother pipe

2.No puncture has happened to branch pipe.

When you are placing a reinforcement pad, it is placed over a pressure containing weld. That is the weld you are doing to the branch to mother pipe is a pressure containing weld. You are placing the reinforcement pad over that weld. So as per your ITP pneumatic test has to be done. [The weld you are doing with branch to mother pipe is not available for inspection at the pressure test(mostly hydro test - depends of design condition) of mother pipe and branch pipe]

Refer 341.3.1(ASME B31.3 Process piping) and Fig 304.3.3 (ASME B31.3 Process piping)

Experts please reply if i am wrong.

 

----------------------
Hareesh K V
+91-9447625012

[cbe swamy]

Dear Mr Saravanan, How are you, After BV where are YOU: nice to meet you from MW.

 

 

Your Quiry is,  " Pneumatic Leak test required for Reinforcement Pad covering Pressure containing welds "

Ans.:  200% required

 

and In addition that as bellow:

 

Telltale Holes. Telltale holes may be used to provide some positive indication when the thickness has been reduced to a dangerous degree. Telltale holes shall not be used in vessels that are to contain lethal substances [see UW-2(a)], except as permitted by ULW-76 for vent holes in layered construction. When telltale holes are provided, they shall have a diameter of 1⁄16 in. to 3⁄16 in. (1.5 mm to 5 mm) and have a depth not less than 80% of the thickness required for a seamless shell of like dimensions. These holes shall be provided in the opposite surface to that where deterioration is expected. [For telltale holes in clad or lined vessels, see UCL-25(b).]

 

Reinforcing plates and saddles of nozzles attached to the outside of a vessel shall be provided with at least one telltale hole [maximum size NPS 1⁄4 (DN 8) tap] that may be tapped for a preliminary compressed air and soapsuds test for tightness of welds that seal off the inside of the vessel. These telltale holes may be left open or may be plugged when the vessel is in service. If the holes are plugged, the plugging material used shall not be capable of sustaining pressure between the reinforcing plate and the vessel wall.

Thank & Best Regards,

 

M Veera SAMY- Bureau Veritas.

Coimbatore-9790964530

 

 
 

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Date: Thu, 7 Mar 2013 09:20:18 +0530
Subject: Re: [MW:16982] Re:Pneumatic Leak test required for Reinforcement Pad covering Pressure containing welds
From: spkarth...@gmail.com
To: material...@googlegroups.com

[MM]

Dear Mr. Veera Samy,

 

Pls. correct me if I am wrong,

 

As per UG 37 (g) tell tale hole is a “SHALL” for RF pads, but performing leak test is “MAY be performed” only, so it’s not a must to perform a pneumatic leak test

And as per UG 82, when pressure or non pressure parts extends over weld, it shall be ground flush only and code doesn’t asks for pneumatic test

 

Mr. Saravanan,

The term RF pad denotes the branch connections / nozzles contains RF pads, bcoz saddles, lifting lugs can also cover the weld, which is not called as RF pads.

Reinforcement is the term used where the opening is compensated as stated in UG 37

 

Cheers

MM

[pankaj...@wipro.com]

Dear all

Can we plug the TT hole by welding after pneumatic test

And what to do if leak has been observed thru TT hole of Nozz RF pad during hydrotest of vessel can we plug directly by reducing pressure ATM?

 

Pankaj Kolhe

QC

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[G Sreenivas Rao]

Dear sir
If leak from TT hole observed, the pressure shall be reduced and and
the testing mediaum shall be drained till 300 below the RF pad level
and the back side surface shall be cleaned DP test to be performed to
know the point of leakage and repair shall be carried out. and oafter
sucssesfully completion of repair, re testing to be carried. the TT
hole shall be pulged with grub screews not by welding.

Regards
GSR

[MM]

Dear Pankaj,

 

As per UG 37 (g) of section VIII the tell tale holes shall not be welded, it may be left open or it may be plugged but “

“If the holes are plugged, the plugging material used shall not be capable of sustaining pressure between the reinforcing plate and

the vessel wall”

 

If its leaking thru RF pad then there is a serious problem in the weldment, that has to be repaired after removing the water with relevant WPS

You just cant weld the TT hole, you have to eradicate the source of leak.

 

Cheers

MM