Painting before pressure test on pipings - B 31.3

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madhan chozhan

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Mar 17, 2012, 11:42:16 PM3/17/12
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Gents,

Good day.

I need to know whether leak test (hydro or pneumatic) can be done on piping after painting is done on the welds of pipe line?

ASME B 31.3 says "345.3 Preparation for Leak Test
345.3.1 Joints Exposed. All joints, welds (including
structural attachmentwelds to pressure-containing components),
and bonds shall be left uninsulated and
exposed for examination during leak testing, except that
joints previously tested in accordance with this Code
may be insulated or covered. All joints may be primed
and painted prior to leak testing unless a sensitive leak
test (para. 345.8) is required."

"345.8 Sensitive Leak Test
The test shall be in accordance with the Gas and Bubble
Test method specified in the BPV Code, Section V,
Article 10, or by another method demonstrated to have
equal sensitivity. Sensitivity of the test shall be not less
than 10−3 atm·ml/sec under test conditions.
(a) The test pressure shall be at least the lesser of
105 kPa (15 psi) gage or 25% of the design pressure.
(b) The pressure shall be gradually increased until a
gage pressure the lesser of one-half the test pressure or
170 kPa (25 psi) is attained, at which time a preliminary
check shall be made. Then the pressure shall be gradually
increased in steps until the test pressure is reached,
the pressure being held long enough at each step to
equalize piping strains"

here text in green says it shall be left uncovered expect that joints previously tested in accordance with this code(which test to be done for exception and where it is mentioned on code?) but the text in red says it may be primed and painted which looks controversial, kindly advice me what to follow.



Padmanabharaju Konduru

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Mar 18, 2012, 6:25:43 AM3/18/12
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Hi Dear,
 
           Painting and Coating could be done after hydro testing or pneumatic Testing of the Spools(Welded joints Should be exposed to Atm).

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Ramchandra vichare

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Mar 19, 2012, 1:14:06 AM3/19/12
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No. there should not be paint application on joints of piping  which are to be Hydro test or Pneumatic test .


Regards,
RK Vichare





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

From: madhan chozhan

To: material...@googlegroups.com

Sent: Sun, 18 Mar 2012 09:12:16 +0530 (IST)

Subject: [MW:13914] Painting before pressure test on pipings - B 31.3

Ramchandra vichare

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Mar 19, 2012, 5:50:46 AM3/19/12
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Samuvel

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Mar 19, 2012, 9:57:47 AM3/19/12
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If u have 100% joint  NDT,you can obtain a concession request from your client


DOKKU AJAY

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Mar 20, 2012, 4:03:52 AM3/20/12
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Hi,
 
The statement "except that joints previously tested in accordance with this Code may be insulated or covered" means that if the piping is already leak tested before i.e. at a fabircation shop or at site prior to assembly, then the joints can be insulated or covered. Please note that here the code is not talking about the priming and painting. It's only about the insulatioin or covering.
 
The second statement " All joints may be primed and painted prior to leak testing unless a sensitive leak test (para. 345.8) is required." means that the joints may be primed and painted which are subjected to initial (first time) leak testing subjected to the applicability of sensitive leak test.
 
 
Dokku Ajay Kumar
Mobile: +966 500071054

madhan chozhan

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Mar 20, 2012, 4:09:13 AM3/20/12
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Hi all,

Thanks for your valuable comment and now i am more clear with the particular section.

Regards,
Madhan

Thanks & Regards
Srirammadhan
Piping/painting inspector
Great drill Chaaya
Great Ship
Hamriyah Free zone, UAE

Roger Ciullo

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Aug 21, 2015, 12:16:32 AM8/21/15
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Dear All,

Is also the the insulation (rockwool+alluminium) allowed to be on the welds during the hydrotest? 

Thanks in advance.
Best Regards,
Roger
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