Re: [MW:13942] Painting before pressure test on pipings - B 31.3

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

 

From: Samuvel <samuvel.masilamani@gmail.com>
To: "materials-welding@googlegroups.com" <materials-welding@googlegroups.com>
Cc: "materials-welding@googlegroups.com" <materials-welding@googlegroups.com>
Sent: Monday, March 19, 2012 4:57 PM
Subject: Re: [MW:13936] Painting before pressure test on pipings - B 31.3

If u have 100% joint  NDT,you can obtain a concession request from your client

On 18-Mar-2012, at 6:42 AM, madhan chozhan <madhanchozhan@gmail.com> wrote:

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.

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