Sunday, March 18, 2012

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

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.



--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.

No comments:

Re: [MW:35289] Welding consumable for S355J2WP material

S355 J2 WP  is a weathering structural steel  It has better atmospheric corrosion resistance. Use E 8018 - W1/W2  Electrodes This is regular...