B31.3 tracers

Date 05-02-2011 22:27

We have a radiograph failure. Therefore we need to take 2 tracers to satisfy code requirements. Job spec requires 5% RT by piping system. Do the tracers count towards the required %ages? My research has not proven this to be true. If I'm wrong, can someone please indicate where the code states that tracers do count?

By js55

Date 05-04-2011 19:30 Edited 05-04-2011 19:36

It is not explicit in B31.3, however, the language indicates that the 'additional samples' are representatives ("all items represented") of the original defective item and are therefore NOT part of the random sampling percentage.
Read through 341.3.4 slowly.
And there may even be some interpretations.
Think of the logic of it. If they were counted in the sampling percentage you would essentially be rewarded for having defective welds. If you shoot 1 for 20 (5%) and miss it and then count the additional two in the percentage you essentially do not have to shoot again for 60 welds, which is essentially no tracers at all. 3 welds for 60 in one case, 3 welds for 60 in the other. It defeats the whole purpose to tracers.
Of course the reward is exactly why many try and make the argument.

By Shane Feder (****)

Date 05-05-2011 02:19 Edited 05-05-2011 02:22

Hi guys,
I think the answer is shown in Reply 2 (1) , (2) & (3)

B31.3 Interpretations No. 1
Interpretation: 1-62
Subject: 336.5, Types and Extent of Required Examinations
1-62
Date Issued:
File:
June 9,1982
1578

Question (2): Please refer to the progressive examination delineated in 336.5. For 5% radiography, at
the point of original examination, a 5% sampling has been represented (1 out of 20). Should that radiograph
fan to meet specification, two additional examinations are required, which represents a 15% (3 out of 20)
sampling.
(0) If any of the second group faUs to meet Code, is it mandatory, as the Code implies, that
further examinations are required? Is the alternative available whereby all welds of that given group of 20
may be totally repaired without subsequent radiographs?
(b) If any of the third group of radiographed welds fails to meet Code, does one progress to a
fourth group?

Reply (2):
(0) No to both questions. The following options are available.
(1) Replace all items in the group. Examinations performed on items which are subsequently
replaced may not be counted as contributing toward the required percent random examination.
(2) Continue progressive examination, repair and reradiograph all defective welds until they
are acceptable. Only the first weld in the group may be counted toward the required percent.
(3) Repair and radiograph all welds in the group until all are acceptable. Only the first weld
in the group may be counted toward the required percent.
(b) No. At this point in the progression. aU welds in the group (20) shall be replaced or repaired
and radiographed until acceptable.

Regards,
Shane