Hi Joe!
I just sent you a reply to your PM... I'll just copy & paste it here... I noticed Jon beat me to it with respect to the answer to your query, but nonetheless they certainly can go the route they chose to do so according to ASME B31.3, and I try my best to explain it to you without going off on a tangent or two, so please read carefully...
I believe the difficult part of understanding B31.3 is the fact that class "M" piping is always referring to the inspection and examination requirements in the previous section covered and sometimes one has to go back and forth within the code to properly understand what these friggin code writers are trying to convey!!! :( :( :( In other words, they do a pizz poor job sometimes of putting it all together where it can be easily understood...
So, now that I confided my own experiences with ASME, let's get to the heart of the matter...
Part 10, Inspection, Examination, Testing and Records of Metallic Piping
M340
Paragraph 340 applies in it's entirety
M341 Examination
Paragraphs 341.1, 341.2, 341.3, and 341.5 apply in their entirety. See para. M341.4.
M341.4
Extent of Required Examination
Paragraph 341.4.1 Applies with the following exceptions:
(a) Visual examinations
(1) All Fabrication shall be examined. (2) all Threaded, Bolted and other Mechanical joints shall be examined.
(b) Other examination
(1) Random Radiography/Ultrasonic examination requirements of para. 341.4.1(b)(1) apply except that at least 20% of circumferential butt and miter welds and o fabricated lap and branch connection welds comparable to those shown in Figs. 328.5.4E and 328.5.5 sketches (d) and (e) shall be examined.
(2) The in-process examination alternative permitted in para. 341.4.1 (b)(1) may be specified on a weld for weld basis in the engineering design or by the inspector.
It shall be supplemented by appropriate non-destructive examination.
This is where the senior inspector is referring to when he mentions his alternatives to you in order to avoid RT examination.
Now, let's go back to paragraph 341.4.1 (b)(1) found more towards the beginning of ASME B31.3 shall we???
341.4.1
Extent of Required Examination
Now, we have to find
"Other Examination" first, and then go down to read parentheses (1) which reads like this:
(b) Other examination
(1) Not less than 5% of circumferential butt and mitered groove welds shall be examined fully by random radiography in accordance with para. 344.5 or by random ultrasonic examination in accordance to para. 344.6. the welds to be examined shall be selected to ensure that the work product of the welder or welding operator doing the production welding is included. They shall also be selected to maximize coverage of intersecting longitudinal weld(s) is examined, at least the adjacent 38mm (1-1/2") of each intersecting weld shall be examined.
In-process examination in accordance to para. 344.7 may be substituted for all or part of the Radiographic or Ultrasonic examination on a weld for weld basis if specified in the engineering design or specifically authorized by the inspector.
So what does paragraph 344.7 state?? Let's go there and see for ourselves!
344.7
In Process Examination
344.7.1 Definition
In Process examination comprises examination of the following, as applicable:
(a) Joint preparation and cleanliness
(b) preheating
(c) Fit up, Joint clearance, and internal alignment prior to joining
(d) Variables specified by joining procedure, including filler metal
(1) (For welding) Position and electrode
(2) (For brazing) Position, flux, brazing temperature, proper wetting and capillary action.
(e) (For Wedling) Condition of the root pass after cleaning - External, and where accessible, Internal - aided by liquid penetrant or by magnetic particle examination when specified in the engineering design.
(f) (For welding) Slag removal and weld condition between passes.
(g) Appearance of the finished joint.
344.7.2 Method
The examination is visual, in accordance with para. 344.2 unless additional methods are specified in the engineering design. So this is the key sentence in the clause!
So if you read what I just emphasized here above, you will understand how they are correct in going this route as opposed to performing the usual 5 to 20% minimum RT/UT examination. I hope you now understand that this clause gives them the option of going 100% visual instead.
Respectfully,
Henry