BS EN 12953-5:2020 pdf free download – Shell boilers Part 5: Inspection during construction, documentation and marking of pressure parts of the boiler.
5.5.4 Non-destructive examination of welded joints – techniques and acceptability of imperfections
5.5.4.1 General
All welded joints which are to be subjected to non-destructive examination shall be prepared so as to be suitable for the method to be used.
NOTE Acceptance limits for imperfections occurring at the surface of welded components have been modified to reflect current European boiler manufacturing practice. When this has been done, an identifying letter “S” has been utilized in the tables in the columns “EN ISO 5817 level”.
5.5.4.2 Visual testing
5.5.4.2.1 Examination
All welded joints shall be visually examined for profile imperfections in accordance with EN ISO 17637:20 16 or EN 130 18:2016. This shall be additional to other NDT of welds.
5.5.4.2.2 Acceptance level of imperfections in welds
The acceptance level of imperfections shall be in accordance with Table 3.
5.5.4.3 Radiographic examination
5.5.4.3.1 Examination
Radiographic examination of welds shall be carried out in accordance with class A of EN ISO 17636-1:2013 and/or EN ISO 17636-2:2013.
5.5.4.3.2 Acceptance level of imperfections in welds
The acceptance level of imperfections in welds shall be in accordance with Table 4.
5.5.4.3.3 Radiographs
A complete set of radiographs for each job shall be retained by the manufacturer and kept on file for a period of at least 10 years.
5.5.4.5 Magnetic particle examination and penetrant testing
5.5.4.5.1 Examination
Magnetic particle examination of welds shall be carried out in accordance with EN ISO 17638:2016, and penetrant testing of welds shall be carried out in accordance with EN ISO 3452-1:2013.
5.5.4.5.2 Acceptance criteria
The following imperfections shall be judged unacceptable in magnetic particle examination or the dye penetrant test:
a) discontinuities interpreted as cracks, lack of fusion or penetration, regardless of the length;
b) any defect greater than the acceptance levels in accordance with Table 3.
5.6 Weld production control test plates
5.6.1 General
In order to control the continuing quality of manufacture and the compliance of the mechanical properties of the welded joints to the specification, a test plate shall be welded to the boiler and tested in accordance with the requirements detailed below.
Production control test plates shall only apply to main shell longitudinal and circumferential welds.
5.6.2 Quantity of test plates
5.6.2.1 Automatic or semi-automatic welding process and considered as serial production
a) For v = 1,0: required once a year;
b) For v = 0,85 or v = 0,7: not required.
NOTE Definition of serial production is given in EN 764-1:2015+A1:2016.
5.6.2.2 Other welding process or non-serial production
The following test plates shall be prepared:
a) For v = 1,0: one test plate per boiler;
b) For v = 0,85 or v = 0,7: one test plate per 100 m of longitudinal joints or at least once a year;
c) if circumferential seams are welded to a different procedure to the longitudinal seams, one test plate per year. If the circumferential welds are made to the same procedure as the longitudinal welds no test plates need be provided for the circumferential seams;
NOTE After 10 test plates successfully pass the tests, testing can be reduced to the following.