Section 2 Prefabrication primers
Clasification Society 2024 - Version 9.40
Clasifications Register Rules and Regulations - Rules and Regulations for the Classification of Offshore Units, July 2022 - Part 8 Corrosion Control - Chapter 3 Coating and Paint Systems - Section 2 Prefabrication primers

Section 2 Prefabrication primers

2.1 General

2.1.1 Where a primer is used to coat steel after surface preparation and prior to fabrication, the composition of the coating is to be such that it will have no significant deleterious effect on subsequent welding work and that it is compatible with the paints or other coatings subsequently applied.

2.1.2 To determine the influence of the primer coating on the characteristics of welds, tests are to be made as detailed in Pt 8, Ch 3, 2.1 General 2.1.3 to Pt 8, Ch 3, 2.1 General 2.1.5. See Lloyd’s Register’s (LR’s) List of Paint Resins, Reinforcements and Associated Materials.

2.1.3 Three butt weld assemblies are to be tested using plate material 20 to 25 mm thick. A vee preparation is to be used and prior to welding, the surfaces and edges are to be treated as follows:
  1. Assembly 1 – Coated in accordance with the manufacturer’s instructions.
  2. Assembly 2 – Coated to a thickness approximately twice the manufacturer’s instructions.
  3. Assembly 3 – Uncoated.
2.1.4 Tests as follows are to be taken from each test assembly:
  1. Radiographs. These are to have a sensitivity of better than two per cent of the plate thickness under examination, as shown by an image quality indicator.
  2. Photo-macrographs. These may be of actual size and are to be taken from near each end and from the centre of the weld.
  3. Face and reverse bend test. The test specimens are to be bent by pressure or hammer blows round a former of diameter equal to three times the plate thickness.
  4. Impact tests. Tests are to be carried out, at ambient temperature, on three Charpy V-notch test specimens prepared in accordance with the requirements of the Rules for the Manufacture, Testing and Certification of Materials. The specimens are to be notched at the centreline of the weld, perpendicular to the plate surface.

2.1.5 The tests are to be carried out in the presence of an LR Surveyor or by an independent laboratory specialising in such work. A copy of the test report is to be submitted, together with radiographs and macrographs.


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