Pipeline rust removal→primer coating→full topcoat→second topcoat→winding glass cloth→topcoat→topcoat;
Inner wall construction process: pipeline derusting → primer coating → all-over top-coat → second-pass top-coat → third-pass top-coat
1. Pipeline rust removal
Before applying the primer, the surface of the pipe should be cleaned of grease, ash, rust, and iron scale. The quality standard of sandblasting to remove rust reaches Sa2.5 level.
2. After removing the rust on the surface of the pipe, apply primer, and the time interval between them should not exceed 8 hours. When applying the primer, the base surface should be dry. The primer shall be applied evenly and fully without clotting or blistering. The two ends of the tube shall not be painted within the range of 150～250mm.
3. After the surface of the primer is dry, apply the topcoat and wrap the glass cloth, and the time interval between the primer and the topcoat should not exceed 24 hours.
4. Epoxy coal tar pitch paint adopts two-component, room temperature curing type paint; glass fiber cloth adopts drying, dewaxing, non-twist, edge banding, medium alkali, and the density of warp and weft is 10*12 pieces/cm～12*12 pieces/ cm glass cloth. Wrap the glass cloth immediately after the topcoat is applied. The width of the glass cloth is 30-40mm, and the lap length of the joint is not less than 100mm. The lap joints of each layer are staggered with each other. The oil penetration rate of the glass cloth is more than 95%, no gaps larger than 50mm*50mm should be present, and 150-250mm stepped stubble should be left at the end of the pipe.
5. The construction of the pipe joints should be carried out after the welding pressure test is qualified, the new and old anti-corrosion blanks should not be less than 50mm, the joint lap length should not be less than 100mm, and the stubble should be firmly and tightly bonded.
6. Steel pipe outer wall coating mechanism: one bottom and two sides, one cloth and two sides, the total thickness of the dry film is 400µm.
7. Steel pipe inner wall coating mechanism: one bottom and three sides, the total dry film thickness is 300µm.
8. After the external anti-corrosion construction is completed, the quality inspection shall be carried out according to the design requirements or the corresponding requirements in Table 4.3.11 in the “Code for Construction and Acceptance of Water Supply and Drainage Piping Engineering”.
Post time: Jun-23-2021