DM Water Drainage Line Reclamation Using Belzona Solutions
Challenge
Replacing the damaged section of the drainage line would have required shutdown of the water treatment unit, extensive cutting, welding, and hydro-testing—making it a costly and time-consuming process. The client therefore sought a cold-applied repair solution that could:
- Be executed in situ while the plant remained in operation.
- Provide long-term corrosion protection against continuous exposure to DM water.
- Eliminate the need for hot work and replacement.
Proposed Solution
NESL recommended a Belzona polymeric repair and protection system comprising:
- Belzona 1161 (Super UW-Metal) – for rebuilding and profiling the heavily pitted surface.
- Belzona 1321 (Ceramic S-Metal) – as a corrosion-resistant topcoat providing a smooth, hydrophobic finish.
- Belzona 9341 Reinforcement Sheet – used to strengthen the repair in high-stress or structural areas.
Application Procedure
All work was carried out by NESL’s certified Belzona applicators under live plant conditions.
- Surface Preparation
- The pipeline surface was mechanically cleaned using power tools and abrasive blasting (where accessible) to achieve a minimum SA 2.5 surface cleanliness and a surface roughness of 75–125 microns.
- All corrosion products and loose scales were removed, and the area was thoroughly degreased using Belzona 9111 (Cleaner/Degreaser).
- Rebuilding of Metal Loss
- Deep pitting and wall thinning were rebuilt using Belzona 1161.
- The material was mixed in the prescribed ratio and applied using a steel spatula to rebuild the original profile of the pipeline.
- In areas where the pitting exceeded 3 mm depth, Belzona 9341 reinforcement sheet was embedded into the first layer to provide additional mechanical strength.
- Surface Smoothing and Coating
- After initial curing, the surface was lightly abraded to achieve a smooth transition.
- A full overcoat of Belzona 1321 (Ceramic S-Metal) was then applied in two coats, with contrasting colors to ensure uniform coverage and desired DFT (Dry Film Thickness).
- This coating provided an impermeable, corrosion-resistant barrier against DM water and environmental moisture.
- Quality Checks and Curing
- Coating thickness was verified using a DFT gauge, ensuring consistent coverage (minimum 500 µm total).
- After full cure, a spark test was conducted to confirm coating integrity.
- The system was then allowed to cure before exposure to service conditions.
Results
- The Belzona-applied section was reinstated within 24 hours, avoiding any production loss.
- The pipeline integrity was fully restored without any hot work or welding.
- The client achieved significant cost savings—over 70% compared to replacement—and gained a durable corrosion protection system expected to last over 5 years in continuous service.
Conclusion
The use of Belzona 1161 & 1321 with 9341 reinforcement provided a cold, safe, and efficient repair method for the DM water drainage line.
This case highlights how NESL’s expertise in polymeric repair technology enables industrial plants to restore critical assets without costly shutdowns, ensuring operational continuity, safety, and sustainability.
