Corroserve was asked by uBH International, a world-leading manufacturer of tanks and containers, to recommend a coating system for the internal corrosion protection of 10 newly fabricated stainless steel tanks and 20 pipe spool sections. The equipment would be operating in aggressive conditions – carrying Sodium Hypochlorite at 15% maximum concentration at temperature ranges between – 20°C and 50°C.
Sodium Hypochlorite is used for water purification in processes such as, bleaching, odour removal and water disinfection. As such, the coating recommended had to offer outstanding resistance to chemicals at specific temperatures.
Corroserve engineers recommended Corroglass AR4, a coating specifically formulated to offer excellent protection in aggressive chemical environments. In particular AR4 offers exceptional resistance to base environments such as Sodium Hydroxide and Sodium Hypochlorite, the resin and cure system having been modified to give optimum resistance to these environments.
• Machined surfaces were masked and protected prior to abrasive blast cleaning in accordance with ISO 8501-1 Sa 2 ½ to achieve a surface profile of 50μm.
• After a final blow down the vessels were vacuumed to remove all dust and debris.
• A first coat of AR4 was applied by airless spray to an average wet film thickness of 600-800μm followed by a second coat to achieve the specified minimum DFT of 1250μm.
• The coating was thickness tested and spark tested to ensure it was free from holidays and pin holes and then left to post-cure at 60–80°C for 8 hours to provide the best chemical resistance.
The work was carried in batches with each batch taking between 2–3 weeks to complete. UBH International were extremely pleased with the quality of the work and the vessels are now in service.