Corrosion Science and Technology

The Corrosion Science Society of Korea (한국부식방식학회)
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Inhibition of Pitting Corrosion of Copper Tubes in Wet Sprinkler Systems by Sodium Sulfite

아황산나트륨을 이용한 스프링클러 동배관 공식 부식 방지

  • Suh, Sang Hee (Center for Electronic Materials, Korea Institute of Science and Technology) ;
  • Suh, Youngjoon (Center for Electronic Materials, Korea Institute of Science and Technology) ;
  • Kwon, HyukSang (Dept. of Materials Science & Eng., KAIST)
  • 서상희 (한국과학기술연구원 전자재료연구단) ;
  • 서영준 (한국과학기술연구원 전자재료연구단) ;
  • 권혁상 (한국과학기술원 신소재공학과)
  • Received : 2017.09.22
  • Accepted : 2017.10.20
  • Published : 2017.10.31
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Abstract

Inhibition of pitting corrosion of the copper sprinkler tubes by removing dissolved oxygen in water with sodium sulfite was studied on the wet sprinkler systems operated in 258 household sites. First, air in the sprinkler tubing was removed by vacuum pumping. The tube was then filled with sodium sulfite dissolved in water. Sodium sulfite was very effective in maintaining a very low dissolved oxygen concentration in water in the sprinkler tube for the observation period of six months. Water leakage from the copper sprinkler tube was reduced significantly by using sodium sulfite. Both pitting corrosion process and pitting corrosion inhibition mechanism were investigated by examining microscopical and structural aspects of corrosion pits formed in failed copper sprinkler tube. Pitting corrosion was caused by pressurized air as well as sediments such as sand particles in copper tubes through oxygen concentration cells. It was confirmed microscopically that growth of corrosion pits was stopped by reducing dissolved oxygen concentration to a very level by using sodium sulfite.

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References

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