Analysis of pitting corrosion failure of copper tubes in an apartment fire sprinkler system
| Autor: | Jeong Han Oh, Youngjoon Suh, Young Jun Kim, Hyuk-Sang Kwon, Hyung Goog Yoon, Ki Min Jung, Sang-Hee Suh |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Copper tubing
Materials science 020209 energy Fire sprinkler system Metallurgy General Engineering chemistry.chemical_element Malachite 02 engineering and technology 021001 nanoscience & nanotechnology Copper Corrosion chemistry visual_art 0202 electrical engineering electronic engineering information engineering Pitting corrosion visual_art.visual_art_medium General Materials Science Limiting oxygen concentration Erosion corrosion of copper water tubes 0210 nano-technology |
| Zdroj: | Engineering Failure Analysis. 64:111-125 |
| ISSN: | 1350-6307 |
| DOI: | 10.1016/j.engfailanal.2016.03.009 |
| Popis: | Microscopical and structural analyses as well as visual inspection of copper tubes were used to investigate the cause of pitting corrosion failure of copper tubes in the wet pipe sprinkler system. Chemical analysis of the water in the copper tubing and XRF/XRD analysis of its sediments were also used to obtain hints on what was happening in the copper tubing during the progress of the pitting corrosion. It was found from the failed copper tube that a significant amount of pressurized air was present over the water in the copper tubing during operation and a series of corrosion pits were aligned adjacent to the water/air line. The waterline localized corrosion, a type of differential oxygen concentration cell corrosion, induced by pressurized air over the water in the copper tubing was identified as the cause of the pitting corrosion failure. A state of a very low oxygen concentration was maintained under the envelope of a dense layer of malachite, the corrosion byproduct, which was evidenced by the formation of Cu2O crystalline particles inside the corrosion pit. CuO particles observed on the inside surface of the copper tube do not seem to help prevent local as well as general corrosion. Accelerated pitting corrosion of the copper tube in the wet fire sprinkler system was simulated using a differential aeration cell. Finally, measures for stopping or delaying the pitting corrosion of the copper tube in the wet sprinkler system are suggested. |
| Databáze: | OpenAIRE |
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