Erosion corrosion of copper tube is well known and many workers studied this phenomenon. However laboratory corrosion test often does not duplicate operating factor in actual forced circulating system and erosion corrosion of copper tube does not always occur in similar form and conditions to those of actual plumbing system. In this paper, one hundred nine cases of erosion corrosion failures were statistically analyzed to duplicate erosion corrosion of copper tube and corrosion test was carried out at model plumbing system. Most of erosion corrosion failures of copper tubes have occurred at the nearby joints, especially elbows of return tubes in the hot water forced circulating system. Erosion corrosion of copper tube has been duplicated at model plumbing system in similar form and conditions to those of actual plumbing system. As regards the erosion corrosion of copper tubes, importance of two factors must be stressed ; one is the supersaturated dissolved oxygen of water which forms the tiny gas bubble, and the other is fluid dynamic condition which mechanically breaks down the protective film on the tube surface. In addition, erosion corrosion resistance of tin coated copper tube, which has been developed as an anti-corrosion material, was evaluated. Tin coated copper tubes showed the excellent erosion corrosion resistance under the turbulent flow of model plumbing system.
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