Hello all, I am doing failure analysis of hot water heater copper tube. Client noticed some pitting corrosion and subsequent leaks and she replaced that with new 1/2" tube. Now I am doing the analysis to find out why it was leaking. I noticed that it is general corrosion and assume that it may be due to erosion corrosion due to higher velocity associated with temp. I perform chemical test on the the deposit and found no lead and ruled out the corrosion due to flux. Can any one help me to find out the velocity through an 1/2" copper tube when the inlet pressure to the tank is known (55 PSI) and also assume that outlet pressure is same. Ofcourse we know the cross sectional area of the tube. This is a 40 gallon/ hour water heater. Thanks

Thanks for the reply. I also think so, that the velocity is the problem. I calculated the velocity for a 40 gallon/ hour water heater is supposed to be 1.08 feet/sec. But when I refered AWWA stanadard (internal corrosion of water distribution system), I learned that erosion corrosion due to high velocity associated with temperature occurs only when the velocity of hot water is above 1.5 feet/sec. That is the reason why I could not argue that. Any insight in to this information. Thanks