Copper is a very durable material but it does corrode in certain circumstances. By understanding the causes of the different types of corrosion it is possible to treat them before they cause a leak.
Keep Water Velocity Low
Water moving too fast through narrow sections of pipe can lead to erosion corrosion. The flow rate in pipework should be as low as possible for a domestic situation, typically below 1.5 m/s.
Avoid Contact With Dissimilar Metals
Copper pipework in contact with dissimilar metals can also suffer from galvanic corrosion. This type of attack is driven by the electrical difference between two metals and is most common when copper pipes are connected to steel radiators and boilers. In these circumstances, dielectric unions or short sections of pipe with a plastic liner can be used to separate the two metals.
Test Your Water pH
The type of water fed to the pipes also has an influence on the rate of corrosion. Soft, slightly acidic water will corrode copper more quickly than hard water. The standards for the quality of drinking water set out by water suppliers in the UK give a guideline for the pH value of drinking water and this will give an indication of the potential for corrosion in a particular area. It is possible to test the pH of the water at the tap using a simple pH test strip such as those used to test the water in an aquarium. If the reading is below 6.5 it would be worth investigating the possibility of using a neutralising filter.
Flush Out Flux After Soldering
Most importantly, make sure that any flux which has penetrated the joint is washed out of the pipe after soldering. This will prevent the flux breaking down into an acid which can cause local pitting. Allow the joint to cool and then run water through the pipe for several minutes to flush out the flux. For a complete system this should be done before it is put into operation. For Copper Pipe, visit /watkinspowis.co.uk/products/copper-pipe-fittings-and-press-systems/.
Insulate Pipes in Cold Spaces
Condensation on the outside of pipes in cold areas such as utility rooms, storage rooms and outside spaces such as conservatories, and rooms that have high humidity such as kitchens, cause surface attack of copper pipework. This type of attack is prevented by insulating cold pipes with foam pipe lagging in these types of locations. This is a very cheap and very quick fix for pipework.
Fix the problem, not the symptom. Your copper pipework can last for decades.
