Plumbing: Corrosion and Dezincification

Whether you work as a plumber or fancy yourself a handy-man, it bears to know a thing or two about some of the processes that can happen, should you accidentally put two materials together that should not be together. In this article I will tell you a bit more about two of these processes – corrosion and dezincification.

Corrosion Inside


When it comes to water, you have to be careful what material you use with it. Take metals as an example – if you are using two different metals in the same system, they will inevitably cause corrosion. This means that if you are using copper pipe by a galvanised water cistern (which has a coating of zinc) – corrosion will occur. When it comes to copper pipes, there will unfortunately always be a very small amount of copper that dissolves in the water, despite how careful you are to clean out any copper filings. However, it is still important to take care cleaning the pipes once any work has taken place, making sure to remove all copper filings. This is because copper filings travel and ends up being deposited on the galvanised surface of the cistern. What happens when copper and zinc are in contact is that they act as a battery. This means that tiny electrical currents are produced and that the water acts as the connection between the two elements, completing the circuit. The current produced from this causes small particles of the zinc to be dissolved and it makes the coating porous. This in turn means that the water in the cistern will come in contact with the steel underneath the coating and the steel will also start to corrode. If you come across this issue, my best advice is to replace the corroded cold water cistern to a new plastic one.

Copper Corrosion


Some areas of the country have chemicals that occur naturally in water and they can sometimes react to metals found in certain brass fittings. This reaction is known as dezincification and it basically dissolves the zinc found in brass, leaving it just as porous as the copper pipes mentioned above. As a result, it can cause them to disintegrate. You can avoid dezincification by using brass fittings with gunmetal inhibitors. Speak to your local water company to find out more about the water in your area and whether you will need to take any of these measures. When it comes to inaccessible concealed fittings, it is mandatory to use gunmetal or another similar resistant metal for the job.


Plumbing and Frost Protection

Here in the United Kingdom we are fortunate enough to have four different seasons and nice as it is, the colder months bring with them a drop in temperature and this is sometimes enough to cause problems with our plumbing systems. The issues we face as it gets colder are not only frozen pipes but also burst pipes. Luckily, there are ways to avoid this and in this article I will tell you a bit more about preventing this from happening.

Frozen Pipe

Prevention and Protection: Pipes

When it comes to cold water pipes, all of them – despite ownership, should be insulated as to avoid frost damage and possible water leaks. Even though all cold water pipes should be insulated, it is especially important for the pipes found in the loft close to the eaves and the ones underneath the floorboards and close to the air-bricks to be so. Nowadays you can get modern preformed pipe lagging in most sizes and they are not only inexpensive but also a lot easier to install than the older versions. However, preformed insulation might not work everywhere and I have found that a felt or a glass fibre wrap-around seem to work best for valves and some compression fittings. These are easy enough to fit yourself.

Pipe Insulation

Prevention and Protection: Cisterns

When you insulate cold water pipes, it is important not to forget that the cold water cistern itself will need some sort of insulation as well. It is best to insulate the top of the cistern but to leave it if off underneath, allowing instead for some of the heath from the house to rise up to it. It is a good idea to bring up the ends of the blanket towards the sides of the cistern when insulating the loft floor. If you come across a pipe that is very exposed, it would be a good idea to use a small heater to keep the cold off the pipe. Alternatively, you can purchase tapes that protects against frost and these are called electric frost protection tapes. They incorporate a very low wattage heater and you simply wrap it around the pipes that need protection. The great thing is that they do not need special wiring and some are even thermostatically controlled to switch on when the temperature drops.


A good tip for you if you have a cistern kept outside, is that the cistern could be kept from freezing by simply hanging a light-bulb by it and leaving it on.