Almost all plumbing in UK houses since the 1960s is comprised of copper pipework, replacing old lead pipework known to leach small amounts of poisonous lead into the water supply. Modern installations and replacement pipe are frequently completed polypipe as this is interchangeable with copper.

 

Use

Domestic Copper pipe is supplied in multiple sizes. The most common are 10mm, 15mm, 22mm and 28mm. Used for central heating, hot and cold water pipes, gas and heating oil supply. Copper isn't normally used outside the house, external water and gas main supply is fed with Poly (MDPE) pipe (historically called Alkathene pipe) although after lead pipe was first removed from water supplies, this was used underground for a short time.

 

Gauge

In 1972 the gauge in the UK changed to metric from the original imperial, however today many fittings are still provided in imperial 1/2" (12.7mm), 3/4" (19mm) and 1" (25mm). BS 2871 (Now EN1057) is the standard for thickness and type. Domestic plumbing copper pipe is generally Type X (Table X) which is half-hard. Other options are Type Y and W for thickness and hard or soft (annealed) for flexibility.

 

Maintenance

SBS promote good practices for maintenance in the home. Copper pipes, along with all your plumbing, require good upkeep. A few things to consider are;

• Making sure you monitor water supply pressure or by installing a PRV (pressure reducing valve) are some ways to reduce stress on plumbing.
• Check the operation of stopcock and gate valves regularly to prevent ceasing or leaking when operated.
• Check pipes are lagged (preferably to Bylaw 49 regulation) to save energy and avoid burst pipes.
• Are pipes earthed properly to avoid stray current corrosion.

 

Lifespan and Failure

Copper is used for water because it does not rust or corrode like other metals. It is also soft enough to work with and bend, making it a good replacement for lead. Manufacturers specify a lifespan of 25-30 years, but this has often been shown to be conservative and well maintained plumbing can stay leak free for much longer.

Factors that can contribute to premature failure of copper pipes are generally down to 3 factors;

1. Poor installation:
   • Pipes not secured properly, allowing them to bang and flex with changing water pressure when you turn on/off taps (washing machines do this very rapidly and so secure pipework is important for appliances).
   • No lagging / bad location of pipes allow them to be subject to freezing temperatures.
   • Incorrectly bent pipework, copper pipe can be safely bent but must be done with the correct tools and temperature, failure to carry this out during installation can reduce the lifespan of pipework considerably.
   • High pressure. If the supply to your property is above 3 bar, we would recommend the installation of a PRV on the mains supply stopcock. Very high water pressure puts strain on pipes and connections that may prematurely fail.
2.  Stray current corrosion:
   • If electrical circuitry / appliances fail in your home and pipework is temporarily made live, this needs to have a safe earth discharge point to avoid current discharging to metal nearby. This can cause pinholes in copper pipework and costly repairs in locating and replacing them.
3. Low PH water / contaminants:
   • Acidic water can eat away at copper pipe, thinning it and causing pinholes.
   • If pipes are laid into concrete or plaster, these should always be of a plastic covered nature, as construction materials can be corrosive and degrade the copper.

Left: Normal 15mm Pipe
Right: Thinned 15mm Pipe due to acid erosion

Copper pipe pinhole caused by erosion

 

We routinely check plumbing, including many of the items raised on this page, during property pre-purchase / pre-rental inspections or as part of a property maintenance inspection.