A proper water supply is essential for countless domestic and commercial projects. MDPE water pipes are what’s used for transporting water from the distribution mains to a property.
While their function is straightforward, when it comes to choosing the right product, there are several sizes to be aware of. We consider the MDPE basics and which factors you’ll need to consider to ensure you order the correct pipe and fittings.
What are MDPE Water Pipes?
MDPE stands for medium density polyethylene and refers to the durable, flexible water pipes that carry potable water and other liquids to properties. They are commonly installed underground but can also have above-ground applications due to a resistance to corrosion.
This piping system offers a more reliable water supply with an increased flow rate (depending on the pipe size) than older copper pipes, which is among the reasons why many choose to upgrade existing plumping with newer MDPE pipes.
Alkathene Vs MDPE
MDPE water pipes are blue, but you may also see black versions referred to as alkathene (another name for polyethylene). Sizing for older alkathene pipes may differ slightly from modern MDPE.
These black MDPE pipes are used for above ground-application, while blue MDPE pipes are used as below-ground cold water pipes.
What Size MDPE is Available?
You can source several MDPE sizes, with some of the most common including:
- 20mm
- 25mm
- 32mm
- 50mm
- 63mm
How Does MDPE Diameter Affect Performance?
The size of your MDPE water pipe will affect a couple of things, which is why it’s important to consider the needs of your project before simply reaching for the most common size without question.
The diameter will influence:
- Water pressure – Narrower pipes will cause more frictional losses, leading to lower pressure at the point of use.
- Water flow rate – Wider pipes allow more water to flow through them, increasing the flow rate.
- Water velocity – Narrow pipes allow the water to flow at a higher velocity.
What Size MDPE Should I Use For Domestic Buildings?
For a domestic water supply in the UK, 25mm is the standard size and is sufficient in most cases.
In some cases, 32mm may be preferred. This size is slightly more expensive but not significantly more than the smaller options.
At Fastbuild, we stock both 25mm and 32mm MDPE pipes with various lengths available.
What Size MDPE Should I Use For Commercial Buildings?
The level of demand will also likely play a role in the size you choose – commercial sites with more people using more water throughout the day will likely require MDPE pipes with a larger diameter to ensure that the water pressure and flow rate remain consistent.
For larger commercial buildings, 32mm to 63mm pipes typically work better than the narrower domestic standard.
Using the Right MDPE Fittings
Compression fittings offer the easiest way to connect separate lengths of MDPE pipes. To ensure you can find the most convenient way to install MDPE, we stock a range of compression joints, including 90° elbow, coupling and equal tee junction fittings, as well as pipe liners, which need to be used when attaching compression fittings.
MDPE adaptor fittings can also be especially useful when you want to connect pipes of different sizes or join new MDPE pipes to copper pipes.
Hopefully, we have pointed you in the right direction. Ultimately, you will likely require the standard MDPE size of 25mm unless you have more specific requirements.
For anything else you may need to get the job done, discover our range of building materials and supplies at great trade prices.
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