Frequently Asked Questions

Find answers to common questions about MDPE pipe, PE pipe, compression fittings, electrofusion fittings, SDR ratings and water pipe installations. If you can't find the answer you're looking for, please contact the T-Mex Express team.

Pipe Connections

How do I connect two water pipes together?

There are two main ways to connect water pipes: compression fittings and electrofusion fittings.

Compression fittings are the quickest and most cost-effective option for most installations. They can be installed using standard hand tools, making them ideal for repairs, maintenance and general water pipe connections.

Electrofusion fittings create a permanent, high-strength joint using a specialist electrofusion welding machine. They are commonly used for larger infrastructure projects and installations where a fully fused connection is required.

T-Mex Express supplies both systems:

Pipe Materials & Specifications

What is the difference between blue, black and yellow pipes?

The colour of a polyethylene (PE) pipe indicates its intended application.

Blue pipe is designed for potable (drinking) water systems.
Yellow pipe is manufactured to BS EN 1555 and is used exclusively for natural gas and LPG distribution.
Black pipe is typically used for non-potable water and industrial applications including irrigation, slurry, wastewater and agricultural systems.

Using the correct pipe colour helps ensure compliance with industry standards and prevents incorrect installation.

What is the difference between PE80 and PE100 pipe?

The main difference between PE80 and PE100 is their mechanical strength.

Over a 50-year design life at 20°C:

PE80 has a minimum required strength (MRS) of 8.0 MPa.
PE100 has a minimum required strength (MRS) of 10.0 MPa.

Because PE100 is stronger, it can either operate at a higher pressure using the same wall thickness or achieve the same pressure rating with a thinner wall, resulting in a lighter pipe and increased internal bore.

For most modern water, gas and industrial pipeline applications, PE100 is the preferred material.

What is the difference between SDR17 and SDR11 PE pipe?

The difference between SDR17 and SDR11 is the thickness of the pipe wall.

SDR stands for Standard Dimension Ratio, which is the ratio of the pipe's outside diameter to its wall thickness. The lower the SDR number, the thicker the pipe wall and the higher the pressure rating.

SDR11 has a thicker wall and is designed for higher-pressure applications.
SDR17 has a thinner wall and is suitable for lower-pressure systems.
SDR17 has a larger internal bore, which can provide slightly better flow characteristics.

For PE100 pipe, SDR11 is commonly rated to PN16, while SDR17 is commonly rated to PN10, depending on the manufacturer's specification.