Brightly coloured underground ducting pipe coils
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Underground Ducting Colours Explained

Underground ducting pipes come in a wide range of colours. In this article, we discuss what these different colours mean and provide some installation advice.
Watch What do underground ducting colours mean? on YouTube.

Underground ducting is the most colourful product that Drainfast stocks. Coils and stacks of purple, green, yellow and blue tubing give parts of our depot storage areas a rainbow-like appearance. But what do all the colours mean?


Picking the right colour

There are guidelines for ducting that include a recommended colour coding scheme for identification of ducting. By colour-coding the ducting we create a safer and simpler working environment for groundworkers.


Recommended Burial Depths

Different types of ducting should be buried at different depths. Check with the authorities on what depth your ducting should be buried at.


Marker Tapes

Make sure your ducting is clearly labelled with marker tape, and use detectable tape for non-metallic pipes and ducts to aid future groundworkers.

What Is Black Underground Ducting Used For?

Black ducting is used for domestic mains electric cables underground. High-voltage electric cables are carried in red or black ducting (varies regionally). Drainfast stocks a wide range of black electric cable ducting in a variety of sizes, including 40mm, 63mm, 75mm, 90mm, 110mm, 160mm, 150mm, 225mm & 300mm:

What Is Yellow Underground Ducting Used For?

Yellow underground ducting is used for gas pipes. It's also perforated so that gas can vent safely in the case of a gas leak; the perforations are small enough to let the gas out without letting the surrounding soil in. Drainfast sells the most popular sizes of perforated gas ducting:

What Is Purple Underground Ducting Used For?

Purple ducting runs along motorway central reservations or verges and alongside some ‘A’ roads. It carries National Roads Telecommunications Services (NRTS) such as emergency telephone, speed camera and CCTV traffic monitoring. Drainfast stocks a variety of sizes including 63mm & 110mm.

What Is Blue Underground Ducting Used For?

Blue ducting is used for underground water pipes. Ducting must be a minimum of 750mm below the surface to avoid frost damage. It is necessary to use ducting to house water pipes where they enter or go under buildings for accessibility. Drainfast stocks various sizes including 63mm, 110mm, 150mm, 225mm & 300mm.

What Is Grey Underground Ducting Used For?

Grey ducting carries telephone and broadband cables. The majority of the UK’s network of cables are owned by BT, so ducting must laid in accordance with their specifications. STAKKAbox is the only modular access chamber approved for use on BT’s cable network.

What Is Green Underground Ducting Used For?

Green ducting is used to carry CCTV cables (except on motorways), cable TV and fibre optic cables for high-speed broadband. Drainfast stocks a range of sizes including 54mm & 96mm for cable TV and 63mm, 110mm & 178mm twinwall:

What Is Orange Underground Ducting Used For?

Orange ducting is used for streetlight, traffic signal and traffic light cables.

Marker Warning Tape

To aid early visibility of underground ducting, warning tape is often laid above the run of the duct. This can avoid interference damage caused by subsequent groundworks. Early warning of utilities that lie below keeps workers safe and avoids the necessity for costly repair work should they inadvertently be damaged. Drainfast stocks a wide range of underground warning tapes and detectable underground warning tapes. Detectable safety tape features an aluminium backing so that it is detectable by a non-ferrous metal detector. Non-detectable tapes provide a visual indication that utilities are buried below.

Buy Ducting Online

Drainfast’s underground ducting products can be bought online or by calling our customer service team. If you need any help or advice, please ask to speak to one of our technical team who will be happy to help.

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