Support Article

Underground Works

Amongst other applications, underground pipework serve as a useful and safe way to transport water into a household or building. However this work takes special consideration due to the corrosive and harsh nature of soil and below ground conditions.

Due to the very nature of being outside, many things contribute to making this a harsh environment; the presence of minerals and toxins, pH levels of the soil and surrounding ground water, freezing and thawing, surface loading, vibrations and settlement will all contribute to a shorter lifespan of underground works.

Copper and Copper Alloys are excellent candidates for use in this environment due to Copper’s corrosion resisitance and longevity. Capillary fittings can be installed as normal. However when Brass fittings are used, there are two caveats.

Brass fittings used underground should be made from DZR material. Alternatively Bronze fittings can be used, but never standard brass. Furthermore the type of joint needs to be considered. If using Compression, Type B Manipulative fittings are recommended. These fittings give extra strength and longevity, but moreover they are designed and work best with the soft copper tube (R220) which is recommended for underground works for its flexibility.

When looking at exposure to weather patterns and surface activity, the deeper the pipework is buried, the better. Depth provides greater protection from frost, vibrations, surface loading and settlement. However, it doesn’t provide excellent access for inspection and maintenance. Also deep excavations add significant cost to any project. Therefore in order to strike a good balance between cost, accessibility and protection, it is recommended to install any underground works between 750mm and 1350mm from the surface.

Finally, wrapping or sheathing pipework and fittings will give an extra layer of protection for further peace of mind. This provides valuable protection to the system from corrosive compounds in the ground water and soil, however extreme care must be taken to ensure that tears or breaks don’t appear in the protection during or after installation. If unwanted chemicals or water collect on or around the system, this will ensure shorter than expected life spans.

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