Choosing the correct water pipe for contaminated ground
This entry was posted on March 30, 2017.
When you are laying water pipes in contaminated ground, it is essential to choose suitable piping which cannot be corroded or damaged in any way by the hazardous substances in the vicinity. Corrosion not only causes leaks and wastage in the water supply, but more importantly can also result in contamination of the water which passes through the pipe. The consequences of this can be extremely serious, with the potential for consumers to be poisoned by toxins in the water.
If you are developing a brownfield site there is a risk that the area could have chemicals in the ground. In particular, if the land you are working on has had historical industrial use, there is a strong likelihood of residual contamination. As an increasing amount of development is being done on reclaimed sites, it is no longer the norm for metal pipes and fittings to be specified for underground piping, since they carry too high a risk of corrosion and contamination.
An area which has been polluted with toxins from chemicals and metals can remain contaminated for a very long time – in some cases between 50 – 100 years. If you know or suspect that the ground where you are laying pipes is contaminated, it is vital to use specialist barrier piping which carries no risk of being affected by the substances. If you lay standard MDPE pipe for water supply in an area of contamination, you are at risk of being required by the local authority to remove it and replace it with barrier pipe. If you fail to comply with this, the local water board may refuse to connect your water supply.
If you would like to find out for certain whether your land is contaminated, you can arrange to have a ground condition assessment carried out and a report produced. There are levels of contaminants deemed low enough to present no or negligible risk, in which case you may be allowed to install MDPE piping. However, if you cannot prove that contaminants are sufficiently low, you will be required to fit barrier piping.
A barrier pipe is made from a combination of aluminium and plastic tubes, designed so that the outer plastic protects the aluminium and prevents it from coming into contact with any potentially harmful material.
Where metal pipes are used in ground where there is a risk of harmful substances being present, the pipes need to be sleeved to prevent any risk of damage and contamination. One of the advantages of using Puriton 2 type A barrier pipes is that they can be laid with no wrapping of joints required, which helps to reduce time and materials costs.
Another advantage of using barrier piping is that it futureproofs your water supply from contamination. Even if the ground is currently unpolluted, if harmful substances were to leak into the ground at some point in the future, conventional piping could be damaged and the water supply contaminated. Using barrier piping means you can be sure that your piping will deliver safe drinking water for years to come.
Puriton 2 is a newly developed range of barrier piping products and fittings which have been specifically designed for carrying water safely through contaminated ground. The construction of Puriton 2 piping makes it easy to work with as well as being ideal for use in contaminated areas. Puriton 2 pipe is manufactured from high-quality polyethylene and aluminium and is specifically designed to be used where pipes need to be buried. A central layer of aluminium is sandwiched between an outer and inner layer of light blue PE80 polyethylene. The inner core prevents the aluminium layer from coming into contact with the water, making it completely safe for drinking water applications. The aluminium layer means that the piping is both lightweight and flexible. The pipe’s flexibility helps to reduce the number of joints required, thereby saving on fitting time and costs.
Drain Depot is an approved Puriton stockist. We have an extensive range of Puriton products in stock at all times, including the new Puriton 2. This is available in several diameters: 25mm, 32mm, 63mm and 90mm. We also supply a wide selection of Puriton 2 fittings for use with the piping. Puriton piping is available in coils and in straight lengths and has a maximum operating pressure of 12.5 bar. Puriton 2 barrier pipes have been WRAS approved, so you can be assured of their quality and durability. Contact us to speak to one of our advisors if you would like to find out more about the new Puriton 2 range of pipes.
If you would like further information on the requirements for underground pipes, you can refer to the WRAS Guidance Note 9-04-03 Issue 1, The Selection of Materials for Water Supply Pipes to be Laid in Contaminated Land. These guidelines can be found online.
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