Clearing obstacles and working on the surface when we install and inspect conductions is a dream which came true due to the technologies without trench for plastic pipes, denominated ‘NO-DIG’ or TT (Trenchless Technologies). The electricity, telephone, gas, distribution of drinking water, sanitation or cable television services are some of the most favoured services due to this kind of technique. A good example of its use is the water conductions and sewage which need some possible periodic maintenance without intrusive means.


This type of technologies has experienced a huge growth in the civil engineering. It shortens the working time when it is about the channelization to which it could cost effort and money to access to it and besides, it has with a huge precision. Understand as trenchless technology for plastic pipes to the set of techniques which allows installing, inspecting and restoring an underground channelization without interrupting, or with minimum interruption in the surface.  If it is about an installation of pipes, these don’t usually have a diameter higher than 3 metres.

One of the great advantages of this technique is that this requires a lower amount of workers to do it. Besides, due to the time saving, the cost is significantly lower than the traditional excavations, something that also impacts on the client. As we involve a lower amount of resources, it is possible to save in logistical needs as the moving of material in trucks, something that implies lower expenditure of fuel and a higher respect for the environment. It is also avoided large traffic jams in car transit areas. The cleaning after doing the job is also much simpler.

We differentiate the main techniques of the trenchless technology for plastic pipes:

  • Directed drilling. It is done with polyethylene (PE) pipes up to 1200 mm of diameter, in several occasions. It allows to do crosses at different depths.
  • Simple piping. With PE or polypropylene (PP) pipes for applications with and without pressure.
  • Tight piping. With PE pipes for applications with and without pressure.
  • Tight piping reduced in the factory. With PE or polyvinyl chloride (PVC) pipes for applications with and without pressure.
  • Piping with unobtrusive pipes. With PE, PP or PVC pipes for applications without pressure.
  • Bursting. With PE pipes.

These types of technique require to take into account which ones are the characteristics of the soil on which they are going to be done and the loads which will be applied to the surface. If the phreatic level is shallow, the soil is sandy, or it supports heavy loads, the excavation depth must be right so the pressure of the load on the surface does not affect to the drilling. If this happens, there will be a risk of sinking of the surface.

There are two normative are highlighted in this kind of trenchless technology, although it is a wider subject:

  • UNE-EN ISO 11295:2011. Classification and information about the design of systems of channelling in plastic materials used in the renovation.
  • UNE-EN 15885:2011. Classification and performance characteristics for renovation techniques and reparation of drainages and sewers.