english \ \

Spirally wound in place pipe technology


It is applied for rehabilitation of brick, concrete, cast-iron, fiberglass, plastic and other sewer lines and low pressure water mains, rain water pipes and culverts. The technology provides a structural rehabilitation of severely damaged pipelines, including in tough terrain conditions and absolutely without any excavation works. The technology is suitable for improving hydraulic irregularities, as well as for restoring the inclination of the original pipe and allows installation of the liner along an arc path.

SPR technologies depending on the specific requirements:

  • SPR™ EX – for circular shape pipelines with diameters from 150mm to 750mm.
  • SPR ™ PE - for circular shape pipelines with diameters from 900mm to 3000mm. 
  • SPR™ - for pipelines of random cross sections: circular, egg-shaped; rectangular etc. 



  • 100% without excavations

  • Improving the hydraulic properties and wear resistance of the pipeline due to the smooth inner surface and the small reduction of the cross section

  • Extending the lifetime of the sewer by 50 and more years

  • Structural resistance

  • No steps, even in case of dislocated joints of the existing pipe.

  • Constant diameter of the new pipe even in presence of cavities and lack of parts of the old pipe

  • Fine cleaning of the existing pipe is not necessary

  • Can be installed even in live flow conditions up to 20% of the existing pipe capacity


Technological process

The technology is based on the principle of “in-place” pipe production of continuous plastic (PVC or HDPE) factory manufactured strip of high stiffness and low weight. Pipe installation is implemented without any excavations, as the existing shafts are used. 

The pipe is formed by a strip, which is spirally wound by a special machine, located in the existing access or collector shaft. Depending on the type of SPR technology, simultaneously with winding the machine pushes the newly formed pipe in the existing one, as soon as it reaches the next shaft (in case of SPR™ PE and SPR™ E) or the machine itself moves along the existing pipe, as it leaves the wound pipe behind (in case of SPR™).

The profile of the strip has special locks, which during the spiral winding form a continuous watertight pipe inside the existing one. Then the newly formed pipe is expanded until it sticks close to the existing pipe (in case of SPR™ E) or is grouted towards the existing pipe (in case of SPR™ PE and SPR™).

Video: SPR EX
Video: SPR PE
Video: SPR
Significant projects
Trenchless technology SPR rehabilitation Bulgaria Ruse
Rehabilitation of a sewer pipeline