Type EEM-KNT spiral pipe

The spiral pipe type EEM-KNT is produced from polyethylene (PE) or polypropylene (PP), with nominal diameters between ID 1300mm-2000 mm, with honeycomb type structural walls.

The spiral pipe type EEM-KNT provide the same technical advantages as polyethylene/polypropylene corrugated pipes, with reduced weight, combining the easy installation with reduced costs. Its unique structure provides a wide range of ring dimensions and rigidity levels, according to the costumer’s requirements.

  • Sewerage systems – for wastewaters
  • Highway construction
  • Surface water draining
  • Sewerage systems for industrial wastewaters
  • Collection systems for rainwaters (basins)
  • High resistance to abrasion
  • The resistance to corrosion (chemical compounds)
  • Very good properties of the fluid flow
  • Non-toxic material
  • 100% watertight joints
  • Flexibility
  • Light Weight
  • Reliability

High resistance to abrasion is part of the distinctive characteristics of most of the pipes on / PP, among other materials used in the construction of the pipes. Due to this advantage, pipes on PE / PP may be used for the transport of mud, sand and other environments very abrasives.

The pipes, manufactured from materials used in the usual way, have been tested using the method Darmstadt. The samples of pipes have been filled with a mixture of water and sand, and subject to a cyclical movement with the oscillation. The quantity of abrasive material tube has been measured on a regular basis. The results of the tests show a high resistance to abrasion of Polyethylene pipes. For example, a loss of 0.3 mm from the surface of the pipe / PP has been measured after 400,000 cycles, while the losses measured for pipes of glass fiber (GRP) was 6-8 times higher.


The pipes from the PE/PP are resistant to many chemical compounds - unlike conventional tubes made of materials, which corrodes and "grow older" with ease when they are exposed to the majority of the acids (with the exception of the nitric acid), bases, salts, aliphatic solvents (pH 0 to 14).


The PE / PP pipes maintain a low and constant degree of roughness k = 0.01 mm. The lack of corrosion and the low risk of blockage of PE / PP pipes are among the most important functional qualities of PE / PP pipe sewerage systems.

EEM-KNT PE / PP type spiral pipes can be welded using a polyethylene / polypropylene yarn (extrusion method) or connected using EPDM sockets and seals.


Having a radius of natural curvature R = 50, the PE / PP spirals pipes EEM-KNT type can be easily mounted on the basis of the variations in the pipe routing, and, in many cases, can be avoided by the use of expensive fittings. Flexibility is the distinctive feature of the pipe PE / PP pipe, as compared to other conventional materials.

The LOW WEIGHT features

The low weight of the EEM-KNT spiral pipes allows cost savings and shorter installation times. Due to their low weight, the EEM-KNT type spiral pipes do not require heavy equipment for mounting as well as unloading pipes at the construction site.

Installing the piping spirals EEM-KNT type

The determination of the soil is essential for the design and installation buried piping spirals EEM-KNT type
Compacted soil up to approx. 90-95% SPD

Table G.2 shows Compaction classes and Standard Proctor Density (SPD) according to EN1046 for the four soil groups recommended as filling material for spiral pipes and listed in Appendix 1.

The main roadbed (2) and The upper roadbed(3):

Compacted soil up to approx. 90-95% 90-95% SPD
The roadbed should be symmetrical on both sides of the pipe in layers not exceeding 300 mm, paying particular attention to soil compaction in the pipe support area.

It is recommended to use a compactor, gently (weight of up to 100kg). Use compactorului directly above the pipe is prohibited. This can only be used where the upper layer is at least 500mm thick.

When used in the native soil pipe area from the excavation of the trench, it must meet the following criteria:

  • No particle shall be larger than the one shown in the table above
  • No bulk of the soil shall be greater than twice the maximum dimension provided for the respective diameter of the pipe
  • There should be no frozen material
  • No discarded waste (bottles, roots, asphalt, miscellaneous objects, etc.)
  • When compacting is required, the material must be able to be properly compacted. The filler material should be applied in successive 30 cm layers and compacted properly.

Underneath traffic-free areas, a compaction class N (see table G.2) may be sufficient. Under traffic areas, it is advisable to use a W compaction class. Compliance with the required quality requirements for the correct installation must be confirmed by one or more of the following methods:

  • Careful monitoring of bedding and pipe coating procedures
  • Check initial deflection of installed pipes
  • Field check of the soil compaction

There is a direct dependence between the filling material used, the degree of compaction and the deformation of the flexible pipe
Maximum sizes of sorts used in contact and in immediate proximity

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