Krah Community - Members' Magazine #5
Article 1 Comtruder®:
Large Plastic Pipe Production Line with CaCo3
Article 2 Drinking water storage systems
made out of PE 100 helically wound pipe

English | Spanish
Article 3 Elastomeric Joints for Polypipe
See also: Mickey - Composite profiles
ImProfil of: Peeter Kirtsi / Krah Pipes OÜ
Relining with large diameter Polyethylene Pipes
Preview: Members' Magazine #6
Informations: Current Market Prices for Commodities in Middle and Eastern Europe

Welcome to the 5th issue of ImProfil

Alexander Dear readers,

I am very delighted to invite you to read the first issue of our newsletter in 2012.

Until today the number of recipients has been increased to approximately 1500 and we can record continuously new registrations of pipe consultants, pipe producers and other organizations related to our business.

Also in this issue we have a lot of interesting technical reports on larger diameter pipes, especially also regarding CaCO³ as filling material for sewage pipes out of PE and PP.
Also the newly developped Comtruder®Technology offers the pipe producers the possibility to avoid expensive compounds by adding filling materials up to 25% inline directly during production according to existing norms. The filling material increases the stiffness of the pipes considerably and thus helps to safe costs.

Furthermore you can find some projects reports of Krah Pipes in the application of drinking water and relining, as well as regarding the mathematic calculation of the moment of inertia used for the pipe dimensioning.
Last but not least you can learn something about our long-term partner Peeter Kirtsi from Estonia in our interview serie “10 questions for…”

I hope you will enjoy this issue of improfil and we are looking forward to receiving your feedback and improvement suggestions.

Best regards from Germany,
Alexander Krah / CEO of Krah AG

Comtruder® - Large Plastic Pipe Production Line with CaCo3

Our last development in the field of large plastic pipes is the production of pipes filled with 25% Calcium Carbonate. The new pipe system fulfills all requirements for pipes according to the European standard EN13476. We produced several pipes on one of our latest extrusion lines with an integrated Comtruder®. During the extrusion process, PE100 and calcium carbonate powder are mixed and extruded in one step. The pipes were produced with 75% Sabic HDPE P6006 (PE100) and 25% calcium carbonate powder CaCO3 (in further tests we produced pipes with 30% calcium carbonate). The same pipes were also produced with virgin HDPE SABIC P6006 (PE100). Pipes were produced as solid wall and also as structured wall pipes.

The following pipes were manufactured:
  1. Pipe DN1000 x 6000 structured wall pipe: PR54-4.5 ends: smooth-smooth
  2. Pipe DN1000 x 2000 VW12/24 smooth-smooth ends
  3. Pipe DN600 x 6000 VW20 smooth-smooth
  4. Pipe DN600 x 6000 VW20 smooth-smooth
All pipes were produced with our standard machine “KDR750+”, standard dies were used and the output was according to the programmed settings. A large effect by using calcium carbonate was the significant reduction of the cooling time by approx. 10%. After the production, the pipes were stored for 24 hours before starting the pipe tests.

(Read more...)

Drinking water storage systems made out of PE 100 helically wound pipe
( Spanish version below)


Potable water is the most important food on earth and is not replaceable. The natural element of water is the basis of earthly existence. In Germany, water is the purest and most monitored food. It is constantly tested for quality and ingredients. The daily consumption of water in Germany is 120 liter per citizen – this corresponds to an annual consumption of 4 billion cubic meters. Such huge amounts of water are not required simultaneously throughout the day and are therefore not taken from the water system at the same time. Therefore water storage systems are needed to cover the consumption peaks and the operational standstill periods during the water transportation.

Standards and guidelines
The quality of potable water is legally regulated in the Drinking Water Ordinance. Fundamental basis of the Drinking Water Ordinance is its direct connection to the generally accepted rules of technology like for instance the DVGW regulations and the DIN standards. The harmonized European standard DIN EN 1508 “water supply – requirements on systems and components of the water retention” comprises the normative foundations for storing drinking water. In addition, the DVGW worksheet W 300 “water retention – design, construction, operation and maintenance of water supply tanks within the drinking water supply” reflects detailed regulations of the actual state of knowledge in Germany. Both regulations were originally created for storage systems made of concrete but are also applicable to storage systems out of other materials. It is not intended to change existing tanks but to correspond to the standard, it is intended to “support“ the production of new water storage tanks.

(Read more...)

Elastomeric Joints for Polypipe

Trelleborg Forsheda Pipe Seals have proudly supplied elastomeric seals for pipe joints to Polypipe in the UK and Irish markets for more than 10 years. From EN 1401 pipes through to Ridgidrain and structured wall pipes up to DN 1050mm.

We were therefore very pleased when Polypipe became the Krah licensee for the UK and Ireland and asked us to help to develop a ‘push fit’ rubber jointing system for their DN750, 900 1050 & 1200mm Krah pipes. We had previously been involved with other Krah Licensees in Estonia, Italy, Mexico and the US so the Krah pipe technology was not new to us but ensuring a robust joint to meet the demands of EN 1277 is never an easy task.

In the demanding installation environments of today, the main criteria for designing joints are:
  • Leak tightness from both infiltration and exfiltration
  • Ease and reliability of jointing on site
  • Long term durability
In approaching this type of design, and before practical jointing and physical testing can begin, a clear understanding of pipe joint geometry, dimension and achievable tolerance has to be reached. The engineers and technicians at Polypipe have an excellent understanding of the information needed and this allows us to model the joint design options using non linear finite element analysis (FEA) taking into account the maximum and minimum joint conditions. A typical simulation is shown below.

(Read more...)

Mickey - Composite profiles

This article explains how the calculation of composite profiles works and how you can do it.

Table of contents:
  • Calculation center of gravity (e)
  • Calculation of the moment of inertia (Ix / Jx)
  • Sample for composite VW + PR-profile
  • Profile name generation

(Read more...)


10 Questions for...

Peeter Kirtsi / Krah Pipes OÜ

(Read the interview online...)

Relining with large diameter Polyethylene Pipes


Damaged and leaky pipes out of concrete, GRP, steel, ductile iron can be relined and renovated with Profiled Polyethylene Pipes in almost every diameter. Here, the old pipe serves as an empty conduit for the new pipe out of PE and therefore a completely new, self-contained pipe system can be built. However, the use of profiled pipes especially in big diameters creates new stable pipe systems with a high static load capacity. For the static calculation of the new pipeline two things must be taken into consideration, the installation process and the operating condition of the pipeline. The new system will benefit from the extremely long service life of polyethylene pipes (> 100 years).

The relining process with polyethylene pipes has proven its reliability in almost all fields of application for many years:
  • Renovation of leaky sewer pipelines
  • Renovation of corroded drinking water pipelines
  • Provide a seal against leakage or infiltration
  • Gas supply systems (Changeover to higher operational pressures)
  • Renovation of inverted siphons
  • Industrial applications (aggressive media, acids, alkalis etc.)

(Read more...)

Preview: Members' Magazine #6

During the winter of 2012 a renovation ca 1000m of concrete pipeline was planned. Several different solutions were considered for completing the job. The local water authority and the construction company both found the solution proposed by Krah Pipes OÜ the best. This solution proposed Di800 e-fusion connected pipe segments to be installed inside the existing pipeline.

Find out more information about this report in the next issue of this newsletter!