Krah Pipes

The high-performance plastic pipe production technology by Krah Made in Germany

Leak free, sustainable, homogenous and flexible Krah Pipe System

Since generations the mankind is busy by transporting water/sewer or any other liquids from one point to another point. The challenge was always to assure a conveyance system without fails and leakage. Most pipe failures were occurring on the joints through corrosion or cracks on the rigid inflexible pipe material.

Over the last decades, the inherent weaknesses of concrete, clay, ductile, PVC and steel caused tremendous problems in existing water supply, sewer pipes systems, as they tend to be brittle or are too sensitive for aggressive chemicals and soil conditions. Leakages have become a common occurrence worldwide in water, sewer and other large diameter pipe applications. In addition, they have an unprofitable relationship between cost and benefit due to short life time and high maintenance costs.

Krah Pipes are made out different grades of pure Polyethylene or Polypropylene who are providing superior properties against corrosion, leakage, pipe displacement and ex-infiltration. In addition to the permanent solution that lasts through generations, the Krah piping system is able to provide a sustainable, environment friendly and economical solution with its wide-ranging fields of applications, f.e. water supply, sewer systems, drainage, storm water management, sea outfalls/intake, manholes and reservoirs.

In order to meet the demand of the at least 100 years leak free, sustainable and flexible pipe system, Krah Pipes are produced with an integrated electro fusion joint system, which assures a melting of the pipes to a homogenous and monolithic pipe system.

Krah Pipes can be produced from the following thermoplastic materials: 

High density polyethylene (PE80 and PE100))

Polypropylene – random (PP-R, PP-B)

Polypropylene – homo (PP-H)

Flame retardant polypropylene (PP-S)

Other materials can be used after prior acceptance of the producer and a third party for quality control.

Most Krah pipes are produced with an integrated socket and spigot.

These are adaptable to the following listed jointing technologies. As various tests and decades of experience have shown, the jointed part of a pipe system is usually the most vulnerable part. Here, the pipe is mostly exposed to possible leakages. The Krah system offers a well-known connection method developed further for large scale application which eliminates these concerns by guaranteeing a solid homogenous pipe line.

If requested all pipes can be manufactured either with a bright, inspection friendly or an electro-conductive inner surface made by the co-extrusion process.

The co-extrusion provides an inspection- friendly, bright inner surface and at the
same time a long term UV-resistant outer surface (for example for the storage
of pipes outside for a long time).

Elastic pipes can react to changes in their environment.

Due to the deformation performance, the load is distributed
to its surroundings and the force acting on the pipe will be diminished.

Within a short time there is a balance in the area around the pipeline and
the deformation comes to a standstill. Plastic pipes react very flexibly to static
loads, while the loads do not concentrate themselves on the pipe, but are diverted
to the surrounding soil. Flexible pipes still work when other rigid pipe
systems already show damages like breaks or cracks.

The Krah pipe system can withstand low working pressure up to 3 bar, depending on the thickness of the waterway wall (e4,e5).

Equivalent to DIN8074 the hoop stress formula can be used with
minimum (e4,e5) as the minimum wall thickness of the A1 pipe, or
the minimum wall thickness of the waterway for A2 pipes.

e = minimum wall thickness
p = internal pressure
di = internal diameter
σ = permitted strength (MRS/C)
MRS = Minimum Required Strength
C= Safety Factor (for water 1,25)

The lifetime of the complete Krah pipe system for gravity and low
pressure application is 100 years.

Basically every component is designed for a 50 year full and constant load case.
In the upper shown diagram you can see that the stability of the pipes are designed for a usage of 100 years (a), including a calculated safety margin. A stability (b) is reached - with constant load, in our case due to the usage of polyolefins we have an additional safety. As soon as the load is released the time is starting again, and
you have the extra safety again.

Both profiled and solid wall pipes with wall thicknesses of up to 300mm can be produced.

The quality of the pipe is highly dependent on the quality of the waterway wall, therefore all Krah pipes are usually produced with a minimum waterway wall of 4mm.

According to different norms and standards, the pipes shall be designed according to nominal ring stiffness classes.

(SN) like SN2 (only for pipes DN > 500), SN4, SN8 or SN16 (according to ISO 9969), or other standard stiffness classes (DIN16961, ASTM F894, NBR 7373 etc) not depending on the testing method (constant speed or constant load).