Krah pipe systems guarantee durable tailor-made solutions in excellent quality. After many years , characterized by technical challenges under globally varying conditions, we have become an expert in finding solutions taking economic, technical and environmental issues into account.
Plastic is an excellent material when it comes to resistance against a chemically aggressive environment such as aqueous solutions of salts, dilute acids and alkalis, especially when used in sewer applications. Also in aggressive soil conditions (pH between 1.0 and 5.0) polyethylene performs well and long. Even in termite-affected countries no damage to pipelines made out of polyethylene has ever been recorded. Polyethylene and polypropylene are not nutrient media for bacteria, mushrooms and spores, so that the material is resistant to all forms of microbial attacks as well as both sulphurous acid and sulphates.
You can find further detail regarding this topic in our download section.
Frequent damages which have been observed on concrete pipelines are cracks, fractures, collapses and socket mismatches. These failures can mainly be attributed to settlements resulting in overstress of the pipe crown. Concentrated traffic and earth loads strain pipe systems all the time.
Therefore, it is very important to develop pipe systems, which will adapt to the future stresses and will not break down under these loads. The above mentioned damages are not likely to happen to thermoplastics pipes. KRAH pipes have integrated deflection zones and deform up to a point where the loads are minimized. When the load decreases, the KRAH pipe can reach its new lowest-stress shape due to its elasticity.
Deflection of a Krah flexible pipe (b) compared to an inflexible pipe (a)
The smooth inner surface of the polyethylene pipes offers a brilliant flow characteristic while other benefits like chemical or abrasion resistance are not restricted. There will be no deposits distracting the flow velocity.
A bright colored inner surface is produced by co-extrusion, that's why inspections or repair works are comparably easy. The black outer surface and the bright inner color are extruded simultaneously.
KRAH has developed this technique for larger pipes (up to DN/ID 4000mm). With this very quick jointing method the whole pipeline becomes a homogenous system and is absolutely safe against wanted and unwanted in- and ex-filtrations. A welding wire is included in the socket and then heated with the help of a special welding device, joining the two pipe ends (socket and spigot) together.
One of the outstanding engineering characteristics of High Density Polyethylene pipes are their long term hydrostatic strength behavior under various thermal and environmental conditions. Life expectancy is conservatively estimated to be in excess of 100 years, using the standard design basis. Furthermore the pipes are consequently highly resistant to UV-rays such as to scale and sediment build-up.
The weight of Krah Pipes is one of the major advantages compared to conventional pipe materials. Being determined with 0,955 kg/dm³ for gravity pipes, the material is the lightest amongst others. Therefore, this extremely low weight allows a much easier and quicker transport and installation of the pipes. Generally no heavy machinery is necessary for the installation and handling of them.
With the third generation of high performance polyethylene, pipes could be manufactured for higher pressures and higher temperatures. Special polymers are available for working temperatures up to 50° Celsius / 122° Fahrenheit.
This characteristic derives from the chemical and physical properties of raw material as well as through the effective extrusion process: the material is able to absorb energy. Additionally the material is very ductile, it flexes and bends and absorbs impact loads within a wide range of temperature without fraction. Even in areas of high earthquake activity the pipes have proofed to resist: