Krah pipes are often used for pressure applications, whether the requested pipe material is a standard High Density Polyethylene (HDPE) or Polyethylene reinforced with glass fibres (PE-GF). For the flow-characteristic and pressure loss the surface quality is essential, since the surface-roughness affects the friction between fluid and pipe wall. Polyethylene pipes (HDPE and PE-GF) provide in general very low roughness values in comparison to steel or concrete pipes. The low roughness and the kind of waxy surface can also avoid incrustations which is another point to reduce the pressure-loss.

Furthermore also the jointing procedure can be important. Any interruption of the surface generates additional turbulences, which increase the pressure loss. In the pipe design that aspect should be considered. A smooth surface after jointing is very preferable, e.g. by using Electrofusion socket / spigot joints.

Especially in comparison with other pipe materials like concrete or steel the advantages of Polyethylene pipes become clear after calculation. By using Polyethylene pipes very often the necessary pipe diameter can be reduced because of better flow-behaviour and less pressure loss!

1. Pressure loss
The pressure loss in pipe systems is the sum of all pressure losses for any element of the pipe system. All fittings, valves and constructions have an individual pressure loss and even the pipe joint can affect the pressure loss.

1.1 Pressure loss of straight pipelines
The pressure loss for pressure pipes can be calculated by using the following Darcy-Weisbach-equation, first time established by Jean François d’Aubuisson de Voisin in the year of 1834.

The Krah team installing the pipeline

Krah Pipes Manila, Inc. has again made a landmark accomplishment in the installation of a DN/ID 1500mm diameter pipe for its client, SM Telabastagan, Pampanga.

The project which Krah Pipes Manila Inc was able to forge is basically a 24 meter distance of cross drain pipes which ran across a major road, MacArthur Highway considered a very busy road within Fernando City, Pampanga. The 24-meter distance or length is practically 4 pieces of 1500mm diameter Krah Pipes. It was a quick overnight process of installation where the excavation of the trench took only 4 hours and 3 hours for the jointing of 4 pieces of pipes (at 6 meters in length per pipe) and laying them down the trench after which the excavated area was immediately back filled making the road ready for the passage of the various vehicles and motorists the following day. The works conducted did not cause disruption and inconvenience to the public.

Jeneleen Lansangan

Krah Pipes Manila, Inc. (KPMI) is one of the latest extension and additional part of Krah community in South - East Asia, particularly in the country with 7,107 islands and known as the pearl of the orient, the Philippines.

KPMI was listed in the Philippine’s directory of corporations last September 2015 and opened its plant doors last May 2017. In between those years, the first ever employee of Krah Pipes Manila joined the team. KPMI’s first employee is Miss Jeneleen Lansangan, we like to call her Jen. At the age of 25, she joined KPMI as Mr. Alexander Krah’s executive assistant in April 2016. She graduated and passed the local licensure exam for Civil Engineering and was able to help out in the supervision of KPMI’s plant construction which started in October 2015.

Krah pipes, made of Polyethylene PE100 in typical black colour, provide a perfect weather and UV resistance. If a Polyethylene pipeline is planned for an application in exposed conditions the external loads and influences have to be considered for the design.

Typical applications are:
• Mining industry
• Sewage and water pipelines
• Hydropower plants (headrace, penstock)
• Industrial applications

For exposed installations we mainly differ between industrial pipelines installed in clamps and free installed pipelines on the ground. In the following abstract we concentrate on free installed pipelines under exposed conditions. Often we receive inquiries regarding the planning of Polyethylene pipes for such exposed conditions. People ask for installation rules and what has to be considered in general.

Typical Krah profile for double wall pipes