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FAQ - Part 3

This is the third part of our “Frequently Asked Questions” section. In every issue we will answer some of the most asked questions we get from potential customers and interested parties about the Krah Technology.
Also feel free to send us some new ideas for our FAQ in he form below. We will try to publish as many as we can.

 

Can Krah pipes be used for outfall and intake pipelines?
Yes, Krah pipes are 100% applicable for marine applications and have a multitude of successfully reference projects worldwide. Both Krah profiled wall pipes and Krah solid wall pipes can be used for outfall and intake pipelines. However, the profiled wall in combination with the Krah Electrofusion technology is mostly used.Notice: The Krah marine pipe profile provides a higher stiffness and buckling stability than normal solid walls. And also an axial strength is excellently given by using this special Krah profile!
How is the chemical resistance of Krah pipes against acid and lyes?
Krah pipes and Polyethylene products in general have been successfully used for decades in the chemical industry for transport of chemicals as well as for storage tanks. Notice: Polyethylene has a very good chemical resistance against most of acids and lyes.
Will Krah pipes float in the water?
Yes, Krah pipes are made of Polyethylene and Polypropylene, and due to being slightly less dense than water, they will float even when they are full of water. For underwater anchored pipeline installations, it is important to specify the proper weights and distance of the weights. Whenever possible, an underwater pipeline should be installed in a trench with a protective crushed rock cover.Notice: Krah can support you with designing marine pipes!
What is the maximum recommended flow velocity for possible fluids going through Krah pipes?
In a pumped system the maximum operating velocity is limited by the surge pressure capacity of the Krah pipe. If surge is not a consideration, water flow velocities exceeding 7,5 meter per second may be acceptable. This number can also be used as a maximum for gravity applications.

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Krah Pipes App

Powerful tool for take-away: Krah Pipes App

To improve the know-how transfer from us to our customer we choose the way of a free app, so after half a year of further developments, we are proud to present our latest improved Krah-Pipe Calculation App. The app can run without an internet connection, so you are free to use it nearly everywhere.

A small tool, but a lot of functions:

1. The first main part of the App is handling the field of hydraulic calculations:

  • This feature enables you to calculate the flow speed and flow rate (according to ATV A110) just by entering your diameter, slope and filling height and rather choose your Kinetic viscosity and working roughness from a list ore entry a free chosen value.
  • If you already got a flow rate and a filling height but need a diameter you can calculate this by tapping on “FIND THE RIGHT DN/ID” on the tab bar on the top of the page.
  • Last but not least you can even calculate the right slope for your flow rate, diameter and filling height.
Calculating flow speed and rate
Calculating flow speed and rate
Determing your internal diameter
Determing your internal diameter
Calculating the slope
Calculating the slope

2. The second part is handling the field of “Storm water retention”:

  • This feature is made for dimensioning storm water retention regarding to diameter, length and volume at different filling heights.
  • On the “REQUIRED VOLUME” tab you are able to enter the volume you need and you will get a table with diameters between 300 mm and 2000 mm and 3 different filling heights showing you which length you will need.
  • On the “AVILABLE LENGTH” tab you are able to enter your given length to calculate a table with diameters from 300 mm to 2000 mm and 3 different filling heights (full filling, 2/3 filling and 7/8 filling) showing you what volume you will need.

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Laguna Krah Heroes

LAGUNA KRAH HEROES, is new expansion team that recently joined the MAHARLIKA PILIPINAS BASKETBALL LEAGUE.  Laguna Krah Heroes is team formed for Laguna province with Biñan City as the LGU Partner spearheaded by the most sports enthusiast, Vice Mayor Gel Alonte of Biñan City in Laguna.

Laguna Krah Pipes team during a match
Laguna Krah Pipes team during a match
Giving their best to win the match
Giving their best to win the match

The Maharlika Pilipinas Basketball League (MPBL)  is a regional men‘s professional basketball league in the Philippines. It is founded by no other than the World Boxing Champion, now a senator in the Philippines, Senator Manny Pacquiao.  The  League was founded in August 29, 2107 and started  the founding league with Bulacan Kuyas Team emerging as the Champion last year.

Senator and World Boxing Champion Mr. Manny Pacquiao
Senator and World Boxing Champion Mr. Manny Pacquiao
Mr. Sajid Anonuevo motivating his team
Mr. Sajid Anonuevo motivating his team

In January 25, 2018, the League kicked off its first formal  Inaugural MPBL CUP, The Anta Raja Cup where 10 Teams had participated and just recently,  last April 17, 2018, Batangas Atheletics Team  was the Champion and known to be the Team to beat in the League. The MPBL features both Regional Commercial and Barangay-Level League with teams on the commercial side to have a Home-locality. The League is initially organized in Luzon with plans to expand to include teams in the Visayas and Mindanao.  MPBL plans to conduct the next conference Season which will be patterned after the NATIONAL BASKETBALL ASSOCIATION (NBA) with additional expansion team including those from the Visayas and Mindanao Regions wherein the Teams will be divided into Northern and Southern Divisions.

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Ashkelon Wastewater Project

water authorities project
Engineer Mr. David Yaloz at construction site

Israel is known as the land of the Bible, but it is actually much more than that. Israel is a modern, developed country located along the Mediterranean Sea.

Due to the long, hot and dry summers with very short rainy winters, water becomes one of the most important issues in the country. Therefore, as one of the most arid environments on earth, the available water system has to be handled and developed very carefully.

On this basis, the Water Authority approached the engineer Mr. David Yaloz with the task of finding the most suitable piping system to enlarge and replace an existing wastewater system in the town of Ashkelon. The existing pipeline is constructed from a 48” asbestos cement pipe. The new 3.6 km pipeline will replace the existing pipe and a further 3.6 km pipe will be laid after the existing pipe is decommissioned to provide additional capacity and flexibility for this expanding town. The Israeli pipe market offers many different pipe materials i.e concrete, HDPE, PP, steel, and PVC etc. for a sewer pipeline project like this.

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Hydraulic calculation of PE pressure pipes

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.

Formula to calculate 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.

Formula to calculate pressure loss

Formula to calculate pressure loss

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