Phone: (472) 791 0242 [email protected]


Technical basis

To select the right pipe for a project, there are some formulas to determine the pipe stiffness ahead. For better examples, as well as advanced calculations and formulas, consult our technical employees so they can guide you in selecting the pipe best suited for your needs

Structural analysis and profile selection

Usually, given the huge variety of profiles offered by Krah Pipes, each project is analyzed, and according to data supplied by the customer, we offer a tailor-made solution for the specific project.

When the more information or data is used, the better we can optimize the pipe profile design so it can adapt exceptionally well to each project. One of our greatest advantages, is that our pipe does not need to be overly dimensioned, helping save on cost, buying only what the project needs. With Krah pipes, every costumer can have a specifically designed pipe to fulfill their project needs. It is also possible to combine different kinds of pipes in the same line if there are different needs along the pipeline.

a= Profile step (mm).

s1= Internal liner thickness (mm).

s4= Profile thickness (mm).

h= Profile height (mm).

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To determine the best suited pipe, it’s crucial to determine the pipe stiffness needed. This pipe stiffness can be obtained from various standards available. In the next table you can find 3 of the most used with our pipes.

Ring stiffness, should be determined to work in a scenario where a structural analysis is run and a ring stiffness is calculated. The client should provide some information, such as cover height, internal pressure, native soil characteristics, soil compaction, etc.). With the piper properly designed, a proper installation is required, as it was designed in the structural analysis. Krah México, uses AWWA M55, which gives the possibility to analyze different type of installations, where you can be able to choose which one is more suitable for your project, and then select the appropriate pipe.

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Ring Stiffness produced by Krah Mexico

  • Available
    (-) Not available

*  Consult with a Krah Mexico technician for Special Rigidity classes.

Pressure rating analysis

Pressure Rating (PR) is defined as the maximum working pressure for any pipe, in which the pipe can continuously handle with high certainty that no fail points are going to occur (ISO 161-1, 3.3.2). This Pressure Rating is obtained by three variables, SDR which is a dimensional ratio, Minimum Required Strength and the working pressure.

For controlled outside diameter pipe a SDR is used and for controlled inside diameter a SiDR is used, the relationship between the two is a sum of two time de wall thickness.

For a given SiDR, and using de MRS and C values specified in the HDPE Standard applicable (ISO 12162), the maximum operating pressure can be obtained with any of the following equations.


Do you need more information about our high density polyethylene pipes?



(472) 791 0242


Av. de los industriales Col. Villa de las flores. C.P. 36270 Parque Industrial Fipasi. Silao, Guanajuato Mexico.



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