KRAH® TECHNOLOGY

Krah® high-density polyethylene (HDPE) structural pipes have the particularity of achieving high annular and longitudinal rigidity with very low weight. This is achieved by combining: The helical arrangement of the ribs, which give it longitudinal rigidity. The design of a structural profile dimensioned according to the requests of annular rigidity of the conduction, achieving efficiency and avoiding the oversizing of the pipes. The characteristic low specific weight of high-density polyethylene.

Krah® high-density polyethylene (HDPE) pipes can be manufactured with the necessary rigidity, assigning different profiles depending on the different load conditions that the conduction will have to face along its route. IRAM 13414 Standard establishes that the annular rigidity of HDPE pipes must be at least SN2. When this rigidity is not sufficient, the profile must be designed according to the requirements of the work or project, the minimum data necessary to size it are: Type of conduction Minimum and maximum cover Type of traffic Type of natural and containment soil Depth of the water table Once the rigidity necessary for driving has been determined, the type of profile is determined and dimensioned.

High Density Polyethylene (HDPE) has the lowest Manning coefficient (internal roughness) compared to other materials on the market. Therefore, under the same hydraulic design conditions (section, slope) with traditional technology, HDPE pipe has greater hydraulic capacity. When comparing HDPE pipes with Concrete pipes, it can be deduced that: - To conduct the same amount of flow, HDPE Krah® high-density polyethylene pipes need a diameter 10% smaller than that required for concrete pipes. - In the case of having the same diameter in HDPE and in concrete, the HDPE will conduct 30% more flow. - To conduct the same flow and with equal diameters, HDPE pipes will need a 40% lower longitudinal slope than that of concrete pipes, with the corresponding reduction in capping and consequent savings in excavation.

Because the pipes are lightweight, logistics use light equipment, aiding efficient and safe truck loading. Optimizing transportation involves sending deeper pipes, cutting costs, and boosting shipment capacity. Handling lighter pipes reduces work risks and heavy machinery use. Collection in confined spaces near the trench simplifies pipeline lowering.

The standard length of the pipes is 6mts, but in the event that you have to solve specific requirements, such as hard-to-reach pipes, crossroads, streets, high-traffic routes, or culverts, you can request specific advice for manufacturing custom lengths. The standard length, when compared to traditional concrete technology, will greatly increase the progress of your work.

High-density polyethylene (HDPE) is one of the most resistant materials to the majority of chemical compounds that appear in pipes, including SH2, which is the most dangerous element in sewer pipes. Due to this, HDPE Krah® high-density polyethylene pipes guarantee their durability without the need for internal/external coatings and without any restriction on the magnitude of deformations in the pipe, since, on the one hand, the material does not crack and, on the other hand, is completely homogeneous and resistant throughout its mass.

Abrasion is defined as wear on the surface of one body caused by particles from another body, called an abrasive. It is a fundamental parameter when defining the field of application of a pipe, since it will determine the use, or not, of different materials. In the case of installations that carry suspended solids, or are unblocked with hydrojet, this property must be evaluated as essential. Wear depends mainly on four variables: The characteristics of the abrasive material (such as its granulometry or its chemical composition) The constituent material of the surface (or the constituent surface material) The relative speed between the surface and the abrasive material The frequency of the solicitation To determine the resistance to abrasion, the overturning test is performed using the Darmstadt method. This test allows comparing the behavior of different types of pipes. As seen in the graph above, high-density polyethylene has the least wear.

In general, long-term deflections of no more than 5% are often asked of commercially available materials to prevent the tube section from losing its circular shape and cracking of the liner or inner layers. In the case of HDPE pipe, these drawbacks will not take place at any degree of deflection, since the material does not crack, its entire mass is inert and its molecular fusion joints maintain their properties. The ductile properties of HDPE and the structural capacity of the pipe will not be affected by large deformations. The elastic properties of the HDPE allow the formation of curves, between a certain range of values ​​of the radius of curvature, to make adjustments on site, without presenting dents or localized collapses, avoiding in these cases the need to resort to the inclusion of elbows or special pieces.

The lifetime of the entire Krah® High Density Polyethylene Pipe System for gravity and low pressure applications is estimated to be 100 years, including a safety margin. Each component is designed for a 50 year full and constant load case. Krah® pipes, due to the use of polyolefins, have additional security. As soon as the load is released, the time starts again, and with it the extra security.

HDPE Krah® high-density polyethylene pipes have a full range of connection possibilities, even to other materials: Electrofusion Joint The union is bell-tang, with an electrical resistance built into the bell. It has two protruding terminals that are connected to an electrofusion machine that generates the current flow, heats the material and produces the molecular fusion that makes the system monolithic. This type of union is incorporated in the pipes, allowing the contractor to work quickly, safely and efficiently. Butt Merger Union Krah® pipes can be Butt Fused, in this case the pipes will have straight ends. Elastic Gasket with Double Rubber Ring The union is bell-spike, the latter has two housings that prevent the rubber rings from being swept, facilitating installation and guaranteeing tightness. Material Contribution Union The High Density polyethylene with which Krah® pipes are made allows their welding by contribution of the material. This type of weld can be used either for joining two tubes with bell-dowel ends or for joining tubes with straight ends. Flanged Union Allows connection to other systems, accessories, branches, among others, using flange adapters.