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Pressure Pipes
KRAH MISR - Pipes are large polyolefin pipes up to an internal diameter of 4000mm.

Production process
Krah-Pipes are produced according to the Krah- Spiral-Cross Winding-Extrusion Process. During the production process the pipe is produced seamless and all sub-processes are continuously controlled by the integrated CPV and control visualizing software.

Material
The base material, high density polyethylene (PE100, with a minimum MRS of 10.0 N/mm2), is normally stabilized by the addition of carbon black. On special request and for special applications other polyolefin can be used, like for example polypropylene grades.

Pipe ends
The pipe ends are cut in-line, Square cut. Should Electro fusion joints or stubends be produced, the pipe ends are produced accordingly with socket and spigot.

Surfaces
The internal and external pipe surface is smooth. The inner surface can be produced of electro conducive or inspection-friendly coloured material.

Pipe length
The standard pipe length is 6m -/+ 10 mm. If required, shorter pipe lengths are possible. The shortest length is 1m.



Standard dimension ratio
Is the difference between the external diameter DN/ OD and the wall thickness (s).








Relevant Standards
DIN 323: Preferred numbers and series of preferred numbers; basic values, calculated values, rounded values
DIN 8074: Polyethylene (PE) pipes PE63, PE80, PE100, PE-HD
DIN 8075: (at present at the stage of draft) High-density polyethylen (HDPE) pipes; dimensions
DIN 50011: Testing of materials, components and equipment; ovens; concepts, requirements
DIN 16776: Plastic moulding materials; polyethylene (PE) moulding materials; classification and designation
DIN 50049: Materials testing certificates
DIN 53759: Testing of plastic articles; long-term internal pressure testing of hollow bodies
ISO 161: Thermoplastics pipe for the transport of fluids – Nominal outside diameters and nominal pressures
ISO 4065: Thermoplastics pipes – Universal all thickness table
DIN 16961: Thermoplastics pipes and fittings with profiled outer and smooth inner surfaces
EN 13476: Plastics piping systems for non-pressure underground drainage and sewerage - Structured-wall piping systems of unplasticized poly (vinyl chloride) (PVC-U). polypropylene (PP) and polyethylene (PE)
SR04B023: Krah-Pipes in relation to internal pressure



Dimensions
All dimensions are related to the reference temperature of 23 -/+ 2 C.



Nominal diameters
The nominal diameter (DN) is related to the internal diameter (ID) regardless of the pressure rate.
The hydraulic radius is the same for each nominal diameter.

DN/ID DN/OD range
300 mm 310 - 460 mm
500 mm 510 - 660 mm
600 mm 610 - 760 mm
800 mm 810 - 960 mm
1000 mm 1010 - 1160 mm
1200 mm 1210 - 1360 mm
1400 mm 1410 - 1560 mm
1600 mm 1610 - 1760 mm
1800 mm 1810 - 1960 mm
2000 mm 2010 - 2160 mm
3000 mm 3010 - 3160 mm


Wall thickness
The wall thickness (s) is half of the difference between the internal diameter and the external diameter.

Pipe marking
Generally the pipes have to be marked according to DIN 8074 No.8. The minimum marking should indicate:
  • Manufacturer Code, e.g. KRAH MISR
  • If available, third-party control marks
  • Material Code, e.g. PE100
  • DIN-Number, e.g. DIN16961
  • External diameter, e.g. DN/OD 1200 or internal diameter, e.g. DN/ID 1200
  • Wall thickness, e.g. 30 mm
  • Melt Flow Rate, e.g. MFR005
  • Standard Dimension Ratio, e.g. SDR11
  • Date of Manufacturing, e.g. 20030824
  • Machine No., e.g. no. 7/KR600 The marking should be clear and should be placed outside of the pipe in radial direction, at least once per 1m pipe length.
Jointing
For the jointing of the pipes the integrated electro fusion joint is recommended. or The Butt-Fusion technology according to DVS 2207. Also the flange connection, where the stub ends are integrated in the pipes, is applicable.

Quality control
The quality control requirements and tests are according to DIN 8075, or other international standards.

Fittings
All kinds of fittings can be manufactured out of pipe segments.

Certificate
If agreed so, a test report shall be issued, giving the results of the routine tests carried out by the manufacturer.




Tolerances for diameters
DN/ID <=700 mm + 3.0 mm
800 mm < DN/ID <=1000 mm + 5.0 mm
DN/ID > 1000 + 6.0 mm
DN/ID > 1600 + 8.0 mm







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