Our site uses cookies necessary for its proper functioning. To improve your experience, other cookies may be used: you can choose to disable them. This can be changed at any time via the Cookies link at the bottom of the page.


PE technical guidance
HDPE Pipe technical guidance (High quality Polyethylene Pipes)
 

How is PE pipe designed for given operating conditions?

Quick access

First  it is necessary to decide what the pipe is to be designed for;

  • Internal pressure capability e.g. water or gas distribution main or pressure sewer
  • External pressure capability e.g. submerged pipeline
  • Soil loading e.g. buried sewer pipe
  • Dynamic loads, surge and fatigue e.g. sewer rising main

The starting point for the design of a PE pipe is the MRS (Minimum Required Strength) of the grade of PE to be used. Note that the MRS quoted takes into account the creep properties of PE 100 & PE100-RC and applies to operating temperatures up to 20°C. For operating temperatures in excess of 20°C, reference should be made to ISO 13761. The MOP (Maximum Operating Pressure) is related to the MRS of the material used; the pipe geometry (SDR; standard dimension ratio) and operating conditions by the following formulae:

When the SDR is known;

MOP = (20 x MRS) / (C x (SDR-1))

Or when the operating conditions are known;

SDR = 1 + ((20 x MRS) / (C x MOP))

Where:

  • C is the ‘overall service (design) coefficient, or Safety Factor . (For PE the minimum values of C are: for gas 2.0; for water & presure sewerage 1.25)
  • MRS is in MPa; (PE100/PE100-RC = 10 MPa, PE80 = 8 MPa)
  • MOP is in bar

To calculate the SDR or MOP for a given standard pipe, use the SDR-MOP calculator.

The pipe size required is determined by the flow capacity needs. Hydraulic capacity is influenced by the frictional head loss in a pipe, which in turn is influenced by its surface roughness. PE has excellent surface characteristics and as a result the frictional losses are lower than with most other pipe materials, leading to a lower energy requirement to pump water or gas through the pipe.

The roughness coefficients for PE  in hydraulic calculations are:

  • Colebrook-White equation: k =  0.00152 mm
  • Hazen-Williams equation: c = 150 (dimensionless coefficient)

Related keywords : pipe roughness coefficient, hazen williams coefficient for hdpe, roughness of plastic pipe, hdpe roughness coefficient, roughness values for pipes, hdpe pipe roughness coefficient, hdpe pipe friction coefficient, head loss in hdpe pipe, colebrook white roughness coefficient, hdpe pipe roughness, rising main design, how to design a pipe, c factor pipe

Last update Wednesday 27 March 2024

Members of the Association

BOREALISBOROUGEFormosa Plastics CorporationHanwha TotalEnergiesINEOS O&PIRPCKorea Petrochemical IND. Co., LTD (KPIC)LyondellBasellORLEN UnipetrolPetroChina Dushanzi Petrochemical CompanyPRIME POLYMERSABICSCG Chemicals & Thai PolyethyleneSinopecTASNEE