HDPE Pipe Thickness Calculations

HomeAbout Us Products Certificates Quality Solutions Scientific Information&Articles Contact Us HDPE Pipe-Polyethylene Water Pipes & Fittings Calculation Methods 1. CALCULATING WALL THICKNESS Pipe calculation formula in ISO 161-1 is used in order to calculate wall thickness. The long forms of the symbols in this Formula are as follows: PN s S σs SDR da Normal Pressure Wall thickness Pipe serial Hoop stress Standard Size Rate External diameter The minimum wall thickness according to that: Pipe (mm) (Bar) (mm) (-) (N/mm2) Hoop stress calculation depends on safety factor. MRS: Minimum Required Strength extra loads such as loads that ground water creates. although the pipes are laid under the ground.0036 .62 2.3 8.6 WEIGHT (kg/m) PE 63 PE 80 PE 100 6.25 1. And the formula below is used: m=0. A .0036 . Acceptable Stability Pressure Calculation for PE Pipes Pk. stability calculation must be done in projects that have overstress such as sleeve concrete made for filling the gap in pipes that engage by sleeve method or additional loads in vacuum pipes that have absorption function. A .25 3. ρ . continuity balance is established if passage flow rate at the water passageway is constant.1 6. continuity balance is established. v Q : Amount of Load A : Pipe Section V : Flow Rate If the passage flow rate at the gas and vapour passageway is constant.0 SAFETY FACTOR (C) WALL THICKNESS s (mm) 10.3 8.CALCULATING PIPE DIAMETER The determination of the pipe section.14 2.zul Acceptable Pressure Critical Collapse (bar) fr s Reduction Factor Safety Factor (-) (-) Stability Pressure Calculation for PE Pipes σk Pk rm s Stability Pressure Critical Collapse Pressure Average radius Wall thickness (N/mm2) (bar) (mm) (mm) 4. v .0 10.2.17 STABILITY PRESSURE Pipes that are laid under the ground are exposed to loads other than earth load.0 1. as it is the case in sea discharge when pipes are laid straight into the sea. HOOP STRESS PE CLASS MRS (N/mm2) STRESS σ (N/mm2) 5. Q=0. Apart from these. Stability Pressure Calculation for PE Pipes Pk Ec Critical Collapse Pressure Elasticity Module Number Thermoplasts of Transverse (bar) (N/mm2) (-) s rm Wall Thickness Average Pipe Radius (mm) (mm) 3. Those are.0 6.0 8.25 1. the formulas below are used: a)Darc-Weisbach Formula di : Internal Diameter of the Pipe (mm) I : Length of the Pipe Line (mm) V : Average Fluid Flow Rate (m/s) p : Fluid Density (kg/m3) I : Coefficient of Friction (-) High energy loss stands for the elevation differences intended for the desired flow rate in the line. b)Colebrook-White Formula Re : Reynold’s Number v : Kinematical Fluidity of Water k : Hydraulic Smoothness Value of Internal Pipe Surface When the previous formula is transformed.m ρ : Passage flow rate : Density of the material carried 5. Positive value is observed while the armatures are switched off and the pump is switched on. flow rate and pressure decrease in HDPE pipes. Ps value: a vo p : Spreading Speed of Press Wave (m/s) : Flow Rate of the Fluid (m/s) : Fluid Density (kg/m3) Ps value can be positive or negative in practice. PRESSURE LOSSES Calculating Separate Pressure Losses In order to calculate the high energy loss or pressure loss due to passage amount. Spreading speed of press wave is calculated by the formula below: . Ps negative value is observed while the pump is switched off or hydraulic property suddenly changes.PRESSURE IMPACT There may be a pressure impact while the valve or the pump is switched on and off. V : Flow Rate g : Gravitational Acceleration Je : Energy Line Centering Trend d : Kinematical Hardness : Pipe Diameter Kb : Working Smoothness There are two smoothness values: · Plate smoothness is ‘k’ · Working smoothness is ‘kb’ 6. Thus. and at low temperature there will be a decrease in the length of the pipe. At high temperature. pipe. Let us assume that.3 8 The possibility of breaking is the critical point while calculating the bending diameter for thin-walled pipes. when there is an increase or decrease in pipe length depending on temperature. 30 for PP. for every ‘K’ amount of temperature change. Thus. stretching-shrinking limit is the critical point. FLEXIBILITY Maximum bending radius for PE pipes: R Dm : Bending Radius(mm) : Average Radius(mm) HDPE CLASS PE 63 PE 80 PE 100 E : Pipe Elasticity Module (N/mm2) : Stress (N/mm2) HOOP STRESS N/mm2 5 6.07 0. normal working temperature Tv=20 0C.12 0. The formula below is used while calculating the acceptable bending radius for thin-walled pipes: . maximum working temperature T1=65 0C and minimum working temperature T2=10 0C.5 for PVC) 8.18 0. while calculating the bending diameter.14 0. length changes depending on temperature are calculated as follows: Increase in length depending on temperature rise : Decrease in length depending on temperature drop : Ls d k : Fixing Range (mm) : Pipe Outer Diameter(mm) : Factor (26 for HDPE.15 0. there will be a dislocation in the pipe line.02 Coefficient of elongation for various plastic materials table For instance. there will be an increase. 7.DILATATION Elongation ratio dependent on heat variability must be taken into consideration while the HDPE pipes are laid. part of the PE pipe. MATERIAL HDPE PP PVDF PB PVC GFK FACTOR mm/m. There will be 0. in a line made of PE pipes. for a 12m. 33.Em : Elasticity Module of the Fluid (Esu) p : Fluid Density (kg/m3) Er :Elasticity Module of the Pipe (N/m2) Dm: Pipe Mid-Diameter(m) e : Pipe Wall Thickness (m) Short-term changes in pressure and the effect of pressure impact do not cause harm in HDPE pipes.18 mm increase or decrease in length of 1m. not at the fixed point but at the turning point of the pipe.K 0. For thick-walled pipes. rm s : Average pipe radius (mm) : Wall thickness(mm) The formula below is used while calculating the acceptable bending radius for thick-walled pipes: ra : Pipe external radius (mm) E : Stretching-shrinking rate (%) Site Ma p Copyright © 2010 KUZEYBO R U All rights rese rved Ma vi Pik se l .