PE100 Pipeline Design, Installation and Jointing - Muscat Handout.pdf

April 24, 2018 | Author: ayaz | Category: Polyethylene, Pipe (Fluid Conveyance), Thermal Expansion, Welding, Pipeline Transport
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PE100 Pip eli ne Desi gn , Jo in ti ng and Installation Muna Noor and Bo rou ge PE Pipe Semin ar May 2016

1 © Borouge

Contents  An introduction to Borouge  A brief introduction to multilayer PE pipes  PE100 pressure pipe design  PE100 pipeline hydraulic design  Points to remember when designing a PE100 pipeline  Design of valve installations and chambers  PE100 pipeline structural design (more detail in handout)  Installation considerations  On site hydrostatic pipeline testing  Introduction to the jointing of PE pipe systems  Conclusion 2 © Borouge

An introduction to Borouge

© Borouge

Borouge , part of a globa l polyole fins family  Borouge – A JV between ADNOC and Borealis, combining the best of Europe and

the Middle East  JV formed in 1998, production start up in 2001 in Ruwais, Abu Dhabi using the Borealis Borstar technology.  Current capacity of 4,500 kT per year of Polyethylene (PE) and Polypropylene (PP). This equates to more than 450 no. 40’ ISO containers every day. 4 © Borouge

Borouge Our foo tpr in t in East Afr ic a, Asi a & Middl e East


| BorECO™ PP

© Borouge

A leading provider of sustainable plastics solutions


Automotive 6 © Borouge

Advanced packaging

A brief introduction to multilayer pol yethy lene pi pes

7 © Borouge

Nearl y all m ult il ayer pipes fa ll in t o one of two categories Inte grated Functi onal L ayers

Sacri fi cial Protecti ve La yers

Co-extruded PE100-RC systems where the layers work together to resist the hoop stress

PE pipes with additional PP or PE outer layer which may be mineral filled / reinforced where the hoop stress is taken by the inner layer emin

Bo th th ese desig ns co vered i n ISO 4427 and ISO 4437 8 © Borouge


What are the re ason s f or the grow th o f p ip e sys tems wit h pr ote ctiv e oute r l ayers?  Multilayer pipes combine properties and advantages of different layers.  More demanding installation techniques such as narrow trenching, horizontal directional drilling and pipe bursting have significantly increased the risk of installation damage.  A scratch resistant outer PE or PP layer can minimise any damage. 9 © Borouge

What a re the cur rent t yp es o f PE Pip es for d emanding inst alla tion condi tion s?  Pipes incorporating PE100-RC layers that have a much higher resistance to crack initiation and growth though the pipe wall  PP coated pipes are popular in Europe for protection against external damage. In the UK the main aim is to improve joint quality  Thicker PP layers are used to provide a higher level of protection against external damage  Alternatives involve the use of a mineral modified (reinforced) outer PE or PP layer which has an even higher level of scratch and abrasion resistance 10 © Borouge

One exampl e are the dif fere nt sacri fi ci al sys tems p rod uced by E gepl ast

Sacrificial outer layer of mineral reinforced PP-B or PE

Regular PE100 or PE100-RC pipe

 The fully pressure rated inner pipe is a black PE100-RC material whilst the sacrificial outer layer is a mineral reinforced PP-B or PE both, of which have relatively high scratch resistance. 11 © Borouge

Exampl es of i ntegra l mu lt il ayer pi pe sys tems: Muna Noor ’s blue multilayer pipe range  Some pipe producers, such as Muna Noor have promoted the use of integral layer systems.  By combining inner and outer layers of a

PE100-RC material with an inner layer of regular PE100 the pipe system increases its resistance to slow crack growth as a result of external damage or point loads, whilst minimising cost,  In order to also improve the visibility and identification of the pipe systems, along with facilitating CCTV inspection Muna Noor have gone inner and outer blue layers

each of which is 25% of the pipe wall. 12 © Borouge

Exampl es of i ntegra l mu lt il ayer pi pe sys tems: barr ier s yst ems and fl ame re tard ant laye rs  Barrier layer pipe systems such as Protecta-Line have a thin aluminium layer sandwiched between two PE100 layers.

This is used contaminated when pipes are laid through soils containing hydrocarbons etc. that can permeate through plastic pipe walls.  The Marley Pipe Systems MagaTuff FR pipes have a thin modified PE outer layer that forms a carbonaceous char when it comes in to contact with a flame, protecting the pipe. 13 © Borouge

PE Pressur e Pipe Desi gn Stand ard s, SDR, press ur e rati ng s and resis tance to sur ge pre ss ures

© Borouge

Pri nci pal st andards rela ted to manuf act ur e and desi gn o f PE pr essu re pipelines  ISO 4427 : 2007 par ts 1, 2, 3 and 5 Plastics piping systems — Polyethylene pipes and fittings for water supply  ISO 4437 : 2007 par ts 1, 2, 3 and 5 Plastics piping systems for the supply of gaseous fuels - Polyethylene (PE)  Europe EN 12201 : 2011 and EN 1555 : 2014 - very similar to ISO standards  EN 1295 : 1997 Structural design of buried pipelines under various conditions of loading  BS 9295 : 2010 Guide to the structural design of buried pipelines  ISO 15494 : 2015 Plastics piping systems for industrial applications — polybutene (PB), polyethylene (PE) and polypropylene (PP) © Borouge

Pip e Hoo p Str ess and ho w PE ma terials are classified  Hoop stress is the stress in the pipe wall (T) created by the internal pressure (P) of the liquid of gas being

carried by the pipe  The strength of PE materials used for pipes is classified by the hoop stress that they will be able to sustain after 50 years  PE that can continuously sustain a hoop stress of at least 10 MPa (N/mm2) for a period of 50 years at 20oC is said to have a MRS (Minimum Required Strength) of 10 MPa and can be classed as a PE100 - PE num ber = 10 X MRS in MPa  In the same way a material with an MRS of 8 MPa is classed as a PE80. © Borouge

SDR - Standard Dimension Rati o and th e basi c pressur e pi pe equation SDR 17

SDR 11 σh = p x dm


P x do - s 10


dm = mean pipe diameter (mm)

σh = hoop stress (N/mm 2)

do = outside pipe diameter (mm)

P = internal pressure (bar)

s = wall thickness (mm)

© Borouge

Safety factors and pr essu re ra ti ngs Combining the equation for hoop stress and the SDR expression we get: σh = P x (SDR -1)


PN = 20 x MRS

MRS = min. required strength (MPa)

(SDR -1) x SF

PN = pipe nominal pressure (bar)

SF = safety factor  As MRS refers to the maximum continuous hoop stress, which is due to operation pressures, rather than peak pressures, the safety factor is only 1.25 for water and 2. 0 for gas pi peline sys tems  The most frequently used SDR classes are SDRs 11 and 17 SDR11


Water PN 16 bar

Water PN 10 bar



© Borouge

PN 10 bar

PN 6.3 bar

Material l if eti me ass ess ment – 100 years li feti me with mod ern hi gh q uali ty PE100 σLPL = lower confidence limit hydrostatic strength 50 years = 10.633 MPa 100 years = 10.50 MPa High quality PE100 still exceeds the MRS after 100 years at 20o C Muscat for example has an average annual temp. of 28.6oC hence derating is required, but the pipe will have a life of 100+ years. © Borouge

50 years = 105.64 hours

100 years = 105.94 hours

Material l if eti me ass ess ment – 100 years li feti me with mod ern hi gh q uali ty PE100 σLPL = lower confidence limit hydrostatic strength 50 years = 10.633 MPa 100 years = 10.50 MPa High quality PE100 still exceeds the MRS after 100 years at 20o C Muscat for example has an average annual temp. of 28.6oC hence derating is required, but the pipe will have a life of 100+ years. © Borouge

50 years = 105.64 hours

100 years = 105.94 hours

Servi ce lif e and resist ance to sur ge pre ssu res  PE100 pipes are designed for service life, not catastrophic or ultimate conditions  PE100 is a viso-elastic material and the short term (1 minute) burst resistance of the material is between 3.0 and 4.5 the rated pressure when tested in accordance with ASTM D1599 : 1999  PE100 pipelines have a ‘surge rating’ of up to twice operational pressure in accordance with UK

and US design guides © Borouge

Pipes that have been burst tested

PE100 Pipeli ne and netw or k hydr aulic design

22 © Borouge

Mino r head lo sses due to t ur bul ence at fi tti ngs Typica l minor head loss coefficie nts

Standard equation HL = Kv 2 2g HL = head loss at fitting v=

velocity (m/s)

K = minor loss coefficient G = gravity (9.81m/s 2) 23 © Borouge

Prin cipals of hydr aulic d esign – commonly used e quation s Head losses are normally calculated using the Colebrook-White equation, or various deviations

Some Engineers still prefer the simpler Hazen – Williams equation

or for SI units

24 © Borouge


= velocity (m/s)


= co ns tant (0.849 fo r SI un it s)


= roughness c oefficient


= hydr aul ic radi us (m) = (A/P)


= hydraulic g radient (m)


= flow rate (m 3/s)


= pipe diameter (m)

Prin cipals of hydr aulic d esign – commonly used coe ffi ci ents and rou ghn ess v alu es Typical Colebrook – White roughness value s

Typical Ha zen - Willia ms coeffic ients

C factor (low)

C factor (high)

 PE Pipe Manufacturers recommend ks values between 0.003 & 0.005 mm


 The GPPA recommends 0.01 mm to make some conservative allowance for weld beads

Asbestos cement Castiron

135 100

140 140




 Comparison with cement mortar lining:










• Old pipe = 0.5 – 2 mm




• Turbuculated pipe = 2 mm+




• New pipe = 0.06

25 © Borouge

- 0.25 mm

Col ebr ook -Whi te hyd raulic d esi gn ch art s Some engineers still use Hazen Williams because Colebrook-White is an iterative process where the answer is put back in to the equation Many designers therefore use design charts such as this one from Frankische for a ks of 0.5 mm

26 © Borouge

Cole brook - White pre ssure loss and flow nomograms  Other designers prefer to use pressure loss and flow nomograms such as this one from Polypipe for a ks of 0,003 mm  With design charts, nomograms and design tables designers have to use a different one for different roughness values and water temperatures  Many now use spreadsheets which employ derivatives of the Colebrook – White equation, for single pipe design  For network design most employ network analysis software 27 © Borouge

28 © Borouge

Hydr aul ic / pum pi ng st ati on sp readsh eet fr om the S wamee Jain approxi matio n of CB- W Pipeline H ydr aulics us ing the Colebroo k-White Equation The spreadsheet is for use with pipelines specified by OD & wall thickness & will default to these. If OD is set to0 it will instead use the DN value. Outside Dia. Wall thickness Lining thickness pipes of Nr

mm mm mm Nr

0 0 0 1

Flow or Flow Length Roughness Temperature PipelineMinorlosses/km PumpStationMinorLosses

OD Tw Tl Np

l/s m³/hr 100.0 m 350 mm 0.01 °C 35.0 K/km 1.00 K 3.00 Margin % 0.0% Head Loss = (1+margin)*(friction+ minor/km + PS minor) TotalHeadLoss m 1.3 Overall slope m/km 3.6 NominalBore SuctionLevel(datum) DeliveryLevel(datum) PumpStationLosses Pump Duty Hd TOTALHEADLOSS

29 © Borouge



m m m m m

0 0 0 1.27 1.27


Q L k TMP K1 K2 K3


FactorDescription Flow Internal Dia Area Flow of

Symbol D

Flow velocity m/s 0.902 V Vel. head m 0.041 Hv Slope CW m/m 3.24E-03 Scw Friction (CW) m 1.133 HFcw Minor losses, lumped m 0.124 HM1 Minorlosses,distributed m 0.015 HM2 Marginonfrictionlosses m 0.000 HM3 Minor losses, total m 0.139 HM Frictionfactor (inclminor losses) 0.01735 f' Kinematicviscocity m2/s7 .21E-07 Vis Reynolds Nr 2.48E+05 Re fr factor(1st estimate, Swamee Jain) 0.01541 ffr1 frictionfactor(Col'White2ndest) 0.015459 ffr2 frictionfactor(Col'White3rdest.) 0.015455 f ViscosityAppr.Coeffs. Gravitationalconstant



Unit Value m³/s 0.0278 m 0.1980 0.031 A


0.0005 9.81

CFFT1 -0.0484 CFFT0

Some poi nts to r emember wh en design ing a PE100 pipeline

30 © Borouge

Comp ari son of di ffere nt p ip eli ne materi als Prope rty & performance

Ductile Iron

Corrosion resistance




Ease of jointing Joint integrity Flexibility

GRP excellent poor

Steel poor excellent

excellent poor

PE100 excellent excellent

easy spigot & socket

very difficult - laminating

difficult - welding

easy spigot & socket

difficult - welding


laminated – good

welded - excellent


welded excellent




Ease of installation No dig techniques Abrasion Resistance



poor poor







Capital cost

high → medium

low (large dia.)



© Borouge



easy verylimited good

excellent medium excellent excellent

high → medium low (small dia.) medium → high medium



Key design p oint s concerning the cont inuo us natu re of PE100 pi peli nes  PE100 pipes should be welded or mechanically joined together to form a continuous pipeline  By doing so designers can avoid the need for thrust blocks and the construction

of large valves chambers or anchors designed to take thrust  The ends of the PE100 pipeline must be anchored in some way in order to prevent ‘pull out’ due to thrusts at bends and tees, together with some very limited movement due to thermal effects and changes in pressure  Because of their high level of toughness, flexibility and continuity, PE100 pipelines are the best option for areas having poor ground conditions  Using coiled pipes greatly reduces the number of joints so reducing costs, jointing time and risks associated with poor jointing

32 © Borouge

Key poi nts c oncerning the contin uous nature of PE pi pelin es – therma l expansio n  Experienced pipe fitters can cope with the problem HDPE

 Thermal movement on

unrestrained pipes willofbe obvious eg. ‘snaking’ small diameter pipes in an open pipe trench as the HDPE coefficient of thermal expansion is 0.18mm/m/OC  Once buried there will be only very small thermal movement due to friction

between pipe and soil 33 © Borouge

1.8m PVC

0.8m 0.1m






Expansion (m)



Pip e expansio n & co ntr acti on due to pressur e change s als o result s in change s to p ipe le ngt h

No pressure

 When a PE pipe is pressurised it will increase in diameter. Since the volume of plastic in the pipe cannot change, the pipe becomes shorter


 When the pressure falls the pipe becomes longer no pressure P  The movements are very small, but over a period of weeks or months the repeated reduction and extension in the pipe life will cause it to pull (actually it wriggles) out of a flexible joint. Hence designers must use restrained joints 34 © Borouge

Therefo re anc ho r PE100 pi peli nes wh ere they conne ct to pipe line s wi th push on joi nts Use a concrete anchor cast around a PE wall flange

When a concrete anchor cannot be used then need to connect several pipes together with restrained joint sets 35 © Borouge

Also anchor PE pipes at chambers and use restraine d mechanical joi nts alon g the pipeline Wall anchors should be used when the pipework joints inside a chamber are not fully restrained eg. flanged or welded

36 © Borouge

PE80 and PE100 pi pes can b e su pp li ed i n c oi ls and on drums The current practical limit for coiling pipes is 315 mm OD though trials have been made using pipes of up to 630 mm OD

In Europe pipes of up to 225 mm OD are coiled on a regular basis either as coils or on drums for long lengths. In the ME typical max. is 125 mm 37 © Borouge

Speci fy c oil ed pi pes reduce the number of s it e welds, spe ed up in stallation and reduce cost s  Coil lengths vary with OD typical lengths are: ≤ 63mm OD: 200m 90 - 160mm OD: 100m

160 – 225mm OD: 50m  Check coil weight for manual handling: 200m x 63mm SDR 17 = 144kg  With larger dia. pipes use a hydraulic rerounder on site to reduce ovality

38 © Borouge

Pipe inst allation - the pipe bed and sur roun d Minimum compaction above pipe bed and surround typically 70 – 85% depending on whether in a trafficked area

Minimum compaction of 85% standard Proctor density (preferably 90%) required for the pipe bed and surround 39 © Borouge

Take particular care with the pipe haunching

Pip e co ver a nd t he de si gn o f t he pipe be d and surround  The absolute minimum cover to the pipe is recommended as 600 mm, though 900 mm is the preferred minimum, especially in areas where there is traffic.  Beneath highways with heavy traffic, use a minimum of 1.2m and preferably 1.5m cover. No need for a concrete bed and surround or protection / cover slabs.  This is to allow the dispersion (spreading) of any imposed loads from the surface, including both traffic and construction loads. See next sli de  The trench must be fairly dry in order to achieve the required compaction.  The bed and surround should comply with UK standard WIS 4-08-2. Otherwise:

• good quality granular material free sharp stones or lumps > 10% pipe OD • gravel or broken stone graded 5 – 10 mm • coarse sand or a sand and gravel mix with gravel less than 20mm and not > 10% of pipe OD 40 © Borouge

Tabl e 7 fr om BS 9295 sho wi ng th e relativ e impact of calculated soil and tr affic loads

Reducing pipe

Combined Load

Traffic Load

41 © Borouge

Soil Load

cover from 1 m to 0.6 m inc reases th e traffic load by > 50%

Don’t forget pressure derating factors at hi gher a mbi ent tempe ratures - ISO 4427  Annex A of ISO 4427 includes a temperature reduction table conservatively based on an old PE100 grade (Type A)  As modern PE100 grades have a much better performance it allows designers to take account of these  The pressure reduction for the type A material at 30oC is 13%  The pressure reduction for a

modern suchisas5% Borougematerial HE3490-LS 42 © Borouge

ISO 4437 temperature derati ng = 1.3% per o C above 20 o C

Buri ed pi pelin e desig n mu st also take in to acc ou nt t he lon g term ave rage tempera tu res  MRS is the continuous hoop stress that the polyethylene must be able to sustain for 50 years at a continuous temperature of 20o C.  Long term operational temperatures above 20oC can, in effect, accelerate the aging of pipeline and affect its operational lifetime.  If operational temperatures ie. average flui d temperatures over the year are above 20oC these must be taken in to account and the nominal pipe pressure (PN) derated.  If fluid temperatures are not known use average annual air temperature provided the pipes are buried. The worst conditions in deserts are around 30oC, though some Middle East utilities specify a design temperature of 35oC. © Borouge

Above ground pipeline design must take in to acc oun t bl ack b ulb tempe ratures  All thermoplastic pipes are effected by temperature which temporarily softens the material and reduces its strength and hence the pressure rating of the pipe.  When pipes and fittings are installed above ground they are subject to the full variation in daily and seasonal temperatures together with direct heating from the sun.  In these cases the pipe must be designed for the ‘black bulb’ temperature - the maximum temperature on surfaces exposed to sunlight  The harshest conditions are in the ME and typical oil and gas specifications state that pipelines shall be designed for a black bulb temperature of 80oC © Borouge

Derating of s egme nte d fi ttings - bends

The angle of each butt fusion joint (β) should not exceed 15o and if it is between 7.5o and 15o the pressure rating of the bend should be derated by 20%. 45 © Borouge

Derating of segme nted fit ti ngs – tees and ang le branches

As the segmented fabrication process fitting requires one area of the pipe to be cut and butt fused twice the derating factor is 50% (40% in EN 12201) 46 © Borouge

Derating of segme nted fit ti ngs – tees and ang le branches

Remember No de ratin g wi th i nje cti on moulde d fittings As the segmented fabrication process fitting requires one area of the pipe to be cut and butt fused twice the derating factor is 50% (40% in EN 12201) 47 © Borouge

Desig n of valve installation s and ch ambers

48 © Borouge

Typi cal valve ins talla ti on – buri ed v alve with preca st con cr ete spind le cha mber  This design can be used when the valves are buried, the end user still

wants to be able to inspect the valve body for signs of leakage  All buried metallic components must be protected with petrolatum impregnated tapes,

primers and mastic 49 © Borouge

Typi cal valve ins talla ti on – buri ed v alve with PE100 sp in dl e tu be This simple low cost design can be used when the valves are buried

and no visual inspection is required. Valves can still be sounded to detect leaks

50 © Borouge

Typi cal valve ins talla ti on – valv e and pip ewor k within a insitu concre te cha mbe r  This expensive design can be used when the water utility

requires valves to be housed in chambers.  This may be for maintenance purposes or in the case of aggressive ground conditions

51 © Borouge

Typi cal valve ins talla ti on – buri ed v alve with preca st c onc rete ins pecti on c hamber  This design can be used when the water utility are willing to accept

buried valves, but want full access for visual inspection and to replace the gland packing, if required.

52 © Borouge

PE100 pi peline st ru ct ur al desig n Can gene rally b e ig no red wit h pr ess ur e pip es und er nor mal ins tall ati on conditions

More detail is provided in the copy of this presentation given on the memory stick 53 © Borouge

Struc tural de sign of buri ed pi pelin es du e to ext ern al l oads EN 1295 can be rather difficult to follow. BS 9295 explains the design process and explains how EN 1295 should be used

Both cover the structural design of buried rigid, semirigid and flexible pipes

© Borouge

Thermoplastic pip e struct ura l design flow ch art f ro m B S EN 1295 Note: T he solid lin e represents the preferre d r oute

55 © Borouge

Alternative approach – The Europ ean Plasti c Pip es and Fit ti ng s As so ci ati on (TEPPFA) Try doi ng this w ith plastic pipes – misconceptions and disi nfor mation

Not Relevant Source: American Conc rete As soc iation © Borouge

Misco nce ptio ns a bout pla sti cs pipes  Deflection increases with installation depth and with traffic load.  Pipe ring stiffness is the governing factor determining the performance.  Pipe looses stiffness with time, the load bearing capacity reduces.  Flexible behaviour is a disadvantage.  Deflected pipe lose a significant part of their discharge capacity and tightness.

TEPPFA undertook an extensive research project to provide the information needed to address these misconceptions.

© Borouge

Struc tural de sign of buri ed fl exib le pipe s rin g sti ffness a nd nomi nal sti ffness  A pipes ability to resist external loads is referred to as its Ring Stiffness  Pipe ring stiffness (S) = E I/D3


= pipe wall moment of inertia (I = e 3/12 for solid walled pipes)

e = wall thickness E = short term modulus of elasticity for the pipe material (Young’s Modulus) D = mean pipe diameter  ‘E’ for different materials

PE 100 = ~1100 MPa

PPB = ~1500 MPa

PPHM = 1700+ MPa

 Nominal stiffness is the pipe ring stiffness in KPa or KN/m2  Most gravity pipe manufacturers and TEPPFA refer to nominal pipe stiffness classes. Typically SN4 and SN8 with SN16 being the highest class. © Borouge

Inst all ati on practi ces used in the pro ject to determ in e the e ffect of com pacti on etc. Qualit y of backf ill pla cing and co mpacti on Well / High

94% Proctor Density © Borouge


87- 94% Proctor Density

None / Poor

Littl e or N o Compaction

Measur ed s hor t t erm pip e defl ect io ns Measured deflections for different types of installation 8 ] % [ 6 n tio c4 e fl e d2 l a c it r 0 e V

No Compaction


Well Com pacted

-2 0

20 Distance [m]

© Borouge


The pipe - soil intera ction, why a litt le bit of fle xibi lity is not a ba d thin g! Ring deflection of flexible pipes is controlled by the settlement of the soil. After settlement, traffic and other loads do not affect pipe deflection.

When pipestoare more loads have berelatively resisted by therigid pipe.than the soil, the traffic and other 61 © Borouge

Shor t term pip e defl ect ion afte r in stallation lik ely to oc cur in t he fir st m onth / 30 days

62 © Borouge

Lon g term p ip e defl ect ion afte r in stallation cou ld t ake up to 2 years – soi l dependent

63 © Borouge

Fact s about defl ect ion fr om experim ental obse rva tions - 1 of 3 Installation phase

Settlement phase

% [] n o ti c le f e D

Traffi c effect


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