a rational approach to the hydraulic design of pipe conduits

7/28/2019 A Rational Approach to the Hydraulic Design of Pipe Conduits

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A Rational Approach tothe Hydraulic Designof Pipe Conduits

Concrete PipeAssociationof AustralasiaACN 007 067 656

TECHNICALBULLETIN


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CONCRETE PIPE ASSOCIATION OF AUSTRALASIAA RATIONAL APPROACH TO THE HYDRAULIC DESIGN OF PIPE CONDUITS

SECOND EDITION 1995

ABSTRACTDesign formulae used in determining pipe diameters, particularly since the advent of the personalcomputer, are often interpreted with a great deal of precision. Often overlooked is the accuracy of thedesign flow which is derived from hydrological data, which may be even less accurate.

Commonly used hydraulic formulae are:

q Hazen-Williams

q Manning and

q Colebrook-White

Manufacturers often select inappropriate formulae together with parameters which show their product inthe most favourable light and neglect important considerations such as actual pipeline diameter, theeffects of silt and debris, joint eccentricities etc.


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CONTENTS

PREAMBLE

1 INTRODUCTION

2 HYDRAULIC PERSPECTIVE

3 PIPE FLOW FORMULAE

4 SELECTION OF PIPE ROUGHNESS

4.1 General4.2 Clean water pipelines4.3 Foul water sewers4.4 Stormwater drains

4.5 Analysis of manufacturers technical information5 CULVERT DESIGN

5.1 General5.2 Culvert flow with inlet control5.3 Culvert flow with outlet control

6 COMPARISON OF DISCHARGES FROM ALTERNATIVE PIPELINE MATERIALS

7 CONCLUSION

8 REFERENCES

This Bulletin was originally written by Mr. Cliff Baker of C.A.Baker Concrete Technology and presented to the 1991 CPAAseminar series, Pipe Performance in 2041.

It has since been modified and supplemented by Mr. AndrewOsborne of Fisher Stewart Pty. Ltd., and subsequently verified fortechnical and hydraulic accuracy by Associate Professor R.J. Kellerof Monash University.

Associate Professor R.J. KellerB.E. (Hons.) Ph.D.,M. ASCE, A.R.P.E.N.Z., M.I.E. Aust.

Clifford A. Baker

B.A., B.Sc., A.R.M.T.C., M.I.E. Aust.Andrew G. OsborneDip. C.E., B.E.(Civil)M.Eng. Sc., E.W.S., M.A.W.W.A., M.I.E. Aust.


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PREAMBLE

The purpose of this documentis to set out a series of technical and engineering factsconcerning the relativedischarge capacity of pipelinesconstructed from differentmaterials. The document isconcerned primarily with theselection of appropriateroughness coefficients for thecalculation of pipeline capacityand the consequent selectionof pipe diameter.

1 INTRODUCTION

There are numerous pipe flowcharts and flow formulaeavailable for use by pipelinedesigners. Indiscriminate use of these design tools can,however, result in errors inselection of pipe sizes. There isalso the tendency for somedesigners to overlook importantaspects of pipeline design suchas selection of pipe roughnesscoefficients appropriate tospecific in-service pipe

conditions, and considerationof actual as opposed tonominal diameters. Theaccuracy of design flowestimates should be kept inperspective when choosingbetween various pipe sizes.

This document clarifies thesepoints and provides designerswith a rational approach forhydraulic design of pipeconduits.

2 HYDRAULIC PERSPECTIVE

Design formulae which areused for determining therequired diameter of a pipelineare often interpreted with agreat deal of precision, but it isoften overlooked that thestarting point for suchcomputations is the design flow- a parameter which is derivedfrom often less accuratehydrological data usingcalculations based on methodssuch as the Rational Method(1).

The estimated flow rates areonly as accurate as the data onwhich they are based.Evaluations of the accuracy of peak runoff estimates rangefrom 10% to 25% inAustralian Rainfall andRunoff (1) and from 15% to25% in the Australian RoadResearch Board handbook (2).

For foul water sewer reticulationsystems, uncertainties similarly

arise in the estimation of thesewage flow. For example, theestimation of the daily sewageflow per household and theinfluence of infiltration into thesewerage system have asignificant impact on flowestimates.

Described another way,inaccuracies in the selection of the design flow rates often

overshadow differences in thecomputed pipe dischargecapacities. For practicalpurposes, it is thereforenecessary to accommodatetheoretical discharges by amargin of say 5-10% before achange in pipe diameter can be

justified.

3 PIPE FLOW FORMULAE

When designing a pipeline orconduit carrying liquid, anengineer is faced with thechoice of an appropriate flowformula on which to base thecalculation. Some of the morecommonly used formulae are:

q Hazen-Williams equation

q Mannings equation

q Darcy-Weisbach equation,incorporating the Colebrook-White equation for thedetermination of frictionfactor.

The Hazen-Williams and theMannings equations are bothempirical and containdimensional coefficients whichtake account of the roughnessof the conduit. Within thelimited range of applications inpipe networks, stormpipecalculations, etc., the formulaeare, in general, of reasonableaccuracy (3).

The Darcy-Weisbach equationprovides a more rational basisfor flow computations. Thisequation is written as follows:

hL = f L v2D 2g

where f = dimensionlessfriction factor

v = velocity

g = acceleration due togravity

D = pipe diameter

L = pipe length

hL = head loss over pipelength, L.

The friction factor, f, varies withthe Reynolds Number of the

flow and the relative roughnessof the pipe except for fully-rough turbulent flow where f isindependent of the ReynoldsNumber.


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Early experiments on pipe flowcarried out by Nikuradse (citedin (4)) enabled calculations of the friction factor.These experimentsincorporated pipes artificallyroughened using sand grains toobtain the variation of thefriction factor with ReynoldsNumber. This invaluable stepprovided a rational estimate of the actual roughnesscontributing to fluid friction orhead loss in pipes under arange of flow conditions.

Unfortunately, commercial piperoughness differs from sandgrain roughness in both shape

and arrangement. However,Colebrook carried outexperiments on commercialpipes, expressing thecommercial pipe roughness interms of an equivalent sandgrain roughness size (5).The equivalent sand grainroughness is sometimes termedthe Colebrook RoughnessCoefficient, ks.

In conjunction with White,Colebrook developed anequation which described thevariation of the friction factorwith Reynolds Number forpipes of different equivalentsand grain roughness. Thisequation is now commonlyreferred to as the Colebrook-White equation, and inconjunction with the Darcy-Weisbach equation, is used inthe calculation of head loss incommercial pipes. A graphicalrepresentation of theColebrook-White equation isembodied in the so-calledMoody Diagram which may befound in any textbook on pipeflow. The diagram permits arapid solution of the implicitColebrook-White equation.

4 SELECTION OF PIPE ROUGHNESS

The following comments arebased on the ColebrookRoughness Coefficient k smm. However, the commentsare equally applicable to anyother measure of roughnesssuch as the Hazen andWilliams C or Mannings n.

4.1 General

It is important to realise that,whilst the inherent surfaceroughness of a pipe is aproperty which could beexpected to be a constant for aspecific pipe, the roughnesscoefficient used in energy losscomputations is a parameterwhich is dependent on both thepipe surface condition and theservice conditions. Forexample, a pipeline in aspecific installation flowing fullwill discharge a greaterquantity of clean water than itwill discharge if the watercontains significant solids.The computation of pipedischarge under theseconditions is achieved by useof two different roughnesscoefficients.

In selecting the value of theroughness coefficient, twonotes in AS 2200-1978 (6) areimportant. Firstly, Coefficientsmay need to be varied for anyof the following reasons:

a. Biological growths and otherobstructions.

b. Slime deposits, encrustation,detritus and other debris.

c. Deterioration of unlinedferrous surfaces, hence boredimunition, by oxide.

d. Irregularities at joints suchas:

q eccentricity

q abrupt decrease indiameter

q protrusions of mortar orother jointing materials.

q Inadequate closure,especially if this haspermitted tree roots toenter.

e. Amount and size of solidsbeing transported.

f. Disturbance of flow frombranches, especially in

sewers.and secondly,

In the choice of frictioncoefficients (or roughness) tosuit an infinite variety of circumstances, the requirementof prime importance iseducated engineering

judgement.

Much of the availableinformation regarding themagnitude of the roughnesscoefficient has been derivedfrom experimental work carriedout under laboratoryconditions, using shortpipelines and clean water.These conditions do notrepresent practical fieldinstallations for the reasonspreviously explained and

therefore laboratorymeasurements of the roughnesscoefficient must be adjustedwhen applied to fieldsituations. This approachapplies irrespective of pipematerials.


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4.2 Clean water pipelines

Since slime growth and debrisare not likely to be present inclean water pipelines, k svalues determined fromlaboratory tests are likely to bemore applicable to the designof in-service pipelines,provided separate allowance ismade for losses due to bendsand fittings, etc.

For example, laboratory testscarried out on centrifugallyspun concrete pipes indicateks values lie in the range0.006 mm to 0.06 mm (7).By comparison, tests carriedout on concrete pipelines inthe field indicate k s valuesactually lie in the range 0.09mm to 0.12 mm (7).These higher values of k sare attributed to head lossescaused by bends and fittings.Designers can, when usingconcrete pipe, base theirhydraulic calculations onks=0.06 mm (clean water)with separate allowances for

fitting losses, or allow for lossesby using an equivalentroughness coefficient. In thelatter case, the Concrete PipeAssociation of Australasia (7)has adopted a k s=0.15 mmfor field applications.

4.3 Foul water sewers

For foul water sewers, theinitial surface roughness of thepipe is often of no relevencebecause of the growth of sewerbiological slimes on the pipesurface. The HydrogenSulphide Control Manual (8)indicates the thickness of theslime layers may range from1 mm to 5 mm depending onflow velocity and location inthe sewer.

Slime growth is also reportedon the PVC lining of concretesewers (for example, theAdelaide Trunk Sewer (9)),where such sewers arepurportedly designed tomaintain self-cleansingvelocities.

Characklis et al (10) haveshown that microbial cellsattach firmly to almost anyinanimate surface submergedin an environment and thatthere is a coupled relationshipbetween biological slimeaccumulation and hydraulics.

The effect of biological slimesoverall, is to increase theequivalent pipe roughnesscoefficient. The AustralianWastewater AuthoritiesStanding Committee (9)suggests that for a smoothsewer lining the roughness islikely to be in the range0.6 mm to 1.5 mm. A study byClifford (11), showed that theroughness coefficient of anoperating sewer rising main at

Geelong ranged from 0.5 mmto 0.7 mm. Other studies (12,13 and 14) suggest even highervalues of the roughnesscoefficient ks, up to 6.0 mm,may be experienced in gravitysewers. Some quoted values of ks include the effects of bends and pipe fittings.

As the cost penalty foradoption of a roughness

coefficient of ks=1.5 mmcompared with k s=0.6 mm isnormally very small, theexercise of sound engineering

judgement is to use aroughness coefficient of ks=1.5 mm for gravitysewers, and k s=0.6 mm forpumped mains where slimethickness is lower due to thehigher wall shear under

operating conditions whichserves to strip back the slimesfrom the pipe wall.

These values are applicable toall types of pipe material.

4.4 Stormwater drains

The selection of appropriateroughness coefficients forstormwater drainage is notprecise because of thenecessity to assess the effects of any debris which is carried bythe stormflows. Unfortunately,but understandably, there is adearth of relevant test data forin-service stormwater drains.

To design a stormwaterdrainage system withoutallowance for debris (that is, forclean water with k s=0.06 mmfor concrete pipe), representsan unlikely situation.Equally, the effect of debris onequivalent pipe roughness isunlikely to be as severe as theinfluence of biological slimesin a heavily slimed sewer. Forthese reasons the concrete pipeindustry recommends theadoption of a k s value of 0.6mm for most stormwater draindesigns, but this value of k sshould be modified throughengineering judgement where

additional data is available. Avalue of ks of 0.6 mm isconservative compared withthe ks range (0.15 mm to0.30 mm) recommended inAustralian Rainfall and Runoff (1), but again it should benoted that generally the costpenalty for adopting k s=0.6mm compared with 0.06 mmis at most one step in pipediameter.


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4.5 Analysis of manufacturers technicalinformation

Technical brochures frommanufacturers of the followingpipes have been analysed withregard to calculation of pipedischarge capacity:q uPVC pipe AS 1712 (15)

q HDPE pipe to AS 1159 (16)

q Hobas GRP pipe to AS2634 (17)

q Black Brute pipe (no AS/NZSstandard) (18)

q Ribloc pipe (no AS/NZSstandard) (19)

The first two technicalbrochures use the Hazen-Williams formula for thecalculation of pipe flow.The flow charts in the Hobasdesign manual and the BlackBrute pipe brochure are bothbased on the Colebrook-Whitepipe flow equation. Further, theHobas design manual is basedon pipeline applications usingwater at a temperature of 20Cwhereas the Black Brute pipebrochure is based on thetemperature of the water being15C. The design guidelinescontained in the Ribloc pipebrochure are different againand based on the use of theMannings equation. Anycomparison between the

quoted pipe flow capacities istherefore difficult.

Only one value of roughnesscoefficient is nominated ineach of the technical brochureswith the exception of theHobas design manual whichnominates a Colebrookroughness coefficient of 0.10 mm for pipelinesconveying sewage and 0.01 mmfor other pipelines.All literature refers to a given

pipe for multiple applications -water supply and/or irrigation,sewerage, drainage andindustrial applications. Thereare no qualifications on theflow chart published in theBlack Brute pamphlets, nor theRibloc literature. The PVC andHDPE charts are qualified bythese charts are for straightpipes without fittings andcarrying clean water at 20C.

The Australian Standard AS2200 (6) lists roughnesscoefficients for uPVC andpolyethelene pipe as:

Hazen-Williams 160-155

Colebrook-White k s0.003-0.015

Mannings n 0.008-0.009

Hardie Iplex validate theirchoice of k s=0.010 mm forBlack Brute by quoting AS2200 but do not provide dataestablishing that the values forsmooth bore HDPE made to AS1159 also apply to Black Brute.

Laboratory tests by Tullis et al(20) suggest that corrugatedHDPE pipe with a smooth liner(such as Black Brute) can havea Mannings n value in therange of 0.009 to 0.015. This isapproximately equivalent to aks value ranging from 0.015to 1.0 mm. These tests werebased on a subset of pipe sizesup to a maximum pipediameter of 450 mm.

The Black Brute flow charttypically gives a slightly higherdischarge than the others but,within the accuracy of hydrological calculations all 5pipe types could be consideredthe same. Further comment isbased on Black Brute publishedinformation, but it is equallyapplicable to all the flexiblepipes.

From the foregoing discussionit is appropriate that BlackBrute pipeline discharges basedon flow charts with k s=0.010mm should all be identified asapplicable ONLY to clean waterin straight pipelines withoutfittings, joint irregularities,bends, manholes, pits, etc.

For the flexible walled pipematerials, there is no evidencein the literature to suggest that

joint irregularities have beenconsidered in the selection of the equivalent pipe roughnesscoefficient. These jointirregularities (or eccentricities)tend to be more pronounced in

larger flexible walled pipes andhave been observed in anumber of Black Brute pipelineinstallations (21) and (22).

Because of these jointirregularities, it must bequestioned whetherks=0.010 mm is appropriateeven for long straight pipelinesconveying clean water. It shouldalso be noted that Australian

Rainfall and Runoff adoptsks=0.060 mm for uPVC pipeswith rubber ring joints (1).

It can be shown thatdeformation of a pipe to anelliptical shape reduces the areaof waterway and hence pipecapacity. For an elliptical pipedeflection of around 6% thedischarge is reduced by about2%.

The available technicalliterature does not providesufficient data to allow preciseselection of roughnesscoefficients for the variousconditions. For sewers andstormwater drains, k s isobviously larger than 0.010 mm,and in the absence of morequantitive data, it isrecommended that thefollowing values of the


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EQUIVALENT ROUGHNESSCOEFFICIENT be adopted forsewers and stormwater pipelinedesign:

Sewers 0.6-1.5 mm

Stormwater drains 0.6 mm

The indiscriminate use of thepublished flow charts, based onks=0.01 mm, will in normalcircumstances for sewer orstormwater drains, significantlyover estimate the discharge of pipelines.

5 CULVERT DESIGN

5.1 General

Calculation of the dischargecapacity of culverts depends onwhether the flow is occurringunder inlet or outlet controlconditions. Where theprevailing control is notobvious, the situation must beanalysed separately, assuminginlet control and outlet control,and the results compared todetermine the limitingdischarge.

The following sections brieflydescribe these controlconditions and the influence of culvert pipe equivalentroughness on the dischargecapacity of the culvert.

5.2 Culvert flow with inletcontrol

In short, steep culverts, flowmay be restricted by inletcharacteristics with thedischarge controlled by theheadwater depth and thegeometry of the inlet. In effect,the inlet to the culvert behaveslike an orifice. The dominanceof the inlet causes part full flowin the remainder of the culvertsunless, of course, the tailwatercauses the culvert to beflooded under whichconditions outlet characteristicscontrol the flow.

For the inlet control conditionsdescribed, culvert surfaceroughness does not affectculvert capacity.

5.3 Culvert flow with outletcontrol

Outlet control always occurswhere the tailwater depthcauses the pipe to run full andmay occur in cases where thepipe runs part full. Under thiscondition, the culvertcharacteristics control therelationship between the flowof the drainage water and thehead difference across theculvert, and nomographs have

been developed which relatethe energy head difference (H),entrance loss coefficient (k e),culvert length (L), pipe internaldiameter (D), and surfaceroughness (as Mannings n) tothe culvert discharge capacity(Q). The nomograph in Figure 1for pipe flowing full is takenfrom CPAA Hydraulic DesignManual (7) which is a metricatedversion of US charts (25).

This nomograph can be used toassess the effect of equivalentsurface roughness on theinternal diameter of a culvertpipe required for a givendischarge under specifiedconditions of afflux. Shown inTable 1 are examples whichhave been selected to providereasonable coverage of a rangeof pipe culvert conditions.

The Mannings n values usedin the analysis have beenselected from AS 2200-1978(6) as follows:

q Plastic pipe (HDPE, uPVC) -0.008 to 0.009.

q Spun concrete - 0.009 to0.012 (with 0.011 thecommonly adopted value).

q Corrugated metal pipe -0.016 to 0.024; (with n =0.024 being typical of annular corrugations whilst

for helical corrugation nranges from 0.016 at 600mm diameter to 0.024 at1500 mm diameter (23)).

All the above selected Manningn values apply for cleanwater and new pipes. Should

the water contain silt anddebris the Mannings n valueswill have to be increased.As previously noted, Manningsn is not dimensionless andwill depend on the size of conduit and velocity of flow aswell as on surface roughness.

It can be observed fromexamination of Table 1 that:

q there is no significantdifference between plasticand concrete pipe culvertswhere flow is controlled byoutlet conditions.

q the required diameter of corrugated metal pipeculverts is generally one totwo sizes larger than plasticor concrete pipe of the samehydraulic capacity.

This is illustrated graphically inFigure 2, based on theAmerican Iron and SteelInstitute publication (23). It isalso significant to note that theactual diameters of concretepipes are usually larger, thanthe nominal diameters given inTable 1.


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Table 1 - Comparison of pipe culvert capacities for varying conditions, withoutlet control.

EXAMPLENo.

CULVERT DESIGN PARAMETERS REQUIRED DIAMETER(mm)

Q(m3/S)

ke H(m)

L(mm)

Manningsn

Material Calculated Nominal

.008

.009

.011

.012

.016

.024

.008

.009

.011

.012

.016

.024

.009

.011

.012

.016

.024

.008

.009

.011

.012

.016

570585605610

650725

116011801200121012751430

16101645165017001800

13601390142014601550

600600600600

675750

120012001200120013501500

16501650165018001800

15001500150015001650

1.

2.

3.

4.

1.05

1.95

8.0

5.0

.05

.05

0.2

0.2

2.0

0.29

1.07

1.0

40

40

30

100

plasticplastic/concreteconcreteconcrete

helical corr.annular corr.

plasticplastic/concreteconcreteconcretehelical corr.annular corr.

plastic/concreteconcreteconcretehelical corr.annular corr.

plasticplastic/concreteconcreteconcretehelical corr.


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Figure 1 - Energy head H for concrete pipe culverts flowing full n = 0.011,from Reference 7 and 25

NOTE:

(a) For a different value of n, use the length scale shown with anadjusted length L 1 = L (n1 /n)2.

(b) For a different value of k e connect the given length on adjacentscales by straight line and select a point on this line spacedfrom the two chart scales in proportion to the k e values.


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Figure 2 - Comparison of required diameters of smooth concrete pipe culvertscompared to corrugated metal culverts, from Reference 23.


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6 COMPARISON OF DISCHARGES FROM ALTERNATIVE PIPELINE MATERIALS

In any assessment of pipelinedischarge there are twoimportant factors:

q The roughness coefficientselected must beappropriate; and

q actual internal diametersshould be used in the pipeflow calculations.

Misleading information hasbeen published because thesetwo fundamentals are often

ignored.For example the Black Brutebrochure (18) quotes themaximum computed dischargecapacity of 900 mm pipe on a0.5% energy slope as follows:

HDPE - 1854 L/s.

Reinforced concrete - 1665 L/s.

The equivalent roughnesscoefficient ks used for HDPEhas been taken as 0.010 mm.This value lies in the middle of the range for straightpipelines carrying clean water(6). The ks value used forconcrete pipe has been takenas 0.10 mm, a figure whichincludes generous allowancefor field conditions includingbends, valves, fittings, etc.

A ks of 0.06 mm is thereforeconsidered more appropriate inthis comparison.

The selection of pipe internaldiameters in the aboveexamples has also beenmisleading. By referring to therelevant pipe literature (24) and(18), the actual minimuminternal pipe diameters are 890mm for HDPE and 908 mm for

Class 2 reinforced concretepipe. (The 908 mm is derivedfrom actual diameter of 915 mm

with a tolerance of 7 mm).

Accepting that k s=0.01 mmapplies to HDPE pipe andassuming that the pipe remainscircular, substitution of theactual minimum diameters inthe Colebrook-White formula

gives discharges of:HDPE - 1779 L/s.


These discharges are notsignificantly different.

In some situations, thedischarge from reinforcedconcrete pipe is calculated tobe higher than from plasticpipe - for example, for anominal 450 mm diameterpipe on a 0.25% slope usingactual minimum diameters(440 and 452 mm) andcomparable k s values (0.01and 0.06 mm), the dischargesare calculated as:

HDPE - 194 L/s.


Again, these discharges are notsignificantly different.

In the above examples it hasbeen assumed that the flexiblewalled pipes remain circularwhen installed in the ground.This is not strictly correct aspipe deflections do occur dueto loading exerted on the pipeand due to long term creep.

As discussed in Section 4.5,pipe deflections can result in areduction in pipe hydrauliccapacity. For example, anelliptical pipe deflection of 6%in the two examples outlinedabove would reduce thecapacity of the HDPE pipes to1763 L/s and 190 L/srespectively. Hardie Iplex (18)generally allow for a maximumdeflection of 7.5% for BlackBrute pipes.

Actual deflections of flexiblewalled pipes would of coursedepend upon a number of factors including trench design,depth of pipeline, soil type,construction control, etc., andin many installations themaximum deflection may notbe realised.

From the above discussion, it isclear that the claims in theBlack Brute brochure that thisallows design engineers to usesmaller diameter pipe and thatusing concrete gives anapproximately 10% reductionin flow capacity are notsustainable.

The facts are that for practicalpurposes and within the totaluncertainties of computation of design flows, discharges fromplastic and concrete pipes areequivalent, and nominal pipediameters required in any givensituation are the same.


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7 CONCLUSION

In addition to the physicalroughness of a particular pipematerial, there are a number of other factors which must beconsidered when carrying outthe hydraulic design of pipelines, such as the effects of slime growths, silt, debris, jointeccentricities, etc. Theseadditional factors often result inthe effective roughness of apipe being significantly greaterthan that which is determinedfrom laboratory tests usingclean water and straightconcentrically jointed pipes.In fact, the effective field

roughness of a pipelineconveying sewage, isindependent of the pipematerial. In pipe culvert design(for both inlet and outletcontrol conditions), the choiceof pipe equivalent roughnesshas little bearing on theselection of pipe size, for bothconcrete and plastic pipes.For corrugated metal pipeculverts, the required diameteris generally one or two sizeslarger than plastic or concretepipe of the same hydrauliccapacity.

Care should be exercised wheninterpreting pipemanufacturers technicalbrochures as many of thebrochures include charts androughness coefficients whichare only applicable to cleanstraight pipes conveying cleanwater.

It is also important that actual,as opposed to nominal, pipediameters be used for hydraulicdesign calculations anddesigners are referred to themanufacturers literature toobtain actual diameters.

Finally, the accuracy of theestimate of the design flow fora pipeline should always bekept in perspective whencomparing the hydrauliccapacity of pipelinesconstructed from alternativepipe materials. The assumptionsused in establishing the designflow, the quality of pipelineconstruction, and the operatingconditions of the pipelinethroughout its economic life,are usually of greatersignificance than the roughnesscoefficient selected.


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8 REFERENCES

1. Institution of EngineersAustralia, Australian Rainfalland Runoff, Vol. 1. RevisedEd. 1987, pp 10, 37, 324and 325.

2. Argue, J., Australian RoadResearch Board Specialreport No. 34 - StormDrainage Design in SmallUrban Catchments: AHandbook for AustralianPractice, 1986, p 106.

3. Ackers, P., Resistance of Fluids Flowing in Channelsand Pipes, HydraulicsResearch Paper No. 1, 1958.

4. Vennard, J.K. & Street, R. L.,Elementary FluidMechanics, Wiley, 6th Ed.,1982.

5. Colebrook, C.F., TurbulentFlow Pipes, with ParticularReference to the TransitionRegion between the Smoothand Rough Pipe Laws, Jnl.Institute Civil Engineers,

London, Feb. 1939.6. Standards Association of

Australia, AS 2200-1978Design Charts for WaterSupply and Sewerage, p 23.

7. Concrete Pipe Association of Australasia, Hydraulics of Precast Concrete Conduits,Pipes and Culverts:Hydraulic Design Manual,

1986 Ed., pp 40 and 67.8. Technological Standing

Committee of HydrogenSulphide Corrosion inSewerage Works, HydrogenSulphide Control ManualSepticity, Corrosion andOdour Control in SewerageSystems, MelbourneMetropolitan Board of Works, December 1989,Monograph 2, Section 3, p 4.

9. Ibid, Monograph 9.3, Section5, p 9 and Monograph 9.2,Section 9, p 11.

10. Characklis, W.G.,Cunningham, A.B., Escher,A.B. Crawford, D.,Biofilms in Porous Media,International Symposiumon Biofouled Aquifers:Prevention and Restoration,American Water ResourcesAssociation, 1986, pp 57-78.

11. Clifford, T., Head lossmeasurements on 450 mmsewer rising main,Geelong Water andSewerage Trust, 1978.

12. Johnson, M., A literatureReview on the Effects of Slime in Sewers, TheBritish Hydro-MechanicsResearch Association,Crasfield Bedford England,1980.

13. Perkins, J.A., Gardiner, I.M.,The Hydraulic Roughnessof Slimed Sewers, InstituteCivil Engineers, Part 2, Vol.79, 1985, pp 87-104.

14. Bland, C.E.G., Bayley,R.W., Thomas, E.V., SomeObservations on theAccumulation of Slime inDrainage Pipes and theEffect of theseAccumulations on theResistance to Flow, PublicHealth Engineering, No.13, 1975, pp 21-28.

15. Humes Plastic brochure,Flow Charts for uPVC.Pipes and Fitting, 1983.

16. Humes Plastic brochure,Flow Charts forPolyethylene Pipes, 1983.

17. Hardie Iplex, HobasPipelines Manual, 1990.

18. Hardie Iplex brochure,Black Brute Pipe, FlowCharacteristics, pp 14 and15.

19. Ribloc brochure,Comparative HydraulicPerformance.

20. Tullis, J.P., Reynolds, K.,Watkins, Barfuss, S.L.,Innovative New DrainagePipe, Preceedings of theInternational Conferenceon Pipeline Design andInstallation, ASCE, March25-27, 1990.

21. Goodman, W.J.,(Consulting Engineer),Inspection Report: NorthLanyon Trunk Sewer,Unpublished, August 1988.

22. Fisher Stewart Pty Ltd,Report on Inspection of HDPE Drain Lines YarraPark, Unpublished, April1991.

23. Modern Sewer Design,American Iron and SteelInstitute, 1980, pp 132-133.

24. Humes Concrete,Humespun ConcretePipes, brochure, 1988, pp8 and 9.

25. Bureau of Public Roads,

Washington, USA,Hydraulic Charts for theSelection of HighwayCulverts, HydraulicEngineering Circular, Nos 5and 10, 1965.


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AUSTRALIAN OFFICE:Locked Bag 2011St Leonards, NSW 2065Phone (02) 9903 7780Fax (02) 9437 9478

NEW ZEALAND OFFICE:26-30 Prosford Street,(PO Box 47-277)Ponsonby, Auckland, NZPhone (09) 378 8083Fax (09) 378 6231

MEMBER COMPANIES:ATHLONE CONCRETE PIPES

BCP PRECAST

CSR HUMES

HUME INDUSTRIESHYNDS PIPE SYSTEMS

MIDLAND CONCRETE PIPES

ROCLA PIPELINE PRODUCTS

DISCLAIMERThe Concrete Pipe Association of Australasia believes the information givenwithin this brochure is the most up-to-dateand correct on the subject. Beyond this

statement, no guarantee is given nor is anyresponsibility assumed by the Associationand its members.

Second Edition: January 1995Publication: TB1/95

Concrete PipeAssociationof AustralasiaACN 007 067 656

a rational approach to the hydraulic design of pipe conduits

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