Technicalinstructions

Krah drainage, waterand sewage piping systems

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32

Table of contents

KRAH Structured pipes 41. Technical parameters 1.1.Specificlightweight 6 1.2.Flexibility 6 1.3.Abrasionresistance 6 1.4.Impactresistance 6 1.5.Hydraulics 7 1.6.UV-resistance 7

2. Profiles 2.1.Profileandringstiffness 8 2.2.ProfiletypesofKRAHpipes 8

3. Designing 3.1.Calculatingofhydraulicparameters 10 3.2.Staticcalculationofpipesforundergroundinstallation 12 3.3.Pipefittings 12 3.4. Branches 12 3.5. Bends 12 3.6.Reductions 13 3.7.Manholes 13

4. Jointing methods for KRAH pipes 4.1.Jointingpipesusingintegratedelectro-fusionfittings 16 4.2.JointingKRAHpipesusinggasket 18

5. Installation of KRAH pipes 5.1. Trench 19 5.1.1Widthofatrench 19 5.1.2Removalofwater 20 5.2.Fillingmaterialandsupport 20 5.3.Backfill 21 5.4.Packing 21 5.5.Leakagetest 21

6. Pipe-in-pipe-method renovation 227. Transportation 228. Storage 229. Quality control 23

DIN 16961-2:2010-03 24

4

Additionallyitispossibletoproducepipeswithanylengthbetweenoneandsixmeters.Thelongerapipeis,thefewerjointsarenecessaryandthisisadvantageousfortheinstallationofthepipe.Moreoveritispossibletodeliverthepipesalreadyjointed,wherebytheinstal-lationtimeonsitecanbereducedsignifcantly.Lengthsupto18mconsistingof3pipesectionsarecommon.

Krahpipescanbeproducedwithinternaldiameters(ID)fromDN500mmtoDN3000mm.Thenomi-naldiameters(DN)coincidentswith

DN/ID = internal diameter (mm)L= length (mm)

Materials

KRAH Structured pipes

Polyethylene(PE63,PE80andPE100)andpolypropylenearethermoplasticswithexcellentpropertiesfortheapplicationofwaterandsewer,aswellasforthefabricationofcontainersforliquidsandsolidmaterials.Theenvironmentalfriendlypolyethyleneandpolypropyleneareresistanttomanyche-micalsandverysuitableforconveyingandstoringvariousliquids.

Krahpipescanbeproducedofthefollowing thermoplasticmaterials:•Polyethylene(PE80andPE100)•Polypropylene(PP-R;PP-H;PP-S)

Thesematerialsfeaturebelowmentionedproperties.Othermaterialscanbeusedafterprioracceptanceoftheproducerandathirdpartyforqualitycontrol.However,theprocessedmaterialshouldhavethebelowlistedspecification.Sincethelatestdevelopments,polypropylenewithareallyhighstiffnesscanbeused,ifyouareinterestedaskforfurtherinformationanddata sheets.

Pipe diameter

Pipe length

Typical material specification

Property Standard Unit PE 80 PE 100 PP-R

Density DIN 53479ISO 1183

g/cm³ 0.95 0.96 0.91

Melt index MFR 190/5MFR 190/21.6MFR 230/5

Code TCode VCode V

ISO 1133 g/10 min

ca. 0.43ca. 10-

0.456,6-

0.50-1.25-1.5

Tensile modulusShort termLong term (50 years)

ISO 178 N/mm² 1.000170

1200170

750160

Yield stress DIN 53495 N/mm²

Tensile strength DIN 53495 N/mm² 32 38 15

Elongation at break DIN 53495 % > 600 > 600 > 50

Ball indentation hardness ISO 2039 N/mm² 42 46 45

Coefficient of linear thermal expansion

DIN 53752 1/°C 1.8 x 10-4 1.8 x 10-4 1.6 x 10-4

Colour - - black/ yellow

black/ yellow

gray

Thestandardlayinglength(L)oftheKrahpipesissixmeters,becauseinthiswaytheyareeasytohandle,storeandtransport.

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profiledpipe,theweightcanbereducedupto65%com-paredtoasolidwallpipewiththesameringstiffness.Krahpipesofferthebestsecurityanddurability.Thewallthicknessesofourpipescanbeadaptedinsmallstepstotherespectiveload.

TheKrahpipesystemcanwithstandlowworkingpres-sureupto3bar,dependingonthethicknessofthewaterwaywall(s1).EquivalenttoDIN8074thehoopstressformulacanbeusedtocalculatethes1astheminimumwallthickness.

Ifrequestedallpipescanbedeliveredeitherwithabright,inspectionfriendlyoranelectroconductiveinnersurfacemadebytheco-extrusionprocess.

Theco-extrusionensuresan inspection friendly,brightinnersurfaceandatthesametimealongtermUV-resistantoutersurface(forexampleforthestorageofpipesoutsideforalongtime).

TheKrahpipesystemisdesignedtomeettherequi-rementsofpresentapplicableinternationalnormsandstandards.KrahAGismemberofthemajorstan-dardizationcommitteestoguaranteethatthepipesarecorrespondingtothestandards,butalsothatthestandardsarecorrespondingtothepipes.

Thequalityofthepipeishighlydependingonthequalityofthewaterwaywall,thereforeallKrahpipesareproducedwithaminimumwaterwaywallof4mm.

Thegreatadvantageofthisdevelopmentisthataprofi-ledpipehasaverylowweight,butatthesametimecanbeusedforhighloadapplications.Alotlessmaterialisneededtoproduceapipewiththesamestaticalproperti-esthanasolidwallpipe,whichmeanssignificantsavingsinmaterialcosts.

Thesupportablestaticloadisdeterminedforeverypro-filegeometrybythefactorselasticmodulus(N/mm2)oftherespectivematerialandthemomentofinertiaoftheprofilegeometry(mm4/mm)referringtothepipediameter.Theresultiscalledringstiffness.Byusinga

theinternaldiameter(ID)ofthepipe,becauseincaseofanychangeinthedesignofthepipe,thewallthicknesscanbeincreasedorreducedwhiletheinternaldiameterremai-nsthesame.Thisensuresthatthedesignatedhydrauliccapacityfortheinstallationismaintained.

Bothprofiledandsolidwallpipeswithwallthicknessesupto300mmcanbeproduced.

Wall thicknesses

Minimum wall thickness in accordance with the standard EN 13476, Figure 5.

Normal pipe dimen-sions DN/ID (mm) s1 PE pipe (mm) s1 PP pipe (mm)

300 2.0 2.0

400 2.5 2.5

500 2.5 3.0

600 3.3 3.5

800 4.5 4.5

1000 5.0 5.0

> 1200 5.0 5.0

Profiled pipe wall

Internal pressure

Co-extrusion

Norms and standards

6

Thehighimpactresistance,evenatlowtemperatures,ensuresarobustpipe,resistantagainstimpactsduringtransport,installationonthesiteandduringthewholeservicelifeconditions.

anybreaksorcracks,sothattheactivityofthepipelineisnotdrasticallyaffected.Assoonastheoverloadandearthmovementends,thepipewillgobacktoitsinitialconditionandposition.

Anotheradvantageisthehighflexibility.Eveninareaswhicharehighlyaffectedby11earthquakes,ourpipesarehardlydamagedincomparisontopipesmadeofothermaterials.DespitetheflexibilityoftheKrahpipestheyhaveagreatcapacitytocarryloads,sothattheyarealsosuitableforroadconstruction.

Polyethyleneandpolypropylenepipesareamongthemostabrasionproofpipes.Thishasbeentestedintheso-calledDarmstadtprocedureandtheresultsareshowninthebelowdiagramandconfirmthequalityofpolyethylenepipes.Testshavebeenperformedatthe”SüddeutscheKunststoffzentrum”foritsapproval.

1. Technicalparameters

TheKrahpipeshaveaverylowweightandthereforeareeasytohandleduringinstallation,whichmakestheusageofacraneonsiteinmostofthecasesunnecessary.

1.1. Specific light weight

Material characteristic values

Specific weight in kg/dm3

Concrete pipe coated

Concrete pipe

PP or PE pipe

Clay pipe

GFK pipe

Abrasion in mm

Cycles

PVC pipe

PE PVC GFK Clay Concrete Ductile Steel

PipesmadeofPolyethyleneandPolypropylenehaveconsi-derableadvantagestootherpipematerialslikeconcrete,steel,ductileetc.DuetotheirmaterialtheKrahpipespossesoverahighelongationatbreak.Thissignifies,thatthepipecansupportevenloadsordeformations,thatwerenotincludedintheactualcalculationanddesignofthepipe,likeforexamplesearthquakes.TheKrahpipesdeformconformwiththemovementoftheearthwithout

By using profiled pipes we can safe weight up to 65% compared to equivalent solid wall pipes with the same statical capacity.

1.2. Flexibility

1.3. Abrasion resistance

Abrasion curve of various pipe materials according to the Darmstadt procedure.

1.4. Impact resistance

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1.6. UV-resistance

1.5. Hydraulics

Wall roughness

InnerdiameterandhydraulicpropertiesofKrahpipeswillremainconstantregardlessofthewallthicknessortheprofilesduetothesmoothantiadhesiveinnerpipesur-face.Thenominaldiameter(e.g.DN/ID500)correspondstotherespectiveinnerdiameteraccordingtoDIN16961.Comparedtootherpipematerialslikeconcrete,smallerdiameterscanbeused,whichmeansthatcostsformate-rialandinstallationcanbereducedconsiderably.

BlackpolyethylenepipesarepermanentlyresistanttoatmosphericcorrosionandUVradiation.Thusthepipescanbeusedandstoredoutsidewithoutthepipematerialbeingdamaged.Noagingeffectwilloccur.

Tank 60m3

Pump room

Pump room (internal view)

PE Clay ConcreteSteel

Inch

Ductile

8

Profile type: SQ

Thisprofilepipehasasmoothinsideandoutsideinclud-inginternalprofileswithoneormorelayers.Thisprofilehasaveryhighlong-termstiffnessthereforeitisverysuitableforextremelyhighloadsandbigdiameters.

Profile type: VW

ThetypeVWisahomogeneoussolidpipewithsmoothinsideandoutsidesurface.Thesepipescanbeusedforinternalworkingpressure.Theminimumwallthicknessmeasures5mm,themaximumthicknessis80mm.

Profile type: ST

PipeswiththeprofiletypeSTarespeciallymadeforver-ticaltanks,wheredifferentwallthicknessesinonepipearerequiredtosavematerial.ThecalculationmethodisaccordingtoDVS2205.

2. Profiles

Theringstiffnesswillbedeterminedforeachprofile,baseduponthelong-termelasticitymoduleofthePolyethylene(Young’smodule),themomentofinertiaoftheprofileandthediameterofpipe.Usingstructuralpipewallssignificantlyreducestheweightofthepipescom-paredtopipesusedinregularconstructionwithequalringstiffness.ThestructuralwallofKrahpipesmakesitpossibletousethesepipesforlargestaticloads.

Profile type: PR

ThemainpropertiesoftheprofileseriePRisthesmoothinsideandtheprofiledoutside.Thelowweightandthehighstiffnessaresignificant.

Thefieldsofapplicationforthiskindofprofilesarepipelinesystemslikeforexamplesewer,drain,stormdrainandventilation.

Profile type: OP

ThisprofilehasasmoothinsidesurfaceandtheoutsidesurfaceisprofiledwithanOlympic-rings-alikepattern.Themaincharacteristicsofthisprofilearealsoitslowweightandveryhighstiffness.

2.1. Profile and ring stiffness

2.2. Profile types of KRAH pipes

Profile no

Ix [mm4/mm]

e [mm] se [mm]

PR 317 - 47 548 6.02 - 36.38 15.61 - 82.94

OP 14 942 - 194 000 32.98 - 75 56.39 - 132.44

SQ1 7 700 - 27 000 22.74 - 37.52 45.35 - 68.68

SQ2 34 400 - 107 900 41.32 - 65.07 74.48 - 108.99

SQ3 92 000 - 300 000 60.04 - 95.99 103.35 - 153.18

List of typical profileslx = moment of inertia, e = distance of inertia,se = equivalent solid wall thickness

Technical data of stepped pipes

Stepped pipes minimum maximum

Nominal width (Di) 300 (mm) 4000 (mm)

Number of steps (n) two six

Length of step (L) 200 (mm) length of a pipe

Wall thickness of step (s) 5 (mm) 300 (mm) for PE150 (mm) for PP

Step distance 5 (mm)

Profile type

Cross-section View

PR

OP

98

Sketch of a stepped vertical storage tankS1 = wall thickness of the step iL1 = length of the step i

ID Profile SN h OD a

500

PR21 2 27 554 120

PR34 4 39 578 120

PR34 6 39 578 120

PR34 8 39 578 100

600

PR21 2 29 658 120

PR34 4 39 678 120

PR34 6 41 682 120

PR42 8 46 692 100

800

PR34 2 39 878 120

PR42 4 48 896 120

PR54 6 60 920 120

PR54 8 60 920 120

1000

PR42 2 46 1092 100

PR54 4 60 1120 120

PR65 6 71 1142 140

PR65 8 73 1146 140

ID Profiil SN h OD a

1200

PR54 2 60 1320 120

PR65 4 71 1342 120

PR75 6 83 1366 140

PR75 8 85 1370 140

1400

PR65 2 71 1542 140

PR75 4 83 1566 140

PR75 6 87 1574 140

PR75 8 91 1582 140

1500

PR65 2 71 1642 120

PR75 4 85 1670 140

PR75 6 89 1678 120

PR75 8 95 1690 140

1600

PR65 2 73 1746 140

PR75 4 87 1774 140

PR75 6 93 1786 140

PR75 8 97 1794 140

1800

PR75 2 83 1966 140

PR75 4 91 1982 140

OP65 6 122 2044 120

OP65 8 127 2054 120

2000

PR75 2 85 2170 120

OP65 4 117 2234 120

OP65 6 127 2254 120

OP65 8 132 2264 140

2200

PR75 2 89 2378 120

OP65 4 127 2454 100

OP65 6 135 2470 100

OP65 8 142 2484 120

2400

PR75 2 93 2586 140

OP65 4 132 2664 120

OP65 6 141 2682 120

OP65 8 151 2702 100

3000

OP65 2 131 3262 100

OP65 4 148 3296 120

OP65 6 169 3338 100

SQ354-299.51 8 171 3342 61

Figure 1.1 Profile types of KRAH pipes

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Relative fulfill-ment of the pipe h/D

Correlation between hydraulic radius and diameter 4R

h/D

Relative fulfill-ment of the pipe h/D

Correlation between hydraulic radius and di-ameter 4R

h/D

0.1 0.2500 0.6 1.1104

0.2 0.4824 0.7 1.1848

0.3 0.6836 0.8 1.2168

0.4 0.8568 0.9 1.1920

0.5 1.0000 1.0 1.0000

3. Designing

Hydraulic calculations

ThebasisforhydrauliccalculationsforpipesistheEuropeanstandardEN752:2008[1].Tocalculatetheaverageflowvelocityindrainageandsewagepipingsystemstheflowisconsideredtobeinturbulentmode.Thisstandardincludestwoequationsforcalculatingtheturbulentflow:Colebrook-White’sandManning’sequations.

Colebrook-White’s equation

Theaverageflowvelocityinaroundpipecompletelyfilledwithfluidcanbecalculatedusingthefollowingequation:

where:visthecross-sectionalaveragevelocityofflow,m/s;g–theaccelerationofgravity,m/s2;D–thepipeinsidediameter,m;I–thedimensionlesshydraulicgradient;k–theroughnessofpipeinsidewall,m;v–thekinematicviscosityoffluid,m2/s

Incaseswherethepipewhichispartiallyfulloffluidornon-circularforcalculatingtheaveragespeedusingthisequation(1),internaldiameterDisreplacedwith4Rh,whereRhishydraulicradius(ratiooftheflowsectionAandwettedperimeterχ).Figure1presentshowthisvalue4Rh/Dcorrelateswiththerelativefulfillmentofthepipe(hisdepthofwaterinpipe).

3.1. Calculating of hydraulic parameters

Manning’s equation

Averageflowvelocityinapipewithroundornon-roundcross-sectionincasesoffullorpartialfulfillmentiscalculatedwiththefollowingequation:

where:KisManning’scoefficient,m1/3/s;Rh–thehydraulicradius,m;I–thedimensionlesshydraulicgradient

Head losses

Piperoughness(k)orManning’scoefficient(K)willdeter-minethefrictionhead,whichisrelatedtothematerialofthepipe,theunevennessinpipejointsanddebriswhichaccumulatesbelowthesurfaceofthewater.

Inadditiontothat,headlossesoccurinthebranchingofpipes,atchangesofcross-section,inmanholes,inbendsandotherfittings.Forcalculatingpurposesthefollowingequationcanbeused:

where:hListhelocalheadloss,m;kL–thedimensionlesscoefficientoflocalobstruction;v–theaveragevelocity,m/s;g–theaccelerationofgravity,m/s2

(2)

(1)

(3)

1110

Total head loss

Tocalculatethetotalheadlossthefollowingmethodsarerecommended[1]:

• Toaddlocalheadlossestofrictionheadlossescausedbyflowinpipes;

• Assuminghigherhydraulicroughnesswhile calculatingthefrictionheadlosses,thelocal headlossesareconsideredtoaccruetothe totalheadloss.

Whenusingrecommendedhydraulicroughnessincalculatingthepipesitisnecessarytodeterminewhe-thertheimpactoflocalheadlosseshasbeenaddedtothevalueoftheroughness.Inpractice,thekvaluesfortheroughnessofthepipeinsidewallarenormallybetween0.03mmand3.0mmandManning’scoef-ficientKisbetween70and90m1/3s-1.

Anapproximatecomparisonbetweenestimationsofcomputationalvelocitiesbaseduponequations(1)and(2)canbeperformedusingthefollowingequation:

where: KisManning’scoefficient,m1/3/s; g–theaccelerationofgravity,m/s2; D–thepipeinsidediameter,m; k–thepipeinsidewallroughness,m

Thechoiceofpipediameterisdependentonthepipegradient,thevolumetricflowrateandtheaverageflowvelocity.Thisisaidedbyanomogram,whichisshowninFigure1.ThisnomogramwascreatedusingColebrook-White’sequation(1)ontheconditionthatthepipeisentirelyfull,theviscosityofwaterv=1.0310-6m2/sandthepipe’sinsidewallroughnessk=0.00710-3m.Incaseswherethereisapartiallyfullpipe,inequation(1)diameterDshallbereplacedwith4Rh.

Figure 1. Nomogram

(4)

Gradient

Volu

met

ric fl

ow ra

te

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AllfittingsarefabricatedfrompipesofthetypeVWorSQ.Generallytheittingsaredesignedcorrespondingtotherequiredstiffnessesandinconsiderationoftheweldingfactors.Everyfittingcanhaveanykindofpipeendandcanbeassembledwiththeexistingpipesys-temwithanyjointingtechnique.

AllpipeenddimensionsfulilltherequirementsofthestandardEN14376,liketheminimumlengthsandstiff-nesses.Thestandardspigotlength(Ls)is140mmandthestandardsocketlength(Lm)is140mm.

AsignificantadvantageofKrahpipesisthattheycanbeeasilytailoredtotheneedsofvarioustypesofprojects.Inaccordancewiththedifferentnormsandstandards,thepipesmustbeselectedinaccordancewiththeirclassofnominalringstiffness(SN),asSN2(onlyforpipesDN>500),SN4,SN8orSN16(inaccordancewiththestandardISO9969),orinaccordancewithanyotherstiffnessstandard(DIN16961,ASTMF894,NBR7373etc)notwithstandingthetestingmethods(atconstantspeedorconstantload).

In addition to this, in accordance with Article 9.1 of the standard EN 13476-3, the manufacturers are allowed to produce pipes DN/ID > 500 that fall between the above listed SN-classes. To qualify for this admission the producer must be able to prove this solution with static calculations. With Krah pipes, we are able to provide any project with pipes of the precise stiffness that the project demands.

ItisusefultoperformstaticcalculationsforKrahpipestakingintoconsiderationthespecificationsofeachpar-ticularproject.In99%ofcasesthepipesselectedforaparticularprojectareover-dimensionedintheoriginalprojectdesigndocumentation.Usingthecalculationsitispossibletoprovethatitissufficienttoinstallapipewithlessstiffnessbutthecorrectprofile,includingtherequiredsafetyfactorwhichisalsocheaperandfastertoinstall.Inadditiontothis,firstofall,theactualqualityofthepipesdependsonthecorrectwallthickness,therawmaterialsusedandreliablejointingtechnology–butnotonstiffness.

3.2. Static calculation of pipes for underground installation

3.3. Pipe fittings

TheKrahpipecanbeprovidedinthecompleterangeofdiametersandstiffnessclassesbutalsofittings,manholesandothercomponentsaredeliverabletoaccomplishthemissionofahomogenousandreliablepipe system.

Branchescanbemanufacturedanddeliveredineverytypeandform.Theanglecanbeadaptedindividuallyfrom15°to90°aswellastheendsandtherespectivesegmentlengths.

Bendscanbemanufacturedandsegmentedindifferentanglesandtherelatedradiusofthebendtopipediame-tercanbeselectedindependently.

3.4. Branches

3.5. Bends

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ThefigurepresentstheanglesofthestandardbendsinaccordancewiththeDIN16961standard.Othersolutionsare inaccordancewith thecustomer’srequirements.

Reductionscanbemadebothcentricandeccentricsothatthereductionswillalwaysmeettherequirements.Forstandardreductionsthemaximumdifferenceindiameteris200mm,otherdifferencesonrequest.

3.6. Reductions

α Number of segments

15° 2

30° 2

45° 3

60° 3

75° 4

90° 4

Number of segments

Devision and new arrangement of the pipe segments to create a 90° angle.

KrahPipesproducesmanholesinaccordancewiththedesigner’sspecifications.Manholesaremadeofpolye-thyleneandtheyareinaccordancewithalltheinterna-tionalregulationsandstandards.Thematerialsusedareenvironmentallyfriendlyanddurable.Therefore,theyarethebestchoiceforproducingpipes,manholesandtanks.

Krah’sproductportfolioincludesawidechoiceofman-holesforwaterandsewagepipelines.Accordingtothecustomer’srequirementstheycaneitherhaveahatchmadeofcastironorplastic.Hatchescanbejoinedtothemanholesinoneoftwoways:eitherfixedrigidlyorbyusingtelescopicpipewhichallowsthemtomove.Weproducemanholeswithsolidandgratedhatches,bothofwhichcanberoundorsquare.

Thediameterofamanholedependsonitspurpose.Normallythediametersofthejointingendsandwheretheyareplacedinrelationtoeachotherwillbethemostimportantfactor.Also,thesizeoftheequipmentusedforcleaningthesewagesystemmustbeconsidered.

Diametersofmostcommonmanholes(body/telescope): OD200/OD160mm

OD400/OD315mm

OD560/OD500mm

ID800/OD500mm

ID1000/OD630mm

3.7 Manholes

14

Tomakeiteasiertoinspectthem,allKrahmanholeshaveayellowinsidesurface.

Pipelines fromadiameterofDN/ID800mmandupwardswerecommend,ifpossible(curvatureman-holes,flowing-throughmanholes)themoreeconomicalsaddlemanholes.

Rainwater and drainage manholes

Thesemanholesaremeanttodivertrainwater.Inmostcasesthesemanholeshaveasmoothbase,andarebetween200mmand1000mmindiameter.Grated

manholesarealsoproduced,whicharenormallyusedtodivertwaterfromparkinglotstothepiping.

Sewage manholes

Theseareusedfortheinspectionandmaintenanceofsewagepiping.Manholesaremadewithaflowingchanneltoprovideasteadyflowofrefuseliquids.Therecommendedsizefortheflowingchannelis1/3–½fromthediameterofthemainline.Thismeansthatthereisachannelatthebaseofthemanholetoensurethebetterflowofrefuseliquids.

NB!Ifpossible,pleaseavoidusingsquareangleturnsintheflowchannel.Topreventaturnwithasquareanglewerecommendtheuseofamanholebodywithasuitablediameterintowhichagentlyslopingflowchannelcanbebuilt.

Main functions of manholes:

Inspection manhole for rainwater DN/ID1600

Saddle manhole OD560mm, for ID1000 mm pipe

Inspection manhole for rainwater DN/ID1500

Inspection manhole for sewage DN/ID800

1514

Gate valve manholes

Toopenandclosesectionsofwaterandsewagepiping.Agatevalvemanholefacilitatesall-year-roundmainte-nanceofthepiping.

Air release manholes

Theseareusedtoreleaseairthatemergesfromwaterandsewagepipingwheretherearesignificantheightdifferences.

Water meter manhole

Theseareusedtomeasuretheamountoffluidswhichpassthroughthewaterandsewagepiping.

Inspection manhole

Theinspectionmanholeisusedtoinspectthequalityofthefluidsthatflowinthesewagepiping.

Flow reducing manhole

Thisisusedtoreducetheflowspeedinrainwaterandsewage piping.

A turn inside manhole ID800 Rainwater manholes

Saddle manhole

Rainwater manholes with electro-fusion fittings

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FusionadapterSocket

SpigotElectro-fusionwire

Insidesupportring(forpipesoverDN/ID800)

Pullingchainforfusion

3. Thefusionareasmustbefreefromdirtandhumi-dityandbeoutofdirectsunlight.

4. Iftheoutsidetemperatureisbelow+5°C,additio-nalmeasuresmustbeused,suchasatentandheatingfan.

5. Checkthesocketsandspigotsforpossibledama-geduringtransportation.

6. Removetheprotectivefilmonlywhenyouarereadytostartcleaningthepipesandaregoingtojointimmediately.

7. Installthepipeinawaythattheweldingwireiseasilyaccessible.

8. The sockets and spigotsmust be cleanedwithdetergentandpaperwhichisnotfluffyorcolored.

9. Markthespigotwithwaterproofmarkeronthelengthofthepipewhichentersthesocket(atleast120mm).

10. Jointthepipesandmakesurethatthespigotgoesintothesocketasfarasthepreviouslymarkedline.Makesurethatthereisnomoisturebetweenthesocketsandspigots.

11. IncaseswherethepipesarelargerthanDN/ID800,aninternalsupportringforthespigotmustbeinstalled(ca20mmfromtheendofthepipe).

12. Afterfinishingthesepreparationsstartimmedia-telywiththefusionprocess.

13. PlacetheKRAHpullingchainintothespecialchan-nelattheendofthesocket.Thetensionermustbeplacedatleast25cmawayfromtheweldingwire.

14. Pullthechainuntilthevalueofthetighteningtorque isreached,aspresented inthechartbelow.

Acompletepipesystemisalwaysjustassecureasitsweakestcomponent.Theweakestcomponentisthejoint.Thereforeitisimportanttochoosethemostsuitableandpermanentone.Theweldingofsmalldiameterplasticpipesandfittingswiththehelpofelectrofusionhasbeenacommonmethodinthemarketforyears.Aboveallbecausethisjointingtechniqueisveryfavourable,simpleandsecure,whichhascausedKrahtodevelopthistechniqueforbigpipesaccordingtoDVS2207-1.

Afusionwireisincludedintothesocketofthepipe.Afterputtingthesocketandspigotofthetwopipes,thatshallbejointed,together,thewireisheatedwiththehelpofaspecialfusiondevicewherebythetwopipeends(thesocketandthespigot)areweldedtogether.Thisjointingtechniqueallowspipestobeinstalledinsuchashortperiodoftimeneverachievedbefore.Withonlyoneweldingdeviceitispossibletoinstallapipelineof72mwithadiameterof1200mminbetween8hours.Theinstallationspeedisnowdependingonthetrenchworks.

4. Jointing methodsfor KRAH pipes4.1. Jointing pipes usingintegrated electro-fusion fittings

Items 13 and 14

Jointing and fusing instructions for KRAH pipes with electro-fusion socket

1. Powersource:Thepowerofthegeneratormustbeatleast15kVA.Ensurethestablecharacteristicsofthecurrent!

2. Fusioncanonlybeperformedbyauthorizedpersonnel.

1716

15. Incaseswherethepipelineisshortmakesurethesocketsandspigotsarefixedproperlyandcannotmove.

16. Jointthefusionequipmentwiththeweldingwireusingtheadapter.Ifnecessary,bendandcuttheendsoftheweldingwirefortheadaptersoitisascloseaspossibletothesocket.Makesurethewel-dingwireswon’ttoucheachother(shortcircuit).

17. Enterthefusionparameters(readfromthebarco-dewithspecialequipmentorentermanually).Beginthefusionprocess.

18. Atthebeginningofthelastthirdofthefusion,pullthepullingchainagainuntiltherequiredvalue

ofthetighteningtorqueisreachedinthechartbelow.

19. Whenthefusiontimeisovermarkthefusionwithwaterproofmarker(No.offusion,date,voltageused,time,nameofoperator).

20. Removetheadapterfromtheweldingwires.21. Donotmovethepipeduringthecoolingperiod.22. Afterthecoolingperiod(about35–45mins)

removethepullingchainandtheinsidesupportring.

23. CheckingandtestingofthedrainageandsewagepipingjointsisregulatedwiththestandardEN1610:200.

item 14 item 16

DN/ID (mm) Voltage (V) Time (sek) No. of fusion equipment Tightening torque at the beginning of fusion

Tightening torque forover-tightening after 2/3 of

fusion period

500 20 900 1 50 Nm 60 Nm

600 24 1020 1 50 Nm 60 Nm

800 33 1020 1 55 Nm 65 Nm

1000 40 1080 1 55 Nm 70 Nm

1200 43 1260 1 60 Nm 70 Nm

1400 28 1020 2 60 nm 70 Nm

1500 32 1020 2 65 Nm 75 Nm

1600 32 1080 2 65 Nm 78 Nm

1800 40 880 2 75 Nm 90 Nm

2000 39 1200 2 80 Nm 90 Nm

2200 41 1260 2 85 Nm 95 Nm

Fusion parameters for KRAH pipes for manual input and tightening torques for pulling chain.Send an enquiry for the parameters for bigger diameter.

18

• Twogasketsperjoint

• Installthegasketsasshowninthefigure

• Tofacilitatetheinstallation,itwouldbegoodifthegroundaroundoneofthepipestobejointedcouldbepartiallybackfilledasthisensurespropersupportduringthejointingandpreventsthepipelinefromwaving.

• Markthespigotwithwaterproofmarkerontheleng-thofthepipewhichwillenterthesocket(atleast125mm).

• CoverthesocketsandspigotswithPLENTYoflubricant.

• Thespigotsandsocketsmustbekeptcleanduringthelubricationaswellasthejointingprocess.

• Jointthepipesupuntilthemarkedlineonthespigothasbeenreached.

• Duringthejointingperiodamechanicalaidisnee-ded.Ifyoujointbypushing,adevicetospreadthepressuremustbeused(e.g.awoodensheet),topreventthesocketfrombeingdamaged.

• Avoiddraggingthepipeends.

• Krahpipeswithagasketjointingareforuseinstraightpipelines.Incaseswherethereisacurva-tureintheproject,apipebendmustbeused.

4.2. Jointing KRAH pipes using gasket

Gaskets

Marking

Grooves for gaskets on the pipe

Spigot

Gasket

1918

a–depthoflowerbedlayer b–depthofhigherbedlayer c–depthofinitialbackfill

b=kxOD(seechapter“fillandsupport”)

where: k–afactorwithoutunit,ratiobetweendepthofhigherbedlayerbandOD

OD–outerdiameterofpipeinmillimeters

Note 1.

Forminimalvaluesforaandcseechapter“fillandsupport”

Note 2.

InsomenationalstandardskxODreplacesthedeter-minationofthebedangle.Thebedangleisnotthesameasthereactionangleofthebedusedinthecon-structiondesigndocumentation.

5. Installation ofKRAH pipes5.1. Trench Trenchesmustbedesignedandexcavatedinawaythat

guaranteesaninstallationwhichissafeandwhichfitstherequirements.

Iftheundergroundconstructions,e.g.manholes,needtobeaccessedfromtheside,aprotectedworkingzonewithaminimumwidthof0.5mmustbeprovided.Iftwoormorepipesaregoingtobeinstalledintothesametrenchorembankment,theminimalhorizontalinter-pipeworkingareamustbeobserved.Ifithasnotbeenstatedotherwise,itmustbe:forpipesuptoandinclud-ingDN7000.35mandpipesoverDN7000.5m.

Installation of Krah pipes DN/ID1000 at a construction site

1. Trenchwalls2. Finalbackfill3. Initialbackfill4. Sidefill

5. Bed 6. Depthofcover7. Depthofbed8. Depthoftrench

5.1.1.1 Maximum width of a trench

Themaximumwidthofatrenchcannotexceedthemaximumwidthasprovidedintheconstructiondesigndrawings.

Ifthisisnotpossible,thedesignermustbecontacted.

5.1.1.2 Minimum width of a trench

TheminimumwidthofatrenchmustexceedthevaluesprovidedinFigures1and2,exceptinthecasescove-redinSection5.1.1.3.

5.1.1 Width of a trench

20

5.1.1.3

TheminimumwidthofthetrenchbaseduponTables1and2canbeamendedinthefollowingcircumstances:

• Ifthestaffmustnevergointothetrench;• Ifthestaffmustnevergobetweenthepipingand

thewallofthetrench;• Inunavoidablelimitedsituations. Inallthesecasesspecialprecautionsmustbeconsi-deredduringthedesignandconstruction.

Duringinstallationtheexcavationsmustbekeptfreeofwater.Methodsfordisposingwatermustnotdamagethefillingmaterialorpiping.Afterthewaterhasbeendisposedof,allthetemporarydrainsmustbeclosedproperly.

Materials,baselayer,supportandthicknessofthefillinglayermustbeinaccordancewiththedesigndocumentation.Thefillingmaterialanditsfractionalcompositiontogetherwiththesupportmusttakethefollowingintoconsideration:

• Sizeofpipe;• Materialofpipeandwallthickness;• Characteristicsoftheground.

DN

Minimum width of trench (OD+x)m

Supported trenchUnsupported trench

ß > 60° ß ≤ 60°

≤ 225 OD + 0.40 OD + 0.40

> 225 to ≤ 350 OD + 0.50 OD + 0.50 OD + 0.40

> 350 to ≤ 700 OD + 0.70 OD + 0.70 OD + 0.40

> 700 to ≤ 1200 OD + 0.85 OD + 0.85 OD + 0.40

> 1200 OD + 1.00 OD + 1.00 OD + 0.40

Figure 1 – Minimum width of trench with respect to nominal size (DN). In the equation OD+x, x/2 equals the minimum working space between the pipe and the wall of the trench or supports, where: OD is the external diameter in meters and ß designates the angle of the unsupported wall of the trench, measured with respect to the horizontal (see Figure 2).

Depth of trench m

Minimum width of trench m

< 1.00 No minimum width required

≥ 1.00 ≤ 1.75 0.80

≥ 1.75 ≤ 4.00 0.90

> 4.00 1.00

Table 2 – Minimum width of trench with respect to depth of trench

Figure 2 - angle of unsupported wall of trench ß

5.1.2 Removal of water

5.2. Filling material and support

2120

WhileinstallingKrahpipes,theside-andinitialbackfillmustbepackedatleastupto90%ofthestandardden-sity-Proctordensity.

Ifrequired,theinitialbackfill,whichisdirectlyoverthepipe,mustbepackedmanually.Thefinalbackfill,whichisdirectlyoverthepipe,cannotbepackedmechanicallyuntilthetotaldepthofthefillingmaterialoverthepipeis300mm.Thetotaldepthofthecoverdirectlyoverthepipebeforemechanicalpackingdependsonthetypeofpackingequipment.Whiledecidinguponthepackingequipment,thenumberofpassingthroughsandthedepthofthelayertobepacked,thematerialtobepac-kedandthepipetobeinstalledmustbeconsidered.

Accordingtotherequirementspipesystemshavetobetestedforleakage.Thereexistdifferentkindsoftestprocedures.

Thefirstalternativeisthesectiontest,wherethetotalpipesections(betweentwomanholes)aretestedinall.Airhosesareblownupandtheylockthepipesatbothends.Then,waterwithacertainnominalpressureispumpedintothetightenedsection.Thisoverpressureistestedafteracertainperiodoftimewhichgivesinfor-mationabouttheleakageofthesection.

Theotheralternativeisthejointingtest(onlypossiblewithdiametersgreaterthanDN/ID600mm),whereonlythepipejointsaretestedasitisassumedthatthepipesthemselvesaretight.Aleakagetestingdeviceisusedbutthetestingprincipleisthesameappliedinthesectiontest,theonlydifferenceisthatthetestareaisthejoint.

Thewidthofthebaselayermustbeequaltothewidthofthetrench,ifithasnotalreadybeendeterminedotherwise.ThewidthofthebaselayerforthepipinginstalledintotheembankmentmustbefourtimesOD,ifithasnotbeendeterminedotherwise.

Thedepthoftheinitialbackfill,c(seeFigure1)mustbe150mmoverthecylinderand100mmoverthejoints.

Allsoftgroundunderthebaseofthetrenchmustberemovedandreplacedwithmaterialsuitableforthebaselayer.

Placingthesidefillandbackfillcanonlybestartedifthepipejointsandthebaselayerallowloading.

Backfill,includingplacingthefillingmaterialandthefinalbackfill,theremovalandpackingoftheclosingwallofthetrenchmustbecarriedoutinawaythatensurestheloadingcapacityofthepipinginaccor-dancewiththeprojectdocumentation.

Thefillingmaterialmustbeplacedinawaythatpre-ventstheexistinggroundfromfallinginorthefillingmaterialbeingmixedwiththeexistingground.Inspecialcases,especiallyifgroundwaterispresent,geotextilesoraninvertedrectifiermaybeneededtokeepthefillingmaterialinplace.

Suitableprecautionsmustbeobservedinlocationswheretheflowofgroundwatermayreplacesmallgroundparticlesorwherethelevelofgroundwatermaybereduced.

Shouldpartsofpipingneedtobeanchored,thismustbedonebeforethefillingmaterialisputinplace.

5.3. Backfill

5.4. Packing

5.5. Leakage test

22

A sample about storing Krah pipes

6. Pipe-in-pipe-method renovationThereconstructionofdamagedsewagepipesusingtherestoration“Pipe-in-pipe-method”isveryimportant.Krahpipesareperfectforrestoringbrokenpipes.Thestiffnessofthepipesiscalculatedusingactualloads.Also,inordertorestoreshortpipes,Krahprovidessuitablesolutions.Weldingwilltakeplacewithinthepipe.Pipesareavailableinlengthsof1mto6m.WithKrahpipesitispossibletorestorethestaticthroughputcapacityofasewagepipingsystemwithoutdiggingitout.Incasesoflongertrenches,itispossibletouseupto18mofpre-producedpipes.IncasesofDN800pipesorwithpipesthathavelargerdiameters,itispossibletoinsertsinglepipesintotheexistingsewagepipingandtojointthemusinginternalextrusionwelding.

ItisveryeasytotransportKrahpipes,asthepipesarelightweight.Duringtransportationthepipesmustbesecuredtopreventthemfrommoving.Inspecialcases,ifthepipesaredeliveredinacontainer,thespaceshouldbeusedefficientlyandthelengthsofpipemustbeadjustedtothetransportationconditions.

7. Transportation

8. StorageWhilestoringpipesandpipefittingsitisimportanttoensurethatthegroundissmoothandtoavoidpointloads.Further,itmustbemadesurethattherearenostonesoranyotherobjectswithsharpends.Then,itisimportanttocheckthatthespigotsandsocketsofthepipesloadedoneachotherareindifferentdirections.

Thismeansthateachlayerofpipesshallbeintheoppositedirectiontothenextlayer–thesocketisside-by-sidewiththespigot.Socketscannotbeincontactwiththesocketsinthenextlayer.

2322

Thequalityassurancedemandsagreatknow-howandthereforetheKrahAGhascreatedaQualityhandbookinwhichalltheimportanttestsincludingthenecessarymachinesaredescribed.Inordertogivethecustomeranimpressionofthequalitycontrolitispossibletohavealookintothehandbook.

9. Quality controlTotal quality management

ThequalityofthepipesandthepipeproductsisthecriterionforalldevelopmentsofKrahAGandcompa-niesusingtheKrahtechnology.Astheinternationalrequirementsvarybecauseofthedifferentnormsandstandards,thereexistsamultiplicityoftestproceduresforthequalityassurance.ThewholeproductionprocessisincludedinanextensiveTotal-Quality-Management-System.Therearetwomainfields,theoneistheinternalqualitycontrolandtheotheristheexternal(third-party)qualitycontrol.

Generallytheinternalqualitycontrolisdividedintothreedifferentsteps:

1. BEFORE PRODUCTION CONTROL

Therawmaterialsandanyotherinputaretestedregardingthemeltingflowratio,moistureandcolour.Usuallyanynewdeliveryofmaterialistestedbeforeitisstored.Everytestisdocumented,analysedandfiled.

2. DURING PRODUCTION CONTROL

Duringtheproductiontheindividualworkingstepsarecontinouslysupervisedanddocumented.Moreoverthemostimportantdimensionsaremeasuredandifnecessary,corrected.

Inspection of ring stiffness

3. AFTER PRODUCTION CONTROL

Aftertheproduction,thefinalproductistestedandcomparedwiththerequirementsofthecustomer.Thefinalminuteiswrittenandthedocumentationisfinished.InordertoguaranteethatthestatictheoreticvaluesareconformtotherealitypipesarecontinuouslytakenoutoftheproductionandtheyaretestedwiththehelpofaringstiffnesstestaccordingtoDIN16961orISO9969.

Measuring the width of the pipe wall

24

Dependingontheusedpipestandard,themarkingcanbedifferent.Aminimummarkingis:Thepipesshallbemarkedatintervalsofmaximum2m,atleastonceper pipe.

Themarkingmustincludeatleastthefollowing:

• No. of standard(e.g.EN13476)• Nominal dimension(e.g.DN/ID1000)• Producer(e.g.KrahPipes)• Ring stiffness class(e.g.SN8inaccordancewith

thestandardEN13476)• Ring elasticity(e.g.RF30inaccordancewiththe

standardEN13476)• Material of pipe(e.g.PEHD)

Ingeneralthewholeproductionisconstantlysupervisedbyathirdpartyinspection.ThequalitycontrolexceedsbyfartheISO9000certificationsbecauseinourcasethequalityofthefinalproductistested.Asresultweareinthepositiontoissuequalitycertificatesforeverydeliveryofpipesfromthemostsimplequalitycertificate2.2tothefirstclasscertificate3.1baccordingtoEN10204.

TherecentcertificatesgiventoKrahpipesarealwaysavailableonourwebsite:www.krah-pipes.eeinthe sub-directory:Certificates.

Quality certificates

Marking

Annex B (INFORMATIVE)Methods of assessing the load capacity of pipes

B.1 General

Oneofthemostfrequentusesofprofiledpipesisinburiedpipingsystems.Beforetheseareinstalled,proofoftheirloadbearingcapacityisrequiredtobeprovided.

Thisproofcanbeprovidedintheformofstructuraldesigncalculationsorcomputationalgraphsortablesbasedonpracticalexperienceandcomparativecalculations.

Structuraldesignbasedonanalysisorcomputationisnotgenerallynecessaryinthermoplasticpipedesign.Inpractice,eachcalculatedpredictionofthebehaviourofapipeisheavilydependentontheconditionsassumedforthepurposesofthecalculationcorrespondingtoactualconditionson-site.Withthisinmind,incriticalcasesitisrecommendedthattheinputdatabecarefullycheckedandverifiedbycarryingoutsoilanalysesandmonitoringpipe-layingoperations.

Instandardinstallationsituations(seeTableB.1),pre-dictionsofthebehaviourofundergroundpipescanbemadeonthebasisofpracticalexperience.

B.2. Structural design based on practical experience

Onthestrengthofdecadesofexperience,andprovidedthepipesusedareatleastoftheminimumquality-requiredbythisstandardandareproperlylaid,mostconstructionworkinvolvingundergroundpipescanbecarriedoutwithoutanyneedforcomplicatedstructu-raldesigncalculations(seeCEN/TS15223,DINEN13476-1).

ThelimitingvaluesspecifiedinTableB.1shallbeobser-vedinrespectoftheinstallationconditionsandtheinstallationquality.

StudiesattheEuropeanlevel(seeBibliography[1])andextensiveresearchintothedeflectionbehaviourof

DIN 16961-2:2010-03Marking

2524

KeyXRingstiffnessSN,inkN/m2

YGroundwaterlevelabovetheinvert,inm1Compaction“GOOD”2Compaction“AVERAGE”

Joonis B.2 – Maximum permissible groundwater level above the invert (GW) as in ATV-DVWK-A 127 (DWA-A 127 Code of practice)

NOTE 1TherelationshipbetweenSNandSR24asshowninFigureB.2,basedonpolyethylene,isintendedforguidance.Thecurvehasbeencalculatedassumingalayingdepthof6mandgoodlayingquality(seeTableB.1).Highergroundwaterlevelsarepermittedforpipeslaidatadepthlessthan6m.

NOTE 2“Good”and“average”compactionwith95%and90%standardProctordensityrespectivelyareusedforalltypesofgroundinwhichpipesareinstalled(i.e.includingnaturalground).OnlyinstallationcaseIasinATV-DVWK-A127isconsidered.Mixedsoilsofgroups1and2asinATV-DVWK-A127(DIN18196)are assumed.

AccordingtoCEN/TS15223,pipingsystemsofstiffnessclassesSN4orSR2416designedtobeusedunderg-roundaresufficientlyresistanttoexternalwaterpressu-re.ThemorestringentrequirementsofATV-DVWK-A127(DWA-A127)[3]withregardtoexternalwaterpressurecanbecheckedinFigureB.2asafunctionoftheringstiffnessofthepipe.

pipes in existing European pipe systems (seeBibliography[2])haveinvestigatedthesubjectofdef-lectionofundergroundpipes.Inthelatterstudy,actualdeflectionwasmeasuredseveraltimesoveraperiodof25years.ThefindingsofthetwostudieshaveresultedintheempiricalvaluesshowninFigureB.1.

FigureB.1illustratestheexpectedmaximumlong-termdeflectionofburiedpipesasafunctionofthelayingqualityandtheringstiffnessofthepipes.

KeyXRingstiffnessSN,inkN/m2

YLong-termdeflection,in%ACompaction“AVERAGE”BCompaction“GOOD”

Joonis B.1 – Long-term pipe deflection: maximum values

TheringstiffnessofapipeorfittingcannotbedirectlyconvertedfromtheSR24totheSNvalueandvice-versa.Duetotheinfluenceofvariousfactors:themodulusofelasticityoftherespectivematerial,thenominalsizeofthepipe,thevariousmethodsoftestingstiffnessandthedifferingdurationsofthetests,thevalueofringstiffnessisrequiredtobedeterminedindividuallybytesting.Practicehasshownthatthesefactorsdonothaveanymeasurableinfluenceontheactualdeflectionofpipesoncetheyarelaid.

Theringstiffnessvalues<SN4(SR2416)showninthediagramsaremostfrequentlyfoundinlargepipes.

Tabel B.1 – Conditions on which the graphs in Figure B.1 are based

Pipe system Systemsintendedtobeinstalledundergroundandcomplyingwiththerequirementsof DIN16961Parts1and2

Depth 0,8m–6,0mTraffic load includedTrench width asinDINEN1610Ground water seeFigureB.2andNotesLaying quality asinDINEN1610

Compaction “GOOD” Granularsoiltobeusedasbeddingiscarefullyplacedintheembedmentand compacted,afterwhichthesoilisplacedinlayersnotmorethan30cmthick andeachlayercarefullycompacted.Thepipeshallbecoveredwithalayerat least15cmthick.Thetrenchisthenfilledwith(anytypeof)soilandcompacted. Proctordensityofembedment95%

Compaction “AVERAGE” Granularsoiltobeusedasbeddingisplacedinlayersnotmorethan30cm thickandeachlayercarefullycompacted.Thepipeshallbecoveredwitha layeratleast15cmthick.Thetrenchisthenfilledwith(anytypeof)soiland compacted. Proctordensityofembedment!90%

Timbering Priortocompaction,thetimberingshallberemovedasrecommendedinDINEN1610.

Theprovenflexibilityofthepipesissuchthatfailurewillnotoccur,evenwhenthepipesaresubjectedtounforeseenloadsorareimproperlyinstalled.Deflectionsofupto15%donotadverselyaffectthecorrectfunctioning(i.e.thedurability,hydraulicpropertiesandleaktightness)ofthepipesystem.

B.3 Structural design based on design calculations

Ifstructuralcalculationsarenecessary(forinstancebecausethelayingconditionsareotherthanthosegiveninTableB.1),amethodspecifiedinDINEN1295-1shouldbeused.InGermany,methodATV-DVWKA127(DWA-A127)isgenerallyused.RecommendeddeflectionvaluescanbefoundinCEN/TS15223.

B.4 Suitability of methods for large pipes

ThespecificationsofCEN/TS15223andDINEN13476-1arelimitedtopipesupto1200mmindiameter.However,theinteractionbetweenpipeandthegroundsurroundingitisalwayslargelythesame,irrespectiveofthediameterofthepipe.Thereasonforthisisthedominanceofthesurroundingground.CalculationsinaccordancewithATV-DVWK-A127(DWA-A127)showthatthepipediameterhardlyaffectstheresultsofthestressanddeflectionanalyses. ThisisalsoconfirmedinFigureB.1.Themainfactoristheexcellentsoilandlayingqualitythatisrecommendedforlargepipes.

Gaasitee11/75306Raevald/Harjumaa/Eesti/Tel:+3726841050/Fax:+3726841051/info@krah-pipes.ee/www.krah-pipes.ee