VSBK DESIGN OPTION Guidelines
Authors : Heini Müller, Prabin Chhetri, Tobias Müller Editors : Karl Wehrle, Urs Hagnauer Proofreader : Madeleine Cannon Illustrations :PrabinChhetri,KesharJoshiLayoutandgraphics :KiirtistudioFirstedition :September2013Contact :SkatFoundation([email protected])
ISBN978-3-908156-49-9Copyrights©Skat,2013
ThisdocumentisnotintendedtobeaconstructionguideandentrepreneurswhoconsiderconstructingaVSBKarestronglyadvisedtocontactanexperiencedlocalorregionalVSBKexpert/consultant.
VSBK Design Option Guidelines
VSBKDeSIgNOPTIONgUIDeLINeS \ iii
Acknowledgements v
Background vi
Purpose of this documentation vi
Potentials and limits of this documentation vii
Feedback and up-grading of this documentation vii
Overview of VSBK viii
01 Foundation 1
02 Unloading mechanism support unit 3
03 Trolley guide 5
04 Brick corbelling 7
05 Brick support I-beams 9
06 Girder system 11
07 Arch/slab 13
08 Shaft 16
09 Cavity between shaft and shaft support structure 19
10 Shaft support wall 21
Contents
iv / VSBKDeSIgNOPTIONgUIDeLINeS
11 Kiln insulation boxes 23
12 Peep-hole pipes 25
13 Outer kiln wall structure 26
14 Working platform 29
15 Flue-ducts 31
16 Shaft top structure 33
17 Emission exhaust system 34
18 Flue gas dampers/valves 36
19 Shaft lid 38
20 Unloading bars 40
21 Unloading trolley 42
22 Brick unloading system 43
23 Access to the working platform 45
24 Roof 48
VSBKDeSIgNOPTIONgUIDeLINeS \ v
TheVerticalShaftBrickKiln(VSBK)developmentprocessdocumentationstartedduringitsappliedResearch&Developmentstagein1997andreachedafirstimportantmilestoneinthelegendary“BrickbyBrick-TheHerculeanTaskofCleaninguptheAsianBrickIndustry"in2008.Yettheactualconstructiondevelopmentprocesshasbeencontinuedsince.Inparticularthe“South–South”VSBKtechnologytransfertoSouthAfricaliftedtheVSBKtechnologysignificantly.AdditionalconstructionoptionshavebeenrealizedthatpromotetheVSBKtechnology as a globally recognized clean brickproductionsystem.However,theresultofthisprocesshasuntilnowneverbeensystematicallydocumentedandupdated.
SkatwouldliketoexpressitssincereappreciationtoSwissDevelopmentCooperation(SDC)foritscontinuedsupporttothedevelopmentoftheVSBKtechnologyanditsadaptiontospecificlocalcontexts.Withoutthispersistentcommitmentandtrust into the involved partners over a period ofmorethanadecadethedevelopmentoftheVSBKtechnologyasatechnicalandeconomicalviableenvironmentfriendlyalternativetotraditionalbrickproductionsystemswouldnothavebeenpossible.
SkatlikestoexpresssincerethankstothepilotingentrepreneursfromvariouscountrieswhomadetheVSBKtechnologylearninganddevelopmentpossible.OnlythroughthespiritofVSBKpioneers,whowereandarepreparedtopracticallytestnewapproachesandatthesametimetakesomerisks,theVSBKtechnologycouldbeexposedandtestedinthepracticalbusinessenvironment.
Skatisalsoverygratefultoallpartnerorganizationsandindividualprofessionalsfromvariouscountries,whoeachintheirownwaycontributedtowardsimportant“puzzles”inordertoup-gradeandperfecttheVSBKtechnology.TheymadeaSouth-Southtechnologytransferpossible.
Specialthankstoallthosewhocontributedtothedevelopmentandcompilationofthisdocumentation,inparticulartotheeuropeanexpertsinenergy&environment,kilnconstructionandceramics,Mr.MaxMüller,germany,Mr.HansSchmid,Switzerland,Mr.ekhardRimpel,germany,andMr.AloisMüller,Switzerland,aswellastoMr.UrsHagnauer,formerVSBKProjectManager,Nepal.
LastbutnotleastSkat,asthepartnerinchargeforthetechnologytransfertoSouthAfricawouldalsoliketoacknowledgetheVSBKProjectinSouthAfricawhichfinancedthedevelopmentandpublicationofthisdocumentaswellasourconsortiapartner,Swisscontact,whofacilitatedtheprojectimplementation.
Karl WehrleSkatConsultancy
Acknowledgements
vi / VSBKDeSIgNOPTIONgUIDeLINeS
ThispublicationispartoftheongoingeffortsoftheVSBKtechnologytransferprocessfromAsiatoSouthAfrica.ItispartofthetasksentrustedtoSkatinanoverallprocessofknowledgetransfer.ThefocusofthispublicationareboththemaindesignoptionsaswellasconstructionelementsoftheVerticalShaftBrickKiln.TheVSBKisthemostenergyefficientcoalfiredclaybrickproductiontechnology.eversinceSDCsupportedthesystematicVSBKtechnologytransferfromChinatoIndiain1996alotoflocalandinternationalVSBKworkingexperiencehasbeenaccumulated.Initsquesttocontributetocleanerclaybrickfiringsystems,andtherebytoacleanerenvironment,SDCalsosupportedtheVSBKtechnologytransfertoNepal,Vietnam,Afghanistan,Pakistanandsince2009toSouthAfrica.
IntheVSBKtechnologytransfertotheabovementionedcountries,excepttoVietnam,SkatConsultancyistheonlyinternationalorganisationthathasbeenaconstantpartnertoSDC’senvironmentalendeavoursince1996.ThisprofessionaltrustwascontinuallyacknowledgedbySkatConsultancywithitsprincipleworkingstrategy;tolocallyanchorthe
VSBKtechnologyandtherebybuildinglocalVSBKexpertswhileatthesametimecreatingandoverseeinganinternationalnetworkofexpertsandspecialiststosustaintheVSBKtechnologyaswellasitsconstantimprovements,documentationandinternationaldissemination,thereforemakingbestuseoftheinvestmentsmadebySDCandallotherpartners.
TheVSBKtechnologyisnotpatented.Sinceitscommercial,environmentalandsocialdevelopmentwasfinancedbySDCthistechnologyisconsideredan“opensource”technology.Theresultsof17yearsofVSBKdesign/constructionexperienceandknowledgefromallstagesofthevariousVSBKtechnologytransfershavebeencollectedandcompiledas“VSBK Design Option Guidelines”.
ThisdocumentationistheresultofprofessionalinvolvementofexperiencedeuropeanbrickkilnexpertswithglobalVSBKtechnologyexpertsandlocalpractitioners/entrepreneurs.Hencethisdocumentationconsidersboth;thecurrentstate-of-artbrickkilnknow-howateuropeanlevelaswellasgloballyappliedpracticalandtechnicaloptions.
However,latestadaptationstolocalcontextsbylocalexpertsinSouthAfricacouldnotbeincludedinthisdocumentsincetheyarebeingclaimedasintellectualproperty.Dependingoninteresttheymaybemadeavailablethroughaconsultancycontract.
Purpose of this documentation
ThroughtheSDCsupported“South–South"VSBKtechnologytransfertoSouthAfricanewthinking,newviews,newexpertsandtherebynewpotentialswereleadingtoadditionalconstructionoptions.AwarenessoftheuniqueenergyandenvironmentaladvantagesoftheVSBKtechnologyisrapidlybeingdisseminatedatagloballevel.Withthisdocument,expertsnotonlyinSouthAfrica but also at global level are enabled tomakeaneducateddecisionofhowtoadapttheVSBKtechnologyandthereforecontributetowardsanincreasedglobalVSBKdemandwhileatthesametimereducingthegreenhousegasemissionfromapollutingindustrialsector.
ThepurposeofthisdocumentationistoprovideageneraloverviewofdifferentVSBKconstructionoptionsandmakesitclearthatthereisno'One-size-fits-all'.For
Background
VSBKDeSIgNOPTIONgUIDeLINeS \ vii
aprofitableVSBKbusinessexperiencedprofessionalsshouldbeinvolvedwhoassesstheappropriatenessofagivenoptiontoagivensituationandthisdocumentaimstobeavaluableresourcefordecisionmakers.
Potentials and limits of this documentation
VSBKconstructionoptionsarealwayslinkedto,andwiththepurposeof,brickfiringanditsrelatedeconomics.AlthoughnumerousVSBKconstructionoptionsaregloballyimplementedbyvariousorganizations,expertsandentrepreneurs,theauthorsutilizedatwo-shaftVSBKdesignasreferenceandpurposefullylimitedthenumberofpossibleconstructionoptionsinthisdocumentinordertofocusonprovenpracticalandeconomicalpractices.Forindividualswithlimitedaccesstohightechsolutionsandhighup-frontfinancialinvestment,forwhateverreasons,currentindustrialized'stateoftheart'kilnconstructionmaterialsandtechniquesneedtobedownscaledintopracticalsolutions.Thisdocumentationnotonlyshowspracticaloptionsbutalsopresentspotentialfutureoptionsthatwillrequirelocalfine-tuningforviablefinaladaptiontothelocalcontext.ItwouldbewayoutofthescopeofthisdocumenttoexplainthedetailedaspectsoftheVSBKconstruction.Thisdocumenttries
toprovidebasicrationalesandexplanationswheredeemedessential.Itissometimesdifficulttopreciselyandappropriatelyprovidesketchesandexplanationstofullycomprehenddetailedconstructiondrawingsofdifferentoptions.Theycanbemadeavailable through a consultancy contract withanyoftheVSBKtechnologyserviceproviders.
ThisdocumentisnotintendedtobeaconstructionguideandentrepreneurswhoconsiderconstructingaVSBKarestronglyadvised to contact an experienced local or regionalVSBKexpert/consultant.
Feedback and up-grading of this documentation
AnyfeedbackandadditionalexperiencesregardingthevarioustechnicaloptionsismostwelcomedandcanbedirectedtoSkatFoundation([email protected]).SkatFoundation,alongwiththerespectiveexpertsandauthors,willaccordinglysecurefutureup-datestothisdocumentandmakethecollectedinformationavailabletoabroaderaudience,withreferencetothesourceofinformation.
viii / VSBKDeSIgNOPTIONgUIDeLINeS
01 Foundation
02 Unloading mechanism support unit
03 Trolley guide
04 Brick corbelling
05 Brick support I-beams
06 Girder system
07 Arch/slab
08 Shaft
09 Cavity between shaft and shaft support structure
10 Shaft support wall
11 Kiln insulation boxes
12 Peep-hole pipes
13 Outer kiln wall structure
14 Working platform
15 Flue ducts
16 Shaft top structure
17 Emission exhaust system
18 Flue gas dampers/valves
19 Shaft lid
20 Unloading bars
21 Unloading trolley
22 Brick unloading system
23 Access to the working platform
24 Roof
Overview of VSBK
03
20
0405
10
11
1619
17
01
2221
06
08
13
07
09
12
1518
14
24
23
02
VSBKDeSIgNOPTIONgUIDeLINeS \ 1
OPTION 1 : R.C.C. raft foundation(Suitablefornon-cohesivesoils)
Advantages
• equalloaddistributiononanytypeofnaturalgrownsoil
• employedworkingpersonnelcanworkonacleanandsafeplatform
• groundwaterpenetrationcanbeminimized
Disadvantages & Limits
• expensiveconstructionoptionduetotheuseofmassconcreteandreinforcementsteel
FunctionThefoundationisthepartoftheVSBKthatisindirectcontactwiththegroundandthroughwhichstructuralloads,includingtheweightofgreenbricks,coalstorageandmovementsarebeingtransferred.
Design principlesAuniversalfoundationdesignforalltypesofgroundistechnicallyandeconomicallynotfeasiblesincekeyparametersvaryaccordingtothelocalsituationandcontext.Therefore,thefoundationhastobeprofessionally designed, case by case and according tolocalcontexts.
AVSBKshouldneverbeconstructedonback-filledsoilorlandslide-proneareas.Specialdesignprecautionsmustbetakenforareashavingahighgroundwatertableorearthquakeexperience.
01 FOuNDATION
2 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 3 : Pillar foundation(Suitableforbothcohesiveandnon-cohesivesoils)
Advantages
• SuitableoptionforaframestructureVSBKconstruction
Disadvantages & Limits
• Generally requires horizontal concretetie-beamconnection
• Considerableamountsofshutteringmaterialisrequired
• Dependingontherequireddepthofthepillarsarelativelyexpensiveconstructionmethod
• Demandinginskill(preciseness)andsupervision
OPTION 2 : Brick footing(Suitableforcohesivesoils)
Advantages
• ABrickentrepreneurcanusehis/herownbricksforthisfoundationoptionandcanthereforeoptimizeexpenses
Disadvantages & Limits
• Notapplicableforalltypesofgrounds and especially not an optimaloptionincasesofhighgroundwatertable
• Requiresgoodbrickquality
01 FOuNDATION
VSBKDeSIgNOPTIONgUIDeLINeS \ 3
02 uNlOADING mEChANISm SuPPORT uNIT
OPTION 1 : m.S. I-beamsNote:M.S.I-beamsareinstalledperpendiculartothearchwallsinordertotransfertheloadofthebrickssettinginsidetheshafttothekilnfoundation.
Advantages
• economicaloptionduetotheutilisationofthearchwallfoundations
• Canaccommodatebothhydraulicandmanualunloadingmechanisms
Disadvantages & Limits
• Foreignmaterialcouldfallintothepitstructurewhichcouldcreatecomplicationsforunloading procedures and are likelydifficulttoclean
• Inareasofhighwatertable,awatertightpitstructureshould be ensured in order to avoidwatercontactwiththeunloadingmechanism
FunctionTheunloadingmechanismsupportunitaccommodatestheheightofthehydraulicpistonorscrew,protectstheunloadingmechanismfrompotentiallybeingblockedduringoperationandbearstheloadoftheentirebricksettinginsidetheshaftduringunloadingprocedures.
Design principlesTheunloadingmechanismsupportunitmustbeartheentirebricksettingloadanditsunloadingsysteminsuchawaythatnostructuralsettings/damageswillhindertheunloadingoperation.
Therelatedpitshouldbeprotectedfromthenearbyfilledsoilandgroundwatersothattheunloadingmechanismcanmovefreely.
4 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 2 : R.C.C. load bearing unitNote:Thisunitisseparatedfromthekilnstructure.Itbearstheentireloadofthebricksettinginsidetheshaftonitsownfoundation.
Advantages
• Pitstructureismaintenancefriendly
Disadvantages & Limits
• Doesnotutilisethearchwallfoundationforsupport,itsconstructionrequiresheavyduty concrete and steel reinforcementandisthereforeconsidered expensive
• Onlyfeasibleongroundwithsufficientbearingcapacity
02 uNlOADING mEChANISm SuPPORT uNIT
VSBKDeSIgNOPTIONgUIDeLINeS \ 5
OPTION 1 : Recessed mS C-channels
Advantages
• Lowwear&tearofthemasonrywallsduringunloading
• Correctpositioningoftrolleysbelowtheshaftisensured
• Trolleysandtheunloadedfiredbricksarepreventedfrombecomingwedgedbetweentheshaftsupportingwallsduring unloading procedures
Disadvantages & Limits
• Wall corbellings are required near ground level, hence the wallconstructionbecomesmorelabourintensiveandtherefore costly
FunctionThetrolleyguideassistsincorrectlypositioningthetrolleyforunloadingproceduresand,whentheunloadingtrolleyiscorrectlypositioned,actsasasafety feature to prevent unevenly loaded trolleys fromtoppling.
Design principlesThetrolleyguidesaremadewithMSC-Channelsandareproperlyanchoredintothearchwalls.
03 TROllEy GuIDE
6 / VSBKDeSIgNOPTIONgUIDeLINeS
FuTuRE OPTION 1: Screwed-on guides
Advantages
• Lowconstructioncost• Simplifiedtrolleylockshencenomovableparts
• easymaintenance
Disadvantages & Limits
• None
OPTION 2 : Protruded m.S. C-channels
Advantages
• Wallbrickcorbellingisnot required, hence the constructionbecomeslesstimeconsumingandthereforeless costly
Disadvantages & Limits
• Chancesofinjuriesduringunloading procedures
03 TROllEy GuIDE
VSBKDeSIgNOPTIONgUIDeLINeS \ 7
OPTION 1 : Two arch wall corbellings(1stand2nd ,oneachsideofthearchsupportingwalls)
Advantages
• Reducedriskoffiredbrickstumblingfromtheunloadingtrolley
• Lesswear&tearduetoM.S.C-Channeltrolleyguidesconstructedflushwiththearchwallsupportmasonry
Disadvantages & Limits
• Archsidewallbrickcorbellingconstructionbecomestimeconsumingandthereforecostly
• Could hinder pulling out the trolleyduetothesmallgapof3cmbetweenthewallandthetrolleyduringemergencyunloading
FunctionThebrickcorbellingsincreasethearchwalldistanceforunhinderedunloadingofthefiredbricksandmovementofthetrolley
Design principlesThebrickcorbellingofagivenbrickcourseshouldideallynotexceed3cm.
Wallcorbellingscanbemade,butasamatteroffact,areoptionaldependingonthequalityofgreenbricks,firingandoperationpractices.
Sincethearchmasonrywallsdistanceandtheshaftsizehavedifferentmeasurementstherefractoryshaftcorbellingisadvisabletoavoiddamagesduringoperation.
04 BRICK CORBEllING
8 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 2 : Corbelling at refractory brick shaft level
Advantages
• Easy to pull and push the trolley due to increased side space
• Constructionofthearchsidewallsislesstimeconsumingand therefore less costly
• Moreeconomicalbecausetheshaftsupportingcorbellinglayercanbeconstructedjustbeforethefirstrefractorybricklayeroftheshaft
Disadvantages & Limits
• ProtrudedM.S.C-channeltrolleyguides(see3,option2)mustbefixedotherwisethetrolleyguidelockbecomestoolongwhichcouldbedifficultduring unloading
• Increasedriskoffiredbrickstumblingfromtheunloadingtrolley due to increased side space
04 BRICK CORBEllING
VSBKDeSIgNOPTIONgUIDeLINeS \ 9
OPTION 1 : Brick support beam positioned for unloading 6 layers of bricks
Advantages
• Higher unloading capacity, also duringemergencysituations
• Reducedworkloadforpersonnel during regular operationsincelessunloadingproceduresareperformedforthesamenumberofbricksbeing unloaded
• Friendlyworkingenvironmentdue to less heat exposure
• Increasedcoolingdownratepossibility
Disadvantages & Limits
• Thedimensionsoftheunloadingscrew/hydraulicpiston increases due to the increasedliftheight
FunctionThebricksupportI-beamistherestingplaceforunloadingbarsandthegirdersystemduringoperation.Betweenunloadingproceduresthebeamsupportstheentirebricksettingloadinsidetheshaftandtransfersittothearchsupportingwall.
Design principlesThebricksupportI-beamsmustbedesignedtocarrytheentirebricksettingwithintheshaft.
Thetemperatureattheunloadingplacecanattimesbeashighas400°C,whichneedstobeconsideredwhenestimatingtheI-beamdimensions.TheI-beamsshouldbecompletelystraight,neverevenslightlytwistedorbentandmustbepositionedparalleltoeachother.
05 BRICK SuPPORT I-BEAmS
10 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 2 : Brick support I-beam positioned for unloading 4 layers of bricks (including a lower arch and reduced overall kiln height)
Advantages
• Duetothedecreasedliftheightthedimensionsoftheunloadingscrew/hydraulicpiston decreases
• Decreasesoverallconstructioncostsduetothereducedkilnheight
Disadvantages & Limits
• Unloadingdifficultiesduringemergencysituations;hencean experienced & disciplined workingcrewisrequired
• Increasedworkloadforpersonnel during regular operationsincemoreunloading procedures are performedforthesamenumberofbricksbeingunloaded
• Increased heat exposure to workingpersonnel
05 BRICK SuPPORT I-BEAmS
VSBKDeSIgNOPTIONgUIDeLINeS \ 11
OPTION 1 : Girder system with side locks
Advantages
• Noelectricityrequired• Lessupliftmovementofscrew/hydraulicpistonandthereforeeasierforworkingpersonnel
Disadvantages & Limits
• Girder rail prone to bending duetoheatradiationandconstant load
• Increasesconstructiontimeduetofixingofalltherelatedmetalparts
FunctionAfterthetrolleyissecurelypositionedbeneaththefiredbricks,thegirdersystemfacilitatesthereleaseof the unloading bars and hence the load of the entirebricksettingistransferredtothetrolleyandtheunloadingsystem.
Design principlesThegirdersystemneedstobedesignedinawaythatitisabletocarrytheentirebrickload.Further,ithasbeensuredthatthereleasemechanismcannotbetriggeredaccidently(orunintentionally)andthebrickloadcanbetransferredontothetrolleywithoutpotentiallyinjuringworkingpersonnelwhenreleasingthesystem.
Whenahydraulicunloadingsystemisinplacethewholegirdersystemisnotrequired.
06 GIRDER SySTEm
12 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 2 : Girder system with wedge locks(MSsquarerod/wedge)
Advantages
• Costeffective• Noelectricityrequired• Lessupliftmovementofscrew/hydraulicpistonandthereforeeasierforworkingpersonnel
Disadvantages & Limits
• None
06 GIRDER SySTEm
VSBKDeSIgNOPTIONgUIDeLINeS \ 13
OPTION 1 : Arch constructed with brick
Advantages
• Locallyavailablebrickscanbe used, therefore reduced constructioncosts
Disadvantages & Limits
• Requiresanarchmould• Archconstructionwillincreasetheoverallkilnconstructiontime
FunctionThearch/slabstructureensuressafeaccesstounloadthefiredbricks.Italsodistributestheloadsofabovebuildstructuralandnon-structuralloadsintoitssupportingwalls.Further,airentering through this access opening is aiding boththecombustionandthebrickcoolingprocess.
Design principlesDifferentArchtypescanbedesigned.
Concretebeamsandarches;insituorprefabricated;areviablealternativestobrickarches.Afewofthemareshownasoptionsinthisdocument.
Beingarch,beamorslab,thefundamentaldesign criteria is that the structure is safely bearingtheloadplacedontopofit.Concretebased structures should not be exposed to temperaturesabove300°C.
07 ARCh/SlAB
14 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 2 : In situ R.C.C. beam and slab
Advantages
• Savesonoverallnumberoffiredbricksforthekilnconstruction
• Noarchconstructionskillrequired
Disadvantages & Limits
• Requiresshutteringmaterial• Willincreasetheoverallkilnconstructiontime
• Willlikelygetsomedamageincaseofhightemperatureexposure(e.g.brickmeltinginsidetheshaft)
FuTuRE OPTION 1 : Precast R.C.C. beams with 1 layer of front bricks attached as insulation and protection
Advantages
• Reducesoverallkilnconstructiontimeincasethepre-fabricationisdoneinfactories
Disadvantages & Limits
• Requiresamechanicalliftingdevice to place it
• Forachievingeconomicaladvantagesalargenumberofshaftsneedtobeconstructed
07 ARCh/SlAB
VSBKDeSIgNOPTIONgUIDeLINeS \ 15
FuTuRE OPTION 2 : Precast R.C.C. arch with 1 layer of front bricks attached
Advantages
• Reducesoverallkilnconstructiontimeincasethepre-fabricationisdoneinfactories
Disadvantages & Limits
• Requiresamechanicalliftingdevice to place it
• Forachievingeconomicaladvantagesalargenumberofshaftsneedtobeconstructed
07 ARCh/SlAB
16 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 1 : English bond refractory masonry without expansion joints
Advantages
• Uniformexpansionandcontractionproperties
• Uniformthermalmassproperties
Disadvantages & Limits
• Specialmasonryskillsrequired• expansionwilldevelopuncontrolledmasonrycracks
FunctionTheshaftisthecoreelementofthekilnandhastoaccommodatethefiringofthebricksaspertheappropriatefirescheduleaswellastoprovideresistancetomechanicalwearandtearfromverticalmovementoftheloadedbricks.
Design principlesTheshaftdimensionmustbedesignedaccordingtothedrygreenbricksizeandmaximumproductioncapacity.
Further,thefollowingdesigncriteriashouldbeconsideredtoallowfortrouble-freebrickfiring:
• Heatresistanceoftheshaftwallingmaterialinthecentralfiringzoneupto1200°C
• Acidicemissionresistanceinthepre-heatingzone• Structuralexpansionproperties• Perfectverticality• Selfsupportingstructure
08 ShAFT
VSBKDeSIgNOPTIONgUIDeLINeS \ 17
FuTuRE OPTION 1 : English bond refractory brick masonry with expansion joints
Advantages
• Uniformexpansionandcontractionproperties
• Uniformthermalmassproperties
• Controlledexpansionwillavoiduncontrolledmasonrycracks,hencelowermaintenance
Disadvantages & Limits
• Specialmasonryskillsarerequiredandtheconstructionsystemistimeconsuming,therefore costly
• Requiresspecialbrickblocksorcuttings
• Specialcornersupportessentialtoensureexpansionatdefinedjoints
OPTION 2 : English bond refractory masonry; substituted with fired bricks in sections with temperatures below 500°C (pre-heating and cooling zone)
Advantages
• Mosteconomicaloptionundertheconditionthatthefiringzoneisalwaysmaintainedatthecentreoftheshaft
Disadvantages & Limits
• Chancesofshaftdamagesifthefirepositionisnotproperlymaintainedatthecentreoftheshaft
• Firepositionadjustmentislimitedtorefractorymasonryarea
• Potentialdamagestofiredbrickmasonryinthepre-heatingzoneduetoacidicemissions
08 ShAFT
<500oC
>500oC
<500oC
18 / VSBKDeSIgNOPTIONgUIDeLINeS
FuTuRE OPTION 2 : Prefabricated fire resistance refractory concrete elementsNote:Thispossiblefutureoptionrequiresprofessionaloverallkilnconstructionplanningandpracticaldetaildesigns.
Advantages
• Reducedshaftconstructiontime
• Theshapeoftheelementcanbebothverticalorhorizontal
Disadvantages & Limits
• Requiresamechanicalliftingdevice to place it
• Skilltomaintainthetotalverticalityoftheshaftisrequired
• Fire resistant refractory concrete is considered expensive
• Will develop uncontrolled cracksifnoexpansionjointsare provided
08 ShAFT
VSBKDeSIgNOPTIONgUIDeLINeS \ 19
OPTION 1 : unfilled cavity (2-3 cm approx.)
Advantages
• Basicallynoexpenses(Howevertoensureanequalcavity size it is of advantage toplacealowcostthermocolboard.Thisthermocolboardwillmeltassoonasthekilnisinoperationandauniformcavitywillremain)
Disadvantages & Limits
• Someheatlossduetoairmovement,hencereducedinsulationvalue
• Riskofmortarandothermaterialfillingupthecavityifnot carefully protected during construction
• Increased heat exposure at the shafttoparea
FunctionThe cavity is required to ensure structurally independentexpansionandcontractionoftheshaftstructure.
Design principlesThemainprinciplefordesigningthiscavitiyistoensurethestructuralintegrityoftheshaft.
Thetopandbottomofthiscavityshouldbeclosedwithaflexiblematerialafterthekilnisfullydriedoutinordertoavoidheatloss.
09CAVITy BETwEEN ShAFT AND ShAFT SuPPORT STRuCTuRE
20 / VSBKDeSIgNOPTIONgUIDeLINeS
FuTuRE OPTION 1 : Filled cavity(Stonewoolorglasswoolinsulationblanket/board)
Advantages
• Costbenefitfactorisgood
Disadvantages & Limits
• Riskofsaggingwhenfixinginsulationblanketstoaverticalsurface
OPTION 2 : Filled cavitiy (Calciumsilicateboard)
Advantages
• Easy to install since they are availableasselfsupportingboards
Disadvantages & Limits
• Damagepotentialifexposedtocontactwithwater
• Couldbeacostlyoptiondepending on selected materialquality
09CAVITy BETwEEN ShAFT AND ShAFT SuPPORT STRuCTuRE
VSBKDeSIgNOPTIONgUIDeLINeS \ 21
OPTION 1 : English bond brick masonry in mud mortar
Advantages
• Lowconstructioncost• Provides reasonable stability forchimneysystem
Disadvantages & Limits
• Chancesofwallsaggingduetomudmortarshrinkage
FunctionTheshaft-supportwallensurestheindependentworking(expansion/contraction)oftheshaft,reduceslateralpressureandactsasaninsulationlayer.Thechimneysareusuallyconstructedontopoftheshaftsupportingwall.
Design principlesTherearemanyshaftsupportwallconstructionsystemspossible,alldependingoneconomicalinsulatingbuildingmaterials.
Note:Usinga'K-value'calculatorforselectingthesizeofthemosteconomicalinsulationmaterial/structureisrecommended.
Note:Ifashaftisconstructedwithexpansionjoints,theshaftcornersmustbesupportedtoensurecorrectexpansiondirection.(see8,futureoption1)
10 ShAFT SuPPORT wAll
22 / VSBKDeSIgNOPTIONgUIDeLINeS
FuTuRE OPTION 1 : Vermiculite concreteNote:Vermiculitecanalsobeusedasinsulationmaterialbetweenbothstructures;theshaftandthesupportingwall.Note:Itisnecessarytoconsultprofessionalswhoareexperiencedinpracticalapplicationofvermiculiteconcretetechnologyforakilnconstruction.
Advantages
• Lowthermalconductivitymaterial,hencegoodinsulation
• Can be precast or constructed in-situ
• Doesnotrequireanyfurtherinsulationorstructure,exceptaprotectionlayer,e.gsteel
• Thekilnsizecanbereduced,hencematerialandlabourcostcan be reduced
Disadvantages & Limits
• Isanexpensiveinsulationmaterial
• Vermiculiteconcretehasreduced load bearing capacity
FuTuRE OPTION 2 : Insulation bricks walls
Advantages
• Potentialofslimkilnstructureandcostreduction.
Disadvantages & Limits
• Insulationbricksareexpensive• Insulationbrickshavereduced
load bearing capacity
10 ShAFT SuPPORT wAll
VSBKDeSIgNOPTIONgUIDeLINeS \ 23
OPTION 1 : Filled with ungraded soil
Advantages
• Cheapest and easily available fillingmaterial
Disadvantages & Limits
• Lowinsulationvalue,theheatlossisrelativelyhigh
• Difficulttoavoidwaterpenetrationduringconstruction
• Chancesofshaftbulgingincreaseswiththefrequencyofshutdownsduetorepeatedcompactingoffineparticles
FunctionKilninsulationboxesareconstructedtodistributetheloadofinsulationmaterialusedtominimizeenergylosses.Theyalsoproviderigiditytothekilnstructureanddefinethesizeoftheworkingplatform.
Design principlesTheboxdimensionsmustberelatedtotheinsulationmaterialvaluetobeusedandtherequiredworkingspaceandtypeofplatform.Thetopoftheinsulationboxes(platform)shouldideallybecoveredtoavoidheatloss.
Note:Fillingmaterialshouldbeasdryaspossible.
11 KIlN INSulATION BOxES
24 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 2 : Filled with graded brick gravel
Advantages
• Inrelationtotheinsulationvalue it is a good and economicalfillingmaterial
• enhancedinsulationpropertiesduetocreationofmicro-pores
• Decreasedriskofshaftbulging
Disadvantages & Limits
• Difficulttomaintainpropermaterialgradingduringfillingprocess
• Difficulttoavoidwaterpenetrationduringconstruction
11 KIlN INSulATION BOxES
VSBKDeSIgNOPTIONgUIDeLINeS \ 25
OPTION 1 : m.S. pipes
Advantages
• Astraight-forward,practicalandeconomicalsystemforfireposition/temperaturemonitoring
Disadvantages & Limits
• Potentialofexcessairenteringtheshaftifthepipesarenot properly sealed during operation
FunctionPeep-holepipesarenarrowopeningsinthekilnstructurewhichallowavisualand/ormechanicalfiretemperaturemonitoring.
Design principlesPeep-holesmustbedesignedtoallowvisualmonitoringofthefirepositionand/orinsertfiremonitoringequipment(thermocouples)fromtheoutsideofthekilnstructure.
Further,theyshouldbepositionedinawaythattheydonotbendundertheweightoftheinsulationfilling.
Theexactnessofthefirescheduleplottingincreaseswiththenumberofbuilt-inpeep-holepipes.
Therespectivebatchheightandthesoilshrinkagedefinesthepositionanddistanceofthepeep-holepipes.
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OPTION 1 : load bearing brick masonry with buttresses
Advantages
• Can support above built structures(loadingplatform,roof,mechanicaltransportingdevicesetc.)andgreenbrickstorage
• Buttressessupportingtheaccesstoplatformcanreduceconstructioncosts
Disadvantages & Limits
• Buttressesincreasetherequiredconstructionarea
FunctionTheouterkilnwallstructureencasestheinsulationfillingaroundtheshaftsupportingwallsandensuresstructuralrigidityandprotectionagainsttheelements.
Design principlesTheouterkilnwallstructuremustbedesignedsothatitcanprotecttheinsulationandtheshaftstructureagainstmechanicalimpact.
Note:Sufficientweepholesmustbeprovidedtoavoidkilnstructuredamagesduetowaterevaporationduringtheinitialfiring.Theseweepholeshouldbeclosedonlyafterthekilniscompletelydriedout.
13 OuTER KIlN wAll STRuCTuRE
VSBKDeSIgNOPTIONgUIDeLINeS \ 27
OPTION 3 : metal
Advantages
• Can be prefabricated, hence reducesconstructiontime
• Slimmeststructurepossible• Masspre-fabricationpotential
Disadvantages & Limits
• Metalcorrosionislikelythemainproblem,hencehighexpensesformaintenancework
• Separateplatformforbrickstorage required
• Requiresamechanicalliftingdevice to construct it
• High-valueinsulationrequired,hence expensive
• Relativelyunfavourableconstructioncarbonfootprintduetosteelrequirements
OPTION 2 : Concrete frame structure with in-filled brick masonry
Advantages
• Slimkilnstructurepossiblesincenobuttressesarerequired
• Overallconstructiontimereductionpossible
Disadvantages & Limits
• Scaffoldingandformworkincreasetheconstructioncosts
• Additionalcostforreinforcementsteelandconcrete
• Relativelyunfavourableconstructioncarbonfootprintdue to concrete and steel requirements
13 OuTER KIlN wAll STRuCTuRE
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FuTuRE OPTION 1 : load bearing brick masonry without buttresses
Advantages
• Potentialofslimkilnstructure.• Nobulkyinsulationboxes
required
Disadvantages & Limits
• Separateplatformstructurerequiredformovementandstorage
• High-valueinsulationmaterialrequired, hence is considered expensive
13 OuTER KIlN wAll STRuCTuRE
VSBKDeSIgNOPTIONgUIDeLINeS \ 29
OPTION 1 : Partial R.C.C. working platform on buttress
Advantages
• Requireslessreinforcementsteel due to support by masonrybuttresses
• Boxinsulationfillingmaterialcan be topped up
Disadvantages & Limits
• Increased dust exposure potential
• Timeconsumingbecauseofshutteringwork,concretecuringtimeandde-shutteringwork
FunctionTheworkingplatformisconstructedforfreemovementofpersonnelandforstoragespace.
Design principlesTheworkingplatformdesignisbasedonbothloadbearing(buttress)structureorframestructureoptions.
However,theworkingplatformmustbeopen,ventilatedandprovideenoughspacesothatworkingpersonnelcanmovealongandloadgreenbricksintotheshaftwithouthindrancebyanystructureorequipment.
Note:IncaseofaslimVSBKstructure,e.g.metal,aseparateplatformstructureisrequired.
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OPTION 3 : Full R.C.C. working platform
Advantages
• Adds considerable rigidity to thekilnstructure
• Mechanicalgreenbricktransportationpossible
• Lowdustworkingenvironmentachievable
• Decreasedheatlossatplatformlevel
Disadvantages & Limits
• Highconstructioncost• Duetothesettlingoftheboxinsulationfillingmaterialagapiscreatedinbetweentheinsulationfillandtheplatform
• Addsweighttothefoundation
OPTION 2 : Partial R.C.C. working platform on cantilever
Advantages
• Boxinsulationfillingmaterialcan be topped up
Disadvantages & Limits
• Increasedreinforcementsteelandconcreterequirement,henceanexpensiveoption
• Timeconsumingbecauseofshutteringrequirement,concretecuringtimeandde-shutteringwork
• Increased dust exposure potential
14 wORKING PlATFORm
VSBKDeSIgNOPTIONgUIDeLINeS \ 31
OPTION 1 : lower and upper flue-duct system constructed with refractory/fired bricks
Advantages
• Simplecleaningsystempossible
• Bestsuitedfornaturaldraughtsystem
• Costsavingspotentialifconstructedwithfiredbricks
Disadvantages & Limits
• Theflueductsystemistheweakestpartoftheshaft,henceperiodicalmaintenanceis required
• Timeconsumingbrickcuttingworkduringconstruction
FunctionTheflue-ductsarethelowersectionoftheshaftemissionexhaustsystemwhichsystematicallychannelsthefluegasesintothechimneys.
Design principlesTheflueductsmustbedesignedtofunctioninawaythatallfluegassesarepassingthroughtheexhaustgassystem(naturalandforceddraughtsystem)withoutposinghealthhazardstoworkingpersonnel.Furtheritmustbeensuredthattheleastamountofexcessaircanenterthesystematthetopoftheupperflueductsduringunloading.
Theflueductsystemshouldbeconstructedwithacid-resistantmaterialssinceacidicgasesarereleasedduringthefiringprocess.
15 FluE-DuCTS
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FuTuRE OPTION 1 : lower and upper flue-duct system constructed with refractory castables
Advantages
• Reducedconstructiontime• Bestsuitedforforceddraughtsystem
• Calibrationofindividualflueopenings possible
• economicviabilityincreaseswithnumbers
Disadvantages & Limits
• Limitedtocountrieswithfireresistantconcretecastingexperience
15 FluE-DuCTS
VSBKDeSIgNOPTIONgUIDeLINeS \ 33
OPTION 1 : R.C.C. shaft top anchored on the shaft supporting wall
Advantages
• Allowsverticalexpansionmovementoftherefractoryshaft
• Reducedshaftbulgingprobability
Disadvantages & Limits
• None
FunctionTheshafttopprotectstheflueductsystemfrommechanicalandliveloadimpacts.Furtheritprovides a base for the lid cover and usually also for naturaldraughtchimneys.
Design principlesTheshafttopstructureshouldnotdisturbaverticalexpansionoftherefractoryshaft.
Itshouldbedesignedinsuchawaythatadditionalfeatureslikeflueductguides,lid-coverbaseandchimneyscanbesecurelyfixed.
Theexpansiongapmustbesealedwithflexiblematerialtoavoidheatlossafterthekilnisfullydriedout.
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OPTION 1 : Natural draught with flue ducts
Advantages
• Noelectricityrequired,henceaneconomicaloption
• Canbeconstructedwithmaterialotherthanmetal,i.e.firedbricks
Disadvantages & Limits
• Draughtcanvarywithweatherconditions
• Difficulttoerectandtieupthechimneys,especiallyinhighwindproneareas
• Highwearandtearofmetalpartsduetocorrosionfromacidicemissions
FunctionTheemissionexhaustsystemistoprovidethedraftforproperfirepositioningaswellastodischargeexhaustgasesatasafeheight.
Design principlesTheemissionexhaustsystemmustbedesignedbyrespectiveexperts.
17 EmISSION ExhAuST SySTEm
VSBKDeSIgNOPTIONgUIDeLINeS \ 35
FuTuRE OPTION 1 : Natural draught without flue ductsNote:Thissystemispreferredformultipleshafts.
Advantages
• elongatedfiringcurve• Uniformdraught• User friendly draught control• OneShaft-onechimney• Duringloading,emissionscan
be extracted separately• Inbuiltshaftlid,hencereduced
health hazard
Disadvantages & Limits
• Anticorrosivematerialrequired for the hood
• Potentialofincreasedhoodsystemmaintenance
OPTION 2 : Forced draught with flue ducts
Advantages
• Uniformdraught,hencebetterfirepositioncontrol
• Onechimneycanbeusedformultipleshafts
• Brickqualityislikelytobemoreuniform
Disadvantages & Limits
• Requires electricity, including a back-upsystem
• exhaustgastemperaturesmustbemaintainedtoavoidcorrosionofmetalparts
• Increasedmaintenancecosts
17 EmISSION ExhAuST SySTEm
36 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 1 : m.S. sheet flat dampers
Advantages
• Areaneconomicaloption• User friendly to operate and
repair
Disadvantages & Limits
• Probability of excess air entering
• Highcorrosionpotential
FunctionFluegasdampers/valvesregulatetheairflowwithinthesystem,thereforesteeringtheappropriatefirescheduleandensuringacleanworkingenvironmentwhileloadingthebricks.
Design principlesTheupperandlowerflueductsystemrequirestwoindependentvalves/damperseach,hence4valves/dampersarerequiredpershaft.
Valvesanddampersshouldbedesignedsothatleastamountofflue-gassescanpasswhentheyarecompletelyshut.
Damperslotsmustbeconstructedsothatnoexcessaircanenterintotheemissionexhaustsystem.
18 FluE GAS DAmPERS/VAlVES
VSBKDeSIgNOPTIONgUIDeLINeS \ 37
OPTION 2 : m.S. sheet butterfly dampers
Advantages
• Areaneconomicaloption• User friendly to operate• Reduced probability of excess
air
Disadvantages & Limits
• Highcorrosionpotential• Replacementonlypossibleduringshaftclosure,henceexpensive
18 FluE GAS DAmPERS/VAlVES
OPTION 3 : Valves for forced draught system
Advantages
• easiertocontroltheairflow• Airflowmetergaugecanbe
installed
Disadvantages & Limits
• expensiveairflowmanagementsystem
• Highcorrosionpotentialifgreenbrickswith>1%moisturecontentareloaded
• Potentialexcessairproblemsifgapbetweenrefractoryshaft(flueductchannelopening)andvalvemouthisnotsealed
38 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 1 : m.S. sheet lid/elements
Advantages
• Isaneconomicaloption
Disadvantages & Limits
• Highcorrosionpotential
FunctionTheshaftlidsupportstheefficiencyofthecountercurrentairflowprinciple(energyefficiency)andensuresacleanworkingandgeneralenvironmentonaVSBK.
Design principlesShaftlidshouldbedesigneduser-friendlyaswellaslightweight,fireandpreferablycorrosionresistantmaterials.
19 ShAFT lID
VSBKDeSIgNOPTIONgUIDeLINeS \ 39
OPTION 2 : Stainless steel sheet
Advantages
• Lowercorrosionpotential
Disadvantages & Limits
• expensiveoption
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40 / VSBKDeSIgNOPTIONgUIDeLINeS
FunctionTheunloadingbarssupportthebricksettinginsidetheshaftduringregularoperationandtransferthebricksettingloadtothebricksupportI-beams.
Design principlesAnunloadingbarshouldbedesignedlightweight,smallincrosssectionandmustbeabletoresisthighheatstressesunderconstantloadofapprox.4tons.
Note:Unloadingbarsaretobeconsideredoperationwear-and-tearmaterial.
20 uNlOADING BARS
OPTION 1 : m.S. square bars
Advantages
• LighterthanM.S.I-bars
Disadvantages & Limits
• Highchanceofbrickbreakagesduetoreducedflangewidth
VSBKDeSIgNOPTIONgUIDeLINeS \ 41
OPTION 3 : Reinforced m.S. square bars
Advantages
• Canbeusedforlargershaftdimension
Disadvantages & Limits
• Highchanceofbrickbreakagesduetoreducedflangewidth
20 uNlOADING BARS
OPTION 2 : m.S. I-bars
Advantages
• StrongerthanM.S.squarebars• Lesschanceofbrickbreakagesduetobiggerflangewidth
Disadvantages & Limits
• HeavierthanM.S.squarebarsand therefore rarely used for largershaftdimension
42 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 1 : m.S. trolleys
Advantages
• Locally available and economicalfabrication
• Lightweighttrolleyscanbedesignedwhenusinga hydraulic unloading mechanism
Disadvantages & Limits
• Trolleyweightincreaseswithlargershaftsize
FunctionTheunloadingtrolleyisusedtounloadthefiredbricksandtotransportthemtotheunloadingstations.
Design principlesThe unloading trolley should be designed in such a waythatitcanbearthebricksettingloadwithoutwarpingorbending.
Itmustbeaslightaspossiblebutstrongenoughtohandleemergencysituations.
21 uNlOADING TROllEy
VSBKDeSIgNOPTIONgUIDeLINeS \ 43
OPTION 1 : Screw jack mechanismNote:Screwmustbefabricatedwithhighcarbonsteel.
Advantages
• Noelectricityrequired• Anelectromotorcanbe(retro)fittedtomechanicallyoperatethescrewjackmechanism
Disadvantages & Limits
• Complexandtimeconsumingfabricationprocess
• Maintenance of nut is high as itismadeofcast-iron
• Accidentpronesystemandhardworkforpersonnel
FunctionThebrickunloadingsystemraisesandlowersthetrolleyandthebricksettingsinsidetheshaft.
Design principlesTheunloadingmechanismmustbecapableofbearingtheentirebricksettingloadinsidetheshaftandtoliftittothepointwherethesupportbarscanberetractedduringtheunloadingofthebrickswithoutthethreatofsuddenfailure.
Bothscrewjackandhydraulicunloadingsystemareingeneraldesignedtocarryandliftupto30tonsofweight(bricksandtrolley).
22 BRICK uNlOADING SySTEm
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OPTION 2 : hydraulic mechanism
Advantages
• easytohandle,workingpersonnel are not exposed to hardworkandfallingcoal
• Nogirdersystemrequired,henceconstructiontimeandcost saving
• Fewerworkersrequired• Manualpowerpackcanbeappliedincaseofpowerfailure
• Trolleytrackcanbenarrowedand therefore trolley movementiseasier
Disadvantages & Limits
• Requires electricity, including a back-upsystem
• Expensive lubricants required• Requires special dust protection
22 BRICK uNlOADING SySTEm
VSBKDeSIgNOPTIONgUIDeLINeS \ 45
OPTION 1 : Ramp/staircase
Advantages
• Possiblythemosteconomicalconstructionoption
• Requires no electricity• Dependingongradientangle,mechanicalequipmentcanbeusedtocarrybricks
Disadvantages & Limits
• Drudgeryworkforemployedpersonnel
• Highgreenbrickhandlingdamagepotential
FunctionIsthemeanstotransportgreenbricksandcoaluptotheworkingplatformlevelforanuninterruptedfiringprocess.
Design principlesThemaindesignparameteristotransportdrygreenbricksfromthegroundleveltotheworkingplatformlevelinthemosteconomicalway,ensuringthatthegreenbrickqualityisnotcompromised.
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46 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 3 : lift
Advantages
• Reduced drudgery• Lessworkforcerequiredwhencomparedtomanualtransportationsystem
• Lowgreenbrickdamagepotential
Disadvantages & Limits
• Requirespower(electricityorfuelgenerator)tooperate
OPTION 2 : Conveyor belt
Advantages
• Reduces drudgery• Lessworkforcerequiredwhencomparedtomanualtransportationsystem
• Veryefficientandswifttransportationsystem
Disadvantages & Limits
• Highdrygreenbrickhandlingdamagepotential
• Highwearandtear,hencehighmaintenanceandrepaircostpotential
• Requirespower(electricityorfuelgenerator)tooperate
• Potentialoffallinggreenbricksincreasestheriskofinjury
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VSBKDeSIgNOPTIONgUIDeLINeS \ 47
OPTION 4 : Gantry
Advantages
• Reduced drudgery • Lessworkforcerequiredcomparedtoanyothersystem
• Lowgreenbrickdamagepotential
• Mechanized loading of green bricksintogantrycagepossible
Disadvantages & Limits
• Highinitialinvestment• Onlyeconomicalforlargenumbersofshafts
• Requirespower(electricityorfuelgenerator)tooperate
• Requiresconsiderableplatformspace
23 ACCESS TO ThE wORKING PlATFORm
48 / VSBKDeSIgNOPTIONgUIDeLINeS
OPTION 1 : high-end level(Corrugated/plainplasticroofingsheetsorP.V.C.corrugated/plainsheetsonslopedM.S.pipetrussesandpurlins)(Slopedconcreteorferro-cementroof)
Advantages
• Isresistanttodamagingemissions
Disadvantages & Limits
• Is an expensive roof
FunctionTheroofprotectsthekilnstructureandworkingpersonnelfromtheelementssuchasrain,sunandwind.
Design principlesRoofshouldbedesignedaseconomicallyaspossiblewhileatthesametimeensuringthatthekilnremainsdry,greenbricksandworkingpersonnelareprotected.
Aroofmonitorisessentialtoensureproperventilationthatreducestheaccumulationofharmfulemissions.Theheightoftheroofshouldbeenoughforthefiremastertoworkefficientlyabovetheshafttopforloadingbricks.
24 ROOF
VSBKDeSIgNOPTIONgUIDeLINeS \ 49
OPTION 3 : Budget level(Biodegradablematerials:Bamboomatsorclayroofingtilesontimberorbambootrussesandpurlins)
Advantages
• Isalowcostandfunctionalroofingoption
Disadvantages & Limits
• Requiresregularreplacement/repairduetorelativeshortlifespanofmaterial
• Potentialofrainleakingexists
OPTION 2 : Normal range level(Colourcoatedroofsheets/corrugated/plain,galvanizedironsheetsonslopedM.S.pipetrussesandpurlins)
Advantages
• Isaneconomicalsolution
Disadvantages & Limits
• Requires frequent maintenanceduetocorrosionproblems
24 ROOF
Note