bangladesh national building code 2012 part 09 – alteration, addition to and change of use of...

8/11/2019 Bangladesh National Building Code 2012 Part 09 Alteration, Addition to and Change of Use of Existing Buildings

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Part9

Alteration,AdditiontoandChangeofUseofExistingBuildings 91

Chapter 1

Applicability and Implementation

1.1 General

Theprovisionsof thispartare intended tomaintainor increase thecurrentdegreeofpublicsafetyaswellas

healthandgeneralwelfareinexistingbuildingswhilepermittingalteration,additiontoorchangeofuse.

Inaddition,certainenvironmentalmeasurestomaketheexistingbuildingstocksustainable, isalsoarequirement

thatneedstobeaddressedtomakebuildingsmoreenergyefficientandenvironmentallyresponsive.Thisconcept

isintroducedinChapter2ofthisPart.

1.2 Applicability

1.2.1

General

The provision of this part shall apply to existing buildings that will continue to be or are proposed to be in

occupancy groups A, B, E, F, H, I, M, R and S. The provisions shall not apply to buildings of historical or

architecturalvalue identifiedandclassifiedbydesignatedauthorities.Forbuildingsofhistoricalorarchitectural

value buildings, the provisions of Sec 1.5: Historic or Architecturally Valuable Buildings, of Part 1, Sec 1.16:

BuildingsandPlacesofHistoricalorArchitectural Value,ofPart3andchapter3:Conservation andrehabilitation

ofhistoricalandculturalheritage,ofPart9,shallbeapplicable.

Certainprovisions toexistingbuildingsand landuseevenwhenadditions,alterationsoramendmentsarenot

proposedareincludedinSection2.3:SustainabilitymeasuresforexistingbuildingsChapter2ofthisPart.

1.2.2 Changeinuse

1.2.2.1

Nochange

in

use

of

any

existing

building

shall

be

made

without

permission

from

the

permitting

authority.

1.2.2.2 Nochangeinuseofanexistingbuildingshallbeallowed iftheproposeduseisnotinconformitywithland

usepatternasreferredinPart3,Sec1.3,andwithinthepermittedoccupancyclassesofPart3,Sec1.4,as

maybedeterminedbythecityorareadevelopmentauthoritieshavingjurisdictions.

1.2.2.3 Whereanexistingbuildingischangedtoanewusegroupclassification,theprovisionsforthenewusegroup

inthisCodeshallbeusedtodeterminecompliance.

1.2.3 PartChangeinuse

1.2.3.1 Nochangeinuseofanypartofanexistingbuildingshallbemadewithoutpermissionfromthepermitting

authority.

1.2.3.2 Whereaportionofthebuildingischangedtoanewusegroupclassification,andthatportionisseparated

fromtheremainderofthebuildingwithfireseparationassemblieshavingafireresistanceratingasrequired

by Part 4, Fire Protection, for the separate uses, the portion changed shall bemade to conform to the

provisionsofthisCode.

PERSONAL COLLECTION OF

ENGR. PRANOY BARUA

BANGLADESH STEEL RE-ROLLING MILLS LTD

[email protected]


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1.2.3.3 Where a portion of the building is changed to a new use group classification, and that portion is not

separatedfromtheremainderofthebuildingwithfireseparationassemblieshavingafireresistancerating

asrequiredbyPart4,Fire,fortheseparateuses,theprovisionsofthisCodewhichapplytoeachuseshall

apply to theentirebuilding.Where thereareconflictingprovisions, thoserequirementswhichsecure the

greaterpublicsafetyshallapplytotheentirebuildingorstructure.

1.2.4 Additions

1.2.4.1

Noaddition

to

any

existing

buildings

shall

be

made

without

permission

from

the

permitting

authority.

1.2.4.2 AdditionstoexistingbuildingsshallcomplywithalltherequirementsofthisCodefornewconstructionsas

setforthinPart3ofthisCodeandshallcomplywithfirerequirementssetforthinPart4ofthisCode.

1.2.4.3 Thecombinedheightandareaoftheexistingbuildingsandnewadditionsshallnotexceedtheheightand

openspacerequirementsfornewbuildingsspecifiedinPart3ofthisCode.

1.2.4.4 WhereaseparatingwallthatcomplieswithPart4,FireProtection,isprovidedbetweentheadditionandthe

existingbuilding,theadditionshallbeconsideredasaseparatebuilding.

1.2.5

Alterations

1.2.5.1

AnexistingbuildingorportionthereofwhichdoesnotcomplywiththerequirementsofthisCodefornew

construction (Part3) shallnotbe altered in suchamanner that results in thebuildingbeing less safeor

sanitarythansuchbuildingisatpresent.

1.2.5.2 If, in the alteration the present level of safety or sanitation is to be reduced, the portion altered shall

conformtotherequirementsofthisCode.

1.2.6 Removal

1.2.6.1 Any construction within the site which does not have approval of the appropriate authority must be

removedbefore any new addition, alterationor changeof use is carried out.All other types of existing

constructionandtheirchangesshallcomplywithsubclauses1.2.4and1.2.5ofthisPart.

1.2.6.2 Before demolishing a building of construction type 1 (Part 4: Fire Protection) the owner shall notify all

utilities having service connectionswithin thebuilding or plot, such aswater, gas, electricity, sewer and

otherconnections.

1.2.6.3 Apermit todemolishabuildingshallnotbe issueduntilaclearance isobtained fromutilitiesstating that

theirrespectiveserviceconnectionsandappurtenantequipments,suchas,metersandregulatorshavebeen

removedorsealedandpluggedinasafemanner.

1.3 Implementation

1.3.1

Investigation

and

Evaluation

Fortheproposedworksrelatingtoalteration,additiontoandchangeofuse,theownerofthebuildingshallcause

the existing buildings to be investigated and evaluated by competent professionals in accordance with the

provisionsofthisCode.

1.3.2 StructuralAnalysis

1.3.2.1 Theowner shall have a structural analysis of theexistingbuilding carriedout byprofessional experts to

determinetheadequacyofallstructuralsystemsfortheproposedalteration,additionorchangeofuse.


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1.3.2.2 Theexistingbuilding togetherwith theadditionoralterationshallbecapableofsupporting theminimum

loadrequirementsspecifiedinPart6:StructuralDesign,ofthisCode.

1.3.3 Submittal

TheresultsoftheinvestigationandevaluationasrequiredinSec.1.3.1abovealongwithallproposedcompliance

alternativesshallbesubmittedtotheBuildingOfficialforpermissiontoimplementaddition,alterationorchange

ofuse.

1.3.4 DeterminationofCompliance

TheBuildingOfficialshallexamineallrelevantdocuments,asspecifiedbytheauthorities,anddeterminewhether

the existingbuilding,with theproposed additions, alterationsor changeofuse, complieswith theprovisions

specifiedinthisCodefortheoccupancyclassificationandtypeofconstruction.


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Chapter 2

Evaluation and Compliance

2.1 Evaluation

Theevaluationoftheexistingbuildingwiththeproposedadditions,alterationsorchangeofuse,shalltake into

consideration the planning requirements as well as those relating to public safety and environmental

sustainability.

2.1.1 PlanningRequirements

2.1.1.1 ThepermittingauthoritythroughbuildingofficialsshalldetermineifanyprovisionsofthisCodeareviolated

bytheproposedchangeofuse,additionoralterationworks.

2.1.1.2 Thegeneralrequirementsforbuildingsinvariousoccupancyclassesandtypesofconstructionarespecified

inPart3:GeneralBuildingRequirementsandPart8:BuildingServices,ofthisCode.Theseinclude:

a) Landuseclassificationandpermitteduse(Sec.1.3Part3)

b) Requirementofplots(Sec.1.5,Part3)

c) Meansofaccess(Sec.1.6,Part3);andstaircase(Sec.1.12.5,Part3)

d) Universal accessibility requirementsof various Sectionsof Chapter 3 andAppendixD: universal

accessibility

e) Openspaceswithinaplot;minimumseparationofbuildingsinthesameplot;roadfront,sideand

rearopenspaces,PermittedConstruction intheMandatoryOpenSpace(Sec.1.7Part3)

f) GeneralheightandarealimitationsbasedonFAR(Sec.1.8.2,Part3)orbasedonRoadWidth(Sec.

1.8.3,Part3)

g)

Off

street

(on

site)

parking

spaces

(Sec.

1.9,

Part

3

and

Appendix

F:

Road

Hierarchy,

On

street

and

OnsiteParking)

h) Streetencroachment(Sec.1.10,Part3)

i) Communityopenspaceandamenitiesforvarioustypesofbuildings (Sec.1.11,Part3)

j) Ventilation requirements (natural:Sec.1.17,Part3;artificial:Chapter3,Part8:AirConditioning,

HeatingandVentilation)

k) Lighting and illumination requirements (Sec 1.17, Sec 4.4.1: Electric lighting, 4.6.1: Daylighting,

4.6.2:Supplementary lightingsystem, Part3andChapter1:ElectricalandElectronicEngineering

ServicesforBuildings,Part8)

l) Sanitationanddrainagerequirements(Sec1.18,Sec4.2.5:Sitedrainageandrunoffcoefficient,4.3:

WaterEfficiencyandmanagementofPart3andChapters5:WaterSupplyandChapter6:Sanitary

Drainage,Part8)

m)

Minimumdimension

of

habitable

and

non

habitable

parts

of

the

buildings

(Sec.

1.12,

Part

3).

2.1.1.3 The existing building with proposed alteration or addition shall conform to the requirements of new

buildings intheproposedoccupancyclassification.Theproposedalterationoradditionshallnotmakethe

buildinglesssanitarythanpresent.

2.1.1.4 Topromote thepreservationofhistoricbuildings,openspaceoruniquearchitectural/ culturalresources,

the local permitting authority shall transfer development rights (TDR), as decided by the authority, to

ownersascompensation,inaccordancewithAppendixE,Part3ofthisCode.


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2.1.2

Safety

Requirements

2.1.2.1 Additions or alterations to an existing building or structure are not to be made if such additions or

alterations cause thebuildingor structure tobeunsafeormorehazardousbasedon fire safety, lifeand

structuralsafetyorenvironmental degradation.

2.1.2.2 The fire safety requirement shall take into consideration the structural fire resistance, smoke and fire

detection, fire protective signaling and fire suppression system feature of the facility and satisfy the

requirementsofvariouselementsforTypes1,2and3fireresistivebuildingsshallbesatisfied.

2.1.2.3 The fire resistance of the wall used for compartmentalization of a building shall not be less than that

specifiedinsubsectionsofSec2.4,Part3ofthisCode.

2.1.2.4 Ductpenetrationsofthiswallshallnotbepermitted.Ferrousorcopperpipingandconduitshallbeallowed

to penetrate or pass through the wall if the openings around such piping and conduit are sealed with

impervious noncombustible materials sufficiently tight to prevent fire transfer of smoke or combustible

gasesfromonesideofthewalltotheothersideandaresomaintained.

2.1.2.5 Thefiredoorbetweencompartmentsservingashorizontalexitshallbesoinstalled,fittedandprovidedwith

gasketsthatsuchfiredoorwillprovideasubstantialbarriertothepassageofsmoke.

2.1.2.6 Thefloor/ceilingshallbeofsuchconstructionthatthefireresistiveintegritybetweenstoriesismaintained.

2.1.2.7 The smokedetection capabilitywithin the facilitybasedon the location andoperationof automatic fire

detectors shall be evaluated with respect to the requirements of Chapter 3: Means of Escape and 4:

EquipmentandInbuiltFacilitiesofPart4forthevariousoccupanciesinthisCode.

2.1.2.8 Wherea fireprotecting alarmandsignalingsystem isprovided, thecapabilityof thesystemshallalsobe

evaluated(Part4).

2.1.2.9 Theabilityofthenaturalormechanicalventing,exhaustorpressurizationsystemtocontrolthemovement

ofsmokefromafireshallbeevaluated.

2.1.2.10

TheshaftandexitenclosuresshallsatisfytherequirementsspecifiedinPart4:FireProtection,ofthisCode.

2.1.2.11 The configuration, characteristics and support features for means of egress in the facility including the

capacityofand thenumberofexit routesavailable to thebuildingoccupants shallbeevaluatedand the

adequacyof themeansofegress routes leading toasafearea shallbeexamined.The lengthof theexit

access travelpath inwhichbuildingoccupants areconfined toa singlepathof travel shallbeevaluated.

Similarly the length ofexit access travel to an approved exit shall beevaluatedwith respect to theexit

requirementsforvariousoccupanciesasdetailedinPart4:FireProtectionofthisCode.

2.1.2.12 The efficiency and effectiveness of the elevator equipments and controls that are available to the fire

department to rescue building occupants from upper floors during a fire when such an equipment is

installed,shallbeevaluated.

2.1.2.13 Thepresenceofandreliabilityofmeansofegressemergencylightingsystemshallbeevaluated.

2.1.2.14 Theabilitytosuppressfirebasedontheinstallationofautomaticsprinklerandstandpipesystemsshallbe

evaluated (chapter 4: Equipment and Inbuilt Facilities Standards and 5: Specific Requirements for Fire

DetectionandExtinguishingSystem,Part4:FireProtection).

2.1.2.15 The lightningprotectionofthebuildingshallsatisfytherequirementsspecified inchapter1:Electricaland

ElectronicEngineeringServicesforBuildingsofPart8.


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2.1.3 EgressRequirements

2.1.3.1 Additiontooralterationorchangesofuseofabuildingshallnotbepermittedifsuchadditionoralteration

orchangeofusecausesviolationoftheegressrequirementsspecifiedinChapter3,MeansofEscape,Part4:

FireProtection.

2.1.3.2

Permissionsshall

not

be

granted

for

any

such

work

that

will

obstruct

or

block

or

hamper

the

existing

means

of egress of the building or any other building unless an equivalent and adequate means of egress is

provided.

2.1.4 StructuralRequirements

2.1.4.1 Additionsto,alterationsorchangeofuseofanexistingbuildingorstructureshallnotbepermittedifthey

causeanoverloadingorinstabilityofthestructuralelementsincludingthefoundation.

2.1.4.2 Onevaluation,ifthestructureoftheexistingbuildingisfoundinnonconformitywiththesafetyprovisions

ofthiscode,thebuildingwillbedeclaredasunsafebuildingbytheauthority.

2.1.4.3

Forall

buildings

identified

as

an

unsafe

building

the

authorities

shall

identify

measures

that

remove

danger

tothestructure,lifeorpropertysothatthebuildingcanbemadesafeforoccupation.

2.1.4.4 Buildingsthatcannotbemadestructurallysafewillbedeclaredunfitforoccupationanddemolishedbythe

authorities.

2.1.5 EnvironmentalRequirements

Additionsto,alterationsorchangeofuseofanexistingbuildingorstructureshallnotbepermitted if

theycauseenvironmental degradationandunsustainabledevelopmentinthelocality.

2.2 Compliance

2.2.1.1 Whenanevaluationiscarriedoutasdescribedaboveandtheexistingbuildingwiththeproposedalteration,

additionand/orchangeofusesatisfytherequirementspecifiedfortherelevantoccupancyclassification,the

resultsoftheevaluationshallbeacceptedbytheBuildingOfficial.

2.2.1.2 Theownershallfullycomplywiththeresultsofsuchevaluationfortheexistingbuildingwiththeproposed

alteration, addition and/or changeofuse for the relevantoccupancy classification and its recommended

remediesifrelevantassetforthinSec2.1.4above.

2.3 Sustainabilitymeasuresforexistingbuildings

2.3.1 Evenwhen there are no proposals for additions, alterations or change of use,measures tomake Existing

Building stock sustainable and environmentally responsive and energy efficient shall be proposed by the

authority after evaluating the condition of the existing buildings, when it is found that environmental

degradationistakingplaceorsuchisfearedbyexperts.Thesemeasuresmayinclude,butwillnotberestricted

to:

a) introductionofrenewableenergy

b) installationofrainwaterharvesting

c) installationofgroundwaterrechargesystems

d) introductionoflowenergysources


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2.3.2

Any sustainabilityand /orenergyefficiencymeasure suggested shall complywith relevant requirements in

Chapter4:EnergyEfficiencyandSustainability,Part3ofthisCode.


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Chapter 3

Conservation and rehabilitation of historical

and cultural heritage

3.1 Scope

Historical places, buildings, objects and manifestation of cultural, scientific, symbolic, spiritual and

religious value are important expressions of the culture and heritage, identity and religious beliefs of

societies. Their role and importance, particularly in the light of the need for cultural identity and

continuityinarapidlychangingworld,needtobepromoted.

Buildings, spaces, places and landscapes charged with historical, cultural, spiritual and religious value

represent an important element of stable and humane social life and community pride. Without

appropriaterestoration/conservation, thearchitecturalevolutioninrelationtosocioculturalconceptof

acountrys

heritage

remains

misinterpreted,

and

can

lead

to

virtual

disappearance.

3.2 TerminologyandConceptualDefinitions

3.2.1 Conservation

National legislationand international treatiesandregulationsaimtostrikeabalancebetweentheneed

fordevelopmentandtheneedtoconservetheenvironmentforthefuture.Conservationcanbedefined

bythefollowingconcepts:

a) Plannedmanagementofanaturalresource/ecosystemorparticularbuiltformorenvironment

to prevent exploitation, pollution, destruction or neglect to ensure the future usabilityof the

resource.

b)

Retentionof

existing

buildings

or

groups

of

buildings,

landscapes

etc.

taking

care

not

to

alter

or

destroycharacterordetail,eventhoughrepairsorchangesmaybenecessary.

Conservationconventionallyisconcernedtopreserveasmuchoriginalfabricaspossible.

3.2.2 Restoration

Thisistheprocessofcarryingonalterationsandrepairstoabuildingwiththeintentionofrestoringitto

itsoriginalform,often involvingreinstatementofmissingorbadlydamagedparts,so itusually includes

replication. Asfaraspossible,effortsaremadetoreplicatethematerialsandconstructiontechniquesof

theoriginalinthisendeavor.

Whileoftennecessaryafteradisaster, it isgenerallyregardedasmoredrasticthanconservation, which

suggestsretention,repairandmaintenance.

3.3 GeneralGuidelinesforHeritageBuildingsandSites

3.3.1 Conservation, rehabilitationandculturally sensitiveadaptive reuseofurban, ruralandarchitectural

heritageshallbeinaccordancewiththesustainableuseofnaturalandhumanmaderesources.Access

to culture and the cultural dimension of development is of utmost importance, benefiting all the

peoplewhohavesuchaccess.


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3.3.2 Inordertopromotehistoricalandculturalcontinuityandtoencouragebroadcivicparticipationinall

kindsofculturalactivities, theGovernmentattheappropriate levels, includingthe localauthorities,

shouldundertakethefollowing:

a) Identifyanddocument,wheneverpossible,thehistoricalandculturalsignificanceofareas,

sites,landscapes,ecosystems,buildingsandotherobjectsandmanifestations

b) Establish conservation goals relevant to the cultural and spiritual development of the

society;

c)

Promote

awareness

of

heritage

in

order

to

highlight

its

value

and

the

need

for

its

conservation andthefinancialviabilityofrehabilitation;

d) Encourage and support the local heritage and cultural institutions, association and

communities in theirconservationandrehabilitationeffortsand inculcate inchildrenand

youthanadequatesenseoftheirheritage;

e) Promote adequate financial and legal support for the effective protection of cultural

heritage;

f) Promote education and training in traditional skills in all disciplines appropriate to the

conservation andpromotionofheritage.

3.3.3 Tointegratedevelopmentwithconservationandrehabilitationgoals,theGovernmentatappropriate

levels,includingMinistries,localauthoritiesandmunicipalities,shallundertakethefollowing:

a) Recognizingthathistoricalandculturalheritageisanimportantasset,strivetomaintainthe

social,cultural

and

economic

viability

of

historically

and

culturally

important

sites

and

communities;

b) Preserve the inherited historical settlement and landscape forms, while protecting the

integrityof thehistoricalurban fabricand therebyguidingnew construction inhistorical

areas;

c) Provideadequate legaland financial support for the implementationofconservation and

rehabilitation activities, in particular through adequate training of specialized human

resources;

d) Promote incentives for such conservation and rehabilitation to public, private and non

profitdevelopers;

e) Promote community based action for the conservation, rehabilitation, regeneration and

maintenanceofneighborhoods;

f)

Support

public

and

private

sector

and

community

partnership

for

the

rehabilitation

of

inner

citiesandneighborhoods;

g) Ensure the incorporation of environmental concerns in conservation and rehabilitation

projects;

h) Takemeasurestoreduceacidrainandothertypesofenvironmentalpollutionthatdamage

tobuildingsandotheritemsofculturalandhistoricalvalue;

i) Adopt human settlement planning policies, including transport and other infrastructure

policies,thatavoidenvironmentaldegradationofhistoricalandculturalareas;

j) Ensure that the accessibility concerns of people with disabilities are incorporated in

conservation andrehabilitation projects.

3.3.4 Intheeventthattheownerofasite/buildingneedstobecompensatedforcurtailingdevelopment,

thetransferofunuseddevelopmentrightsshallbemadeasstipulatedinAppendixE,Part3.

3.4 CriteriaforprotectionofaHeritageBuilding/monument

3.4.1 Identification

Heritagebuildingsaretobeenlisted/identifiedbyaresponsiblecommitteetobeformedbytherelevant

departmentsof theGovernment,consistingofexperts inhistory,culture,architecture,engineeringand

other relevant fields, in consultation with theAdvisoryCommittee to theDepartmentofArchaeology,

Government of Bangladesh, as constituted under the Antiquities Act of 1968. Once identified, the

Government may, by notification in the official Gazette, declare any heritage building to be a protected antiquity

under this same Act.


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3.4.2

Categorization

Heritage buildings are to be categorized in accordance with its degree of dilapidation / dilapidated

conditions

3.4.3 Chronology

Heritagebuildingsunderconsiderationwillalsobecategorizedchronologicallyinanattempttodetermine

theirancientcharacterandage

3.4.4

Documentation

Beforeanyconservationworkisinitiated,athoroughresearchanddocumentationistobecarriedouton

theheritagebuildingsunderconsiderationbyrelevanttechnicalexpertsonhistory,culture,architecture,

engineeringandmaterialsciences,toensurethattherestorationworkisfaithfullycarriedout.

Asitesurvey (preferablywithdigitalequipments)shallbeconductedbefore initiating theworkofeach

andindividualbuilding/structure.

Inorder tounderstand the location,dimension anddepthof foundationof columns /piersor similar

structuralcomponents,partofthefootingcanbeexposedbyexcavatingtheearthworkwiththeguidance

ofexperiencedtechnicalpersonsexecutedbyexperiencedworkers.

Subsequently at every stage of the conservation work the technical aspects and process of various

activitiesaretobedocumented

3.4.5 CommunityParticipation

Inordertoensurecommunityparticipationintheconservationprocess,scaleddrawingsoftheproposed

conservation shall be appended to the site during construction so that the public may become

accustomedtotheproposalandhavetheoptionofregisteringtheiropinionregardingthesame.

Ifnecessary theproposals shallbeamended if strongpublicopinion is found against theproposal for

conservation/restoration.

Wherepossible,localyouthgroupsshallbeusedforfacilitatingtheconservation process.

3.4.6 Protectionofthebuilding/site

3.4.6.1 Aclearspacearoundeachmonumentshallbeformedasanimmediateenvironmentalprotectionto

themonument.

This

area

should

follow,

as

the

case

may

be,

the

original

line

of

the

enclosure

wall.

3.4.6.2 In ruralor suburban settingnonew structures /built formsof any size, shape shallbeallowed to

developwithin theUNESCO /UNDPsuggestedareaofhalfamile radius from theepicenterof the

monumentunderconsideration.

3.4.6.3 Inruralor suburbansettings,aparceloflandrepresentingapproximatelyacircularareaofahalfmile

radiusofthefarmland immediatelysurroundingtheheritagebuilding/monumentshallbeacquired

toprotectitfromencroachment

3.4.6.4

Inurbanareasormetropolitancitiesan immediatebufferzoneassetbythepermittingauthorities,

butnotlessthan3metersinwidth,adjacenttotheheritagebuilding,mustbekeptabsolutelyfreeof

any

structure

or

establishment

of

similar

nature

surrounding

the

heritage

building

or

its

part

thereof.

The adjacent buildings (proposed) should follow certain height restrictions to be imposed by the

permittingauthorityassetforthinSec3.4.5.5below.

3.4.6.5 Ingeneral,theheightofanyproposedbuildingsadjacenttoheritagebuildingsshallbekeptlimitedto

withintwotimestheheightoftheheritagebuildingunderconsideration.

3.4.6.6 Toprotectthemonumentagainsthuman impact,movementofvisitorswithinthestructureandsite

shallbecontrolled.Climbingoverthefabricofthemonumentshallbeillegalandbepreventedatall

times.


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3.4.6.7

Signages shall be installed within the site and building premises to guide visitors by creating

circumambulatorypathorcirculationareaaroundeachoftheheritagebuildings/monuments.

3.4.7 OriginalElements

3.4.7.1 Structures that impinge directly on the monument/s, identified to be additions, alterations or

extensions of any form or kind on to the original monument/s, shall be removed/ relocated

elsewhere,inanattempttorecognizetheoriginalform/featureofthemonument.

3.4.7.2 Alloriginalstructuresandarchitecturalelementsaretoberetainedandrestored.

3.4.7.3 Intheeventthatsuchelementshavetoberepaired,theirfeaturesaretoberetainedintact.

3.4.8 Useofbuildingmaterials

3.4.8.1 Allrepairing,restorationandrenovationworkshallbedonefollowingtheoriginaldesignanddetails

ineverystepwiththesame/similarbuildingmaterialsused

3.4.8.2 Selectionand applicationofmaterialsare tobemade inharmonywith thematerialsused in the

past/duringtheperiodoforiginalconstructionofthemonument/building underconsideration

3.4.8.3 Sand

3.4.8.3.1 Sandused inthemakingofmortar,shallbecoarsegrained,perfectlyclean,sharpandyellowish

color,inorderthatasuccessfulresultmaybeobtainedforcementandlimemortar.Finegrained,

dustyanddirtysandshallnotbeusedandeachfreshconsignmentshallbecarefully inspectedin

ordertoseethatitcorrespondswiththesampleapprovedinthefirstcase.

3.4.8.3.2 Sands,whichwouldotherwisebeofgoodquality,but containing lumpsof foreignmatter,ora

qualityofdustyparticlesmaybeused,onlyafterithasbeenthoroughlywashedandexamined.

3.4.8.3.3 Seasandcontainsaquantityofsaltwhichwillcauseefflorescencewhenthemortarisset.Ifused

forthe

mortar,

the

salt

from

this

sand

shall

be

eliminated

by

very

thorough

washing

in

clean

water,

thewaterbeingrenewedateachwashing.

3.4.8.4 Brick

3.4.8.4.1 Nomodern bricks are to be used on any old buildingswithout the approvalof an appropriate

technicalperson/expertofConservation.

3.4.8.4.2 Inrepairingbrickwork,bricksofthesamesizeandfabricastheoriginalshallbeused.Inabsenceof

instructions,thebricksshallbe laid inthesamebond,andthemortarjointsshallbeofthesame

thicknessandtonedtothesamecoloras intheoriginalwork.Whendesirable,themortarjoints

mayberecessedabout6.5mm 12.5mmbackfromtheface.

3.4.8.5

Cement

3.4.8.5.1 Cementshallbeslowsetting,complyingwiththestandardspecificationofPortlandcement.Inthe

absence of specific instruction/s, the use of cement on any conspicuous part of a building for

pointing,plasteringorotherpurposes shallbe avoided, as ifvisible, itwillexpressanoticeably

modernnotetothestructure.

3.4.8.6 Cementconcretemix

3.4.8.6.1 TheCementconcreteshallbevariedinaccordancewithlocalnecessities.


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3.4.8.6.2

Themixforfoundationsshallbe1partofPortlandcement,3partsofsandand8partsofclean

stone,brickorgravelbrokentoapproximatelyoneandhalfinch,mixedthoroughly.

3.4.8.6.3 Themixforflooringandterracingshallbe,1partofPortlandcement,2partsofsandand5partsof

stone,brickorgraveletc.brokenapproximatelyto1inchring.

3.4.8.7 Limemortar

Limemortarofwhichthetensilestrengthislessthan100lbs.persq.inchisnottobeusedinconservation

works.A

practical

and

quick

way

of

testing

lime

mortar

on

the

work

itself

is

to

take

ahandful

of

mortar

fromthetroughandafteraminuteortwo,towashitoffthehand.Iftheskinisleftroughafterwashing,

themortarmaybeconsideredfitforuse.

3.4.8.8 Limewash

3.4.8.8.1

Theuseof limewashorpaint isstrictly forbiddenexceptunderspecialcircumstanceswhen the

permissionshallbetakenfromanappropriateauthority/expertonconservation.

3.4.8.8.2 If it is important toremove limewash fromanoldsurfaceofaheritageestablishment,extreme

precautionshallbetakentopreventinjurytoanyinscriptions,relieforpaintingunderneath.Lime

washmayoftenberemovedbybrushingwithsoapandwater,butacidmustnotbeusedforthe

removal

of

lime

wash

from

marble

or

limestone,

the

surface

of

which

is

liable

to

damage

by

the

acidwork.

3.4.9 Upgradingandadaptivereuse

3.4.9.1

Adaptive reuse shall follow logical consequence considering public requirements of the region,

touristinfluxandsocioculturalcontextoftheregionunderinfluence.

3.4.9.2 Thedecisionof includingdifferent functions shallbemadeonlyafter thorough investigationbya

committeeworkingundertheguidelineofexpertsinarchaeologyandarchitecture oftheregion.

3.4.10Repairing,consolidationandrestoration

3.4.10.1

Inorder

to

prevent

salt

action

on

the

buildings,

all

materials

used

in

the

mortar

mixes

shall

be

free

of

anyimpurities.Thebricksshallbeacquiredonlyfromthebestbrickkilnsandtestedtoensurethey

arealsofreefromimpurities.Anylimeshallbepureslakedlimemadefromreallimestoneandnota

substitute.

3.4.10.2 Toprotectthestructuresfrompenetrationbyrainwater,awaterproofmembrane,suchasthinlayer

ofconcrete,shallbeplacedbetweenthearchaeologicalstructureandanygrasscoverings.

3.4.10.3 Major building features such as cornices, string courses, kiosks and/or cupolas etc. shall be

reconstructed, sothatthewaterrunningoffthemainbuiltformofthestructureisthrownclearof

thebrickwallorassociatedfaade.

3.4.10.4 Allreplacementofexternalbrickfacadesshallhaveaheavylayerofpolythenesheetbarrierplaced

between the old and the new brickwork in order to prevent the transfer of salts from the old

brickworktothenew.

3.4.10.5

Toprotectandtreatthebricksofvariousshapesandformsusedinwalls,columns,projectedeves/

corniceusedonexternalfaade,thoseshallfirstlyberecordedchronologically,andthenbecleaned

ofvegetation, particularlyalgae/weedsetc.,priortosoakingthemseveraltimesincleanwaterto

removeanysalttherein.


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Vol.

3

3.4.10.6

Treatment of decorative brickwork and terra cotta shall be carried out step by step; firstly by

thoroughlywashinginfreshwater.Secondly,afterallthesaltshavebeenleechedout,thebrickwork

or the terra cotta shall be treated with a consolidant chemical recommended by conservation

experts.

3.4.10.7 Inordertosecuretheplaques,insitu,thoseshallbeanchoredtothemainfabricwithstainlesssteel

clamps.

3.4.10.8

Surfacedrains

shall

be

installed

in

order

to

discharge

surface

water

from

the

large

courts

and

also

from the nooks and corners of the building premises and monument under consideration. Any

repairing, restoration and renovation work that this entails shall be done following the original

designanddetailsineverystepusingthesamebuildingmaterialsandtechniques.

3.4.11Grouting

Grouting is to put a thin layer ofmortar, following the required technical specification, in the spaces

betweentiles,bricksorsimilarothermaterialsusedinconservationwork.

3.4.11.1 A void which can not be thoroughly cleaned out with water can be satisfactorily filled under

pressure,sincethereareboundtobedustysurfaceswithwhichthegroutwillnotmakeasolidjoint.

3.4.11.2

Numerousholes

must

be

left

in

the

pointing

for

the

escape

of

air

and

for

the

liquid

grout.

3.4.11.3 Thepointingmustbe fairly hard and seton the outer surfacebefore grouting is commenced.A

periodofthreetofourweekisusuallynecessaryforthistotakeplace.

3.4.11.4 Wherecementhasbeenused for filling thejointsat thebackof the limepointing, thengrouting

maybestartedtendaysafterwards.

3.4.11.5 Thewholebodyofthewalltobetreated(wheregroutingistobeperformed)shouldbethoroughly

washedoutwithwater(forcedunderapressureofabout15lbs.to20lbs.persquareinch)starting

fromthetopofthewallandworkingdownwards.Thewallsmust,however,bethoroughlysaturated

beforegroutingiscommenced.

3.4.11.6

Themixture

in

the

machine

is

to

consist

of

not

more

than

three

parts

of

sand

to

one

of

cement,

or

asnearthisratio(inordertoresistthenatureofsandtoflowinthemachine)

3.4.11.7 Thegroutingofcavitiesshouldbestartedatthebaseofthewall.Eachgroutingpointshouldbefed

twicefromthemachine.

3.4.11.8

Thepressuretobeobtainedinthemachineshould,asarule,benotlessthan25lbs.normorethan

35 lbs. per square inch; air should be pumped into to compressor until 35 lbs. per sq. inch is

attained,andthepressureshouldnotbeallowedtoreducebelow25lbs.persq.inchforordinary

cases. However,wherethewallisthinorweakthepressuremaybereducedto12lbs.or15lbsper

sq.inch.Iftheaboveprecautionsaretaken,thisshouldhavenobadeffectuponthelimepointing.

3.4.12

Hand

Grouting

3.4.12.1 Inhandgrouting,theproportionsofcementtosandwilldependbothuponthecharacter

of thevoids tobe filledandupon thedegreesof finenessof the sand. If thevoidsare

large, one part of cement to two parts of sand may be used, but if small, then the

proportionofsandshouldnotexceedonepart.

3.4.12.2 It is importanttokeepthecementandsandthoroughlymixedbycontinuallyshakingthe

caninwhichthegroutisheld.


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Bangladesh

National

Building

Code

2012

915

3.4.12.3

It isnecessary to leave,above thegroutinghole,another smallhole for theescapeofair

whilegroutisbeingpouredin.

3.4.12.4 Incaseswhereawallisweak,orathinskinoffacingmaterialisbondedtomainwall,itmust

beefficientlyboardedandstruttedintopositionbeforethegroutingworkisstarted.

3.4.13Underpinning

3.4.13.1

Underpinning is applied to the building of new work underneath an existing structure

withoutdisturbing its stability.Underpinningmaybenecessarywhen the foundationofa

wallofanancient /heritagebuilding is tobe replacedwithnew foundationorwhen the

existingfoundationofawallisrequiredtobestrengthenedforsustainability.

3.4.13.2 All excavations for underpinning must be carefully and adequately planked and properly

strutted(topreventtiltingandbuckling;inordertopreventthis,thejoistsarestruttedapart

in themidspan all along the length); All themasonrywork etc., immediately above the

proposed stretchofunderpinning,mustbeadequatelyheldbyrakingshoresonagoodsolid

foundation.

3.4.13.3

Wherealong

length

of

wall

has

to

be

underpinned,

the

work

must

be

carried

out

in

sections

about1minwidthandtothedepthindicatedintheestimate;themasonryoverheadandthe

earthatthesidesmustbethoroughlyshoredupandstrutted.

3.4.13.4 Ifunderpinningexceeds1m inheight, themasonry istobebuiltup in layersnotexceeding

0.60m.Eachlayeristobeallowedtosetbeforethelayeraboveisadded.

3.4.13.5 When two sections are to be carried out together, they must not adjoin. Generally, a

minimumdistanceof3.5m is tobemaintainedbetween two sections.Theholesmustbe

keptquitefreefromwaterbypumping.

3.4.13.6 Allconcretemustbewell rammed intoadense solidmasswhenpossible,andwhere the

heightofthehole issufficienttoramvertically,theconcretemustbewellpumped infrom

thefrontface.

3.4.13.7 When the footingsof thewall are very looseanddisintegrated, thejoints shouldbewell

washedoutandfilledwithcementgrout,ifpossible,beforetheunderpinningisstarted.

3.4.14Decoration andDetails

3.4.14.1 Inlaywork(Pietradura)

In therepairof inlaywork (pietradura),thegreatestcare isnecessary inorder toensure that thenew

stonesarefixedexactly,andthattheedgesoftheexistinggroundworkarenotscrapped.Thisshouldbe

donestep

by

step

following

aconservation

manual.

3.4.14.2 The fret cutting should be done by means of a plain soft iron wire mounted on a split

bamboobow.Solidpatternsarecutbyworkingthebowlikeafretsaw.

3.4.14.3 Theinlayblocksarecutontheslantwithaninwardslopeofabout15degreesontheedges

tofacilitatethefitting.


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Part9


3.5 AreaConservationforHistoricDistricts

3.5.1 IndentifyingHistoricDistricts:

Whenneighborhoods/regionsofancientheritagebuiltformsarepresentinanyurban/semiurban/rural

setting, these shallbe identified asHistoricdistrictsby theAdvisoryCommittee to theDepartmentof

Archaeology,GovernmentofBangladesh,asconstitutedundertheAntiquitiesActof1968.Suchdistricts

willbeconsideredasrepresentingahistoricperiodoftheregion.Principlesofareaconservationshallbe

applied

for

the

protection

and

preservation

of

these

historic

districts.

3.5.2 PlanningParametersandConservationGuidelines

3.5.2.1

Anappropriateplanshallbedrawn inordertoshowtheboundaryofconservationareas,thecore

areas, the buildings to be conserved, the residential and other functional areas to be retained /

restoredandtheenvelopecontrolsites.

3.5.2.2 Theschemeshallincludearehabilitationplanforperson/sdisplacedintheConservationprocess.

3.5.2.3 Forbuildingstobeconserved,eachandeverybuildingofhistoricalimportanceistobeconserved/

restoredinaccordancewiththeconservationguidelinessetforthinSections3.3and3.4above.

3.5.2.4

Taking

into

consideration

community

needs,

the

area

shall

be

assigned

functions

that

can

sustain

its

existenceandcontributetotheeconomicfunctioningofthearea.

3.5.2.5 The plan and detailing of the entire area shall comply with energy efficient and sustainability

guidelinessetforthinChapter4:EnergyEfficiencyandSustainability,Part3ofthisCode.

bangladesh national building code 2012 part 09 – alteration, addition to and change of use of...

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