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Indian StandardDEMOLITION OF BUILDINGS -CODEOFSAFETY

( Second Revision )

UDC 690596 : 6148

@ BIS 1991BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002December 1991 Price Group 5

( Reaffirmed 1996 )

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Safety in Construction Sectional Committee, CED 45

FOREWORDThis Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalizedby the Safety in Construction Sectiocal Committee had been approved by the Civil EngmeeringDivision Council.Demolition of any structure is, inherectly, more hazardous than the construction or erection of thesame. From the point of view of safety, the conditions usually encountered while dismantling astructure, whatever its magnitude, do not lend themselves to the degree of control possible inconstruction operations, where more stable conditiors are generally obtainable. It is all the moreimperative, therefore, that adequate attention is given to the planning and the execution ofdemolition work, its various stages, so as to minimize the risk of accidents and injuries to thepersonrel engaged on demolition operations. Adoption of predetermined and well-planned safetymeasures for demolition work will not only prevent accidents but also will increase all-roundefficiency.Generally, the time available and the equipment possible to obtain are the elements limitingthe application of strict safety rules; but these should not, in any case, be allowed to endnagerthe safety of human life or limbs. Although, everyone incharge of a demolition work is alwaysdesirous of preventing accidents, lack of readily available systematic procedures or rules,observance of which will ensure safety in demolition operation, has sometimes led to dangeroussituations and actual accidents.It has, therefore, become imperative that certain safety rules are laid down for the guidance ofthose who are engaged in demolition work, so that they may be meticulously followed.Safety cannot be ensured solely through regulations. It is desirable to have a plannedprogramme and secure adequate cooperation of managements, supervisors and workers, involvedin the work.This standard was first published in 1967 and subsequently revised in 1976. The present revisionhas been taken up based on the experience gained with the use of this standard. In this revisionthe details of removal of debrislmalba from demolition site have been incorporated in additionto some other minor changes.In the formulation of this standard due weightage has been given to international coordinationamong the standards and practices prevailing in different countries in addition to relating it tothe practices in the field in this country.For the purpose of deciding whether a particular requirement of this standard, is complied with,the final value, observed or calculated, expressing the result of a test or analysis, shall be roundedoff in accordance with IS 2 : 1960 Rules for rounding off numerical values ( revised ). Thenumber of significant places retained in the rounded off value should be the same as that of thespecified value in this standard.

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is 4130 1991Indian Standard

DEMOLITION OF BUILDINGS -CODE OF SAFETY( Second Revision )

1 SCOPEThis standard lays down the safety requirementsfor carrying out safely the demolition/dismant-ling of ail types of buildings, for example,residential building ( load-bearing structure,multistoreyed framed structures ), public build-ings and factories.2 REFERENCESThe Indian Standards listed below are necessaryadjuncts to this standard:

IS No.IS 2190 : 1979

TitleCode of practice for selec-tion, installation and main-tenance of portable first-aidfire extinguishers ( secondrerision )

IS 2925 1984 Industrial safety( second revision ) helmetsIS 3696 Safety code for scaffolds and( Part 2 ) : 1991 ladders: Part 2 Ladders (firstrevision )3 PLANNING3.1 Before beginning the actual work of de-molition, a careful study shall be made of thestructure which is to be pulled down and alsoof all its surroundings. This shall, in particular,include study of the manner in which thevarious parts of the building to be demolishedare supported and how far the stage by stagedemolition will affect the safety of the adjoiningstructure. A definite plan of procedure for thedemolition work, depending upon the mannerin which the loads of the various structuralparts are supported, shall be prepared andapproved by the engineer-in-charge and thisshall be followed as closely as possible, inactual execution of the demolition work.Before the commencement of each stage ofdemolition, the foreman shall brief the work-men in detail regarding the safety aspects to bekept in view.3.2 Jt should be ensured that the demolitionoperations do not, act any stage, endanger thesafety of the adjoining buildings. Moreover,the nuisance effect of the demolishing work onthe use of the adjacent bulldings should be keptto the minimum.

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3.3 No sturcture or part of the structure or anyfloor or temporary support or scaffold, sidewall or any device for equipment shall beloaded in excess of the safe carrying capacity, inits then existing condition.4 PRECAUTIONS BKFORE STARTINGDEMOLITION WORK4.1 On every demolition job, danger signs shallbe conspicuously posted all around the structureand all doors and openings giving access to thestructure shall be kept barricad:d or mannedexcept during the actual passage of workmenor equipment. However, provision shall bemade for at least two independent exits forescape of workmen during any emergency.4.2 During nights, red lights shall be placed onor about all the barricades.4.3 Where in any work of demolition it is im-perative, because of danger existing, to ensurethat no unauthorized person shall enter the siteof demolition outside working hours; a watch-man should be employed. In addition towatching the site he shall also be responsible formaintaining all notices, lights and barricades.4.4 All the necessary safety appliances ( see 15 )shall be issued to the workers and their useexplained. It shall be ensured that the workersare using all the safety appliances while atwork.4.5 The removal of a member may weaken theside wall of an adjoining structure and toprevent possible damage, these walls shall besupported until such time as permanent pro-tection is provided. In case any danger isanticipated to the adjoining structure, the sameshall be got vacated to avoid any danger tohuman life.4.6 The power on all electrical service linesshall be shut off and all such lines cut or dis-connedted at or outside the property line,before the demolition work is started. Priorto cutting of such lines, the necessary approvalshall be obtained from the electrical authoritiesconcerned. The only exception will be anypower lines required for demolition work itself.4.7 All gas, wster steam and other service linesshall be shut off and capped or otherwisecontrolled at or outside the building line, beforedemolition work is started.

http://../link/15to30/2190.Bishttp://../link/15to30/2190.Bishttp://../link/15to30/2190.Bishttp://../link/15to30/2925.Bishttp://../link/15to30/2925.Bishttp://../link/15to30/2925.Bishttp://../link/15to30/2190.Bis

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IS 4130 : 19914.8 All the mains and meters of the buildingshall be removed or protected from damage.4.9 If a structure to be demolished has beenpartially wrecked by fire, explosion or othercatastrophe, the walls and damaged roofs shallbe shored or braced suitably.4.10 Walkways and passageways shall be pro-vided for the use of the workmen who shall beinstructed to use them and ail such walkwaysand passageways shall be kept adequatelylighted, free from debris and other materials.4.11 All nails in any kind of lumber shall bewithdrawn, hammered or bent over as soon assuch lumber is removed, from the structurebeing demolished, and placed in piles for futurecleaning or burnmg.5 PROTECTION OF THE PUBLIC5.1 Before any demolition work is started, everysidewalk or road adjacent to the work likely tobe affected shall be closed or protected.5.2 Children and members of the public shall bekept out of the building and the adjoining yard.5.3.If the structure to be demolished is morethan two storeyed or 75 m high, measuredfrom the sidewalk or street which cannot beclosed or safely diverted, and the horizontaldistance from the inside of the sidewalk to thestructure is 45 m or less a substantial sidewalkshed ( see Fig. 1 ) shall be constructed over theentire length of the sidewalk adjacent to thestructure of sufficient width with a view toaccommodating the pedestrian traffic withoutcausing congestion. The sidewalk shed shall belighted sufficiently to ensure safety at all times.5.4 A toe board of at least 1 m high above theroof of the shed shall bc provided on theoutside edge and ends of the sidewalk shed.Such boards may be vertical or inclined outwardat not more than 45 degrees.5.5 Except where the roof of a sidewalk shedsolidly abuts the structure, the face of thesidewalk shed towards the building shall becompletely closed by providing sheatinglplank-ing to prevent falling meterial from penetratinginto the shed.5.6 The roof of sidewalk sheds shall be capableof sustaining a load of 73 N/mm2. Only inexceptional cases, say due to lack of otherspace, the storing of material on a sidewalkshed may be permitted in which case the shedshall be designed for a load of 146 N/mm2.,Roof of sidewalk shed shall be designed takinginto account the impact of the falling debris.By frequent removal of loads it shall be ensuredthat the maximum load, at any time, on theroof of work shed is not more than 6 000 N/mZ.The height of sidewalk shed shall be such asto give a minimum clearance of 24 m.

5.7 Sidewalk shed opening. for loading pur-poses, shall be kept closed at all time exceptduring actual loading operations.5.8 The deck flooring of the sidewalk shed shallconsist of plank of not less than ,20 mm inthickness closely laid and deck made water-tight. All members of the shed shall be ade-quately braced and connected to resis,t disp!ace-ment of members or distortion of framework.5.9 When the horizontal distance from theinside of the sidewalk to the structure is morethan 45 m and less than 75 m, a sidewalk shedor fence may be built or in place of such ashed or fence a substantial railing shall beconstructed on the inside of the sidewalk orroadway along the entire length of the demo-lition side of the property with movable bars asmay be necessary for the proper execution ofthe work.5.10 Where workers entrances to the buildingbeing demolished are not completely protectedby sidewalk sheds, all such entrances shall beprotected by canopies extending from the faceof the building to a point not less than 25 mfrom it. In such case such overhead protec-tion shall be at least 06 m wider than thebuilding entrance or opening and every canopyshall be as strong as the sidewalk shed, specifiedin 5.5.6 SEQUENCE OF DEMOLITIONOPERATIONS6.1 The demolition work shall be proceededwith in such a way that:

a) it causes the least damage and nuisance tothe adjoining building and the membersof the public, andb) it satisfies all saftey requirements to avoidany accidents.

6.2 All existing fixtures required during demo-lition operations shall be well protected withsubstantial covering to the entire satisfaction ofthe rules and regulations of the undertakingsor they shall be temporarily relocated.6.3 Before demolition work is started, glazedsash, glazed doors and windows, etc, shall be re-moved. All fragile and loose fixtures shall beremoved. The lath and all loose plaster shall bestripped off throughout the entire building. Thisis advantageous because it reduces glass breakageand also eiiminates a large amount of dust pro-ducing material before more substantial partsof the buildings are removed.6.4 All well openings which extend down tofloor level shall be barricaded to a height ofnot less than one metre above the floor level.This provision shall not apply to the groundlevel floor.

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IS 4130 : 1991

PLANKING\ I n BUILDING UNDER DEMOLITION

POST .RIGIDLY FIXED

VARIES (FULL

6.5 All floor openings and shafts not used formaterial chutes shall be floored over and beenclosed with guard rails and toe boards.6.6 The demolition shall always proceed sys-tematically storey by storey in descending orderand the work on the upper floors shall becompletely over before any of the supportingmembers or other important portion on thelow-r floor is disturbed. These requirementsshall not prohibit the demolition of structurein sections, if means are taken to preventinjuries, to persons or damage to property..7 REMOVAL OF MATERIALS7.1 GeneralDismantled materials may be thrown to theground only after taking adequate precautions.The material shall preferably be dumped insidethe building. Normally such materials shall belowered to the ground or to the top of thesidewalk shed where provided by means ofropes or suitable tackles ( see also 5.6 ).7.2 Through Chutes7.2.1 Wooden or metal chutes may be providedfor removal of materials. The chutes shallpreferably be provid-d ct the centre of thebuilding for efficient disposal of debris.

FIG. 1 TYPICAL SKBTCHOP A SIDEWALK SHED

7.2.2 Chutes, if provided at an angle of morethan 45 from the horizontal, shall be entirelyenclosed on all the four sides, except foropening at or about the floor level for receivingthe materials.7.2.3 Opening for the chutes ( see 7.3 ) shall notexceed 1.20 m in height measured along the wallof the chute and in all storeys below the topfloor such opening shall be kept closed whennot in use.7.2.4 To prevent the descending material attain-ing a dangerous speed, chute shall not extendin an unbroken line for more than two storeys.A gate or stop shall bs provided with suitablemeans for closing at the bottom of each chuteto stop the flow of materials.7.2.5 Chutes at an angle of less than 45 to thehorizontal may be left open on the upper sideprovidod that at the point where such a chutedischarges into a chute steeper than 45 to thehorizontal, the top of the steeper chute shall beboarded over to prevent the escape of materials.7.2.6 Ary openirg ipto which workmen dumpdebris at the top of chute shall be guarded by asubstential guard rail extending at least onemetre above the level of the floor or othersurface on which men stand to dump the mate-rials icto the chute.

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IS 4130 : 19917.2.7 A toe board or bumper, not less than50 mm thick and 150 mm high shall be providedat each chute opening, if the material is dumpedfrom the wheel barrows. Any space betweenthe chute and the edge of the opening in thefloor through which it passes shall be solidlyplanked over.7.3 Through Holes in the Floor7.3.1 Debris may also be dropped throughholes in the floor without the use of chutes. Insuch a case the total area of the hole cut inany intermediate floor, one which lies betweenfloor that is being demolished and the storegefloor shall not exceed 25 percent of such floorarea. It shall be ensured that the storage flooris of adequate strength to withstand the impactof the falling material.7.3.2 Openings in all the floors below the floorfrom which materials are being removed, shallbe protected by stardard railings and toe boardsor preferably planked over if the holes are notbeing used for dumping materials.7.3.3 All intermediate floor openings forpassage of materials shzll be completely en-closed with barricades or guard rails not lessthan one metre high and at a distance of notless than one metre from the edge of generalopening. No barricades or guard rails shallbe removed until the storey immediately abovehas been demolished down to the floor line andall debris cleared from the floor.7.3.4 When the cutting of a hole in an inter-mediate floor between the storage floor and thefloor which is being demolished makes theintermediate floor or any portion of it unsafe,then such intermediate floor shall be properlyshored. It shall also be ensured that the sup-porting walls are not kept without adequatelateral restraints.7.4 Removal of Debris/MuZba7.4.1 As demolition work proceeds, the releasedserviceable materials of different types shall beseparated from the unserviceable lot ( hereaftercalled Mulba ) at suitable time intervals andproperly stocked clear of the spots where demo-lition work is being done.7.4.2 The Malba obtained during demolitionshall .be collected in well-formed heaps atproperly selected places, keeping in view safeconditions for workmen in the area. The heightof each Malba heap shall be limited to ensureits not toppling over or otherwise endangeringthe safety cf workmen or passers by.7.4.3 The Malba shall be removed from thedemolition site to a location as required by thelocal civil authority. Depending on the spaceavailable at the demolition site, this operationof conveying Mulba to its final disposal locationmay have to be carried out a number of times

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during the demolition work. In any case, thedemolition work shall not be considered ascompleted and the area declared fit for furtheroccupation till all the Molba has been carried toits final disposal location and the demolition areatidied up.7.4.4 Materials which are likely to cause dustnuisance or undue environmental pollution inany other way, shall be removed from the siteat the earliest and till then they shall be suitablycovered. Such materials shall be covered duringtransportation also.7.4.5 Unauthorized use of the debris or Mulbain any work shall not be permitted. The re-leased materials classed as serviceable shall beinspected by a competent person before beingused.8 STAIRS, PASSAGEWAYS AND LADDERS8.1 Stairs and stair railings, passageways andladders shall be left in place as long as possible.8.2 For the use of ladders, provisions laid downin IS 3696 ( Part 2 > : 1991 shall be followed.8.3 All stairs, passageways and ladders to beused by workmen during the process of demo-lition shall be maintained in a safe condition.8.4 Ladders or their side rail extend not lessthan 10 m above the floor or platform to whichsuch ladder gives access.8.5 All ladders shall be secured against, slippingout at the bottom and against movement in anydirection at the top.9 DEMOLITION OF WALLS9.1 While walls or sections of masonry arebeing demolished, it shall be ensured that theyare not allowed to fall as single mass upon thefloors of the building that are being demolishedso as to exceed the safe carrying capacity ofthe floors. Overloading of floors shall beprevented by removing the accumulating debristhrough chutes or by other means immediately.The floor shall be inspected by the engineer-in-charge before undertaking demolition work andif the same is found to be incapable to carry theload of the debris, necessary additional precau-tions shall be taken so as to prevent anypossible unexpected collapse of the floor.9.2 Walls shall be removed part by part. Stagesshall be provided for the men to work on, ifthe walls are very thin and dargerous to workby standing over them.9.3 No section of wall whose height is morethan 15 times of thickness, shall be permittedto stand without lateral bracing unless such wallis in good condition and was originally desig-ned to stand without such lateral bracing orsupport.

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9.4 Structural or load supporting members onany floor shall not be cut or removed until allthe storeys above that floor have been demo-lished and removed.9.5 Before demolishing any interior or exteriorwall within 3 m of the opening in the floorimmediately below, such opening shall besubstantially planked over, unless access isdenied to workmen to that portion of the areaof the floor immediately below the opening, inthe floor of the storey being demolished, whereany debris pieces passicg through this openingmay fall.9.6 In framed structures, the steel frame maybe left in place during demolition of masonrywork. Where this is done, all steel beams,girders, etc, shall be cleared of all loosematerials as the demolition of masonry workprogress downward provided it is still strongenough to stand as an independent structure.9.7 Walkways shall be provided to enable work-men to teach or leave their work on any scaffoldor wall. Such walkways shall be not less than3 planks, nor less than 08 m in width.9.8 At the completion of each days work, allwalls shall be left stable to avoid any danger ofgetting overturned.9.9 Foundation walls which serve as retainingwalls to support earth or adjoining strcuture,shall not be demolished until such an adjoningstructure has been underpinned or braced andthe earth removed by sheet piling orsheathing.10 DEMOLITION OF FLOORS10.1 n cutting holes in a floor which spans inone direction, a slit of width not exceeding300 mm shall be cut at the first stage for theentire length of the slab along which it spans( see Fig. 2 ). The opening shall thereafter beincreased to the desired width by suitableinstalments.

IS 4130 : 199110.2 Planks of sufficient strength not less than50 mm thick and 250 mm wide shall be providedat spacing not greater than 04 mm for theworkmen to work. The length of planks shallnot bz less than 2 mm. These planks shallbe so placed as to give workmen tirm supportto guard against any unexpected floor collapse.10.3 Stringers of ample strength shall beinstalled to support the planks where necessaryand the ends of such stringer shall be supportedby floor beams, girders and not by floor slabalone.10.4 When floors are being removed, no work-men shall be allowed to work in the area,directly underneath and such area shall bebarricaded to prevent access to it.10.5 The demolition of floor shall be startedonly after the floor in question and the surroun-ding floor area for a distance of 60 m havebeen entirely cleared of persons, and the debrisand other unnecessary material removed.lC.6 Planks used for temporary protection shallbe sound and at least 50 mm thick. They shallbe laid close together with the ends having atleast ICO mm bearirg over solid support toprevent tipping under load. If corrugatedGI Sheets are used for temporary protection,it shall be secured to thesolid support withsuitable framework.11 DEMOLI TION OF STEEL STRUCTURES11.1 When a derrick is used, care shall be takento see that the floor on which it is supportedis amply strong for the loading so imposed. Ifnecessary heavy planking shall be used to distri-bute the load to floor beam and girders.11.2 Overloading of equipment shall not beallowed.Il.3 Tag lines shall be used on all materialsbeing lowered or hoisted up and a standard

STRIPS NOT TOEXCEED 300 mm

JNDE PENDENT WORKINGPLATFORM TO BE USEDWHEREVER POSSIBLE

LINES OF SUPPORTUNDER FLOORMAIN REINFORCEMEN

FIG. 2 DEMOLITION OF REINFORCEDCONCRETE LOORS5

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IS 4130 1991signal system shall be used and the workmeninstructed on the signals.11.4 No person shall be permitted to ride theload line.11.5 No beams shall be cut until precautionshave been taken to prevent it from swingingfreely and possibly striking any worker or equip-ment to any part of the structure being demo-lished.11.6 All structural steel members shall belowered from the building and shall not beallowed to drop.12 CATCH PLATFORMS12.1 In demolition of exterior wall of multi-storeyed structure, it is advisable to providecatch platform of heavy planking to preventinjuries to the worker working below and to thepublic, when the external walls are more than20 m in height.12.2 Such catch platform shall be constructedand maintained not more than 3 storeys belowthe storey from which exterior wall is beingdemolished. When demolition has progressedto within 3 storeys of ground level, catchplatform will not be considered necessary.12.3 Catch platforms shall not be less than15 m in width, measured in a horizontaldirection from the face of the structure andshall consist of outriggers and planks. Planksshall be laid tight together, without openingsbetween them and the walls. Catch platformshall be provided with a continuous solid parapetalong its outer edge of at least 1 m height. Theparapet shall be constructed of the same speci-fication as the platform.12.4 Catch platform can be constructed ofmaterial other than wood also, provided suchmaterial is of equal strength.12.5 Catch platform shall be capable of sustain-ing a live load of not less than 6 100 N/mZ.12.6 The outriggers shall be of ample strengthand shall not be spaced more than 3 m apart.12.7 Materials shall not be dumped on catchplatform nor such catch platform shall be usedfor the storage of materials.13 MECHANICAL DEMOLITIONWhen demolition is to be performed by mecha-nical devices, such as weight ball and powershovels, the following additional precautions mybe observed:

a) The ar :a shall be barricaded for aminimum distance of lb times the heightof the wall;b) While the mechanical device is in opera-tion, no workmen shall be allowed toenter the building being demolished;

c) The device shall be so located as to avoidfalling debris; andd) The mechanical device when being usedshall not cause any damage to adjacentstructure, power line, etc.

14 RECOMMENDATIONS FORDEMOLITION OF CERTAIN SPECIALTYPES AND ELEMENTS OF STRUCTURES14.1 Roof TrussesIf a build:ng has a pitched roof, the roof struc-ture should be removed to wall plate level byhand methods. Sufficient purlins and bracingshould be retained to ensure stability of theremaining roof trusses while each individualtruss is removed progressively.14.1.1 Temporary bracing should be added,where necessary, to maintain stability. Theend frame opposite to the end where dismant-ling is commenced, or a convenient intermediateframe should be independentiy and securelyguyed in both directions before work starts.14.1.2 On no account should the bottom tie ofroof trusses be cut until the principal raftersare prevented from making outward movement.14.2 Heavy Floor BeamsHeavy baulks of timber and steel beams shouldbe supported before cutting at the extremities andshould then be lowered to a safe working place.14.3 Jack ArchesWhere tie rods are present between main sup-porting beams, these should not be cut untilafter the arch or series of arches in&he floorhave been removed. Particular care ,iould beexercised and full examination of tl is type ofstructure undertaken before demoliton is co-mmenced ( see Fig. 3 ). The floor should bedemolished in strips parallel to the span of thearch rings ( at right angles to the main floorbeams >.14.4 Brick Arches14.4.1 Expert advice should be obtained and,at all stages of the demolition, the closestsupervision should be given by persons fullyexperienced and conversant in the type of workto ensure that the structure is stabl; at alltimes.14.4.2 As much dead load as possible may beremoved provided it does not interfere with thestability of the main arch rings. but it shouldbe noted that the load-carrying cap?cit, of manyold arches relies on the fi!:ing betwe,.n thespandrels. On no account shou!d the restrain-ing influence of the abutments be removedbefore the dead load of the spandrel fill and thearch rings are removed.

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IS 4130 : 1991

REMOVE ALL ARCHESBEFORE CUTTING TIE RODFIG. 3 DEMOLITION OF JACK ARCHES

14.4.2.1 The normal sequence of demolition isas shown in Fig. 4A, namely:a) Remove spandrel in fil!ing down to thespringing line,b) Remove the arch rings, andc) Remove the abutment.

14.4.2.2 Special temporary support shall beprovided n-r the case of skew bridges.14.4.3 A single span arch can be demoiishedby hand by cutt ng narrow segments pro-gressively from each springing parallel to thespan of the arch, until the width of the arch hasbeen reduced to a minimum which can then becollapsed ( see Fig. 4B ).14.4.3.1 Where it is impossible to allow debristo fall to the ground below, centering designedto carry the load should be erected and thearch demolished progressively. The design ofthe centering should make appropriate allow-ance for impact.14.4 4 Where deliberate collapse is feasiblethe crown may be broken by the demolitionball n- nd working progressively from edgesto th, ,cn$e ( see Fig. 4C )..\14.4.5 Coliipse of the structure can be effectedin one action by the use of explosives. Chargesshould be inserted into boreholes drilled in botharch and abutments. This method is the mostetlective for demolition of tall viaducts.14.4.6 In multi-span arches before individualspans are removed, lateral restraint should beprovided at the springing level. Demolitionmay then proceed as for a single span, carebeing taken to demolish the spandrels down tothe springing line as the work proceeds ( .yeeFig. 4D ). Where explosives are used it ispreferable to ensure the collapse of the wholestructure in one operation to obviate the chanceof leaving unstable portions standing.14.5 Cantilevers ( Not Part of a FramedStructure )A cantilever type of construction depends forits stability on the superimposed structure.Canopies, cornices, staircases and balconies

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should be demolished or supported before thetailing down load is removed.14.6 In-Situ Reinforced Concrete14.6.1 Before commencing demolition, thenature and condition of the concrete, the con-dition and position of reinforcement, and thepossibility of lack of ccntinuity of reinfcrce-ment should be ascertained.14.6.1.1 Attention should be paid to theprinciples of the structural design to determinewhich parts of the structure depend on eachother to maintain overall stability.14.6.2 Demolition should be commenced by re-moving partitions and external non-load bearingcladding. It should be noted that in somebuildings the frame may rely on the panel wallsfor stability.14.6.2.1 Where har~d demolition methods are tobe used, the following procedures should beused:

a) Reinforced concrete beamsFor beams, a supporting rope should beattached to the beam. Then the concreteshould be removed from both ends bypneumatic drill and the reinforcementexposed. The reinforcement should thenbe cut in such a way as to allow the beamto be lowered under control to the floor( see Fig. 5A ).

b) Reinforced concrete columnsFor columns, the reinforcement shouldbe exposed at the base after restrainingwire guy ropes have been placed roundthe member at the top. The reinforce-ment should then be cut in such a wayas to allow the column to be pulled downto the floor under control (see Fig. 5Bfor sequence of operations ).

c) Reinforced concrete wallsReinforced concrete walls should be cutinto strips and demolished as for columns( see Fig. 5C ).

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IS 4130:1991

d) Suspendedfloors and roofs

. . . _RING Y

EDGE OF ARCH

I I_--- -yc - F 4 I-1, L__-L-___! &EDGE of[ci -,;,/- yj/j ARCH-EMPORAAS RY CENTERING / LOELIBERATE COLLAPSENECESSARY FOR CENTRE l*Om STRIP

ELEVATION LABUTMENT PLANLBDEMOLISHING ARCH AT CROWN

cEOGE OF ARCH

LREsTR AINTBEFORE INTERMEDIATE SPANIS D/EMOLISHED

LDNOTE - Order of Demolition.

FIG. 4 DEMOLITION OF MASONRYAED BRICKWORK ARCHES

Before demolishing suspended floors androofs, the type of construction shouldbe ascertained. In solid slabs, thedirection of the main reinforcementshould be determined; the slab shouldthen be cut into strips parallel to themain reinforcement and demolishedstrip by strip ( see 10 and Fig. 2 ).Where ribbed construction has been used,the principle of design and method ofconstruction should be determined before

demolition is commenced. Care should betaken not to cut the ribs inadvertently.14.7 Precast Reiaforced Concrete14.7.1 Precast reinforced concrete units used ina structure are normally held in position by thestrength of the joints made in-situ or on suppor-ting walls, etc. As such, before starting ondemolition, the joint structures and/or thestipporting mechanisms shall be studied andunderstood.

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Is 4130 : 1991

/ ROPE SEC ELY cut2-r L ?bIE0 AROU

\BEAM IN LOWEREOPOSITIONL REQUIRE0OIRECTION OFFALL

SA R C BEAMS 58 R C COLUMNS

RESTRAINING ROPE l(IN OPPOSITE DIRECTIONTO PULLING ROPE)ROPE SECURELYTIE0 TO TOP OF

APPj?OX l-On- WlOE THIS SIDE OF WALL

MOVE CONC (3)ELEVATION SECTION

SC RC WALLSFIG. 5 HAND DEMOLITIONOP In-Siru CONCRETESTRUCTURE

14.7.2 In devising and following the demolitionsequences due precaution shall be taken toavoid toppling over of prefabricated units orany other part of the structure and wherevernecessary temporary supports shall be provided.14.8 Prestressed Reinforced ConcreteBefore commencing of the demolition workinvolving such structures advice of an engineerexpert in such demolition shall be obtained andfollowed.14.9 Chimney and SpiresBefore commencing of the demolition work,involving such structures, advice of an engineerexpert in such demolition shall be obtained andfollowed.15 MISCELLANEOUS15.1 No demolition work should be carried outat night especially when the building or structureto be demolished is in an inhabited area.15.2 No demolition work shall be carried outduring storm and heavy rain.15.3 A warning device shall be installed in thearea to be used to warm the workers in case ofany danger.15.4 Safety helmets conforming to IS 2925 : 1984shall be used by the workmen where there isany likelihood of material falling from top.15.5 Construction sheds and tool boxes shouldbe located away from areas of falling debristo avoid injuries to users.15.6 Goggles preferably made of celluloid lensshall be worn at the time of demolition of walls,

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floors, tearing of plaster, etc, especially when instruments like jack hammers are employedin demolition work, to protect the eyes frominjuries from flying pieces, dirt, dust, etc, thatmay be blown up by the wind.15.7 It is desirable that leather or rubber glovesshould be worn by the workers while demo-lishing RCC work or removing steel work, etc,where the hands of the workers are likely to beinjured.15.8 Screens shall be placed, where necessary,to prevent flying pieces from injuring the fellowworkmen.15.9 Water may be used to reduce dust whiletearing down plaster from brickwork. If thisis impracticable, workmen shall cover the faceand nose with piece of muslin or alternativelyrespirators.15.10 No unnecessary work shall go on belowwhen demolition is in progress above. Whensome work is to be done at the lower level,adequate protection shall be provided for allthe workmen so engaged.15.11 Safety belts shall be used by labourerswhile working at higher level to prevent fallingfrom the structure.15.12 First-aid equipment shall be got availableat all demolition works of any magnitude.Also, by prior arrangement, a qualified doctorshall be available at call.15.13 When there is a possibility of fire breakingout, appropriate portable first-aid fire appliances( see IS 2190 : 1979 ) shall be kept at hand.

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Standard MarkThe use of the Standard Mark is governed by the provisions of the Bureau of Indian

Standards Act, 1986 and the Rules and Regulations made thereunder. The Standard Mark onproducts covered by an Indian Standard conveys the assurance that they have been producedto comply with the requirements of that standard under a well defined system of inspection,testing and quality control which is devised and supervised by BIS and operated by the pro-ducer. Standard marked products are also continuously checked by BIS for conformity tothat standard as a further safeguard. Details of conditions under which a licence for the useof the Standard Mark may be granted to manufacturers or producers may be obtained fromthe Bureau of Irdian Standards.

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Bureau of Indian StandardsBIS is a statutory institution established under the Burew of Indian StattdaFds Act, I986 to promoteharmonious development of the activities of standardization, marking and quality certification ofgoods and attending to connected matters in the country.CopyrightBIS has the copyright of all its publications. No part of these publications may be reproduced inany form without the prior permission in writing of BIS. This does not preclude the free use, inthe course of implementing the standard, of necessary details, such as symbols and sizes, type orgrade designations. Enquiries relating to copyright be addressed to the Director ( Publication ), BIS.Revision of Indian StandardsIndian Standards are reviewed periodically and revised, when necessary and amendments, if any,are issued from time to time. Users of Indian Standards should ascertain that they are inpossession of the latest amendments or edition. Comments on this Indian Standard may be sentto BIS giving the following reference :Dot : No. CED 45 ( 4831 )

Amendments Issued Since PublicationAmend No. Date of Issue Text Affected

BUREAU OF INDIAN STANDARDSHeadquarters :Manak Bhavan, 9 Bahadur Shah Zafar Marg, New Delhi 110002Telephones : 331 01 31, 331 13 75 Telegrams : Manaksanstha( Common to all Offices )Regional Offices : TelephonesCentral : Manak Bhavan, 9 Bahadur Shah Zafar Marg, 331 01 31

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