Safety code for demolition of buildings
1991 Edition

Overview of Scope & Main Provisions

• The code provides comprehensive safety and procedural guidelines for building demolition.
• Rounding rules for calculations follow IS 2:1960 standards.
• Prohibition on storing or dumping debris on catch platforms (Clause 12.7).
• Mechanical demolition requires a safety barricade radius equal to twelve times the wall height, no personnel inside the danger zone, proper placement of equipment to prevent debris hazards, and protection of neighboring structures and utilities.
• IS 4130:1991 remains the primary reference, supplemented by related standards.

Barricade Distance Calculation Example

If the wall height is 5 meters, the barricade radius is 12 × 5 = 60 meters.

flowchart LR
    Height[Wall Height (h)] --> Calc[Calculate Barricade Radius]
    Calc --> Radius[Radius = 12 × h]
    Radius --> Setup[Establish Barricade Zone]

This ensures adherence to safety during mechanical demolition as per the code.

Pre-Demolition Evaluation and Strategy

• Conduct a thorough examination of the building and its environment to understand structural load paths and support systems.
• Draft a stepwise demolition plan with approval from the responsible engineer.
• Inform workers of safety measures prior to each demolition phase.
• Demolition should proceed floor-by-floor from top to bottom, ensuring upper levels are cleared before disturbing lower supports.
• Staged demolition of sections is permissible if safety is guaranteed.
• Material storage on catch platforms is forbidden.
• Mechanical demolition requires barricades with a radius of 12 times the wall height, no personnel inside during operation, and equipment positioning to avoid debris hazards.
• Hard demolition of reinforced concrete components involves controlled cutting and lowering techniques using ropes and temporary supports.

Demolition Process Flowchart

flowchart TD
    Start[Begin Demolition] --> Assess[Assess Structure & Loads]
    Assess --> Plan[Develop & Approve Plan]
    Plan --> TopFloor[Demolish Top Storey]
    TopFloor --> Check{Is Upper Floor Complete?}
    Check -- Yes --> NextFloor[Demolish Next Lower Storey]
    Check -- No --> TopFloor
    NextFloor --> Repeat[Repeat Until Ground Floor]
    Repeat --> Finish[Complete Demolition]

Safety barricade radius must be maintained at 12 times the wall height. Controlled cutting and lowering techniques prevent hazards.

Safety and Electrical Guidelines

• Portable first-aid fire extinguishers must be accessible in areas with fire risk, complying with IS 2190:1979.
• Prior to demolition, all electrical services should be disconnected at or beyond the property boundary, with proper authorization from electrical authorities.
• Exceptions allow certain power lines to remain active if required for demolition operations.
• Equipment placement and barricading during mechanical demolition follow strict rules to prevent injury or damage.

Barricade Distance Quick Reference

graph TD
  Wall[Wall] -->|12 × Height| Barricade[Barricade]
  Barricade --> SafeZone[Safe Area]
  subgraph Danger
    Wall
  end

Always coordinate with electrical authorities and conform to BIS fire and electrical safety standards before starting demolition.

Protecting Public and Adjacent Structures

• Remove or bend nails immediately from dismantled timber to prevent hazards.
• Protect existing fixtures required during demolition with robust coverings or relocate them temporarily.
• Worker access points without sidewalk sheds must have canopies extending at least 2.5 meters from the building face, with widths surpassing entrance width plus 0.6 meters on each side.
• Canopies must be constructed to the same strength as sidewalk sheds, capable of supporting a minimum live load of 5 kN/m².
• All utility mains and meters must be removed or shielded to prevent damage.

Sidewalk Shed Specifications Summary

• Designed for a minimum live load of 5 kN/m².
• Stable against wind and impact forces.

Protection Measures Overview

flowchart TD
    Start[Demolition Begins] --> RemoveNails[Nail Removal]
    RemoveNails --> ProtectFixtures[Fixture Protection]
    ProtectFixtures --> PublicSafety[Public Protection]
    PublicSafety --> InstallCanopy[Canopy Installation]
    InstallCanopy --> ProtectUtilities[Utility Protection]
    ProtectUtilities --> Proceed[Continue Demolition]

This framework ensures safety for workers, the public, and neighboring structures.

Demolition Operation Sequence

• Proceed with demolition systematically from the top storey downward.
• Fully complete demolition of upper floors before removing supports of lower levels.
• Sectional demolition is permitted when safety can be assured.
• Hard demolition of reinforced concrete elements involves:
  • Beams: Secure ropes, expose reinforcement ends, cut reinforcements, and carefully lower beams.
  • Columns: Apply restraining guy ropes at the top, expose base reinforcement, cut reinforcements, and pull columns down in a controlled manner.
  • Walls: Segment into strips approximately 230 mm in width and demolish similarly to columns.
• For arches, remove spandrels down to the springing line first, then arch rings, followed by abutments.
• Implement temporary supports as necessary to prevent instability.

flowchart TD
    Begin[Start Demolition] --> RemoveSpandrels[Remove Spandrels to Springing Line]
    RemoveSpandrels --> RemoveArches[Remove Arch Rings]
    RemoveArches --> RemoveAbutments[Remove Abutments]
    RemoveAbutments --> DemolishFloors[Demolish Floors Top-down]
    DemolishFloors --> DemolishBeams[Beams: Rope & Cut]
    DemolishFloors --> DemolishColumns[Columns: Guy Ropes & Cut]
    DemolishFloors --> DemolishWalls[Walls: Cut into Strips]
    DemolishBeams & DemolishColumns & DemolishWalls --> TemporarySupports[Provide Temporary Supports]
    TemporarySupports --> Completion[Complete Demolition]

Ensure all steps are performed with safety and control to maintain structural stability.

Debris Disposal and Material Management Guidelines

• The opening for debris to drop through intermediate floors should not exceed 25% of the floor’s area.
• The floor beneath the debris drop zone must be capable of bearing impact loads safely.
• Catch platforms are not to be used for dumping or storing materials.
• Mechanical demolition requires a barricade radius of at least 12 times the wall height, with no personnel allowed inside during operation.
• Equipment must be positioned to prevent debris falling on people or adjacent properties.

Debris Handling Summary

flowchart TD
    DemolitionFloor -->|Debris Drop ≤ 25% Area| StorageFloor
    StorageFloor -->|Withstand Impact| DebrisCollection
    MechanicalEquipment -->|Operate in Barricade| SafeZone
    SafeZone -->|No Personnel Inside| DemolitionArea

Always verify floor strength and maintain specified barricade distances based on site conditions.

Guidelines for Safe Use of Ladders, Stairs, and Passageways

• Ladders should conform to IS 3696 Part 2:1991 for design, construction, and safe usage.
• Key ladder specifications include an inclination angle around 75°, minimum rung spacing of 250 mm, rung diameter between 25-40 mm, and load capacities as per the code.
• Stairs and walkways must be safe, unobstructed, and well-lit.
• Workers should be instructed on the proper use of all access routes.
• Materials intended for reuse must be inspected and approved by a competent person to ensure serviceability.

Ladder Dimensions Summary

flowchart TD
    Start --> ProvideLadders[Provide Ladders per IS 3696]
    ProvideLadders --> ClearAccess[Maintain Clear & Lit Stairs]
    ClearAccess --> InspectMaterials[Inspect Materials for Reuse]
    InspectMaterials --> EnsureSafeAccess[Ensure Worker Safety]

Refer to IS 3696 Part 2 for detailed ladder safety requirements.

Wall Demolition Guidelines

• Reinforced concrete walls are cut into strips roughly 230 mm wide and demolished like columns, exposing and cutting reinforcement before controlled lowering.
• Foundation and retaining walls should not be demolished until adjoining structures have been properly supported or earth retained by sheet piling or sheathing.
• Mechanical demolition requires a safety barricade with radius 12 times the wall height, no workers inside during operation, and proper equipment placement to prevent debris hazards.

Stepwise Wall Demolition

flowchart TD
    Begin[Start Wall Demolition] --> CutStrips[Cut into 230mm Strips]
    CutStrips --> ExposeRebar[Expose Reinforcement]
    ExposeRebar --> CutRebar[Cut Reinforcement]
    CutRebar --> PullDown[Lower Strips Under Control]
    PullDown --> Support[Apply Temporary Centering if Needed]
    Support --> Complete[Complete Demolition]

Adhere to safety rules for ladder use and avoid material dumping on catch platforms.

Key Points on Floor Removal and Load Management

• If cutting holes weakens intermediate floors, adequate shoring must be provided.
• Supporting walls should have sufficient lateral bracing to avoid instability.
• Demolition proceeds floor-by-floor, top-to-bottom, completing upper floors before disturbing lower supports.
• A safety clearance zone of 6 meters radius from the demolition area must be maintained, free of personnel and debris.
• Materials lowered or hoisted must have tag lines, and a standardized signaling system should be used.
• Independent working platforms are preferred, and strip widths during floor removal should not exceed 300 mm.

Load Management Flow

flowchart TB
    HoleCutting --> CheckSafety{Is Floor Compromised?}
    CheckSafety -- Yes --> ProvideShoring[Install Shoring]
    ProvideShoring --> CheckBracing[Verify Lateral Restraints]
    CheckSafety -- No --> Proceed[Continue Demolition]
    CheckBracing --> Proceed

Specifications Summary

This ensures safe structural support throughout floor removal.

Essential Practices for Derricks and Steel Handling

• Floors supporting derricks must have sufficient strength to carry loads; heavy planks should be used to distribute weight evenly across beams and girders.
• Steel components must be carefully lowered; dropping is strictly forbidden to prevent damage.
• Tag lines should be attached to all lifted or lowered materials, and communication via standardized signals by trained personnel is mandatory.
• Catch platforms must remain free of stored or dumped materials to avoid overloading and hazards.

Practical Recommendations

Load Transfer Illustration

flowchart TD
    DerrickLoad[Load from Derrick] --> Planking[Heavy Planking]
    Planking --> FloorBeams[Floor Beams]
    FloorBeams --> Girders[Girders]
    Girders --> Structure[Building Structure]

Maintain strong floor support, avoid dropping steel, use tag lines and signals, and keep catch platforms clear during mechanical demolition.

Catch Platform Specifications

• Platforms must extend at least 1.5 meters horizontally from the building face.
• Constructed with closely spaced outriggers and planks, made of wood or equivalent materials.
• Platforms include a continuous solid parapet at least 1 meter high along the outer edge.
• Designed to withstand a minimum live load of 6100 N/m².
• Steel components must be lowered carefully onto platforms, not dropped.

Load Design Formula

[ \text{Minimum Live Load} = 6100 , \text{N/m}^2 ]

Platform structure and connections must be engineered for this load plus self-weight.

Platform Features Summary

graph LR
    BuildingFace -->|1.5 m| Platform[Catch Platform]
    Platform --> Parapet[Parapet ≥ 1 m Height]
    Platform --> Construction[Outriggers + Tight Planks]
    Construction --> LoadCapacity[Supports 6100 N/m² Live Load]

Mechanical Demolition Safety and Methods

• A safety barricade with a radius twelve times the wall height must be established.
• No personnel are allowed inside the building during operation.
• Position mechanical equipment to prevent debris from falling onto people or neighboring properties.
• Damage to adjacent structures and utilities must be avoided.
• Hard demolition of reinforced concrete elements includes:
  • Beams: Attach supporting ropes, remove concrete ends, expose and cut reinforcement, then lower beams under control.
  • Columns: Place restraining guy ropes at the top, expose reinforcement at the base, cut reinforcements, and pull columns down safely.
  • Walls: Cut into approximately 230 mm strips and demolish as columns, using temporary centering if necessary.
• Demolition proceeds storey-by-storey from top to bottom, completing upper floors before lower ones.
• Sectional demolition is allowed only when safety measures prevent injury or damage.

Controlled Beam Lowering Process

flowchart LR
    SecureRope[Attach Supporting Rope] --> RemoveConcrete[Remove Concrete Ends]
    RemoveConcrete --> ExposeRebar[Expose Reinforcement]
    ExposeRebar --> CutRebar[Cut Reinforcement]
    CutRebar --> LowerBeam[Lower Beam Under Control]

Follow systematic and controlled demolition sequences to maintain safety and structural integrity.

Guidelines for Demolishing Special Structural Elements

• Reinforced concrete beams require securely attached ropes; concrete ends must be removed to expose reinforcement, which is then cut to enable controlled lowering.
• Columns should have restraining guy wires at the top; base reinforcement is exposed and cut to permit safe controlled pulling down.
• Walls are cut into strips around 230 mm wide and demolished similarly to columns.
• The mechanical demolition safety perimeter must be maintained with a barricade radius of 12 times the wall height, with no personnel inside during operation.
• Equipment positioning should prevent debris hazards and protect adjacent structures and utilities.
• Before demolishing precast units or prestressed concrete, expert engineering advice must be sought.
• Controlled lowering or pulling methods prevent sudden collapse and ensure safety.

Hand Demolition Sequence

flowchart LR
    AttachRope[Attach Supporting Rope] --> RemoveConcreteEnds[Remove Concrete Ends]
    RemoveConcreteEnds --> ExposeReinforcement[Expose Reinforcement]
    ExposeReinforcement --> CutReinforcement[Cut Reinforcement]
    CutReinforcement --> LowerElement[Lower Beam/Column Safely]

Avoid dumping materials on catch platforms and always maintain controlled demolition practices.

Miscellaneous Safety Protocols

• Portable fire extinguishers as per IS 2190:1979 must be provided where there is fire risk.
• Mechanical demolition zones require barricading with radius 12 times the wall height, with no workers allowed inside during operation.
• Equipment must be positioned to prevent debris from falling on personnel or nearby structures.
• Storing or dumping materials on catch platforms is prohibited.
• Workers must wear safety helmets conforming to IS 2925:1984 where there is risk of falling objects.

Relevant Standards Summary

Mechanical Demolition Safety Visualization

graph TD
    WallHeight[Wall Height H]
    BarricadeRadius[Safety Barricade = 12 × H]
    Equipment[Mechanical Equipment]
    NoWorkers[No Personnel Zone]
    WallHeight --> BarricadeRadius
    BarricadeRadius --> NoWorkers
    Equipment --> NoWorkers

Ensure fire safety equipment is accessible, maintain barricades, restrict personnel access during demolition, and mandate protective gear to reduce risks.