Safety code of scaffolds and ladders, Part 1: Scaffolds

IS 3696 Part 1 - Scope & Key Specifications for Bamboo Scaffolds

Scope (Clause 4.1.1)

• Applicable for single pole and double pole tied bamboo scaffolds up to 18 m height.
• Designed for light duty (150 kg/m²) and heavy duty (300 kg/m²) loads.

Key Tables Summary

IS 3696 Part 1 (1987) — Definitions & Key Specifications

1. Definitions (Clause 2.0)

• Scaffold Platform: Working surface for workers.
• Standard or Upright: Vertical poles supporting the scaffold.
• Putlog or Bearer: Horizontal members supporting the platform.
• Longitudinal Diagonal Brace: Bracing connected to uprights for stability.

(Refer Fig.1 for typical scaffold components.)

2. Key Tables for Bamboo Scaffolds (Clause 4.1.1)

IS 3696 Part 1: Materials & Specifications for Scaffold Construction

Key Load Capacities:

Timber Scaffold Member Sizes (in mm)

Spacing & Dimensions:

IS 3696 Part 1: Types and Components of Scaffolds (Key Points)

Types of Scaffolds:

• Light Duty Scaffolds

  • Safe working load: 150 kg/m²
  • Max platform load: 300 kg (2 men + tools + materials)
  • Used by carpenters, painters, etc.

• Heavy Duty Scaffolds

  • Safe working load: 300 kg/m²
  • Two working platforms allowed simultaneously
  • Used by masons, concreters, etc.

Double Pole Tied Scaffolds (up to 18 m height):

IS 3696 (Part 1) - Key Specifications for Railings and Toe Boards

Railings (Clause 5.2)

• Top rail height: 900 to 1050 mm above platform level.
• Intermediate rail: Positioned halfway between top rail and platform.
• Material: Wood, pipe, or metal sections.
• Mounting: On standards/uprights for stability.

Toe Boards (Clause 5.3)

• Toe boards must eliminate gaps between platform flooring and toe board to prevent falling objects.
• Sizes as per Tables 1 and 2 (typical sizes):
  • Thickness: Minimum 12 mm.
  • Typical dimensions: 50 × 200 mm or 35 × 150 mm (wooden boards).
• Toe boards placed continuously along platform edges.

Additional Notes

• Ledgers and transoms start not beyond 150 mm from base/foundation.
• Plank overlaps only on putlogs/bearers; if end-to-end, putlogs within 100 mm of plank ends.
• Suspended scaffolds tested biweekly with 3× max load, raised 300 mm above ground (Clause 4.7.7).

Summary Table (Typical Dimensions)

flowchart TB
    A[Platform] --> B[Toe Board (min 12 mm thick)]
    B --> C[Intermediate Railing (450–525 mm above platform)]
    C --> D[Top Railing (900–1050 mm above platform)]
    style B fill:#f9f,stroke:#333,stroke-width:2px
    style C fill:#bbf,stroke:#333,stroke-width:2px
    style D fill:#8f8,stroke:#333,stroke-width:2px

This ensures safety from falls and prevents tools or debris from falling off scaffolds.

IS 3696 Part 1: Access to Scaffold Platforms – Key Specs & Formulas

1. Means of Access (Clause 6.4 - Stairways)

• Height: For scaffolds > 4 m, stairways preferred.
• Tread & Riser: Uniform width & height per flight.
• Minimum Width: 1.0 m.
• Max Vertical Rise: 4 m unbroken.
• Max Angle of Ascent: 50°.
• Safety: Railings on open sides, handrails on enclosed sides.
• Landings: Standard railings + toeboards.

2. Ramps & Gangways (Clause 6.3.1)

• Strength equal to scaffold structure.
• No undue sag under loads.
• If ≥ 1.5 m above ground, provide standard railings + toeboards on open sides.

3. Protection from Falling Objects (Clause 5.4)

• Enclose space between toeboard & top railing.
• Use tarpaulin/PVC sheets for chemical protection.

4. Double Pole Scaffold Dimensions & Loads (Clause 4.1.1 & Table 4.1.3)

IS 3696 (Part 1) - Key Safety Provisions for Supervisory & Inspecting Personnel

1. Protection of Supervisory/Inspecting Officials (Clause 7.3)

• Must wear safety helmets complying with IS 2925:1984.
• Helmets mandatory within a 10 m zone around scaffolding to protect against falling objects.
• Use of screens or canopies recommended to prevent falling debris.

2. Platform Width (Clause 8.1)

• Minimum platform widths depend on use; ensure compliance with IS 3696 Part 1 recommendations for safe working space.

3. Load Testing (Clause 10.3.4)

• Scaffolds/rigging must be tested with a load at least 3 times the intended service load to ensure safety.

Summary Table: Safety Helmets & Load Testing

Safety Helmets (IS 2925:1984) Key Points:

• Industrial safety helmets must resist impact and penetration.
• Provide electrical insulation if required.
• Adjustable headbands for secure fit.

flowchart LR
    A[Supervisory Personnel] -->|Wear Helmet| B[Within 10 m Zone]
    B --> C{Falling Objects Risk}
    C -->|Yes| D[Use Screens/Canopies]
    C -->|No| E[Normal Precautions]
    F[Scaffold] -->|Load Test 3×| G[Safe for Use]

Note: Strict adherence to safety codes is essential for both temporary and permanent structures (Clause 9.14).

IS 3696 (Part 1) - Platform Widths & Load Capacities

Platform Widths (Clause 8.1 & related notes)

• Minimum platform widths depend on scaffold type and use.
• Overlap of planks must be on putlogs/bearers only.
• If planks are end-to-end (no overlap), putlogs must be within 100 mm from plank ends.
• Ledgers & transoms start not beyond 150 mm from base/foundation.

Load Capacities & Platform Types

Recommended Timber Sizes (Examples from Clauses)

• Base/Plate: min 12 mm thick, 50 × 200 mm
• Overlap single bearer: 35 × 150 mm
• Intermediate railing: 35 × 75 mm

Important Notes:

• Alternate sizes/spacings allowed if approved by a qualified engineer.
• Load includes men, tools, and materials.

Summary Formula for Load on Platform:

[ \text{Total Load} \leq \text{Safe Working Load} \times \text{Platform Area} ]

flowchart TD
    A[Platform Type] --> B{Light Duty}
    A --> C{Heavy Duty}
    B --> D[SWL = 150 kg/m²]
    B --> E[Max Load = 300 kg]
    C --> F[SWL = 300 kg/m²]
    C --> G[Distributed Load over 2-3 points]

This ensures safe platform design per IS 3696 (Part 1).

IS 3696 Part 1: Construction, Use, and Maintenance of Scaffolds

Key Specifications & Tables

1. Scaffold Types & Loads:

2. Single Pole Scaffold (Timber) - Up to 18 m height

3. Double Pole Scaffold (Timber) - Up to 18 m height

| Component | Up to 10 m | 10 m to 18 m

IS 3696 Part 1: Precautions Against Particular Hazards

Key Points from Clause 10:

• 10.1 Electrical Hazards

  • Bars, rods, or pipes > 3 m length must not touch electric wires.
  • Special care near electric wires to avoid conduction and electrocution risks.

• 10.2 Fire Hazards

  • Timber scaffolds require protection to prevent ignition.
  • Avoid sources of sparks or flames near timber scaffolds.

Additional Recommendations (General Engineering Practice):

Safety Checklist for Temporary Structures:

• Ensure minimum 3 m clearance for conductive materials near electric wires.
• Use non-combustible materials or treat timber scaffolds.
• Provide fire extinguishers and train personnel.
• Conduct daily safety inspections.

flowchart TD
    A[Carrying Bars > 3m] --> B{Near Electric Wires?}
    B -- Yes --> C[Ensure no contact with wires]
    B -- No --> D[Proceed normally]
    C --> E[Maintain safety clearance ≥ 3 m]

Summary: Strict adherence to electrical clearance and fire prevention measures per IS 3696 Part 1 Clause 10 ensures safety in temporary scaffolding.

IS 3696 (Part 1) - 1987: Ropes, Knots, and Fastenings

Key Specifications & Formulas:

1. Fibre Ropes (Clause 4.3)

• Made from natural or synthetic fibers.

• Strength depends on fiber type, diameter, and construction.

• Typical breaking strength formula:

  [ T_b = k \times d^2 ]

  where:
  ( T_b ) = Breaking load (N)
  ( d ) = Diameter of rope (mm)
  ( k ) = Constant depending on fiber type (refer to IS tables)

2. Knots and Hitches (Clause 4.4)

• Desirable features (4.4.1):
  • Quick to tie
  • Easily untied
  • Non-slip under strain
• Common knots for scaffolding:
  • Thumb knot
  • Figure eight knot
  • Reef knot (single/double hitch)
  • Clove hitch knot

3. Reef Knot (Clause 4.4.4)

• Used for joining or extending ropes.
• Should be tied carefully to avoid slipping.
• Refer to Fig. 14 (IS code) for correct tying method.

Summary Table: Common Knots & Uses

graph TD
    A[Ropes] --> B[Fibre Ropes]
    A --> C[Knots & Hitches]
    C --> D[Thumb Knot]
    C --> E[Figure Eight Knot]
    C --> F[Reef Knot]
    C --> G[Clove Hitch]

Note: Always consider safety factors and inspect knots regularly in construction applications.

Bracing and Tying of Scaffolds (IS 3696 Part 1 - 1987)

1. Tying Spacing (Clause 4.2.3.3, Table 3)

• Note: Tie spacing must never be exceeded; if a tie is removed, another must be fixed or additional bracing provided.

2. Additional Bracing (Clause 4.2.3.4)

• When tie spacing cannot be maintained due to attachment difficulties, additional bracing must be provided between tie points.
• Use plan bracing (Fig. 11) when horizontal tie distance is excessive.

3. Heel and Toe Bracing (Clause 4.2.5)

• If vertical tie spacing is impracticable, heel and toe bracing shall be provided between tie points (see Fig. 9).
• Maximum distance between ties with heel and toe bracing: 15 m.

4. Tie Fixing Methods (Fig. 10)

• Tie through openings
• Scaffold fixed to form ties
• Tie around columns

Summary Diagram:

graph TD
  A[Scaffold] --> B[Ties]
  B -->|Horizontal Spacing| C{Height}
  C -->|Up to 6m| D[Every 5th standard or 10m]
  C -->|6-12m| E[Every 4th or 5th standard]
  C -->|12-

Key Specifications and Guidelines for Boatswain's Chair (IS 3696 Part 1 - 1987):

• Seat Dimensions:

  • Thickness: ≥ 30 mm
  • Length: ≤ 600 mm
  • Width: 300 mm

• Construction:

  • Battens nailed underneath the seat
  • Battens project at least 250 mm in front of the seat

• Safety:

  • Each worker must wear a safety belt securely fastened to the supporting tackle to prevent falling (Clause 4.7.6).

• Suspension:

  • Suspension ropes can be fastened to a fixed overhead structure or passed through a securely fastened overhead block.
  • The free end of the rope must be securely fastened to a fixed object (Clause 4.7.4).

Typical Boatswain's Chair Setup (Fig. 6 A & B reference):

graph LR
A[Fixed Overhead Structure] --> B[Overhead Block]
B --> C[Suspension Rope]
C --> D[Boatswain's Chair]
D --> E[Worker with Safety Belt]

Important Notes:

• Always inspect the chair and ropes before use.
• Use quality ropes with adequate breaking strength (typically ≥ 10 kN).
• Ensure secure knots and fastening points.

This ensures worker safety and compliance with IS 3696 Part 1.

IS 3696 (Part 1) - Inspection and Testing Key Points

1. Load Testing (Clause 10.3.4)

• Scaffolds or rigging involving human safety must be tested with a load ≥ 3 times the working load.

  [ \text{Test Load} \geq 3 \times \text{Service Load} ]

2. Recommended Loads for Single Pole Bamboo Scaffolds (Clause 4.1.1, Table 1)

3. Scaffold Components Dimensions (mm)

4. Platform Widths & Spacing (Clause 8.1)

• Minimum platform widths and ledger spacing are specified to ensure safety and stability.

Summary Diagram: Load Testing Concept

graph LR
A[Service Load] --> B[Test Load]
B --> C{Test Load ≥ 3 × Service Load?}
C -- Yes --> D[Safe for Use]
C -- No --> E[Retest or Modify Scaffold]

Contact for further details:
Central Laboratory, Sahibabad Industrial Area, Tel: 8-77 00 32
Regional Offices: New Delhi, Calcutta, Chandigarh, Madras, Mumbai, etc.

This ensures scaffold safety by rigorous testing and adherence to dimensional and load specifications.

IS 3696 Part 1: Key Annexures, Tables & Figures Summary

1. Single Pole Scaffold (Annexure: Table 4.1.3)

• Max height: Up to 18 m.
• Load capacity:
  • Light Duty: 150 kg/m²
  • Heavy Duty: 300 kg/m²
• Pole sizes:
  • Up to 10 m: 75×75 mm or 75×100 mm
  • Above 10 m: 75×100 mm or 100×100 mm (top 10 m: 75×75 or 75×100)
• Ledger sizes:
  • Supporting putlogs: 50×150 mm (heavy duty)
  • Not supporting putlogs: 50×100 mm
• Putlogs/Bearers: 50×100 mm or 75×100 mm
• Braces: 35×100 mm (light), 50×150 mm (heavy)
• Pole spacing:
  • Longitudinal: max 2.5 m (light), 2 m (heavy)
  • Distance from wall: 1.0–1.2 m (up to 10 m), 1.2–1.8 m (above 10 m)
• Ledger vertical spacing: max 1.8 m
• Base plate: min 12 mm thick, 50×200 mm (light), 100×200 mm (heavy)
• Planking: 35×200 mm (light), 50×200 mm (heavy)
• Overlap of planks: 300 mm
• Toe boards: 35×150 mm (light), 50×150 mm (heavy)
• Top railing: 50×75 mm (light), 50×100 mm (heavy)
• Intermediate railing: 35×75 mm (light), 35×100 mm (heavy)

2. Double Pole Tied Scaffold (Table 4.1.3)

• Max height: Up to 18 m.
• Pole sizes:
  • Up to 10 m: 75×75 mm or 75×100 mm
  • Above 10 m: 75×100 mm or 100×100 mm
• Pole spacing:
  • Transverse