Precast Concrete Coping Blocks

IS 5751: Scope & Key Specifications Summary

• Scope: Covers specifications for coping blocks used on walls, including materials, dimensions, and tolerances.

Key Specifications:

1. Materials for Cramps and Dowels (Clause 2.5):

   • Copper, brass, bronze, corrosion-resisting steel, or galvanized steel.
   • Shape & size agreed between manufacturer and purchaser.

2. Dimensions (Clause 3.1):

   • Cross-section form agreed between purchaser & supplier.
   • Overall width based on wall thickness.
   • Minimum dimensions per:
     • Fig. 1: Clip type coping
     • Fig. 2: Flat-bottom coping (bed faces may be serrated or recessed)
   • All dimensions in mm.

3. Tolerances (Clause 3.3):

   • ±3 mm on cross-sectional profile dimensions.
   • Difference between individual coping blocks ≤ half of ±3 mm tolerance.
   • ±6 mm on specified length of coping blocks.

4. Rounding Off (Clause 0.5):

   • Follow IS 2-1960 for rounding test/analysis results.

Typical Dimensions (from Figures 1 & 2):

flowchart LR
    A[Wall Thickness] --> B[Determine Coping Width]
    B --> C{Coping Type}
    C -->|Clip Type| D[Use Fig.1 Dimensions]
    C -->|Flat Bottom| E[Use Fig.2 Dimensions]
    D & E --> F[Apply Tolerances ±3 mm (cross-section), ±6 mm (length)]
    F --> G[Select Materials for Cramps/Dowels]

Note: Always confirm dimensions and materials with purchaser requirements and IS 5751 latest edition.

IS 5751: Materials Key Points

Aggregates (Clause 2.2)

• Must comply with IS 383:1970 (Coarse & Fine Aggregates for Concrete).
• Limits for:
  • Aggregate Crushing Value (ACV)
  • Aggregate Impact Value (AIV)
  • Aggregate Abrasion Value (AAV)
• AIV test is an alternative to ACV test.
• Values must not exceed limits for non-wearing surfaces concrete.

Cements

• Use cements conforming to relevant IS codes:
  • Ordinary & Low Heat Portland Cement: IS 269 (Third Revision)
  • Rapid Hardening Portland Cement: IS 804 (First Revision)
  • Portland Slag Cement: IS 455 (Third Revision)
  • Portland Pozzolana Cement: IS 1489 (Second Revision)
  • White Portland Cement: IS 804 (First Revision)
  • Supersulphated Cement: IS 6909 (First Revision)
  • Hydrophobic Portland Cement: As per relevant IS.

Cramps and Dowels (Clause 2.5)

• Materials: Copper, Brass, Bronze, Corrosion-resistant steel, or Galvanized steel.
• Dimensions: As mutually agreed between manufacturer and purchaser.

Rounding Off (Clause 0.5)

• Follow IS 2:1960 for rounding test results.
• Retain significant figures equal to specified values.

Typical Aggregate Property Limits (from IS 383:1970)

flowchart TD
    A[Materials] --> B[Aggregates]
    B --> C[IS 383:1970 Compliance]
    B --> D[ACV, AIV, AAV Limits]
    A --> E[Cements]
    E --> F[IS 269, 455, 1489, etc.]
    A --> G[Cramps & Dowels]
    G --> H[Material: Copper, Brass, Steel]
    A --> I[Rounding Off]
    I --> J[IS 2

IS 5751: Dimensions and Tolerances for Coping Blocks

Key Specifications:

• Materials for Cramps and Dowels (Clause 2.5):

  • Copper, brass, bronze, corrosion-resisting steel, or galvanized steel.
  • Dimensions agreed between manufacturer and purchaser.

• Cross-Section Dimensions (Clause 3.1):

  • Form as agreed between purchaser and supplier.
  • Overall width based on wall thickness.
  • Minimum dimensions per Fig. 1 (Clip Type) and Fig. 2 (Flat-Bottom Coping).
  • Optional: Angle of weathering and throating shape.
  • All dimensions in millimeters.

• Tolerances (Clause 3.3):

  • ±3 mm on cross-sectional profile dimensions.
  • Difference between coping blocks of the same type ≤ half the tolerance (±1.5 mm).
  • ±6 mm on specified length of each coping block.

• Quality Control (Clause 13.4):

  • Max 2 blocks with tolerance or visual defects per inspection batch.

Summary Table of Tolerances:

Illustration of Dimensions (Simplified):

graph LR
A[Wall Thickness] --> B[Overall Width of Coping]
B --> C{Cross-Section Shape}
C --> D[Clip Type Coping (Fig.1)]
C --> E[Flat-Bottom Coping (Fig.2)]
D -. Optional .-> F[Angle of Weathering]
D -. Optional .-> G[Throating Shape]
E -. Optional .-> F
E -. Optional .-> G

Note: Refer to IS 5751 Fig. 1 & 2 for exact minimum dimensions and shapes.

IS 5751: Shapes and Types of Coping Blocks

1. Shapes of Coping Blocks (Clause 4.1 & Fig. 3)

• 3A Splayed Copings:
  • Hipped
  • Stopped End
• 3B Saddleback Copings, Type 1:
  • Hipped Stopped End (Handed)
  • Angle Return (Handed)
• 3C Saddleback Copings, Type 2

Note: Detailed dimensions per Fig. 1 or 2, agreed between manufacturer and purchaser.

2. Slope and Weathering (Clause 4.2)

• Coping blocks shall slope to the rear for water drainage.
• Slope should be as steep as possible to prevent water/dirt accumulation.
• Optional features:
  • Angle of weathering
  • Throating shape

3. Dimensions and Tolerances

• Cross-section dimensions: See Fig. 1 (Clip Type) & Fig. 2 (Flat-Bottom Coping).
• Overall width: Based on wall thickness.
• Tolerances (Clause 3.3):
  • ±3 mm on cross-sectional profile
  • Max difference between similar blocks ≤ ±1.5 mm
  • ±6 mm on length

4. Mass of Coping Block

• Calculated based on volume and concrete density (~2400 kg/m³).
• Use cross-sectional area × length × density for mass estimation.

5. Typical Dimensions (from Fig. 1 & 2)

flowchart LR
    A[Wall Thickness] --> B{Select Coping Type}
    B --> C[Splayed Coping]
    B --> D[Saddleback Coping Type 1]
    B --> E[Saddleback Coping Type 2]
    C -->

Mass of Coping Blocks (IS 5751 Key Points)

• Minimum Mass for Flat-Bottom Copings (Clause 5.1):

  • Not less than 35 kg/m for copings not fixed by cramps.
  • This ensures resistance against displacement by ladder impact or wind.

• Dimensions & Tolerances (Clause 3.3):

  • Cross-sectional profile tolerance: ±3 mm
  • Length tolerance: ±6 mm (standard length = 1 m unless specified)
  • Variation between same type coping blocks ≤ half of cross-section tolerance (≤1.5 mm)

• Slope Requirements (Clause 4.2):

  • Copings must slope to the rear for rapid water shedding and dirt reduction.
  • Slope should be as steep as possible.

• Typical Coping Types (Figs. 1, 2, 3):

  • Clip type coping
  • Flat-bottom coping
  • Splayed, saddleback, hipped types (dimensions per Fig. details and agreement)

Formula for Approximate Mass of Coping Block

[ \text{Mass (kg)} = \text{Volume (m}^3) \times \text{Density of concrete (kg/m}^3) ]

• Concrete density ≈ 2400 kg/m³
• Volume = Cross-sectional area × Length (m)

Summary Table

flowchart LR
    A[Coping Block] --> B[Cross-Section Area]
    B --> C[Calculate Volume = Area × Length]
    C --> D[Mass = Volume × Concrete Density (2400 kg/m³)]
    D --> E[Check if Mass ≥ 35 kg/m (flat-bottom)]
    E --> F{Mass OK?}
    F -- Yes --> G[Use Coping Block]
    F -- No --> H[Increase Dimensions or Use Fixing Cramps]

This ensures coping

Provision for Cramps as per IS 5751

• Materials: Cramps must be made of copper, brass, bronze, corrosion-resistant steel, or galvanized steel (Clause 2.5).

• Dimensions & Fixing:

  • Holes to receive cramps should be provided in coping blocks at purchaser-specified positions (Clause 6.1).
  • The form and dimensions of cramps are agreed upon between manufacturer and purchaser.

• Mass of Copings:

  • For flat-bottomed copings not fixed by cramps, minimum mass = 35 kg/m to resist displacement (Clause 5.1).

Typical Specification Summary for Cramps

Notes:

• Exact dimensions and shape of cramps are project-specific and agreed upon contractually.
• Ensure corrosion resistance for durability.
• Coping blocks must have holes drilled accurately for cramps to fit tightly.

flowchart LR
    A[Coping Block] --> B[Hole for Cramps]
    B --> C[Cramps (Copper/Brass/Steel)]
    C --> D[Fixing Coping Securely]

This ensures coping blocks are fixed firmly, preventing displacement under wind or impact loads.

IS 5751 – Fixing and Jointing of Coping Blocks

Key Provisions (Clause 6.1 & 7.1)

• Fixing by cramps: Holes must be provided in coping blocks at purchaser-specified positions to receive cramps for holding down copings.
• Jointing methods: Ends of coping blocks should be jointed using:
  • Dowels
  • Cramps
  • Joggled mortar joints

Tolerances (Clause 3.3)

Additional Notes

• Optional features include angle of weathering and throating shape for better water runoff.
• Fixing and jointing should ensure structural integrity and weather resistance.

Typical Fixing Arrangement (Simplified)

graph LR
A[Coping Block 1] -- Dowel/Cramps --> B[Coping Block 2]
A -- Mortar Joint --> B
A -- Fixing Hole for Cramps --> C[Wall/Support]

Summary: Provide holes for cramps as per purchaser, use dowels/cramps/joggled mortar joints for end jointing, and maintain specified tolerances for proper fit and durability.

IS 5751: Manufacturing Process - Key Points

Materials for Cramps and Dowels (Clause 2.5)

• Materials: Copper, brass, bronze, corrosion-resisting steel, or galvanized steel
• Dimensions & form: As agreed between manufacturer and purchaser.

Aggregates (Clause 2.2)

• Must comply with IS 383-1970.
• Limits on:
  • Aggregate Crushing Value (ACV)
  • Aggregate Impact Value (AIV)
  • Aggregate Abrasion Value (AAV)
• AIV can be used as an alternative to ACV for testing.

Sampling & Conformity (Clause 13.1)

• Sampling methods and conformity criteria detailed in Clauses 13.2 - 13.5.
• Ensures representative material testing.

Rounding Off (General)

• Follow IS 2-1960 for rounding numerical values.
• Maintain significant figures equal to specified values.

Summary Table: Aggregate Quality Limits (from IS 383-1970)

Notes:

• Manufacturing tolerances and detailed dimensions are agreed upon contractually.
• Cement specifications refer to various IS codes (e.g., IS 269, IS 1489).
• This standard aligns with IS 456 (Plain & Reinforced Concrete).

flowchart LR
    A[Raw Materials] --> B[Aggregate Testing (IS 383)]
    B --> C{Meets Limits?}
    C -- Yes --> D[Manufacturing Process]
    C -- No --> E[Reject/Replace Aggregates]
    D --> F[Cramps & Dowels: Material Selection]
    F --> G[Final Product Inspection & Sampling]

This concise overview aids in understanding manufacturing controls per IS 5751.

IS 5751 - Surface Finish for Concrete Coping Blocks

Key Specifications (Clause 9.1)

• Finish: Obtained by casting in properly designed moulds.
• Mould Material: Wood moulds must be closely jointed wrought timber.
• Surface Texture: Slight grain of timber and joints may imprint on the block.
• Surface Quality: Exposed surfaces shall be:
  • Plane and true
  • Free from honeycombing or large blemishes
  • Small blemishes due to air or water entrapment are acceptable.

Tolerances (Clause 3.3)

Additional Notes

• Cramps and dowels (Clause 2.5) must be corrosion-resistant metals.
• Aggregates must comply with IS 383:1970 for non-wearing concrete surfaces.

flowchart TD
    A[Properly Designed Moulds] --> B[Casting Concrete Block]
    B --> C[Surface Finish]
    C --> D[Plane & True Surface]
    C --> E[Minor Blemishes Allowed]
    C --> F[No Honeycombing or Large Defects]

This ensures durable, aesthetically acceptable coping blocks with controlled dimensional accuracy.

IS 5751: Weathering and Slope for Concrete Copings

Key Specifications:

• Weathering Angle (Clause 10.1):

  • Top of coping blocks shall be weathered at an angle agreed between purchaser and manufacturer.
  • This angle helps shed water and reduce water ingress.

• Slope (Clause 4.2):

  • Coping blocks must slope to the rear for rapid water shedding.
  • The slope should be as steep as possible to minimize water wash and dirt accumulation on the wall face.

Tolerances (Clause 3.3):

• Cross-sectional profile: ±3 mm
• Length of coping block: ±6 mm
• Variation between blocks: ≤ half the tolerance

Typical Coping Types (Figures 1, 2, 3):

• Clip Type Coping (Fig. 1)
• Flat-Bottom Coping (Fig. 2)
• Splayed, Saddleback Copings with hipped or angle returns (Fig. 3)

Material Specifications:

• Aggregates per IS 383:1970
• Cement types per relevant IS codes (Ordinary, Rapid Hardening, Portland Slag, etc.)

Practical Notes:

• Slope recommendation: Typically 1:20 to 1:30 (5% to 3.3%) slope to rear is effective for water runoff.
• Weathering angle: Usually between 10° to 30°, depending on exposure and design.

flowchart LR
    A[Top of Coping Block] --> B[Weathered Surface]
    B --> C[Slope to Rear]
    C --> D[Rapid Water Shedding]
    D --> E[Reduced Wall Face Wash]

This ensures durability by minimizing water ingress and dirt accumulation on walls.

IS 5751: Fittings and Accessories - Key Points

Materials (Clause 2.5)

• Cramps and dowels: Must be made of copper, brass, bronze, corrosion-resisting steel, or galvanized steel.
• Form and dimensions: As agreed between manufacturer and purchaser.

Dimensions and Tolerances (Clause 3)

• Cross-section dimensions (Clause 3.1):
  • Determined by wall thickness.
  • Minimum dimensions per Fig. 1 (clip type coping) and Fig. 2 (flat-bottom coping).
• Tolerances (Clause 3.3):
  • ±3 mm on cross-sectional profile dimensions.
  • Variation between individual blocks ≤ half the tolerance (±1.5 mm).
  • ±6 mm on length of coping blocks.

Fittings (Clause 11.1)

• Stopped ends, hipped stopped ends, stooled ends, right-angled returns to match coping blocks.
• Other fittings by purchaser-supplier agreement.

Typical Dimensions Summary (from Figs. 1 & 2)

flowchart LR
    A[Wall Thickness] --> B[Select Coping Type]
    B --> C{Clip Type}
    B --> D{Flat-Bottom Type}
    C --> E[Dimension per Fig.1]
    D --> F[Dimension per Fig.2]
    E & F --> G[Apply Tolerances ±3 mm (cross-section)]
    G --> H[Length Tolerance ±6 mm]
    H --> I[Fitments by Agreement]

For detailed dimensions, refer to IS 5751 Fig. 1 & 2.

IS 5751 - Marking of Precast Coping Blocks

Key Specifications (Clause 12.1)

Each precast coping block shall be clearly and permanently marked with:

• Manufacturer's name and trade-mark (if any)
• Year of manufacture (if required by purchaser)
• ISI Certification Mark (optional, per Clause 12.1.1)

ISI Certification Mark (Clause 12.1.1)

• Indicates compliance with IS standards.
• Use governed by Indian Standards Institution (Certification Marks) Act.
• Ensures product quality via inspection, testing, and continuous surveillance.
• License details available from ISI.

Rounding Off Numerical Values (Clause 0.5)

• Follow IS 2-1960 rules for rounding.
• Retain the same number of significant digits as specified values.

Summary Table for Marking Requirements

flowchart LR
    A[Precast Coping Block] --> B{Marking}
    B --> C[Manufacturer's Name & Trade-mark]
    B --> D[Year of Manufacture (optional)]
    B --> E[ISI Certification Mark (optional)]

This marking ensures traceability, quality assurance, and compliance with IS 5751.

IS 5751: Sampling and Criteria for Conformity

Sampling Procedure (Clause 13.3)

• From each lot, select 24 coping blocks at random.
• Check all 24 blocks for:
  • Dimensions (as per Clause 3)
  • Visual defects

Criteria for Conformity (Clauses 13.2 to 13.5)

• Blocks must conform dimensionally within specified tolerances.
• No visible defects such as cracks, chips, or surface irregularities.
• Aggregate quality as per IS 383:1970:
  • Aggregate Crushing Value (ACV), Aggregate Impact Value (AIV), and Abrasion Value must meet limits for non-wearing surfaces.
  • AIV may be used as an alternative to ACV.

Key References:

Summary Diagram of Sampling Process:

flowchart TD
    Lot[Lot of Coping Blocks]
    Sample[Select 24 Blocks Randomly]
    DimCheck[Check Dimensions]
    VisualCheck[Inspect Visual Defects]
    Conformity{Conforms to Criteria?}
    Accept[Accept Lot]
    Reject[Reject Lot]

    Lot --> Sample --> DimCheck --> VisualCheck --> Conformity
    Conformity -->|Yes| Accept
    Conformity -->|No| Reject

Note: Use ISI mark only if the product complies with IS standards under ISI supervision.