Modular co-ordination for normal brickwork - Recommendations, Part 1: Burnt clay bricks

IS 13612 Part 1: Scope - Key Specifications & Formulas

1. Horizontal Coordination Module (Clause 6.3.2)

• Horizontal controlling dimension = 3M = 5 × 60 mm = 300 mm (for non-modular bricks)
• Modular bricks nominal sizes (mm):

2. Tolerance on Brick Dimensions (Clause 7.3)

• For fractional lengths (1/4, 1/2, 3/4 bricks), deduct 10 mm total for joint dimensions.

3. Modular Coordination (Clause 5.1 & 11.4)

• Horizontal dimensions use 3M or multiples (M = 100 mm for modular bricks).
• Vertical dimensions use 2M or multiples.
• Actual openings = Modular dimension + 10 mm
• Wall dimensions = Modular dimension - 10 mm

4. Wall Thickness (Figures 8A & 8B)

• Modular brick wall thicknesses: 1 brick = 100 mm, 1.5 bricks = 150 mm, etc.
• Non-modular brick wall thicknesses: 1 brick = 80 mm, 1.5 bricks = 120 mm, etc.

Summary Table: Brick Dimensions & Tolerances

IS 13612 Part 1: General Concept - Key Formulas, Tables & Specifications

1. Controlling Dimensions of Bricks (Clause 6.3.2)

• Horizontal controlling dimension of 3M = 5 × 60 mm = 300 mm
• Typical dimensions (Nominal / Actual in mm):

2. Tolerance on Bricks (Clause 7.3)

• Deduct 5 mm on all surfaces for joint dimensions.
• Example for Non-Modular bricks (Actual = Nominal - 10 mm):

3. Horizontal Dimensions of Wall (Clause 11.4)

• Actual opening size = Modular size + 10 mm
• Wall dimension = Modular size - 10 mm

4. Wall Thickness Examples

• Modular bricks: One brick = 190 mm thick
• Non-modular bricks: One brick = 230 mm thick

Summary Table: Non-Modular Brick Sizes (Clause 10.3.2)

IS 13612 Part 1: Field of Application - Key Formulas, Tables & Specs

1. Modular Coordination Basics (Clause 5.1)

• Horizontal dimensions use 3M modules or multiples.
• Vertical dimensions use 2M modules or multiples.
• Reference standards: IS 6820:1987, IS 7921:1987, IS 7922:1987.

2. Controlling Dimensions of Bricks (Clause 6.3.2)

• Horizontal controlling dimension 3M = 5 × 60 mm = 300 mm (for non-modular bricks).

3. Tolerance on Bricks (Clause 7.3)

• Deduct 5 mm per joint surface for length, height, width, and cuttings.

4. Opening & Wall Dimension Coordination (Clause 11.4)

• Actual openings = Modular dimension + 10 mm
• Wall dimensions = Modular dimension - 10 mm

5. Wall Thickness Examples

• One and half brick wall thickness varies with brick type (see FIG 8A & 8B in IS 13612 Part 1).

Summary Table for Horizontal Coordination:

Key Formulas, Tables & Specifications for Modular Brickwork (IS 13612 Part 1)

1. Basic Coordinating Dimension (Clause 9.1.1)

• Vertical plane dimension for modular bricks:

  [ \text{Dimension} = n \times 50, \text{mm} - \text{joint dimension (typically 10 mm)} ]

• Where n = number of modular increments.

2. Modular Brick Sizes & Actual Dimensions (After 5 mm Deduction for Joints)

*Quoin closer or 1/2 header.

3. Coordinating Dimensions for Modular Bricks

Tolerance on Bricks as per IS 13612 Part 1 (Clause 7.3)

• General:
  All brick dimensions (length, height, width, including cuttings like closers, bats) shall have a 5 mm deduction on all surfaces to allow for mortar joint thickness.

1. Modular Bricks (50 mm module)

2. Non-Modular Conventional Bricks (60 mm module)

Notes:

• The 10 mm deduction corresponds to two mortar joints of 5 mm each on either side.
• These tolerances ensure proper bonding and dimensional accuracy in masonry.
• Refer IS 6408 (Part 2):1990 for application of tolerances in brickwork.

flowchart LR
    A[Brick Nominal Length] --> B[Deduct 5 mm on each side]
    B --> C[Actual Brick Length for Bonding]
    C --> D[Ensures proper joint thickness]

Summary: Always

IS 13612 Part 1: Horizontal Dimensions of Wall

Key Clauses:

• Clause 8.3 & 8.4: Horizontal dimensions in brickwork should be selected to control wall length, applying the '5-mm Rule' for specifying dimensions and openings.
• Clause 6.2 & 6.4: Preferred horizontal dimensions are based on controlling dimensions for brickwork.

The '5-mm Rule' (per IS 7921:1987):

• All horizontal dimensions of walls and openings should be multiples of the basic brick unit plus mortar thickness, allowing a 5 mm tolerance.
• This ensures dimensional accuracy and reduces cutting or adjustment on-site.

Typical Horizontal Dimensioning:

• Use modular dimensions based on brick size (e.g., standard brick 190 mm × 90 mm × 90 mm with mortar thickness 10 mm).
• Horizontal length = (Number of bricks × (brick length + mortar thickness)) ± 5 mm.

Summary:

• Horizontal wall lengths = n × 200 mm ± 5 mm (where n = integer number of bricks).
• This modular approach simplifies construction and ensures compatibility with openings and other elements.

flowchart LR
    A[Start: Select Wall Length] --> B[Calculate n = Wall Length / 200]
    B --> C{Is n an Integer?}
    C -- Yes --> D[Wall Length = n × 200 mm ± 5 mm]
    C -- No --> E[Adjust Wall Length to Nearest Multiple]
    E --> D

This ensures dimensional control and reduces wastage or rework.

IS 13612 Part 1: Vertical Dimensions of Wall

Key Points from Clauses:

• Clause 9.4: The 5-mm Rule applies to vertical dimensions of walls and openings (refer IS 7922:1987).
• Clause 9.3: Preferred vertical dimensions control sill, lintel, room, and floor heights.
• Clause 6.2: Controlling dimensions for brickwork must be considered.

The 5-mm Rule (IS 7922:1987)

• All vertical dimensions of walls and openings should be multiples of 5 mm.
• This ensures modular coordination and reduces cutting wastage.

Preferred Vertical Dimensions for Brickwork (Typical values)

Summary:

• Use multiples of 5 mm for vertical measurements.
• Select vertical dimensions as multiples of brick course height (75 mm).
• Control sill, lintel, and floor heights for modular coordination.

flowchart TD
    A[Start: Wall Vertical Dimension] --> B{Apply 5-mm Rule?}
    B -- Yes --> C[Dimension = Multiple of 5 mm]
    C --> D{Match Brick Course?}
    D -- Yes --> E[Dimension = Multiple of 75 mm]
    D -- No --> F[Adjust to nearest multiple]
    E --> G[Set Sill, Lintel, Floor Heights]
    F --> G
    G --> H[Final Vertical Dimension]

This approach ensures precision, modularity, and ease of construction.

Thickness of Wall per IS 13612 Part 1 (Clause 10 & 7.3):

The wall thickness depends on the brick size and bonding pattern, considering the '5-mm Rule' for joint deductions.

Key Specifications:

• Modular Bricks (Nominal size 190 × 90 × 90 mm)

• Non-Modular Bricks (Nominal size 230 × 110 × 75 mm)

Notes:

• The '5-mm Rule': Deduct 5 mm on each surface of bricks for mortar joints.
• Thickness is typically multiples of brick width (modular: 50 mm, non-modular: 60 mm).
• Brick-on-edge courses can be introduced to accommodate non-modular sizes or functional needs (Clause 9.5).

Summary Formula for Wall Thickness:

[ \text{Wall Thickness} = n \times (\text{Brick Width}) - 10 \text{ mm} ]

where ( n = ) number of brick widths (e.g., 1/4, 1/2, 3/4, 1 brick thick).

graph LR
A[Brick Width] -->

IS 13612 Part 1: Co-ordinate Dimensioning Key Points

1. Planning Modules (Clause 5.1)

• Horizontal dimensions: Use multiples of 3M.
• Vertical dimensions: Use multiples of 2M.
• Refer IS 6820:1987, IS 7921:1987, IS 7922:1987 for modular coordination.

2. Non-Modular Brick Sizes (Clause 10.3.2)

3. Horizontal Controlling Dimensions (Clause 6.3.2)

• 3M = 5 × 60 mm (for non-modular bricks, 60 mm = 1/4 brick interval)

4. Controlling Dimension Concept

• Use multiples of 3M (180 mm nominal) horizontally to align brickwork.
• This ensures modular coordination and uniform bond patterns (e.g., English or Flemish bond).

flowchart LR
    A[Planning Module] --> B[Horizontal: 3M multiples]
    A --> C[Vertical: 2M multiples]
    B --> D[Brick Length

IS 13612 Part 1: Location of Wall - Key Points

1. 5-mm Rule (Clauses 8.4 & 9.4)

• Apply a 5 mm deduction on all horizontal and vertical dimensions of walls and openings.
• This accounts for mortar joints and ensures accurate modular sizing.
• Refer to IS 7921:1987 (horizontal) & IS 7922:1987 (vertical) for detailed application.

2. Modular Lines of Openings (Clause 11.3)

• Openings (doors, windows) must align along the center line of brick joints (modular lines).
• Ensures structural integrity and uniformity in wall layout.

3. Tolerance on Bricks (Clause 7.3)

• Brick sizes are reduced by 5 mm per joint for modular wall dimensions.

4. Wall Dimension Formula (Horizontal/Vertical)

[ \text{Effective Wall Length} = n \times (\text{Brick Length} - 5, \text{mm}) ] where n = number of bricks in length/height.

flowchart LR
    A[Start: Wall Layout] --> B[Apply 5-mm Rule]
    B --> C[Calculate Effective Brick Size]
    C --> D[Locate Openings on Modular Lines]
    D --> E[Construct Wall with Tolerances]

Summary: Use the 5-mm deduction per joint for precise wall and opening dimensions, align openings on brick joint

IS 13612 (Part 1): 1993 – List of Referred Indian Standards

This part of IS 13612 provides references essential for modular coordination in brickwork, especially for burnt clay bricks.

Key Referred IS Standards

Important Specification Notes:

• Co-ordinating dimensions: Actual openings are 10 mm more, wall dimensions 10 mm less than modular dimensions (Clause 11.4).
• Modular bricks preferred over non-modular for dimensional control.
• IS 1077 & IS 2180 specify modular brick sizes (e.g., 200×100×100 mm).

Summary Diagram of Coordination Concept:

flowchart LR
    A[Modular Dimension] -->|+10 mm| B[Actual Opening]
    A -->|-10 mm| C[Wall Dimension]

This ensures precise fitting and dimensional harmony in brickwork construction.

For detailed dimensional tables and tolerances, refer to the respective IS codes listed above.