Recommendations for modular coordination in the building industry: Location of structural walls and floor slabs

IS 13613: Scope Overview

• Scope: Provides general guidance on modular coordination for placing components and assemblies within a dimensional framework, applicable to all building types and construction techniques.

• Vertical controlling dimensions: Must comply with IS 7922:1987 (modular coordination dimensions).

• Design Details: Clause 6.2 covers specifics on design details for modular coordination.

• Annex A: Lists necessary Indian Standards adjunct to IS 13613 for comprehensive design.

Key Reference: IS 7922:1987 (Vertical Controlling Dimensions)

• Vertical dimensions are multiples of 100 mm (1 MU), ensuring standardization and interchangeability.

Summary Diagram: Modular Coordination Framework

graph TD
    A[IS 13613: Modular Coordination] --> B[Vertical Dimensions per IS 7922]
    A --> C[Design Details (Clause 6.2)]
    A --> D[Annex A: Related IS Standards]
    B --> E[Standard Modular Units (100 mm)]
    C --> F[Component Placement & Assemblies]

Use IS 13613 as a framework to integrate modular dimensions, ensuring dimensional compatibility and efficient building design.

IS 13613 - References Summary

Key Indian Standards Referenced (Clause 2.1 & Annex A)

Important Notes:

• Modular Coordination standards (IS 6820, 7921, 7922, 12073) govern dimensional coordination in building design.
• Vertical and horizontal controlling dimensions must comply with IS 7922:1987 (Clause 7.1.2).
• Use of the Standard Mark ensures compliance with BIS quality control.
• Indian Standards are periodically reviewed; always confirm use of latest edition/amendments.

Contact & Revision Info:

• BIS Headquarters: Manak Bhavan, New Delhi
• Amendments issued are listed in the standard document.
• Comments can be sent referencing Doc No. CED 10 (4453).

Modular Coordination Concept (Simplified)

graph LR
A[Modular Coordination] --> B[Horizontal Coordination (IS 7922)]
A --> C[Vertical Coordination (IS 7921)]
A --> D[Application Guidelines (IS 6820)]
A --> E[Doors & Windows Sizes (IS 12073)]

This ensures standardized, repeatable building dimensions for efficient design and construction.

IS 13613: General Design Prerequisites

Key Clauses Summary:

• Clause 3.1 (Design Prerequisites):

  • Pre-requisites for jointing details, foundations, and parapets in prefabricated systems.
  • Ensures compatibility, durability, and structural integrity.

• Clause 6.2 & 7.2 (Design Details):

  • Specifies detailing for connections, reinforcement, and load transfer.
  • Emphasizes proper anchorage, tolerances, and dimensional accuracy.

• Clause 7.1 (Design of Structure):

  • Overall structural design principles ensuring safety, serviceability, and economy.
  • Load combinations, structural stability, and robustness.

Important Design Considerations:

• Jointing Details:

  • Must accommodate movements (thermal, shrinkage).
  • Use of high-strength connectors or welding as per IS specifications.

• Foundations:

  • Designed for uniform load distribution.
  • Consider soil bearing capacity, settlement, and differential movement.

• Parapets:

  • Designed for wind loads and stability.
  • Proper anchorage to main structure.

Typical Design Formulae:

• Load Combinations (as per IS 456 & IS 13613):

  [ \text{Design Load} = 1.5 \times \text{Dead Load} + 1.5 \times \text{Live Load} ]

• Shear Strength of Connections:

  [ V_u \leq \phi V_c ]

  where (V_u) = factored shear force, (\phi) = strength reduction factor, (V_c) = nominal shear strength.

Summary Table: Design Prerequisites

flowchart TD
    A[General Design Prerequisites] --> B[Jointing Details]
    A --> C[Foundations]
    A --> D[Parapets]
    B

Field of Application - IS 13613 Key Points

• Plinth/Sub-structure Units Design (Clause 3.1.3):
  Consider:

  • Height of floor level from reference plane (normal plinth)
  • Type of soil
  • Foundation system used

• Parapet Units Design:
  Consider:

  • Waterproofing
  • Insulations
  • Height of parapet

• Vertical Controlling Dimensions (Clause 7.1.2):
  Must comply with IS 7922:1987 — Recommendations for modular coordination in building industry: Vertical coordination.

• Modular Coordination:
  Refer to related IS codes for modular coordination:

  IS No.	Title
  7922:1987	Vertical coordination (first revision)
  7921:1987	Horizontal coordination (first revision)
  6820:1987	Modular coordination application
  4993:1983	Glossary of terms relating to modular coordination

Summary Table: Design Considerations

Modular Coordination Concept (Simplified Mermaid Diagram)

graph TD
  A[Building Units] --> B[Plinth/Sub-structure]
  A --> C[Parapet Units]
  B --> D[Soil Type]
  B --> E[Foundation System]
  C --> F[Waterproofing]
  C --> G[Insulation]
  C --> H[Parapet Height]
  A --> I[Vertical Dimensions]
  I --> J[IS 7922:1987 Compliance]

For detailed dimension tables and modular coordination rules, refer to IS 7922:1987 and related modular coordination standards.

IS 13613 - Definitions Summary

• Key Reference Standards for Definitions:

  • IS 4993:1983 — Glossary of terms relating to modular coordination.
  • IS 7921:1987 — Horizontal coordination in building industry.
  • IS 7922:1987 — Vertical coordination in building industry.

• Purpose:

  • Definitions related to modular coordination (dimensions, tolerances, components) are standardized in these IS codes.
  • IS 13613 refers to these for consistent terminology and dimensional control.

• Modular Coordination Concepts:

  • Horizontal Coordination (IS 7921): Defines grid systems for placing components horizontally.
  • Vertical Coordination (IS 7922): Defines vertical dimensioning and stacking of components.

Important Notes:

Practical Use:

• When designing or specifying modular components, refer to the above IS codes for:
  • Terminology
  • Dimensional coordination
  • Tolerances
  • Component placement rules

flowchart LR
    A[IS 13613 Definitions] --> B[IS 4993:1983 Glossary]
    A --> C[IS 7921:1987 Horizontal Coordination]
    A --> D[IS 7922:1987 Vertical Coordination]
    B --> E[Standardized Terms]
    C --> F[Grid & Horizontal Dimensions]
    D --> G[Vertical Dimensions & Stacking]

Summary: IS 13613 defers to IS 4993, IS 7921, and IS 7922 for all definitions related to modular coordination, ensuring uniformity in terminology and dimensional standards for building components.

IS 13613 - Horizontal Location of Components: Key Points

• Modular Planning Grid:

  • Horizontal spacing: 3 meters
  • Vertical spacing: 2 meters
    (Clause 7.1.1)

• Grid System:
  Components are positioned based on a 2D grid for horizontal layout, enabling precise placement in both X and Y directions (Clause 6.1).
  This grid ensures uniformity and ease in design and installation.

• Dimension Fixing:
  The horizontal space dimensions are fixed based on technical requirements (Clause 6.3.3).
  Placement and bearing of units must conform to these fixed dimensions.

• Vertical Location Reference:
  Vertical location requires a single dimension — the distance from the floor plane (Clauses 7.1.1 to 7.1.5).

Summary Table: Modular Grid Dimensions

Conceptual Illustration (Mermaid.js):

graph TD
  A[Floor Plane] -->|Vertical 2m| B(Component Level 1)
  B -->|Horizontal 3m| C(Component Level 1 Adjacent)
  C -->|Vertical 2m| D(Component Level 2)

This grid-based approach simplifies component layout and structural coordination.

IS 13613: Vertical Location of Components - Key Points

• Modular Grid for Vertical Location (Clause 7.1.1):
  Use a modular planning grid of

  • 3 m horizontally
  • 2 m vertically
    This simplifies vertical dimensioning to a single distance from the floor plane.

• Dimensioning (Clauses 7.1.1 to 7.1.5):
  Vertical location of components is specified by the distance from the floor level only.

• Technical Fixing (Clause 6.3.3):
  Space dimensions must be fixed based on technical requirements; bearings and placements are designed accordingly.

Summary Table: Vertical Location Grid

Conceptual Diagram of Vertical Grid

graph TD
  Floor[Floor Plane]
  V1[+2 m]
  V2[+4 m]
  V3[+6 m]
  Floor --> V1 --> V2 --> V3
  style Floor fill:#f9f,stroke:#333,stroke-width:2px
  style V1 fill:#bbf,stroke:#333,stroke-width:1px
  style V2 fill:#bbf,stroke:#333,stroke-width:1px
  style V3 fill:#bbf,stroke:#333,stroke-width:1px

Note: For detailed component placement, refer to IS 4993, IS 7921, and IS 7922 for definitions and additional standards.

IS 13613: Design of Structure – Key Points

• Clause 7.1 & 6.1: Design of horizontal structural components should be related to a modular grid system for convenience and coordination in two directions (see Fig. 2 in the code).

• Modular Coordination: Use modular grids to align structural elements, ensuring compatibility and ease of construction (refer IS 6820, IS 7921, IS 7922, IS 12073 for modular coordination standards).

• Load & Stability (Clause 9.2): Spacing and design depend on:

  • Applied loadings (dead, live, wind, seismic),
  • Material strengths (concrete, steel, etc.),
  • Construction techniques used,
  • Stability requirements of the structure.

Typical Design Considerations:

General Formula for Structural Design:

• Load effect: ( E = \sum (Load \times Load Factor) )
• Design strength: ( \phi f_y A_s ) for steel, ( f_{cd} b d ) for concrete sections

graph TD
    A[Modular Grid System] --> B[Horizontal Components]
    A --> C[Vertical Components]
    B --> D[Load Application]
    C --> D
    D --> E[Structural Analysis]
    E --> F[Design Checks: Strength, Stability]

Summary: IS 13613 emphasizes modular coordination for structural layout and requires design based on loads, material strengths, and stability, referencing other IS codes for detailed specifications.

IS 13613 – External Walls: Key Points & Specifications

1. Modular Coordination (Clause 8.4 & 10.1)

• External walls should align with the modular grid system.
• External spine walls are placed with their inside faces at a basic module distance (with sub-modular increments) from the planning grid lines.
• This ensures dimensional coordination with floor components and structural elements.

2. Wall Placement & Planning (Clauses 7.1.3, 7.2.3)

• Walls form a rectangular mesh; only necessary lines are shown on drawings.
• Placement follows the '5 mm rule' (per IS 7922:1987) for load-bearing and partition walls to ensure proper joint and assembly tolerances.
• Planning grids can be continuous or interrupted (boundary or axial planning) affecting wall location (see Fig. 2, 3, 4).

3. Wall Zones & Connection Types

• Modular Wall Zone: Walls aligned exactly on modular lines.
• Non-Modular Wall Zone: Walls displaced from modular lines.
• Connection between walls and floor slabs varies by planning grid type (continuous/interrupted).

Summary Table: Wall Placement Relative to Modular Grid

Visual Concept (Mermaid Diagram)

graph TD
    A[Planning Grid] --> B[Modular Wall Zone]
    A --> C[Non-Modular Wall Zone]
    B --> D[Wall on Modular Line]
    C --> E[Wall Displaced from Modular Line]
    D --> F[Connection to Floor Slab (Continuous Grid)]
    E --> G[Connection to Floor Slab (Interrupted Grid)]

References:

• IS 7922:1987 for joint tolerances.
• Modular coordination principles ensure structural stability and dimensional accuracy.

For detailed figures (Fig. 2, 3, 4, 5,

Placement of Spine Walls as per IS 13613:

Key Clauses:

• Clause 10.1 (External Spine Walls):

  • Inside faces placed at a distance of basic module (with sub-modular increments for larger spans) from planning grid lines.
  • Refer Fig. 9 for exact placement on modular lines.

• Clause 10.3 (Internal Spine Walls):

  • Can be placed symmetrically or unsymmetrically relative to the planning grid.
  • Depends on wall thickness, opposite wall location, and desired modular room dimension.

• Clause 10.4:

  • Uniform location of spine walls should be maintained throughout the project for dimensional coordination.

• Clause 7.1.3:

  • Planning grid forms a rectangular mesh; only necessary lines shown on drawings.

Practical Guidelines:

• Spine walls align with modular grid lines for systematic coordination.
• Distance from grid lines depends on floor component type (e.g., precast, hollow core) and construction method.
• Symmetrical placement aids structural stability; unsymmetrical placement is allowed based on architectural needs.

Summary Table for External Spine Wall Placement:

Diagram: Spine Wall Placement Relative to Modular Grid

graph TD
  A[Planning Grid Line] -->|Basic Module Distance| B(External Spine Wall Inside Face)
  C[Internal Spine Wall] -->|Symmetrical or Unsymmetrical| D[Relative to Grid]
  B --> E[Floor Components Placement]

Note: Refer to IS 13613 Fig. 7, 8, 9 for detailed graphical representation of modular grid and wall placement.

IS 13613: Openings in Floor Slabs and Walls – Key Points

Location & Alignment (Clauses 11.1, 10.5)

• Openings (internal/external) should align with space planning grid lines or basic modular grids.
• Vertical joints in spine walls must be on modular grid lines for structural continuity.

Modular Floor Planes (Clause 7.4.1)

• Three types of modular floor planes relative to floor coverings and slabs:
  1. At upper surface of floor covering (non-modular height)
  2. At upper surface of sub/base floor (non-modular thickness)
  3. At upper surface of structural slab (non-modular thickness)

Structural Coordination (Clause 8.3)

• Floor slabs and walls must be designed with modular longitudinal/transverse dimensions.
• Thicknesses of walls and slabs can be modular or non-modular but should align with continuous preferred grid dimensions.

Practical Guidelines for Openings:

Typical Reinforcement Detailing for Openings

flowchart LR
    A[Slab with Opening] --> B[Reinforcement bars around opening]
    B --> C[Distribute stresses]
    B --> D[Maintain slab integrity]

Summary:
Openings must be carefully positioned on modular grids to maintain structural integrity, with proper reinforcement detailing around edges to handle stress concentrations.

Modular Planning Grid Adjustments (IS 13613)

Key Points from IS 13613:

• Clause 10.1:
  External spine walls are placed with their inside faces at a basic module distance from planning grid lines. For larger distances, sub-modular increments are used.
  (Refer Fig. 9 for placement details)

• Clause 6.1.1 & 6.3.2:
  Use modular planning grids per IS 7921:1987 with grids spaced between modular lines bounding structural elements.

• Clause 12.2:
  When odd multiples of module ( M ) or non-modular sectional dimensions occur, grids can be displaced within neutral zones following axial planning principles (see IS 7921:1987).

Typical Modular Grid Adjustment Formula:

[ \text{Distance of wall face from grid line} = n \times M + \Delta ]

• ( n ) = integer multiple of basic module ( M )
• ( \Delta ) = sub-modular increment (fraction of ( M )) for fine adjustment

Practical Notes:

• Floor components orientation and type (e.g., precast hollow core slabs) influence the exact ( X ) or ( Y ) offsets.
• Grid displacement helps accommodate non-standard column sizes or load-bearing components without violating modular planning principles.
• Refer to IS 7921:1987 for detailed axial planning and neutral zone displacement rules.

Summary Table (Conceptual)

flowchart LR
  A[Planning Grid Lines] --> B[Basic Module M]
  B --> C[External Spine Wall Face]
  C --> D[Offset = n*M + Δ]
  D --> E[Adjust for Floor Component Type]
 

IS 13613: Positioning of Structural Beams – Key Points

• Clause 13.1:
  Structural beams must be positioned following the axial planning principle, i.e., beams are centered on the grid lines of the structural planning grid for proper load transfer and alignment.

• Clause 13.2:
  External beams should be aligned relative to columns and comply with external wall rules (Clause 9), ensuring proper support and integration with wall elements.

• Clause 13.3:
  Secondary or subsidiary beams (e.g., on purlins) should also follow the axial planning principle or be placed on lines of the basic modular grid, optimizing component size and economic efficiency.

• Clause 6.1:
  A structural grid is introduced for horizontal components in two directions, facilitating systematic positioning (refer to Fig. 2 in IS 13613).

Summary Table for Beam Positioning

Axial Planning Principle (Conceptual)

graph TD
    A[Grid Lines] --> B[Beams Centered on Lines]
    B --> C[Load Transfer to Columns]
    B --> D[Alignment for Structural Stability]

Note: Always refer to the planning grid layout (Fig. 2 in IS 13613) for exact beam line locations and spacing to ensure compliance and economic design.

IS 13613: Modular Floor Height - Key Points

1. Modular Floor Height (Clause 7.3 & 14.4)

• Floor height is based on a modular planning grid.
• Preferred floor height = n × 2.0 m (where n = integer).
• This modular height includes:
  • Structural slab thickness
  • Floor finishing
  • Ceiling and services
  • Sometimes beams

2. Modular Floor Plane (Clause 8.1)

• Floor components and wall elements are placed on a continuous modular grid.
• This ensures compatibility and ease of construction.
• Modular dimensions apply to length, width, and thickness of elements.

3. Typical Modular Floor Height Components

4. Floor Height Definition (Fig. 6 & 10B)

• Floor height is measured between modular reference planes on the upper surface of floor coverings.
• Includes sub/base floor and structural slab.

flowchart TD
    A[Modular Reference Plane - Floor Top] --> B[Floor Finishing]
    B --> C[Structural Slab]
    C --> D[Ceiling + Services]
    D --> E[Modular Reference Plane - Floor Bottom]

Summary: Design floor heights as multiples of 2.0 m to align with modular planning grids, facilitating standardized construction and component compatibility.