Glossary of terms relating to clay products for buildings

IS 2248: Scope Summary

• Scope: Defines common terms related to clay building products (blocks, tiles, etc.).
• Clause 2.8.5: Defines Webs as the partitions dividing blocks or tiles into cells.
• The standard ensures products meet quality via BIS inspection and certification.
• Covers terminology essential for uniform understanding in clay product manufacturing and use.

Key Points:

• Webs: Structural partitions within clay blocks/tiles.
• Products with BIS Standard Mark comply with IS 2248 requirements.
• Periodic review and amendments keep the standard updated.

No specific formulas or tables for scope; mainly definitions and quality assurance provisions.

BIS Contact (for updates & queries):

Summary: IS 2248 primarily standardizes terminology and quality control for clay building products, ensuring consistent definitions like "webs" and product certification under BIS.

IS 2248: Definitions & Terms for Clay Products

IS 2248 (1992) provides a glossary of terms related to clay products used in building construction. It standardizes terminology to ensure uniform understanding.

Key Points from the Glossary:

• Raw Materials: Natural clay, shale, or other materials used as the base for clay products.
• Clay Products: Includes bricks, tiles, blocks, and other fired or unfired clay building units.
• Firing: The process of heating clay products to develop strength and durability.
• Water Absorption: Percentage of water absorbed by a clay product under specified conditions.
• Compressive Strength: The maximum load per unit area a clay product can withstand without failure.

Typical Specifications (from IS 1077 & related):

Summary:

• IS 2248 defines terms only; detailed specs are in IS 1077 (Bricks) and IS 1725 (Tiles).
• Understanding terms like firing, raw materials, and water absorption is essential for compliance.

flowchart TD
    A[Raw Materials] --> B[Clay Products]
    B --> C[Firing Process]
    C --> D[Finished Clay Product]
    D --> E[Properties: Strength, Absorption]

For detailed design and testing, refer to IS 1077 and IS 1725 alongside IS 2248.

IS 2248 primarily defines terms related to clay products but does not provide detailed formulas or tables for raw materials.

Key points on Raw Materials for clay products (general engineering knowledge):

• Composition: Mainly clay, shale, and sometimes sand or other additives.
• Properties: Plasticity, particle size, moisture content, and mineral composition affect product quality.
• Typical raw material specs:
  • Clay content: 40-60%
  • Sand content: 20-40%
  • Moisture content: 15-25% for molding
• Testing: Plasticity index, Atterberg limits, and shrinkage tests ensure suitability.

Common formula for clay content estimation:

[ \text{Clay %} = 100 - (\text{Sand %} + \text{Silt %}) ]

Raw material preparation steps:

flowchart TD
    A[Raw Material Collection] --> B[Sorting & Cleaning]
    B --> C[Grinding & Mixing]
    C --> D[Moisture Adjustment]
    D --> E[Shaping & Molding]
    E --> F[Firing]

For detailed specifications, refer to IS 1077 (common burnt clay bricks) and IS 3495 (testing methods).

IS 2248 – Manufacture of Burnt Clay Building Bricks

Key Specifications & Methods (Clause 2.2 Manufacture)

• Hand Moulding (Clause 2.2.2):
  Bricks are shaped manually using wooden moulds. The clay is pressed into the mould, then turned out onto a pallet board for drying.

• Table Moulding (Clause 2.2.2.4):
  Bricks are moulded by hand on a table surface, then transported on pallet boards to drying grounds. This improves uniformity and handling efficiency.

Important Definitions (Clause 2.8.5)

• Webs:
  Partition walls dividing blocks or tiles into cells, ensuring structural integrity and dimensional accuracy.

Quality Assurance

• Products bearing the BIS Standard Mark ensure compliance with IS 2248 under strict inspection, testing, and quality control by BIS.

Summary Table: Manufacture Methods

For detailed dimensions and testing, refer to the full IS 2248 standard.
Contact BIS regional offices for licensing and further guidance.

flowchart LR
    A[Clay Preparation] --> B{Moulding Method}
    B --> C[Hand Moulding]
    B --> D[Table Moulding]
    C --> E[Pallet Board]
    D --> E
    E --> F[Drying Ground]
    F --> G[Firing in Kiln]
    G --> H[Finished Bricks]

This diagram illustrates the manufacturing flow from clay to finished bricks.

IS 2248 - Surface Features of Clay Building Units

Key Surface Finishes (Clause 2.3)

Specifications Summary

• Exposed Finish: Smooth, uniform surface; no mechanical roughening.
• Roughened Finish: Achieved by mechanical means (e.g., wire brushing) to break the surface plane.
• Sand Finish: Sand is applied on the surface before firing or setting to ensure adhesion and texture.

Practical Notes

• Roughened and sand finishes improve plaster or mortar bonding.
• Exposed finish is preferred when the unit surface is visible in final construction.

flowchart LR
    A[Clay Unit Surface] --> B[Exposed Finish]
    A --> C[Roughened Finish]
    A --> D[Sand Finish]
    B --> E[Smooth, Painted/Exposed]
    C --> F[Mechanical Breaking]
    D --> G[Sand Coating]

This classification helps select the appropriate finish based on aesthetic and functional requirements.

IS 2248 - Key Specifications for Bricks

• Dimensions (Clause 2.4):

  • Length ≤ 300 mm
  • Width ≤ 150 mm
  • Height ≤ 100 mm

• Common Building Solid Bricks (Clause 2.4.2):

  • Burnt clay bricks
  • Frog volume ≤ 20% of brick volume
  • Used typically in general construction

• Heavy Duty Bricks (Clause 2.4.4):

  • For heavy engineering works (bridges, industrial foundations, multi-storeyed buildings)
  • High compressive strength and durability
  • Low water absorption

Typical Properties (as per IS 1077 & IS 2185 for reference)

Notes on Frogs in Bricks:

• Frog: A shallow depression on one face of the brick to reduce weight and provide keying for mortar.
• Volume of frog ≤ 20% of brick volume for common bricks to maintain strength.

flowchart LR
    A[Brick] --> B[Frogs ≤ 20% volume]
    A --> C[Dimensions ≤ 300x150x100 mm]
    A --> D[Types]
    D --> E[Common Bricks]
    D --> F[Heavy Duty Bricks]
    E --> G[General Construction]
    F --> H[Heavy Engineering Work]

This summary aligns with IS 2248 clauses and typical brick standards.

IS 2248 - Tiles: Key Specifications & Definitions

• Tiles (Clause 2.5): Burnt clay units thinner than bricks, used for flooring, roofing, ceilings, and wall coverings.

• Flooring Tiles (2.5.2): Clay tiles made by pressing or extrusion and repressing, designed to be laid level on a prepared base.

• Terracing Tiles (2.5.6): Flat tiles laid level on a prepared base in one or more courses for floor or roof finishes.

• Ceiling Tiles (Plain) (2.5.1): Clay roofing tiles used on sloping roofs beneath interlocking plain Mangalore tiles.

Typical Tile Thickness (Indicative from IS standards):

Important Notes:

• Tiles must be laid level on a well-prepared base for durability.
• Clay tiles are generally pressed or extruded for uniformity.
• Tiles are smaller and thinner than bricks, ensuring a smooth finish.

flowchart LR
    A[Tiles] --> B[Flooring Tiles]
    A --> C[Terracing Tiles]
    A --> D[Ceiling Tiles]
    B --> E[Pressed/Extruded Clay]
    C --> F[Flat Tiles for Roof/Floor]
    D --> G[Used under Mangalore Tiles]

For detailed mechanical properties, absorption, and strength requirements, refer to the full IS 2248 standard.

IS 2248: Key Specifications & Definitions for Blocks

• Block Types:
  • Hollow Block (Clause 2.6.1):
    • Holes > 25% of block volume
    • Holes are not small, oriented either parallel or perpendicular to bearing surface
  • Solid Block (Clause 2.6.2):
    • 100% solid, no hollow spaces
  • Cells (Clause 2.8.1):
    • Hollow spaces inside hollow clay blocks, enclosed by exterior shells

Typical Dimensions & Volume Calculations

Important Notes:

• Hollow blocks reduce weight and improve thermal insulation.
• Ensure hole size and orientation as per Clause 2.6.1 for structural performance.
• Blocks must exceed standard brick size in any dimension (Clause 2.6).

flowchart LR
    A[Block] --> B[Solid Block]
    A --> C[Hollow Block]
    C --> D[Cells (Hollow Spaces)]
    D --> E[Orientation: Parallel or Perpendicular]
    C --> F[Holes > 25% Volume]

This summary aligns with IS 2248 clauses for block classification and design considerations.

IS 2248: Physical Properties and Defects of Clay Building Units

Key Specifications & Definitions:

• Roughened Finish (Clause 2.3.4): Surface broken mechanically to improve bonding.
• Webs (Clause 2.8.5): Internal partitions dividing blocks/tiles into cells, affecting strength and weight.

Typical Physical Properties to Check:

Common Defects:

• Cracks, chips, warping, and uneven surfaces.
• Presence of soluble salts causing efflorescence.
• Incomplete firing causing weak units.

Quick Reference Table: Web Thickness (Typical)

Formula: Bulk Density (ρ)

[ ρ = \frac{\text{Mass of dry unit}}{\text{Volume of unit}} \quad (\text{kg/m}^3) ]

Summary Diagram: Clay Unit Structure

graph TD
A[Clay Unit] --> B[Webs (Partitions)]
A --> C[Cells (Hollow spaces)]
A --> D[Outer Surface (Roughened/ Smooth)]

Note: Refer to IS 1077 for detailed physical tests and IS 2185 for hollow concrete blocks. Always verify latest BIS amendments.

IS 2248: Structural Features of Clay Products

Though IS 2248 primarily defines terms related to clay products, key structural features and specifications for clay bricks and blocks generally include:

Key Specifications:

• Dimensions & Tolerances:
  Typical modular brick size:

  • Length: 190 mm
  • Width: 90 mm
  • Height: 90 mm
    Tolerance ±3 mm (length/width/height)

• Compressive Strength:
  Minimum compressive strength for common burnt clay bricks:

  • ≥ 3.5 N/mm² for general use
  • Higher grades available for load-bearing walls

• Water Absorption:
  Should not exceed 20% by weight for good quality bricks.

• Efflorescence:
  Should be classified as nil, slight, moderate, or heavy as per visual inspection.

Important Formulas:

• Compressive Strength (f_c):
  [ f_c = \frac{P}{A} ]
  Where:
  • (P) = Load at failure (N)
  • (A) = Cross-sectional area (mm²)

Typical Table of Brick Grades (IS 1077 reference):

flowchart LR
    A[Raw Clay] --> B[Shaping]
    B --> C[Firing]
    C --> D[Clay Brick]
    D --> E{Quality Checks}
    E -->|Compressive Strength| F[Pass/Fail]
    E -->|Water Absorption| F
    E -->|Efflorescence| F

Summary: IS 2248 defines clay product terms; structural design depends on compressive strength, dimensions, and water absorption per IS 1077 and related standards.