Guide for the manufacture of standard burnt clay building bricks by semi-mechanized process

IS 11650: Scope - Key Specifications & Tables

Scope (Clause 2.1):

• IS 11650 covers the manufacturing and quality requirements of wire-cut clay bricks.
• It references other Indian Standards (Annex A) essential for testing and materials.

Key Tables & Specifications

1. Clay Composition for Wire-Cut Bricks (Clause 5.1.1)

2. Sandy Loam Composition (Clause 5.2.2)

3. Firing Schedule (Clause 10.3.12)

Additional Notes

• Clay and fuel type influence firing schedule adjustments.
• Coal lumps should be crushed below 10 mm for firing.
• Proper alignment of brick blades and damper checks are critical for uniform firing.

Annex A: Related IS Standards

• IS 2117: Guide for manufacture of handmade clay bricks
• IS 3495: Methods of test for burnt clay bricks
• IS 2720 (Part 5 & 21): Soil testing methods

This concise scope covers raw material composition, firing process, and referenced standards essential for wire-cut brick manufacturing per IS 11650.

IS 11650: Referenced Indian Standards & Key Specifications

Clause 2.1 & Annex A list essential Indian Standards adjunct to IS 11650:

*Revision under print.

Clause 10.3.12: Firing Schedule for Kiln Chambers

Notes:

• Modify schedule based on clay/fuel type.
• Coal must be sieved through 12.5 mm IS sieve; lumps crushed below 10 mm.
• Ensure correct brick blade alignment and damper sealing to avoid uneven firing.

Summary:

• Use the above referenced IS codes for testing and manufacturing standards.
• Follow the firing schedule strictly, adjusting as per material specifics.
• Quality control and inspection under BIS ensures compliance and product reliability.

flowchart TD
    A[Loading] --> B[Preheating & Drying]
    B --> C[Full Fire]
    C --> D[Cooling]
    D --> E[Unloading]
    E --> F[Empty]

This diagram shows the sequential firing stages per IS 11650.

IS 11650: Definitions & Key References

• Definitions: As per Clause 3.1, definitions in IS 2248:1981 (Glossary of terms relating to clay products for building) apply directly.

• Annex A (Clause 2.1): Lists relevant Indian Standards essential for understanding terms and testing methods:

  • IS 2248:1981 – Glossary of terms for clay products.
  • IS 2117:1991 – Guide for manufacture of handmade burnt clay bricks.
  • IS 3495 (Parts 1-4):1976 – Tests for burnt clay bricks.
  • IS 2720 (Part 5 & 21) – Soil tests (liquid/plastic limits, soluble solids).
  • IS 1727:1957 – Pozzolanic materials testing.

• Clay Composition for Wire-Cut Bricks (Clause 5.1.1):

• Firing Schedule (Clause 10.3.12):

Summary

• Use IS 2248 for terminology.
• Clay composition critical for brick quality.
• Refer to Annex A for testing and manufacturing standards.
• Follow firing schedule carefully for uniform brick firing.

flowchart LR
    A[Clay Selection] --> B[Mechanical Composition]
    B --> C{Clay 20-40%}
    B --> D{Silt 30-50%}
    B --> E{Sand 40-60%}
    C & D & E --> F[Wire-Cut Brick Manufacture]
    F --> G[Firing Schedule]
    G --> H[Cooling (12 chambers)]
    G --> I[Full Fire (2 chambers)]
    G --> J[Preheating & Drying (4 chambers)]
   

IS 11650: Selection of Site for Semi-Mechanized Brickworks

Key Specifications (Clause 4.1 & 4.2)

• Site selection factors:

  • Ample reserve of clay of required quality nearby.
  • Abundant potable water supply.
  • Good transport and communication links.
  • Proximity to market.
  • Easy availability of labour, power, and fuel.
  • Sub-soil water level preferably below 3 m in all seasons.

• Must conform to town-planning rules, especially regarding excavation pits' depth and extent.

Clay Composition for Wire-Cut Bricks (Clause 5.1.1)

Summary Diagram: Site Selection Factors

graph LR
A[Site Selection] --> B[Clay Reserve]
A --> C[Potable Water]
A --> D[Transport & Communication]
A --> E[Market Proximity]
A --> F[Labour, Power & Fuel]
A --> G[Sub-soil Water < 3m]
A --> H[Town Planning Compliance]

This ensures optimal raw material quality, operational efficiency, and regulatory compliance for brick manufacturing.

IS 11650 – Selection of Raw Materials for Wire-Cut Bricks

Key Specifications (Clause 5.1.1)

For alluvial clays used in wire-cut brick manufacturing, the mechanical composition must be within:

Chemical Analysis

• Conduct chemical analysis as per IS 1727:1967 and IS 2720 (Part 21):1977.
• This ensures the clay's suitability regarding impurities and chemical composition.

Site Selection (Clause 4.2)

• The clay extraction site must comply with town-planning rules, especially concerning pit depth and extent.

Summary Table for Clay Selection

This ensures optimal plasticity, workability, and strength of wire-cut bricks.

IS 11650 - Selection of Plant and Machinery for Semi-Mechanized Brick Plant

Key Specifications (Clause 6):

• Plant Components:
  • Double-deck extrusion machine
  • Hand-operated cutting table
  • Drying sheds (natural drying on floors/racks)
  • Archless, top-fed zig-zag kiln with fan draught
  • Coal crusher
  • Accessories: manual clay excavation tools, material handling, water & power supply, kiln firing equipment
  • Control instruments: thermocouples, pyrometers, draught gauge

Layout Dimensions (Clause 1.5):

Material Selection (Clause 5.1.1):

For wire-cut bricks, clay composition (% by weight):

Notes:

• Use basalt stone dust as additive (fine, <1 mm, non-calcitic) to improve shaping, drying, firing (Clause 5.2.4).
• Ensure proper layout and control instruments for efficient plant operation.

flowchart TD
    A[Clay Excavation] --> B[Extrusion Machine]
    B --> C[Cutting Table]
    C --> D[Drying Shed]
    D --> E[Zig-Zag Kiln]
    E --> F[Brick Stockyard]

This structured setup ensures optimized production and quality control in semi-mechanized brick manufacturing.

IS 11650: Preparation of Clay and Clay Admixtures

1. Clay Composition for Wire-Cut Bricks (Clause 5.1.1, Table 5.1)

2. Chemical Analysis (Clause 5.1.2.2)

• Conducted as per IS 1727:1967 and IS 2720 (Part 21):1977.
• Ensures suitability of clay for brick manufacturing.

3. Additives (Clause 5.2)

• Common additives: fly ash, sandy loam, rice husk ash, basalt stone dust.
• Purposes:
  • Modify shaping, drying, firing behavior.
  • Enhance conservation and reuse of waste materials.
• Additives must meet physical and chemical criteria to avoid negative effects on durability and performance.

Summary Diagram of Clay Preparation Process

flowchart LR
    A[Selection of Clay] --> B[Mechanical Analysis]
    B --> C[Chemical Analysis (IS 1727, IS 2720)]
    C --> D[Additive Selection]
    D --> E[Mixing & Preparation]
    E --> F[Shaping, Drying, Firing]

This ensures optimal clay mass for quality wire-cut bricks per IS 11650.

IS 11650: Manufacturing Process for Semi-Mechanized Brick Plant

Key Specifications and Tables

1. Clay Selection for Wire-Cut Bricks (Clause 5.1.1)

• Use alluvial clays within these mechanical composition ranges for optimal brick quality.
• Proper clay mix ensures workability, strength, and durability.

2. Plant Layout Dimensions (Fig. 2)

• Machine Shed: 1.5 m × 8 m
• Pump Room: 7 m × 4 m
• Electric Room: 4 m × 4 m
• Drying Shed: 45 m × 10 m (two sheds)
• Kiln Shed: 38 m × 26 m
• Store & Office: 5 m × 5 m each
• Chowkidar Hut: 3 m × 3 m

Summary:

• Select clay with specified particle size distribution.
• Follow layout dimensions for semi-mechanized plant efficiency.
• This ensures consistent brick quality and streamlined production.

flowchart LR
    Clay_Selection --> Wire_Cut_Bricks
    Wire_Cut_Bricks --> Plant_Layout
    Plant_Layout --> Production_Efficiency

For detailed process steps and quality control, refer to full IS 11650 document.

Drying of Bricks - IS 11650 Key Points

• Initial Drying (Clause 9.2.1):

  • Bricks are dried on the floor for 3 to 4 days.
  • Then arranged in hacks (brick stacks) as per IS 2117:1975.
  • Further drying in hacks for 7 to 15 days until moisture content reaches 5-7%.

• Protection from Drying Stresses (Clause 9.2.2):

  • For clays sensitive to drying stresses, protect bricks from high winds especially in summer.
  • Use gunny-cloth screens on drying shed sides.
  • Natural drying on wooden pallets stacked in tiers is also recommended.

• Spacing for Cutting Wires (Clause 8.3.6):

  • Spacing between three cutting wires = 9 + At cm, where At = linear shrinkage (%) of clay.

Typical Drying Schedule Summary

Additional Notes:

• Follow IS 2117:1975 for brick stacking patterns in drying.
• Proper drying reduces cracking and warping during firing.

flowchart LR
    A[Freshly Molded Bricks] --> B[Floor Drying (3-4 days)]
    B --> C[Stacking in Hacks as per IS 2117]
    C --> D[Drying in Hacks (7-15 days)]
    D --> E[Moisture Content ~5-7%]
    E --> F[Firing Process]

This drying process ensures bricks are adequately dried to minimize defects during firing.

IS 11650: Kiln Setting and Firing – Key Points

Kiln Setting Pattern

• Dry modular bricks are set in a high draught kiln as per Fig. 5 (Pattern of setting).
• Correct alignment of brick blades and trace holes is critical to ensure even fire propagation.
• Bricks are transported in wheelbarrows carrying 30-40 bricks (Clause 9.3).

Firing Schedule (Clause 10.3.12)

• Two chambers are burnt every 24 hours (Clause 10.3.9).
• The schedule can be modified depending on clay type and fuel.

Important Specifications

• Coal lumps must be crushed below 10 mm and sieved through 12.5 mm IS sieve.
• Before firing, check all dampers for leakage and alignment.
• Fire initiation and control must be carefully managed to avoid uneven firing.

Summary Diagram: Kiln Chamber Cycle

flowchart LR
    A[Loading] --> B[Preheating & Drying]
    B --> C[Full Fire]
    C --> D[Cooling]
    D --> E[Unloading]
    E --> F[Empty]
    F --> A

This cycle repeats continuously for 24 chambers with the specified number in each stage.

For detailed design and technical drawings, refer to Central Building Research Institute as per IS 11650 Clause 10.1.

IS 11650 - List of Referenced Indian Standards (Annex A, Clause 2.1)

IS 11650 refers to several key Indian Standards essential for clay products and brick manufacturing/testing:

Additional Notes on Usage:

• These standards cover testing methods, manufacturing guidelines, and terminology for clay and bricks.
• Refer to these for quality control, material properties, and testing procedures in brick manufacturing and usage.
• BIS licenses and continuous quality checks ensure compliance with these standards.

Quick Reference Table for Firing Schedule (Clause 10.3.12):

For detailed procedures, testing methods, and manufacturing guidelines, always consult the full text of the referenced IS codes.