Guide for construction of the brick kiln
1978 Edition

IS 4805 - 1978 (Reaffirmed 2002): Scope Highlights

• Chimney Shape & Accessories (Clause 4.10):

  • Must conform to the profile shown in Fig. 3.
  • Installation requires two chimneys.

• Flue Dimensions & Construction (Clause 4.8):

  • To be built as depicted in Fig. 2.
  • Size: 1.20 m by 0.90 m.

• Material Requirements (Clause 2.5):

  • Mild steel sheet thickness ranges from 3 to 25 mm.
  • Base plate thickness: 25 mm or two welded plates of 12 mm each.
  • Brass bush diameter: 50 mm.
  • Brass washer: diameter 100 mm, thickness 12.5 mm.
  • Pin: diameter 25 mm, length 225 mm.

Key Dimensions Summary

Refer to Fig. 2 and Fig. 3 in IS 4805 for detailed drawings and assembly instructions.

Essential Information for Designing Top-Fed Coal Brick Kilns (IS 4805)

Data to be Provided (Clause 2.1)

• Subsoil water table level at the kiln location
• Topography slope and natural drainage characteristics
• Soil classification, with emphasis on expansive black cotton soil
• Climatic parameters including temperature, humidity, and wind patterns
• Proximity to residential areas and availability of communication links

Chimney Base Plate Material Specifications (Clause 2.5)

Dimensions are in centimeters unless otherwise noted.

Notes:

• Soil and drainage data inform foundation design.
• Climatic conditions impact thermal performance.
• Close proximity to habitation demands emission controls.

flowchart TD
    Site_Inspection --> Subsoil_Water_Level
    Site_Inspection --> Ground_Slope_and_Drainage
    Site_Inspection --> Soil_Type
    Site_Inspection --> Climate_Conditions
    Site_Inspection --> Nearby_Residences
    Subsoil_Water_Level & Ground_Slope_and_Drainage & Soil_Type & Climate_Conditions & Nearby_Residences --> Design_Inputs

This information guides the design of a durable and efficient kiln foundation and chimney system.

Site Selection Criteria and Ground Conditions per IS 4805

Core Guidelines:

• Subsoil Water Table:

  • Kiln trench floors must be positioned at least 3 m above the highest water table during rainy periods (Clause 3.2).
  • Trench floor elevation should not be more than 1 m lower than the ground surface.

• Topography and Drainage:

  • Evaluate natural ground slope to prevent water pooling near the kiln (Clause 2.1b).

• Soil Type:

  • Particular caution with black cotton soil due to its swelling properties (Clause 2.1c).

• Trench Dimensions:

  • Trench height fixed at 2.25 m (Clause 4.2).
  • Side walls incorporate flues for chimney integration, with two flues per chamber (Clause 4.3).

Site Selection Checklist:

• Seasonal subsoil water levels
• Slope and drainage patterns
• Soil bearing capacity and type
• Climatic influences
• Distance from populated areas and infrastructure

Floor Level Criteria:

Conceptual Site Diagram:

flowchart LR
    Ground_Surface --> Trench_Floor
    Trench_Floor -->|≥ 3 m above| Water_Table
    Ground_Surface -->|≤ 1 m below| Trench_Floor
    Soil_Type --> Black_Cotton?
    Black_Cotton? -->|Yes| Special_Foundation
    Black_Cotton? -->|No| Standard_Foundation

Summary: Position trench floors safely above water tables, assess soil properties carefully, and ensure natural drainage for stable kiln construction.

IS 4805 Construction Guidelines for Brick Kilns

Construction Details:

• Flue Dimensions:
  • Length: 1.20 m, Width: 0.90 m (Clause 4.8).
  • Constructed as per Fig. 2 (not included here).

Important Construction Considerations (Clause 2.1):

• Subsoil water level measurements
• Assessment of ground slope and drainage
• Soil characteristics, especially expansive soils
• Climatic data
• Distance to inhabited zones and access routes

Additional Notes:

• Kiln type: Top-fed, coal-fired, natural draught.
• Thorough site evaluation is crucial for structural soundness and kiln efficiency.

Flue Dimension Summary:

flowchart LR
    Site_Selection --> Soil_and_Water_Analysis
    Soil_and_Water_Analysis --> Slope_and_Drainage
    Slope_and_Drainage --> Climate_Factors
    Climate_Factors --> Kiln_Build
    Kiln_Build --> Flue_Construction[Flue Size 1.20 x 0.90 m]

This design facilitates effective airflow and combustion.

Specifications for Kiln Size and Capacity (IS 4805)

• Kiln Configuration: See Fig. 1 for typical bull's trench kiln with earth embankments.

• Trench Height: Fixed at 2.25 m (Clause 4.2).

• Large Capacity Kiln (Clause 4.1.1):

  • Chambers: 30
  • Chamber length: 5.0 m
  • Trench width: 9.0 m
  • Capacity per chamber: 28,000 standard bricks

• Small Capacity Kiln (Clause 4.1.2):

  • Chambers: 30
  • Chamber length: 5.0 m
  • Trench width: 4.5 m
  • Capacity per chamber: 14,000 standard bricks

• Flues per Chamber (Clause 4.3):

  • Large kiln: 2 flues (inner and outer walls)
  • Small kiln: 1 flue (outer wall only)

Dimension Summary Table

flowchart LR
    Trench_Height_2_25m --> Large_Kiln
    Trench_Height_2_25m --> Small_Kiln
    Large_Kiln --> Chambers_30
    Large_Kiln --> Length_5m
    Large_Kiln --> Width_9m
    Large_Kiln --> Capacity_28000
    Large_Kiln --> Flues_2
    Small_Kiln --> Chambers_30
    Small_Kiln --> Length_5m
    Small_Kiln --> Width_4_5m
    Small_Kiln --> Capacity_14000
    Small_Kiln --> Flues_1

Specifications for Trench Height According to IS 4805

• Trench Height: Uniformly set to 2.25 m for both large and small kilns (Clause 4.2).

• Trench Floor Elevation (Clause 3.2):

  • Should be at least 3 m above the water table during rainy season.
  • Must not be more than 1 m below ground level.

• Floor Surface:

  • Must be paved with burnt bricks laid on edge to ensure durability (Clause 4.5).

• Access:

  • Sufficient number of access wickets to be provided (Clause 4.4).

Summary Table

flowchart TD
    Ground_Level -->|Max 1 m below| Trench_Floor
    Trench_Floor -->|Min 3 m above| Water_Table
    Trench_Height_2_25m --> Side_Walls_With_Flues
    Trench_Floor --> Brick_Paved_Floor
    Trench_Height_2_25m --> Access_Wickets

This configuration supports structural strength and operational ease.

IS 4805 Guidance on Side Wall and Flue Construction

• Side Wall Thickness:

  • Minimum of 60 cm (Clause 4.6).

• Materials:

  • Preferably constructed from ordinary burnt bricks for durability and ease of maintenance.
  • Two flues per chamber for larger kilns (inner and outer walls).
  • Smaller kilns require only one flue on the outer wall (Clause 4.3).

• Flue Dimensions:

  • Each flue measures 1.20 m by 0.90 m (Clause 4.8).
  • Construction follows Fig. 2 (not included here).

• Trench Height:

  • Fixed at 2.25 m (Clause 4.2).

• Chimneys:

  • Two chimneys per kiln required (Clause 4.10).
  • Chimney shape and attachments as per Fig. 3.

Summary Table

flowchart TB
    Side_Wall_60cm --> Flue_1_20x0_90
    Flue --> Chimney_2_per_kiln
    Side_Wall_60cm --> Inner_Flue
    Side_Wall_60cm --> Outer_Flue

IS 4805 Specifications for Access Wickets

• Clause 4.4: Ensure an adequate number of access wickets for convenient entry into trench sections.

• Material and Construction (Clause 2.5):

  • Wickets constructed from mild steel sheets, thickness ranging 3–25 mm.
  • Base plates for chimneys: either 25 mm thick or two welded plates of 12 mm each.
  • Brass bush diameter: 50 mm.
  • Brass washer: diameter 100 mm, thickness 12.5 mm.
  • Pin: diameter 25 mm, length 225 mm.
  • Base plates are equipped with wheels (3B type) to enable mobility.

• Dimensions:

  • All dimensions in centimeters unless stated otherwise.
  • Flue size remains 1.20 m × 0.90 m (Clause 4.8).

Access Wicket Components Summary

graph LR
    MS_Sheet_Door --> Base_Plate_25mm
    Base_Plate_25mm --> Brass_Bush_50mm
    Brass_Bush_50mm --> Brass_Washer_100mm
    Brass_Washer_100mm --> Pin_25mm_225mm
    Base_Plate_25mm --> Wheels_3B

Summary: Wickets must be sturdy, correctly sized for easy access, and constructed using specified materials to ensure durability and functionality.

IS 4805 Recommendations for Trench Floor Paving

• Floor Paving (Clause 4.5):

  • Trench floors should be paved with burnt bricks laid on edge to withstand thermal and mechanical stresses.

• Floor Elevation (Clause 3.2):

  • Must be a minimum of 3 m above the subsoil water level during rainy periods.
  • Should not be deeper than 1 m below ground surface.

• Trench Dimensions (Clauses 4.2 & 4.1.1):

  • Height: 2.25 m
  • Width: 9.0 m
  • Chamber length: 5.0 m
  • Number of chambers for large kiln: 30
  • Chamber capacity: 28,000 standard bricks

Trench Floor Paving Details

flowchart TB
    Subsoil_Water_Table -->|≥ 3 m above| Brick_Paved_Floor
    Brick_Paved_Floor --> Trench_Walls_With_Flues
    Trench_Walls_With_Flues --> Chimney_Placement

This ensures a durable floor that prevents water ingress and supports kiln operation effectively.

IS 4805 Guidelines on Side Wall Thickness and Materials

• Wall Thickness:

  • Must be at least 60 cm thick (Clause 4.6).

• Materials:

  • Preferably built using ordinary burnt bricks for enhanced durability and easier maintenance.
  • Unburnt bricks are permitted but have lower efficiency.
  • Walls should be plastered with mud mortar (Clause 4.7).

• Insulation Option:

  • Walls can include a 25 cm cavity filled loosely with fine ash to improve thermal insulation (Clause 4.7 Note).

• Additional Details:

  • Trench height remains 2.25 m (Clause 4.2).
  • Flues are incorporated on inner and outer walls for chimney installation (Clause 4.3).

Summary Table

flowchart TD
    Side_Wall --> Thickness_60cm
    Side_Wall --> Material_Burnt_Bricks
    Side_Wall --> Plaster_Mud_Mortar
    Side_Wall --> Insulation_Cavity_25cm
    Insulation_Cavity_25cm --> Fine_Ash_Filling

This ensures side walls are strong, thermally efficient, and durable.

IS 4805 Recommendations for Wall Plastering and Insulation

• Wall Thickness:

  • Side walls should be 60 cm thick, constructed primarily from ordinary burnt bricks (Clause 4.6).
  • Unburnt bricks are allowed but not preferred for efficiency.

• Plastering:

  • Walls must be coated with mud mortar to protect and provide breathability (Clause 4.7).

• Thermal Insulation:

  • Walls may include a 25 cm cavity filled loosely with fine ash to enhance heat retention and reduce heat loss.

Summary Table

Notes:

• The ash-filled cavity reduces thermal conductivity, improving kiln efficiency.
• Mud plaster allows moisture regulation.

flowchart TD
    Wall_Construction --> Thick_Burnt_Brick_Wall
    Thick_Burnt_Brick_Wall --> Mud_Mortar_Plaster
    Thick_Burnt_Brick_Wall --> Optional_25cm_Cavity
    Optional_25cm_Cavity --> Loose_Fine_Ash
    Loose_Fine_Ash --> Improved_Insulation

This method balances durability, thermal performance, and moisture control.

IS 4805 Details on Flue Construction for Top-Fed Coal Brick Kilns

Key Points:

• Flue Dimensions:
  • Length: 120 cm, Width: 90 cm (Clause 4.8).
• Spacing Between Flues:
  • Centre-to-centre distance of 5.0 m (Clause 4.9).
• Chimneys:
  • Two chimneys are mandatory (Clause 4.10).
• Shape and Attachments:
  • Must match the configuration shown in Fig. 3 (not included), with rectangular form and proper draft features.

Construction Recommendations:

• Build flues as per Fig. 2 with a rectangular cross-section.
• Use fire-resistant bricks and mortar.
• Internal surfaces should be smooth to reduce gas flow resistance.

Additional Notes:

• Specified dimensions ensure sufficient natural draught.
• Proper spacing prevents thermal interference between adjacent flues.

Summary Table:

flowchart LR
    Flue1 ---|5 m| Flue2
    Flue1 & Flue2 --> Chimneys
    Chimneys --> Natural_Draught

This design promotes effective combustion and heat flow in brick kiln operations.

IS 4805 Specifications for Flue Size and Spacing

• Flue Dimensions (Clause 4.8):

  • Width: 1.20 m
  • Height: 0.90 m

• Flue Separation (Clause 4.9):

  • Maintain 5.0 m centre-to-centre distance between flues.

• Chimney Requirements (Clause 4.10):

  • Two chimneys per kiln.
  • Chimney shapes and fittings follow Fig. 3 (not shown).

• Material Specifications (Clause 2.5):

  • Mild steel sheet thickness: 3 to 25 mm.
  • Base plate: 25 mm thick or two welded plates of 12 mm.
  • Brass bush diameter: 50 mm.
  • Brass washer: 12.5 mm thickness, 100 mm diameter.
  • Pin size: 25 mm diameter, 225 mm length.

Summary Table

flowchart LR
    Flue_Size --> Flue_Spacing
    Flue_Spacing --> Chimneys_2
    Chimneys_2 --> Base_Plate
    Base_Plate --> Brass_Bush
    Brass_Bush --> Brass_Washer
    Brass_Washer --> Pin_Size

These parameters ensure structural soundness and proper spacing for flue and chimney systems.

IS 4805: Chimney Shape and Fittings Overview

Chimney Shape (Clause 4.10 and Fig. 3)

• Chimneys must adhere to the shape depicted in Fig. 3.
• Each kiln requires two chimneys.
• Attachments include base plates, brass bushes, washers, and pins as specified below.

Dimensions and Specifications

• Flue size: 1.20 m × 0.90 m (Clause 4.8, Fig. 2).
• Trench height: 2.25 m (Clause 4.2).
• Base plate thickness: 25 mm or two welded plates of 12 mm each (Clause 2.5).
• Mild steel sheet thickness: 3–25 mm (Clause 2.5).
• Brass bush tread diameter: 50 mm.
• Brass washer: 100 mm diameter, 12.5 mm thick.
• Pin: 25 mm diameter, 225 mm length.

Attachment Summary (Clause 2.5)

Flue and Chimney Arrangement (Clause 4.3)

• Two flues per chamber: one on inner wall and one on outer wall.
• Small kilns have one flue on outer wall only.

flowchart TD
    Chimney --> Base_Plate_25mm
    Base_Plate_25mm --> Brass_Bush_50mm
    Brass_Bush_50mm --> Brass_Washer_100mm_12_5mm
    Brass_Washer_100mm_12_5mm --> Pin_25mm_225mm
    Chimney --> Flue_1_20x0_90
    Flue_1_20x0_90 --> Inner_Wall_Flue
    Flue_1_20x0_90 --> Outer_Wall_Flue

This setup guarantees chimney stability and effective flue gas movement.