sewer bricks - Specification

IS 4885: Scope & Key Specifications for Sewer Bricks

• Scope: Covers dimensions, tolerances, and quality of sewer bricks made from suitable soil, free from coarse grains, stones, or lime particles.

1. Standard Dimensions (Clause 3.1)

2. Permissible Tolerances for 20 Bricks (Clause 3.2)

3. Material Requirements (Clause 2.1)

• Manufactured from suitable soil.
• Free from coarse grains, stones, pebbles, or visible lime grains.

This ensures uniformity in sewer bricks for construction durability and fitment.

IS 4885 - Materials: Key Specifications & Tables

1. Material Composition (Clause 2.1)

• Bricks must be made from suitable soil.
• Free from coarse grains, stones, pebbles, or visible lime grains to ensure uniformity and strength.

2. Standard Dimensions (Clause 3.1)

3. Permissible Tolerances on Dimensions for 20 Bricks (Clause 3.2)

4. Marking (Clause 9.1.1)

• Bricks may carry the Standard Mark ensuring compliance with IS 4885.
• Marking indicates production under BIS inspection and quality control.

Summary:

• Use soil free of impurities.
• Follow dimensions strictly with tolerances for 20 bricks.
• Standard bricks: 190×90×90 mm or 190×90×40 mm.
• Tolerances ensure uniformity in masonry.
• Standard Mark guarantees quality compliance.

flowchart TD
    A[Suitable Soil] --> B[Manufacture Brick]
    B --> C{Dimensions}
    C --> D[190×90×90 mm]
    C --> E[190×90×40 mm]
    B --> F[Tolerances for 20 Bricks]
    F --> G[±80 mm on 190 mm]
    F --> H[±40 mm on 90 mm & 40 mm]
    B --> I[Marking with Standard Mark]
    I --> J[Quality Assurance by BIS]

This ensures bricks meet IS 4885 quality and dimensional standards.

IS 4885: Dimensions and Tolerances for Sewer Bricks

1. Standard Dimensions (Clause 3.1)

2. Permissible Tolerances on Dimensions (Clause 3.2)

3. Warpage Tolerance (Clause 3.3)

• Maximum distortion or warpage from a plane surface or straight edge: 2.5 mm

Summary:

• Bricks must be free from coarse grains or stones (Clause 2.1).
• Dimensional tolerances are applied cumulatively over 20 bricks.
• Warpage limits ensure bricks maintain flatness and straight edges for proper laying.

flowchart LR
    A[Manufacture Bricks] --> B[Check Dimensions]
    B --> C{Within Tolerances?}
    C -->|Yes| D[Accept Bricks]
    C -->|No| E[Reject Bricks]
    D --> F[Check Warpage ≤ 2.5 mm]
    F -->|Yes| G[Use in Construction]
    F -->|No| E

This ensures quality and uniformity in sewer brick production per IS 4885.

IS 4885 - General Quality Requirements for Sewer Bricks

1. Dimensional Specifications (Clause 3.1 & 3.2)

• Tolerances apply to a batch of 20 bricks, ensuring uniformity.

2. Warpage Limits (Clause 3.3)

• Maximum warpage (distortion) allowed: 2.5 mm
• Applies to both:
  • Face distortion from a plane surface
  • Edge distortion from a straight line

Summary:

• Standard sizes: 190 × 90 × 90 mm or 190 × 90 × 40 mm
• Dimensional tolerance: ±80 mm (length), ±40 mm (width & height) per 20 bricks
• Warpage tolerance: ≤ 2.5 mm per brick face or edge

These ensure bricks are uniform and fit well in sewer construction, maintaining structural integrity and ease of laying.

flowchart LR
    A[Standard Brick Dimensions] --> B[Length: 190 mm ± 80 mm]
    A --> C[Width: 90 mm ± 40 mm]
    A --> D[Height: 90 or 40 mm ± 40 mm]
    E[Warpage] --> F[Max 2.5 mm distortion]
    F --> G[Face from plane surface]
    F --> H[Edge from straight line]

IS 4885: Compressive Strength of Sewer Bricks

• Standard Test: As per IS 3495 (Part 1)-1976 for compressive strength testing.
• Minimum Average Compressive Strength:
  [ f_{avg} \geq 17.5 , \text{N/mm}^2 \quad (175 , \text{kgf/cm}^2) ]
• Minimum Individual Brick Strength:
  [ f_{min} \geq 16 , \text{N/mm}^2 \quad (160 , \text{kgf/cm}^2) ]

Key Specifications:

Testing Procedure Summary:

• Remove blisters, loose clay, and projections.
• Arrange bricks in a line on a level surface.
• Measure overall length with a steel tape in one stretch.
• Test compressive strength per IS 3495 (Part 1).

Notes:

• Sewer bricks must show uniformly fine-grained, compact fracture on breakage.
• Suitable for domestic sewage sewers; industrial effluent requires acid-resistant bricks (IS 4860).

flowchart TD
    A[Select ≥ 20 bricks] --> B[Remove defects]
    B --> C[Arrange in line on level surface]
    C --> D[Measure overall dimensions]
    D --> E[Test compressive strength as per IS 3495]
    E --> F{Strength Criteria}
    F -->|Avg ≥ 17.5 N/mm² & Individual ≥ 16 N/mm²| G[Pass]
    F -->|Else| H[Fail]

This ensures bricks meet durability and strength for sewer lining applications.

IS 4885 - Water Absorption Key Points

• Water Absorption Limit (Clause 6.1):

  • Average absorption after 24 h cold water immersion ≤ 10% of dry weight (5 bricks average).
  • Individual brick absorption ≤ 12%.

• Alternative Test (Clause 6.2):

  • 5 h boiling water immersion test as per IS 3495 (Part 2)-1976 can be specified for special requirements.

Water Absorption Formula

[ \text{Water Absorption %} = \frac{W_{wet} - W_{dry}}{W_{dry}} \times 100 ]

Where:

• (W_{dry}) = Dry weight of brick
• (W_{wet}) = Weight after immersion

Dimensions of Sewer Bricks (Clause 3.1)

Summary: For quality control, bricks must have ≤10% water absorption by weight after 24h immersion, ensuring durability and minimal moisture uptake.

Efflorescence in Bricks (IS 4885: Clause 7)

• Definition: Efflorescence is the white or grey crystalline deposit on brick surfaces caused by soluble salts.
• Test Method: As per IS 3495 (Part 3)-1976, bricks are tested for efflorescence.
• Acceptable Limit: The efflorescence rating shall not be more than 'slight'.

Efflorescence Rating (IS 3495 Part 3)

Related Specifications:

• Water Absorption (Clause 6.1):
  • Average ≤ 10% by weight (5 bricks, 24h immersion, IS 3495 Part 2)
  • Individual brick ≤ 12%
• Water Absorption by Boiling (Clause 6.2):
  • Specified by purchaser if needed (IS 3495 Part 2)

Summary:

• Bricks must be well burnt, free from lime nodules and flaws (Clause 4.1) to minimize efflorescence.
• Efflorescence test ensures aesthetic and durability quality of bricks.

flowchart TD
    A[Bricks Sample] --> B[Efflorescence Test (IS 3495 Part 3)]
    B --> C{Efflorescence Rating}
    C -->|Nil| D[Acceptable]
    C -->|Slight| D
    C -->|Moderate| E[Reject or Rework]
    C -->|Heavy| E

For detailed test procedure, refer to IS 3495 (Part 3)-1976.

IS 4885: Sampling of Burnt Clay Sewer Bricks

Sampling Procedure (Clause 8.1)

• Sampling must follow IS 5454:1978 guidelines.
• Typically involves random selection of bricks from a lot to ensure representativeness.
• Number of samples depends on lot size and acceptance criteria per IS 5454.

Key Dimensions & Tolerances (Clauses 3.1 & 3.2)

Summary

• Standard sizes: 190×90×90 mm and 190×90×40 mm.
• Tolerance: Ensures dimensional consistency in a batch of 20 bricks.
• Sampling ensures quality control per IS 5454, focusing on representative testing.

flowchart LR
    A[Lot of Bricks] --> B[Random Sampling per IS 5454]
    B --> C[Sample Size Determined]
    C --> D[Testing: Dimensions, Strength, Quality]
    D --> E{Accept/Reject Lot}

For detailed sampling steps, refer to IS 5454:1978.

IS 4885: Marking of Clay Building Bricks

Clause 9.1 & 9.1.1 - Marking Requirements:

• Each brick shall be marked with the manufacturer's identification mark or initials.
• Optional: The brick may also carry the Standard Mark issued by BIS, indicating compliance with IS 4885 under BIS inspection and quality control.
• The use of the Standard Mark is governed by the Bureau of Indian Standards Act 1986.

Key Points on Marking:

Dimensions & Tolerances (Clause 3.2)

Summary Diagram:

flowchart LR
    A[Brick] --> B[Mark Manufacturer ID]
    B --> C{Use Standard Mark?}
    C -- Yes --> D[Apply BIS Standard Mark]
    C -- No --> E[Mark only Manufacturer ID]
    D --> F[BIS Quality Control & Surveillance]

For further details on licensing and marking, contact BIS regional offices listed in IS 4885.