sewer bricks - Specification
1988 Edition

Specification Scope & Principal Requirements for Sewer Bricks

• Scope: Defines dimensions, acceptable tolerances, and quality requisites for sewer bricks produced from appropriate soil free from coarse particles and lime.

1. Standard Brick Sizes (Clause 3.1)

2. Allowed Dimensional Tolerances for 20 Brick Samples (Clause 3.2)

3. Material Criteria (Clause 2.1)

• Bricks must be formed using suitable soil.
• Should be devoid of coarse particles such as stones, pebbles, or visible lime grains.

This ensures consistent quality and dimensional accuracy for durable sewer brickwork.

Material Requirements and Dimensions for Sewer Bricks

1. Raw Material Composition (Clause 2.1)

• Bricks are to be manufactured from soil that is suitable for brick making.
• The soil must be free from coarse impurities like stones, pebbles, or lime nodules to ensure strength and uniformity.

2. Standard Brick Sizes (Clause 3.1)

3. Dimensional Tolerances for Samples of 20 Bricks (Clause 3.2)

4. Brick Marking (Clause 9.1.1)

• Manufacturer’s identification mark or initials must be on each brick.
• Optional use of the BIS Standard Mark confirms compliance with IS 4885 and BIS quality surveillance.

Summary:

• Use clean, impurity-free soil.
• Maintain strict adherence to specified dimensions and tolerances.
• Standard brick sizes are 190×90×90 mm and 190×90×40 mm.
• Marking ensures traceability and conformity to quality standards.

flowchart TD
    Soil[Suitable Soil] --> Manufacture[Brick Production]
    Manufacture --> Dimensions{Select Dimension}
    Dimensions --> Size1[190×90×90 mm]
    Dimensions --> Size2[190×90×40 mm]
    Manufacture --> Tolerances{Dimension Tolerances}
    Tolerances --> LengthTol[±80 mm on 190 mm]
    Tolerances --> WidthHeightTol[±40 mm on 90/40 mm]
    Manufacture --> Marking[Apply Manufacturer Mark]
    Marking --> BISMark[Optional BIS Standard Mark]
    BISMark --> Quality[Quality Assurance by BIS]

This guarantees bricks meet the dimensional and quality requirements of IS 4885.

Dimensions and Allowable Variances for Sewer Bricks (IS 4885)

1. Standard Sizes (Clause 3.1)

2. Total Permissible Dimensional Tolerances for 20 Bricks (Clause 3.2)

3. Maximum Warpage Allowance (Clause 3.3)

• Maximum allowable distortion or warping from a flat plane or straight edge is 2.5 mm.

Recap:

• Bricks must not contain coarse impurities (Clause 2.1).
• Tolerances are cumulative for a set of 20 bricks.
• Warpage limits ensure bricks have flat surfaces and straight edges for proper laying.

flowchart LR
    Production[Brick Manufacturing] --> DimensionCheck[Check Dimensions]
    DimensionCheck --> Valid{Within Tolerance?}
    Valid -->|Yes| Accept[Accept Bricks]
    Valid -->|No| Reject[Reject Bricks]
    Accept --> WarpageCheck[Verify Warpage ≤ 2.5 mm]
    WarpageCheck -->|Yes| Use[Approved for Use]
    WarpageCheck -->|No| Reject

This process ensures dimensional consistency and quality in sewer brick production.

General Quality Standards for Burnt Clay Sewer Bricks (IS 4885)

1. Dimensional Requirements (Clauses 3.1 & 3.2)

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

2. Warpage Restrictions (Clause 3.3)

• Maximum permitted warpage is 2.5 mm, affecting both:
  • Surface flatness relative to a plane
  • Edge straightness relative to a straight line

Summary:

• Standard sizes are 190×90×90 mm or 190×90×40 mm.
• Dimensional variation tolerances per batch guarantee consistent masonry.
• Warpage limits maintain brick flatness and edge straightness, aiding proper brick laying.

flowchart LR
    BrickDimensions[Standard Dimensions] --> Length[Length: 190 mm ± 80 mm]
    BrickDimensions --> Width[Width: 90 mm ± 40 mm]
    BrickDimensions --> Height[Height: 90 or 40 mm ± 40 mm]
    WarpageCheck[Warpage] --> MaxWarpage[Max 2.5 mm distortion]
    MaxWarpage --> SurfaceFlatness[Face flatness]
    MaxWarpage --> EdgeStraightness[Edge straightness]

Compressive Strength Criteria for Sewer Bricks (IS 4885)

• Testing Standard: Performed according to IS 3495 (Part 1) - 1976.
• Minimum Average Strength: [f_{avg} \geq 17.5 \text{ N/mm}^2] (equivalent to 175 kgf/cm²)
• Minimum Individual Brick Strength: [f_{min} \geq 16 \text{ N/mm}^2] (equivalent to 160 kgf/cm²)

Key Testing Parameters:

Testing Procedure Summary:

• Remove any surface blisters, loose clay, or projections.
• Line bricks up on a flat surface.
• Measure overall length with a steel tape in a single continuous stretch.
• Conduct compressive strength testing as per IS 3495 (Part 1).

Additional Notes:

• Fracture upon breaking should be fine-grained and compact.
• Bricks are intended for domestic sanitary sewage; industrial effluent applications require acid-resistant bricks (IS 4860).

flowchart TD
    Sample[Select ≥ 20 bricks] --> Clean[Remove Defects]
    Clean --> Arrange[Arrange bricks in line]
    Arrange --> Measure[Measure total length]
    Measure --> Test[Perform compressive strength test]
    Test --> Check{Does strength meet criteria?}
    Check -->|Yes| Pass[Pass]
    Check -->|No| Fail[Fail]

Ensures bricks have adequate strength for sewer lining.

Water Absorption Requirements for Sewer Bricks (IS 4885)

• Maximum Absorption (Clause 6.1):

  • Average water absorption after 24 hours immersion in cold water should not exceed 10% of the dry weight (based on 5 bricks).
  • Absorption for any individual brick should be below 12%.

• Alternative Boiling Test (Clause 6.2):

  • A 5-hour boiling water immersion test as per IS 3495 (Part 2) - 1976 may be specified for special conditions.

Water Absorption Calculation

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

Where:

• (W_{dry}): Weight of dry brick
• (W_{wet}): Weight after immersion

Brick Sizes (Clause 3.1)

Summary: To ensure durability and limit moisture ingress, bricks must not absorb more than 10% water by weight after 24 hours of immersion.

Efflorescence Characteristics and Testing for Sewer Bricks (IS 4885: Clause 7)

• Definition: Efflorescence is a whitish or grey crystalline deposit on brick surfaces caused by soluble salts migrating to the surface.
• Test Method: Conducted according to IS 3495 (Part 3) - 1976.
• Allowed Rating: Efflorescence should not exceed a rating of ‘slight’.

Efflorescence Rating Scale (IS 3495 Part 3)

Related Requirements:

• Water absorption limits (Clause 6.1): average ≤ 10%, individual ≤ 12%.
• Boiling water absorption test (Clause 6.2) as purchaser option.

Summary:

• Bricks must be well-fired, free from lime nodules and defects to minimize efflorescence.
• Efflorescence testing is crucial to ensure aesthetic quality and durability.

flowchart TD
    Sample[Brick Sample] --> Test[Efflorescence Test (IS 3495 Part 3)]
    Test --> Rating{Efflorescence Rating}
    Rating -->|Nil| Accept[Acceptable]
    Rating -->|Slight| Accept
    Rating -->|Moderate| Reject[Reject or Rework]
    Rating -->|Heavy| Reject

Refer to IS 3495 (Part 3) for detailed testing procedures.

Sampling Procedures for Burnt Clay Sewer Bricks (IS 4885)

Sampling Guidelines (Clause 8.1)

• Follow random sampling procedures as per IS 5454:1978.
• Samples should represent the entire lot, selected randomly.
• The number of bricks sampled depends on lot size and acceptance criteria defined in IS 5454.

Dimensional Standards & Tolerances (Clauses 3.1 & 3.2)

Summary:

• Standard brick sizes: 190×90×90 mm and 190×90×40 mm.
• Tolerances ensure batch dimensional uniformity.
• Sampling ensures quality control and representativeness according to IS 5454.

flowchart LR
    Lot[Brick Lot] --> RandomSample[Random Sampling per IS 5454]
    RandomSample --> SampleSize[Determine Sample Size]
    SampleSize --> Testing[Conduct Dimension, Strength, Quality Tests]
    Testing --> Decision{Accept or Reject Lot}

Refer to IS 5454:1978 for comprehensive sampling instructions.

Marking Requirements for Burnt Clay Sewer Bricks (IS 4885: Clauses 9.1 & 9.1.1)

• Every brick shall bear the manufacturer’s mark or initials for identification.
• Optionally, bricks may display the BIS Standard Mark indicating compliance with IS 4885 and ongoing BIS quality surveillance.
• Usage of the Standard Mark is regulated under the Bureau of Indian Standards Act, 1986.

Marking Details:

Dimensional Tolerances (Clause 3.2)

Summary Diagram:

flowchart LR
    Brick[Brick] --> ManufacturerMark[Mark Manufacturer’s ID]
    ManufacturerMark --> UseStdMark{Apply Standard Mark?}
    UseStdMark -- Yes --> BISMark[Apply BIS Standard Mark]
    UseStdMark -- No --> OnlyManuMark[Only Manufacturer Mark]
    BISMark --> BISControl[BIS Quality Surveillance]

For further details on licensing and marking, contact the respective BIS regional offices as referenced in IS 4885.