laterite stone block for masonry
1979 Edition

Overview of IS 3620: Specifications and Dimensions

1. Block Sizes and Dimensional Limits (Clause 3.1 & 3.3): Standard block dimensions (in mm):

• Allowed Tolerance: +5 mm on all dimensions.

2. Physical Properties and Testing (Clause 7.4):

• Sampling based on Table 3 specifications.
• Tests include compressive strength, water absorption, and specific gravity.
• Acceptance criteria require zero test failures.

3. Data Rounding (Clause 0.4):

• Test results rounded according to IS 2-1960 with consistent significant figures.

Summary:

• Refer to Table 1 for block sizes with permissible +5 mm tolerance.
• Conduct physical tests on randomly selected samples as per clause 7.4.
• Apply appropriate rounding rules for reporting results.

flowchart TD
    A[Laterite Blocks] --> B[Size per Table 1]
    B --> C{Tolerance +5 mm}
    A --> D[Sampling per Table 3]
    D --> E[Tests: Compressive Strength, Water Absorption, Specific Gravity]
    E --> F{All tests satisfactory?}
    F -->|Yes| G[Accept Lot]
    F -->|No| H[Reject Lot]

IS 3620: Core Requirements and Testing Overview

1. Dimensional Allowances (Clause 3.3)

• A maximum positive deviation of 5 mm on block dimensions from Table 1 is permitted.

2. Physical Attributes (Clause 4.1 & Table 2)

3. Sampling and Compliance (Clause 7.3, 7.4, Table 3)

• Samples selected randomly according to Table 3.
• Testing sequence: compressive strength → water absorption → specific gravity.
• Lot acceptance if no test failures occur.
• Permissible defective limits specified in Table 3.

Process Flow for Testing

flowchart TD
    A[Select Sample] --> B[Check General Requirements]
    B --> C{Defective Count ≤ Allowed?}
    C -- Yes --> D[Test Compressive Strength]
    D --> E[Test Water Absorption]
    E --> F[Test Specific Gravity]
    F --> G{Failures?}
    G -- No --> H[Accept Lot]
    C -- No --> I[Reject Lot]
    G -- Yes --> I

Note: Consult Table 1 for block sizes and Table 3 for sampling specifics.

IS 3620: Size Specifications and Tolerance Limits for Laterite Blocks

Specifications:

• Standard Dimensions (Table 1):

• Tolerance:

  • Positive tolerance of 5 mm allowed on all listed dimensions (Clause 3.3).

• Non-standard Sizes:

  • Custom dimensions may be supplied if agreed upon by both buyer and supplier (Clause 3.2).

• Curing and Exposure:

  • Blocks require at least 3 months of exposure to stabilize prior to use, protected from rainfall (Clause 2.2).

Summary:

• Use dimensions listed in Table 1 with a +5 mm tolerance.
• Custom sizes need mutual agreement.
• Adequate curing is essential for block durability.

flowchart TD
    A[Laterite Blocks] --> B[Standard Dimension Options]
    B --> C{Tolerance +5 mm}
    A --> D[Custom Sizes]
    D --> E[Agreement Between Buyer & Supplier]
    A --> F[Curing Period]
    F --> G[Minimum 3 Months Exposure]
    F --> H[Protect from Rain]

IS 3620: Physical Property Requirements for Laterite Blocks

Important Notes:

• Dimensional tolerance of +5 mm applies (Clause 3.3).
• Sampling for physical tests must be random and follow Clause 7.4.
• Acceptance requires zero failures in tested properties.
• Final results to be rounded as per IS 2-1960 standards.

Summary Table:

| Property            | Threshold     | Units      | Test Code              |
|---------------------|---------------|------------|-----------------------|
| Water Absorption    | ≤ 12          | % by mass  | IS 1124-1974          |
| Specific Gravity    | ≥ 2.5         | -          | IS 1124-1974          |
| Compressive Strength| ≥ 3.5         | N/mm²      | IS 1121 (Part I)-1974 |

These criteria ensure the blocks’ suitability for masonry applications.

IS 3620: Workmanship Standards and Sampling Protocols

• Inspection Parameters (Clause 7.3): Blocks chosen as per Table 3 are evaluated for:

  • Compliance with general requirements (Clause 2)
  • Dimensional accuracy within ±5 mm (Clause 3.3)
  • Workmanship quality (Clause 5) Any block exhibiting defects is rejected.

• Sampling and Conformance (Table 3, Clause 7.2):

• Physical Testing (Clause 7.4): Sub-sample undergoes testing for compressive strength, water absorption, and specific gravity. Lot acceptance depends on all tests passing.

Summary: Workmanship approval requires minimal or no defects within the sample, with dimensional tolerance ±5 mm. Sampling follows Table 3 to ensure quality prior to physical testing.

flowchart TD
    A[Select Blocks per Table 3] --> B{Evaluate General, Dimensions, Workmanship}
    B -- Pass --> C[Choose Sub-sample for Physical Testing]
    B -- Fail --> D[Reject Blocks/Lot if Defects Exceed Limit]
    C --> E[Test: Compressive Strength, Water Absorption, Specific Gravity]
    E -- All Pass --> F[Accept Lot]
    E -- Any Fail --> D

IS 3620: Marking and Traceability Guidelines

• Manufacturer Identification (Clause 6.1): Blocks must bear the manufacturer’s mark or initials clearly for traceability.

• Dimensional Tolerance (Clause 3.3): A tolerance of +5 mm is permitted on block dimensions specified in Table 1.

• Sampling and Testing (Clause 7.4): Random sub-samples are drawn from the lot for physical property tests:

  • Compressive strength
  • Water absorption
  • Specific gravity Acceptance requires no failures in these tests.

Marking and Quality Control Summary

Process Flow for Marking & Quality Assurance

flowchart TD
    A[Block Production] --> B[Apply Manufacturer's Mark]
    B --> C[Dimension Verification (+5 mm tolerance)]
    C --> D[Sampling per Table 3]
    D --> E[Physical Testing: Strength, Absorption, Gravity]
    E --> F{Test Results}
    F -- Pass --> G[Lot Approved]
    F -- Fail --> H[Lot Rejected]

Note: Refer to Tables 1 and 3 in IS 3620 for detailed dimension and sampling requirements.

IS 3620: Sampling Techniques and Acceptance Standards

Sampling Instructions (Clause 7.2)

• Sample sizes depend on the total lot quantity as detailed in Table 3.
• Blocks must include manufacturer’s marking for identification (Clause 6.1).
• Each lot is sampled and tested individually (Clause 7.1.1).

Conformity Requirements (Clause 7.4)

• After passing general, dimensional, and workmanship inspections, the sub-sample undergoes tests for:
  • Compressive strength
  • Water absorption
  • Specific gravity
• Lot acceptance is granted only if every tested block meets the criteria.

Testing Flowchart

flowchart TD
    A[Begin Sampling] --> B[Mark Blocks with ID]
    B --> C[Select Sample per Table 3]
    C --> D[Evaluate General, Dimension, Workmanship]
    D -->|Pass| E[Select Sub-sample for Physical Tests]
    D -->|Fail| F[Reject Lot]
    E --> G[Test Compressive Strength, Water Absorption, Specific Gravity]
    G -->|All Pass| H[Accept Lot]
    G -->|Any Fail| F[Reject Lot]

Note: Sampling must be random to ensure unbiased results; sub-sample sizes are specified in Table 3.