Limestone (Slab and Tiles)
1974 Edition

Overview & Essential Specifications from the Limestone Slabs and Tiles Code

1. Applicability Scope

• Applies to limestone slabs and tiles used in construction.
• Dimensions follow Table 1; intermediate sizes are rounded downward to the nearest standard size.
• Special dimensions may be agreed upon between parties.

2. Standardized Dimensions (Table 1)

3. Sampling & Compliance (Table 3)

• Each sampled piece is inspected for dimensional accuracy and general criteria.
• The batch is accepted if the number of defective pieces is within the permissible limit.

4. Rounding Guidelines

• Final measurements are rounded following IS 2-1960 standards.
• The number of significant digits is maintained as per the specified values.

This section establishes uniform size, quality, and acceptance parameters for limestone slabs and tiles.

General Requirements Summary per Limestone Slabs and Tiles Code

1. Scope (Clause 1.1)

• Defines the dimensional and physical characteristics for limestone slabs and tiles intended for flooring and facing.

2. Sampling & Acceptance (Clause 6.3, Table 3)

• Defect Definition: Any slab or tile not meeting dimensional or general standards is classified as defective.
• Batch Approval: If defective pieces are less than or equal to the allowed number, the batch is accepted.

3. Rounding Rules (Clause 0.3)

• Test results should be rounded in accordance with IS 2-1960.
• Preserve the same number of significant digits as specified.

4. Sizes (Clause 3.1.2)

• Sizes other than those specified in Table 1 can be supplied if mutually agreed upon.

Summary: Sampling and defect limits enforce quality assurance; strict acceptance criteria maintain dimensional and physical compliance.

Dimensions and Tolerances for Limestone Slabs and Tiles

1. Standard Dimensions (Clause 3.1.1 & Table 1)

• Sizes falling between these increments are rounded down to the closest lower standard size.
• Customized sizes may be provided based on mutual agreement (Clause 3.1.2).

2. Thickness Tolerance (Clause 3.1.3)

3. Rounding Instructions (Clause 0.3)

• Test values are rounded as per IS 2-1960.
• The number of significant figures is maintained consistent with the specified values.

Recap:

• Length and width follow standard increments; intermediate values rounded downward.
• Thickness tolerance: +5 mm for ≤25 mm, ±5 mm for >25 mm.
• Custom sizes available through agreement.
• Rounding complies with IS 2-1960.

flowchart LR
    A[Specify Desired Size] --> B{Is Size Standard?}
    B -- Yes --> C[Use Defined Size]
    B -- No --> D[Round Down to Nearest Lower Size]
    C & D --> E[Verify Thickness Tolerance]
    E --> F{Thickness ≤ 25 mm?}
    F -- Yes --> G[Apply +5 mm Tolerance]
    F -- No --> H[Apply ±5 mm Tolerance]

This guarantees consistency and quality control in limestone slab manufacturing.

Physical Properties Requirements for Limestone Slabs and Tiles

Testing and Sampling (Clauses 6.4, 4.1)

• Sub-sample Size: Selected from each batch according to Table 3 (Column 4) for physical tests.
• Performed Tests:
  • Flexural (Transverse) Strength
  • Water Absorption
  • Durability Assessments

A batch is accepted only if all samples meet the required criteria.

Physical Properties (Table 2, Column 2)

Dimensional Tolerances (Clause 3.2)

• Length and width: ±1 mm
• Thickness: As per Clause 3.1.3 (typically ±1 to 2 mm)

Rounding Protocol (Clause 0.3)

• Test data should be rounded consistent with IS 2-1960.
• Maintain the same significant digits as the stated values.

Calculation Formulas

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

• Flexural Strength (Modulus of Rupture, MOR): [ MOR = \frac{3PL}{2bd^2} ] where: (P) = load at failure, (L) = span length, (b) = width, (d) = thickness.

flowchart LR
    A[Select Sub-samples (Table 3)] --> B[Test Flexural Strength]
    B --> C[Test Water Absorption]
    C --> D[Test Durability]
    D --> E{Any Failures?}
    E -- No --> F[Batch Accepted]
    E -- Yes --> G[Batch Rejected]

Marking Requirements for Limestone Slabs and Tiles

Essential Marking Guidelines (Clauses 5.1 & 5.1.1)

• Manufacturer’s Identification: Each slab or tile must bear the manufacturer’s mark or initials.
• ISI Mark: If the manufacturer is licensed, the ISI certification mark may also be applied, indicating compliance with Indian Standards and quality control.

Purpose of Marking

• Ensures traceability and verification of quality.
• The ISI mark confirms production under ISI supervision and adherence to quality checks.

Summary Table

Sampling for Marking Verification (Clause 6.3)

• Each selected piece is inspected for marking and general compliance.
• Batch passes if defective count is within permissible limits.

Process Flow

flowchart TD
    A[Manufacturer] --> B[Apply Manufacturer ID Mark]
    B --> C{Licensed for ISI?}
    C -- Yes --> D[Apply ISI Certification Mark]
    C -- No --> E[Only Manufacturer ID Applied]
    D & E --> F[Quality Control and Inspection]

Note: Markings must be legible, durable, and comply with the code to ensure traceability and quality assurance.

Sampling and Testing Procedures Overview

Sampling Details (Clauses 6.2 & 6.3)

• Sample Size Based on Batch Size: Refer to Table 3:

• All sampled items are evaluated for dimensional and general requirements.
• The batch is deemed conforming if defective items count does not exceed allowed defects.

Sampling Methodology (Clause 6.2.1)

• Use random selection techniques, preferably employing random number tables as per IS 4905-1968.

Testing and Rounding (Clause 0.3)

• Test outcomes are rounded according to IS 2-1960.
• Maintain the exact number of significant digits as per specified standards.

This method guarantees statistically sound and standardized quality verification of limestone products.

Compliance Criteria for Limestone Slabs and Tiles

Important Points:

• All selected samples must be examined for general quality and dimensions.
• Any sample failing these requirements is considered defective.
• A batch is accepted if the number of defective samples is within the permitted limit.
• Numerical results must be rounded per IS 2-1960 with consistent decimal places.
• Stones must be free from soft veins, fissures, and flaws, with consistent texture (Clause 2.1).

Flowchart for Compliance Check:

flowchart TD
    A[Select Samples as per Table 3] --> B[Inspect General & Dimensional Criteria]
    B --> C{Defects Found?}
    C -- No --> D[Batch Accepted]
    C -- Yes --> E{Defective Count ≤ Allowed?}
    E -- Yes --> D
    E -- No --> F[Batch Rejected]

This approach enables quality control through statistical sampling and strict defect thresholds.