Ceramic unglazed vitreous acid-resisting tile

IS 4457: Scope - Key Dimensions and Specifications

This code covers dimensions, tolerances, and testing for specific tiles with rubber and rod reinforcements.

Key Dimensions (Table 4)

Measurement Accuracy

• Recording Gauge: Accurate to ±2%
• Measuring Gauge: Capable of 0.1 mm precision (Clause 4.2)

Sampling for Conformity (Clause 8.2.2.2)

• For lots of 101–300 tiles: 1 test/sample
• For lots > 300 tiles: 2 tests/samples
• Samples must be randomly selected from pre-inspected lots.

Related IS Standards

• IS 264: Nitric acid specification
• IS 2062: Steel for general purposes
• IS 3400 (Part 2): Vulcanized rubber hardness testing

This scope ensures tile dimensions, reinforcement, and testing meet quality and durability standards.

Key References, Tables & Specifications from IS 4457

1. Dimensions of Rods, Rubber Thickness & Tile Overlap (Table 4)

2. Sample Size and Criteria for Conformity (Clause 8.2.2.2)

• For lots 101 to 300 tiles: 1 test per requirement.
• For lots > 300 tiles: 2 tests per requirement.
• Samples must be randomly taken from those already inspected and satisfactory.

3. Minimum Number of Test Specimens (Table 5)

4. List of Referred Indian Standards

• IS 264: Nitric acid specification
• IS 266: Sulphuric acid specification
• IS 460 (Part 1): Test sieves
• IS 2062: Steel for general purposes
• IS 3400 (Part 2): Test methods for vulcanized rubbers (Hardness)
• IS 4860 & IS 4905: Acid-resistant bricks & sampling
• IS 11643: Silicon carbide for bonded abrasives

Summary Diagram: Tile Dimension vs Rod & Rubber Specs

graph TD
A[Tile Dimension] -->|≥ 95 mm| B[Rod 20 mm, Rubber 5 mm, Overlap 10 mm]
A -->|48 ≤ Tile < 95 mm| C[Rod 10 mm, Rubber 2.5 mm, Overlap 5 mm]
A -->|18 ≤ Tile < 48 mm| D[Rod 5 mm, Rubber 1 mm, Overlap 2 mm]

**Use these tables

IS 4457: Key Definitions & Specifications for Ceramic Tiles

1. Dimension Parameters (Table 4)

• Diameter of Rod (d): Used for supporting tiles during testing.
• Thickness of Rubber (t): Cushioning layer thickness.
• Overlap: The tile extension beyond supports to avoid edge failure.

2. Terminology for Surface Flatness (Clause 6.1)

• Straightness of Sides: Deviation from a straight line along tile edges.
• Rectangularity: Deviation of internal angles from 90°, measured as % deviation relative to tile size.
• Curvature and Warpage: Surface flatness deviations measured by specific apparatus (see FIG. 2 & 3 in IS 4457).

3. Test Report (Clause 5.6)

• Tile description.
• Rectangularity measurements.
• Maximum % deviation from rectangularity related to work sizes.

4. Measurement Apparatus (Figures Summary)

• Fig.1: Shows direction of positive/negative deviation in straightness.
• Fig.2: Apparatus setup for straightness and rectangularity.
• Fig.3: Measurement of rectangularity deviation.

flowchart LR
    A[Tile] --> B[Measure Straightness]
    A --> C[Measure Rectangularity]
    A --> D[Measure Surface Flatness]
    B --> E[Record deviation %]
    C --> E
    D --> E
    E --> F[Test Report]

This summary provides essential definitions, dimensions, and testing parameters per IS 4457 for ceramic tiles.

IS 4457: Dimensions and Tolerances Summary

Key Specifications (Clause 4 & Table 4)

• Diameter of Rod (d): Used in testing for support during dimensional checks.
• Thickness of Rubber (t): Cushioning layer thickness during testing.
• Overlap: Minimum tile extension beyond edge supports to avoid measurement errors.

Tolerances (Improved Stringency)

• Tolerances on length and width are tightened to reduce joint variation, especially for larger tiles.
• Warpage includes surface flatness, center curvature, and edge curvature.
• Testing methods and reporting follow current ISO standards, expressed as percentages.

Practical Notes:

• Larger tiles require stricter control to prevent uneven joints.
• Use calibrated gauges with ±2% accuracy (Clause 3.4).
• Report dimensional deviations as % variation from nominal size.

flowchart LR
    A[Tile Size] --> B[Select Rod Diameter (d)]
    B --> C[Select Rubber Thickness (t)]
    C --> D[Set Overlap Beyond Edge Supports]
    D --> E[Conduct Dimensional Tests]
    E --> F[Measure Warpage & Flatness]
    F --> G[Report % Deviation per ISO]

Summary: Follow Table 4 for test setup dimensions; apply ISO-based dimensional and warpage tests; maintain tighter tolerances for larger tiles to ensure quality and minimal joint variation.

IS 4457: Surface Quality and Flatness of Ceramic Tiles

Key Specifications & Definitions (Clauses 6.1 & 6.1.1)

• Surface Flatness is measured at three positions on the tile surface.
• For tiles with surface relief preventing direct measurement, flatness is measured on the back surface.
• Flatness includes:
  • Centre curvature
  • Edge curvature
  • Warpage

Measurement & Reporting (Clause 6.6)

The test report must include:

Formula for Curvature/Warpage Percentage

[ \text{Curvature or Warpage %} = \left(\frac{\text{Maximum deviation (mm)}}{\text{Reference length (mm)}}\right) \times 100 ]

• Reference length: Diagonal length for centre curvature and warpage; edge length for edge curvature.

Summary Diagram: Flatness Measurement Points

graph LR
A[Tile Surface] --> B[Position 1]
A --> C[Position 2]
A --> D[Position 3]
B & C & D --> E[Measure deviation from flat plane]
E --> F[Calculate max curvature & warpage %]

Note: IS 4457 adopts ISO methods for dimensional and flatness testing, reporting deviations as percentages relative to tile dimensions for uniform quality assessment.

IS 4457: Physical Properties Summary

1. Thickness Criteria (Clause 7.5)

• Thickness ≥ 7.5 mm
• Thickness < 7.5 mm

2. Mechanical Properties

3. Dimensional Tolerances (Table 1, Clause 8.1)

4. Chemical Resistance (Clause iv)

• Resistance classes agreed between manufacturer and purchaser.
• Tested against:
  • Low/high concentration acids and alkalis
  • Household chemicals and pool salts
  • Concentrated HNO3 and H2SO4 (mass loss ≤ 1.5%)

5. Water Absorption

• Average < 0.5%, individual max 0.6%

Additional Notes:

• Test

IS 4457: Mechanical Properties - Key Formulas & Specifications

1. Test Specimens (Clause 6.1 & 6.7)

• Use only specimens breaking within the central length equal to the diameter of the central rod.
• Record breaking strength and modulus of rupture for these specimens.

2. Dimensions for Test Setup (Table 4)

3. Measuring Instruments

• Recording Gauge: Accurate to ±2% (Clause 3.4)
• Measuring Gauge: Capable of 0.1 mm precision (Clause 4.2)

4. Key Formulas

• Breaking Strength (σ):
  [ \sigma = \frac{P}{A} ] where,
  (P) = Load at failure (N)
  (A) = Cross-sectional area (mm²)

• Modulus of Rupture (MOR):
  [ MOR = \frac{3PL}{2bd^2} ] where,
  (P) = Load at failure (N)
  (L) = Span length (mm)
  (b) = Width of specimen (mm)
  (d) = Thickness of specimen (mm)

flowchart TD
    A[Test Specimen] --> B{Breaks within central rod diameter?}
    B -- Yes --> C[Use results for avg breaking strength & MOR]
    B -- No --> D[Discard specimen results]
    C --> E[Calculate σ and MOR using formulas]

This ensures reliable mechanical property evaluation per IS 4457.

IS 4457: Sampling and Criteria for Conformity

1. Sample Size & Acceptance Criteria (Clause 8.2, Table 2)

• Defective tile: Fails any dimension, tolerance, marking, straightness, or flatness criteria.
• Tiles are randomly selected per IS 4905.

2. Additional Testing (Clause 8.2.2.2)

• For lots 101–300 tiles: 1 test per requirement (beyond 8.2.1).
• For lots >300 tiles: 2 tests per requirement.
• Samples for these tests are taken from tiles already passing 8.2.1.
• Lot conforms if all tested samples pass.

3. Notes

• For lots ≤100 tiles, test number and criteria must be mutually agreed (Clause 8.2.2.1).
• Refer IS 4905 for random sampling procedure.

Summary Diagram

flowchart TD
    A[Lot Size] --> B{Lot Size Range}
    B -->|Up to 8| C[Sample 5, Accept 0 defects]
    B -->|9-25| D[Sample 8, Accept 0 defects]
    B -->|26-50| E[Sample 13, Accept 0 defects]
    B -->|51-100| F[Sample 20, Accept 1 defect]
    B -->|101-500| G[Sample 32, Accept 2 defects]
    B -->|>500| H[Sample 50, Accept 3 defects]
    I[Additional Tests] --> J{Lot Size}
    J -->|101-300| K[1 test per req.]
    J -->|>300| L[2 tests per req

IS 4457: Marking and Packaging Key Points

Marking:

• Use of the BIS Standard Mark is regulated by the Bureau of Indian Standards Act, 1986.
• Manufacturers must obtain a license to use the Standard Mark.
• Tiles may be marked with the BIS Standard Mark as per Clause 6.2.

Packaging:

• Tiles shall be packed according to usual trade practice.
• Packaging must adequately protect tiles during transportation and handling.

Relevant Specifications for Testing Setup (Clause 3.4 & Table 4)

• These parameters are used for test specimens support and cushioning during mechanical testing.

Summary:

• Marking: BIS Standard Mark use requires licensing.
• Packaging: Must protect tiles as per trade practices.
• Testing Setup: Use rod diameters, rubber thickness, and overlaps from Table 4 based on tile size.

flowchart LR
    A[Manufacturing] --> B[Marking with BIS Standard Mark]
    B --> C{License from BIS?}
    C -- Yes --> D[Apply Mark]
    C -- No --> E[No Marking Allowed]
    A --> F[Packaging]
    F --> G[Trade Practice]
    G --> H[Adequate Protection]

For detailed license conditions, contact BIS directly.

IS 4457: Referenced Standards & Key Specifications

Referenced Indian Standards (Annex A)

Key Table: Rod Diameter, Rubber Thickness & Tile Overlap (Clause 3.4)

Sampling Criteria (Clause 8.2.2.2)

• 101 to 300 tiles: 1 test per requirement (except 8.2.1)
• > 300 tiles: 2 tests per requirement
• Lot conforms if all samples pass.

Measurement & Testing (Annex B)

• Rectangularity: Max deviation in % relative to work size.
• Surface flatness: Check curvature and warpage.
• Straightness: Use apparatus per Fig. 2 for side deviation.

Summary Diagram: Tile Dimension & Overlap

flowchart LR
    TileDimension -->|≥95 mm| Rod20[Rod Diameter = 20 mm]
    TileDimension -->|48-95 mm| Rod10[Rod Diameter = 10 mm]
    TileDimension -->

IS 4457: Dimensions & Surface Quality for Ceramic Tiles

Key Specifications:

• Dimensions Covered: Length, width, thickness, straightness of sides, rectangularity.
• Surface Quality: Includes surface flatness, centre curvature, edge curvature, and warpage.
• Measurement Reporting: Results as percentages relative to tile dimensions (work size or diagonal).

Important Formulas:

Surface Quality:

• Assessed as per ISO standards adopted in IS 4457.
• Includes visual and instrumental checks for defects, flatness, and surface finish.

Test Report Must Include:

• Tile description.
• All curvature and warpage measurements.
• Maximum values expressed as percentages.

flowchart TD
    A[Tile Sample] --> B[Measure Dimensions]
    B --> C{Check Parameters}
    C -->|Length, Width, Thickness| D[Record Dimensions]
    C -->|Straightness, Rectangularity| E[Measure Deviations]
    C -->|Surface Flatness, Curvatures| F[Measure Warpage & Curvatures]
    D --> G[Calculate % Deviations]
    E --> G
    F --> G
    G --> H[Test Report]

This ensures compliance with dimensional tolerances and surface quality per IS 4457.

IS 4457: Water Impregnation Test Method - Key Points

Test Procedure (Clauses 5.1, 5.2 & 6.1)

• After water impregnation, weigh the specimen suspended in water to nearest 0.01 g.
• Use a wire loop, halter, or basket to suspend the specimen (Clause C-3.8).
• Counterbalance the scale with the suspension device immersed to the same depth before weighing.
• Record mass as m3 (mass of specimen suspended in water).

Water Absorption (Clause 6.1)

• Specimens are immersed vertically to 25 mm depth in test solution.
• Maintain immersion for 28 days at 27 ± 2°C.
• Non-cut side fully immersed.

Expression of Results (Clause 6.2)

• Calculate water absorption based on mass difference before and after immersion.

Typical Formula for Water Absorption (%)

[ \text{Water Absorption} = \frac{m_2 - m_1}{m_1} \times 100 ] Where:

• ( m_1 ) = dry mass of specimen (g)
• ( m_2 ) = mass after water impregnation (g)

Summary Table

flowchart LR
    A[Dry Specimen] --> B[Water Impregnation]
    B --> C[Weigh Suspended Specimen (m3)]
    C --> D[Calculate Water Absorption %]
    D --> E[Evaluate Material Quality]

This method ensures accurate measurement of water uptake critical for durability assessment.

IS 4457: Expression of Test Results - Key Points

• Clause 6.5 / E-6.3:

  • Relief surfaces affecting abrasion resistance tests should be ground off for uniformity.
  • Note: Test results differ from tiles with flat surfaces.

• Rectangularity (Clause 5.5 / B-5.5):

  • Expressed as % deviation in length and width for oblong tiles.
  • For square tiles, expressed as % deviation in size.

• Relief Surface Testing (Clause 5.6 / D-5.6):

  • Use a second rubber layer (thickness from Table 4) on the central rod to contact relief surfaces during tests.

Typical Formula for Rectangularity (% deviation):

[ \text{Rectangularity} = \frac{|\text{Measured dimension} - \text{Nominal dimension}|}{\text{Nominal dimension}} \times 100 ]

Table 4 (Rubber Thickness for Relief Surfaces)

flowchart LR
    A[Tile with Relief Surface] --> B[Place Rubber Layer (Table 4 thickness)]
    B --> C[Conduct Abrasion Resistance Test]
    C --> D[Record Results - Note Differences from Flat Tiles]

This ensures standardized test results despite surface variations.

IS 4457: Determination of Resistance to Deep Abrasion (Unglazed Tiles)

Key Formula (Clause 7.1)

The volume of material removed, V (mm³), is calculated using the groove chord length l on the rotating disc:

[ V = \frac{\pi d^2 h}{360} \times a ]

Where:

• d = Diameter of rotating disc (mm)
• h = Thickness of rotating disc (mm)
• a = Angle subtended by chord at disc center (degrees)
• l = Length of chord (mm) (used to find angle a)

Procedure Highlights

• Abrasion is measured by the groove length produced by a rotating disc with abrasive (White fused aluminum oxide, Grit No. 80 per IS 11643).
• Relief surfaces must be ground off for accurate results (Clause 6.3).
• The test uses a rotating disc apparatus (Clauses 4.1, Fig. 11).

Test Report Must Include (Clause D-7)

• Tile description
• Number of specimens
• Values of d, h, l, L, F (dimensions and forces)
• Modulus of rupture and breaking strength per specimen
• Average modulus of rupture and breaking strength

Abrasive Material

• White fused aluminum oxide, Grit No. 80 (IS 11643 Table 1)

Summary Table: Parameters

flowchart LR
    A[Rotating Disc] --> B[Groove on Tile Surface]
    B --> C[Measure Chord Length (l)]
    C --> D[Calculate Angle (a)]
    D --> E[Calculate Volume Removed (V)]
    E --> F[Assess Abrasion Resistance]

This method quantifies deep abrasion resistance by volume loss, ensuring consistent evaluation of unglazed ceramic floor tiles.

IS 4457: Determination of Chemical Resistance – Key Points

1. Test Setup & Measurement (Clause 7.2 & E-8)

• Chord length (l) of each groove measured to nearest 0.5 mm.
• Volume (V) of each groove in mm³.
• Average volume (Vm) calculated from individual grooves.
• Use Table 6 (Equivalent Values) to convert chord length to volume:

(Refer full Table 6 for intermediate values)

2. Chemical Resistance Test (Annex F)

• Partial immersion of unglazed tile specimens in test solutions.
• Visual inspection after 28 days for surface attack.
• Test solutions include:
  • Low/high concentration acids and alkalis.
  • Household chemicals and swimming pool salts.
  • Concentrated HNO3 and H2SO4.

3. Test Report Must Include (Clause F-7)

• Tile description.
• Test solution(s) used.
• Number of specimens tested and damaged.
• Visual changes on:
  • Proper surface.
  • Non-cut edges.
  • Cut edges.

4. Additional Specifications (Clause 7.5 & Table 4)

• Tile thickness:
  • ≥ 7.5 mm or < 7.5 mm affects test applicability.
• Modulus of rupture:
  • Min 32 N/mm², average 35 N/mm² for tiles with breaking strength < 3000 N.
• Abrasion resistance measured by volume removed (mm³).
• Rod diameter, rubber thickness, and tile overlap for testing per Table 4: