Ceramic Tiles - Methods of Test, Sampling and Basis for Acceptance

IS 13630 Part 1-5: Scope - Key Points, Tables & Formulas

Scope (Clauses 4.8, 5, 6):

• Inspection Lot: One or more homogeneous consignments or sub-consignments.
• Non-conforming Unit: Tile failing to meet specified property requirements.
• Homogeneity: Defined by properties tested; can be agreed upon between supplier & consumer.
• Extent of Inspection: Depends on lot size and agreement; full tests for lots > 5000 m², minimal for < 1000 m².

Sampling & Inspection (Table 1 Summary):

• Acceptance/Rejection: Based on attribute sampling; second sample drawn if initial results borderline.
• Test Methods: Refer to respective parts of IS 13630 for detailed procedures.

Notes:

• Sample sizes scale with lot size and tile

IS 13630 (Part 1-5) - Definitions Key Points

The Definitions section (Clauses 2.1, 4.1, 6.1) standardizes terminology for clarity and uniform application across the parts.

Key Aspects:

• Clause 2.1: Establishes fundamental definitions related to the scope of the standard.
• Clause 4.1 & 6.1: Provide specific terminologies for respective parts (e.g., materials, structural elements, or testing procedures).

Typical Definitions Include:

• Structural Element: Any component like beam, column, slab.
• Load Types: Dead load, live load, wind load, seismic load.
• Material Properties: Yield strength, modulus of elasticity.
• Design Parameters: Factor of safety, partial safety factors.

No explicit formulas or tables in definitions, but these terms underpin the calculations and tables in subsequent clauses.

Example Terminology Table (Illustrative)

For detailed design formulas and tables, refer to respective clauses beyond definitions.

IS 13630 Part 1-5: Sampling and Inspection Lots

Key Clauses:

• 7.2.1: Sampling must be random from the inspection lot.
• 9.1.1: If non-conforming units ≤ acceptance number (Ac1) from Table 1 (col 4), lot is acceptable.
• 9.2.1: If average test result (X) of initial samples meets requirements, lot is acceptable.
• 9.2.3: If average test result (X2) of combined initial + second samples meets requirements, lot is acceptable (see Table 1, col 10).

Important Table Extract (Table 1):

(Refer to IS 13630 Part 1-5 Table 1 for full details)

Summary of Procedure:

1. Random Sampling from lot (Clause 7.2.1).
2. Initial Sample Testing:
   • Check non-conforming units ≤ Ac1 (Clause 9.1.1).
   • Check average value (X) meets requirements (Clause 9.2.1).
3. If initial fails, take second sample and combine:
   • Check combined average (X2) meets requirements (Clause 9.2.3).
4. Acceptance or rejection based on above.

flowchart TD
    A[Start: Inspection

IS 13630 Part 1-5: Test Specimen Preparation

Key Points from Clauses:

• 6.1 Types of Test Specimens: Defines specimen types (e.g., cubes, cylinders, prisms) depending on test purpose.
• 6.2 Number of Test Specimens: Specifies minimum number of specimens for statistical reliability (commonly 3 or more).
• 6.2 Preparation: Specimens must be clean, dry, and free from defects.
• 5.2 Measuring Gauge: Use a gauge accurate to 0.1 mm for dimensional checks.

Typical Test Specimen Dimensions (per IS standards, e.g., IS 516):

Preparation Guidelines:

• Mould specimens immediately after mixing.
• Compact to avoid air voids.
• Store in controlled conditions (temperature, humidity).
• Surface finish should be smooth and even.
• Dry specimens before testing unless otherwise specified.

Measuring Gauge Use:

• Measure length, width, and height to ±0.1 mm accuracy.
• Ensure no surface irregularities affect measurement.

flowchart TD
    A[Mix Concrete] --> B[Prepare Mould]
    B --> C[Fill & Compact]
    C --> D[Cure Specimen]
    D --> E[Dry & Clean]
    E --> F[Measure Dimensions (±0.1 mm)]
    F --> G[Test]

Summary: Use clean, dry specimens of standard dimensions, measure accurately with a 0.1 mm gauge, and prepare at least 3 specimens for reliable test results.

IS 13630 Part 1-5: Measurement of Dimensions and Surface Quality

Key Specifications:

• Measuring Gauge Accuracy:

  • Must measure to 0.1 mm (Clause 5.2).

• Test Specimens:

  • Refer ISO 10545-2:1995 for ceramic tiles dimension and surface quality tests.

Measurement Parameters (Clause 6.6):

Surface Quality (Clause 6.2.2):

• For tiles ≤ 40 mm × 40 mm, use apparatus as per Clauses 6.2.2.1 & 6.2.2.2.
• Apparatus involves 3-off gauge and adjustable mounting (Fig. 2) to measure surface flatness.

Formula for Curvature and Warpage (%):

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

• Reference length: Diagonal or edge length depending on measurement.

Summary Diagram of Measurement Setup:

flowchart LR
    A[Tile Sample] --> B[3-Off Gauge Setup]
    B --> C[Measure Centre Curvature]
    B --> D[Measure Edge Curvature]
    B --> E[Measure Warpage]
    C & D & E --> F[Test Report with % deviations]

Use this framework to ensure compliance with IS 13630 Part 1-5 for tile dimension and surface quality testing.

IS 13630 Part 1-5: Key Formulas & Specifications for Water Absorption and Bulk Density

1. Bulk Density (Clause 6.2.1)

• Definition: Bulk density, ( B ) (g/cm³), is the dry mass divided by the exterior volume including pores.

• Formula:

[ B = \frac{m_1}{V} ]

Where:

• ( m_1 ) = Mass of dry tile (g)

• ( V ) = Exterior volume (cm³), calculated as:
  [ V = m_2 - m_3 ]

• ( m_2 ) = Mass of tile in air (g)

• ( m_3 ) = Mass of tile suspended in boiling water (g)

Note: Specimen size should be ≤ 0.01 m² (100 mm × 100 mm) for boiling water method.

2. Water Absorption (Clause 6.1)

• Determined by measuring the increase in mass after immersion in water, expressed as a percentage of dry mass.

• General formula:

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

Where:

• ( m_{\text{wet}} ) = Mass after water immersion (g)
• ( m_{\text{dry}} ) = Dry mass (g)

Summary Table

IS 13630 Part 6: Modulus of Rupture & Breaking Strength

Key Specifications:

• Test Specimens: Only those breaking within the central length equal to the diameter of the central rod are valid (Clause 7.1).
• Examination: Inspect specimens for visible defects under ~300 lux illumination, optionally using 1% methylene blue stain (Clause 5.5).

Breaking Strength Formula (Clause 7.5):

[ S = \frac{F \times L}{b \times d^2} ]

Where:

• ( S ) = Breaking strength (N/mm²)
• ( F ) = Load at break (N)
• ( L ) = Span between support rods (mm)
• ( b ) = Width of tile (mm)
• ( d ) = Thickness of tile (mm)

Modulus of Rupture (MOR):

• Calculated similarly using the three-point bending test setup with the central load on the glazed surface.
• Only results from specimens breaking centrally are averaged (Clause 7.1 & 7.7).

Test Setup:

• Three-point loading with central rod contacting the tile surface.
• Span ( L ) as per Fig. 2 (typically ~10x tile thickness).

Summary Table:

graph LR
A[Support Rod 1] -- L --> B[Support Rod 2]
B -- Central Load F --> C[Tile Specimen]

Note: Use only specimens breaking within the central rod diameter length for valid MOR and breaking strength results.

Key Formulas and Specifications from IS 13630 (Parts 1-5) for Thermal Properties of Ceramic Tiles

1. Coefficient of Linear Thermal Expansion (α) — Clause 6.1 (Part 4)

[ \alpha = \frac{\Delta L}{L_0 \times \Delta T} \times 10^6 \quad (10^{-6}/°C) ]

• (L_0) = Original length at ambient temperature (mm)
• (\Delta L) = Increase in length after heating (mm)
• (\Delta T) = Temperature rise (°C)

Test Range: Ambient to 100°C
Report must include: Apparatus description, tile description, and α for each specimen.

2. Moisture Expansion — Clause 6.2 (Part 4)

[ \text{Moisture Expansion} = \frac{I}{L} \times 1000 \quad \text{(mm/m)} ]

• (I) = Increase in length due to moisture (mm)
• (L) = Original length (mm)

3. Resistance to Thermal Shock (Part 5)

• Test Method: Cycle tiles 10 times between cold water (~15°C) and hot water (~145°C).
• Acceptance: No visible damage or cracks post cycling.
• Test depends on: Tile water absorption (different procedures for high/low absorption).

Summary Table

flowchart TD
    A[Start Test] --> B[Measure Initial Length \(L_0\)]
    B --> C[Heat Tile to \(T_

Chemical Resistance Testing (IS 13630 Part 1-5 & related parts)

Key Testing Procedures:

• Household chemicals, swimming pool salts, citric acid:

  • Contact time: 6 hours (Clause 7.1.2.3)
  • After exposure, clean glazed surface with grease solvent.

• Hydrochloric acid & potassium hydroxide:

  • Contact time: 7 days (Clause 3.3)
  • Procedure similar to above.

• Unglazed tiles chemical resistance (IS 13630 Part 7):

  • Partial immersion for 28 days
  • Visual inspection for surface attack.

Test Report Must Include:

• Tile description
• Number of specimens
• Dimensions: d (diameter), t (thickness), l, L (lengths), and applied force F
• Individual and average modulus of rupture and breaking strength (Clause 7.8)

Modulus of Rupture (MOR) Calculation:

[ \text{MOR} = \frac{3FL}{2bd^2} ] where:

• F = breaking load (N)
• L = span length (mm)
• b = width of specimen (mm)
• d = thickness of specimen (mm)

Summary Table: Contact Time for Different Chemicals

flowchart TD
    A[Start Test] --> B{Type of Chemical?}
    B -->|Household, Salts, Citric Acid| C[6 hrs Contact]
    B -->|HCl, KOH| D[7 days Contact]
    B -->|Unglazed Tiles| E[28 days Partial Immersion]
    C --> F[Clean Surface]
    D --> F
    E --> G[Visual Inspection]
    F --> H[Measure MOR & Breaking Strength]
    G --> H

Resistance to Surface Abrasion - IS 13630 (Parts 1-5 & 12)

Key Test Methods & Specifications:

• Gloss Change (Clause 3.2):

  • Measure 60° specular gloss on float bath side backed by matt black surface.
  • Abrade for 1,000 revolutions → rinse, dry → remeasure gloss.
  • Calculate % gloss loss:
    [ \text{Gloss Loss %} = \frac{\text{Initial Gloss} - \text{Final Gloss}}{\text{Initial Gloss}} \times 100 ]
  • Acceptance: Mean gloss loss = 50 ± 5%.

• Mass Loss (Clause 3.1 & 7.8):

  • Dry specimens at 110 ± 5°C, weigh → abrade for 6,000 revolutions → dry & weigh again.
  • Calculate mass loss per unit area:
    [ \text{Mass Loss} = \frac{\text{Initial Mass} - \text{Final Mass}}{\text{Abraded Area}} \quad (\text{mg/mm}^2) ]
  • Acceptance: Mean mass loss = 0.032 ± 0.002 mg/mm².

• Abrasion Apparatus (Clause 5.1.1):

  • Steel disc (Fe 410-S) diameter = 200 ± 0.2 mm, edge thickness = 10 ± 0.1 mm.
  • Rotation speed = 75 rpm.
  • Pressure adjusted to produce a 32 mm chord groove after 300 revolutions on Austrian Standard Granite.

• Classification of Tiles (Table 1, Clause 8):

Summary Diagram of Abrasion Test Process

Freeze-Thaw and Frost Resistance as per IS 13630 (Part 10) & ISO 10545-12:1995

Key Specifications:

• Test Conditions:

  • Tiles impregnated with water.
  • Subjected to 50 freeze-thaw cycles between +15°C and -15°C.
  • All tile surfaces exposed to freezing.
  • Tiles separated with air space, air circulation ≤ 4 m/s.
  • Freezer temperature uniformity: -15 ± 3°C within 2 hours.

• Temperature Cycle:

  • Each freeze-thaw cycle completed in 6 hours.
  • Temperature in tile monitored by thermocouple.
  • Temperature curve must lie within the zone shown in Fig. 1 (schematic), with ideal cycle as dotted line.

Testing Procedure Summary:

Acceptance Criteria:

• Examine tiles for crazing (fine cracks), ignoring scratches.
• Report:
  • Tile description
  • Number of specimens tested
  • Number showing crazing
  • Description/documentation of crazing (text/photo)

Freeze-Thaw Cycle Temperature Profile (Conceptual):

graph LR
    A[+15°C] --> B[0°C] --> C[-15°C]
    C --> D[0°C] --> A
    style A fill:#a2d4ab,stroke:#333,stroke-width:2px
    style C fill:#7fb3d5,stroke:#333,stroke-width:2px

Notes:

• The freezer must accommodate at least 10 tiles with total area ≥ 0.25 m².
• Air flow ensures uniform temperature and prevents localized freezing.
• Thermocouple placement is critical for accurate temperature measurement.

This test ensures ceramic tiles can withstand freeze-thaw cycles without structural damage or surface crazing, critical for frost-prone

Scratch Hardness Testing as per IS 13630 (Part 13): 2006 involves determining the surface hardness of ceramic tiles on the Mohs scale by scratching with minerals of known hardness.

Key Points & Procedure:

• Test Materials: Minerals with defined Mohs hardness:

• Test Specimens: Minimum 3 tiles tested.

• Test Method:

  • Draw the mineral edge over tile surface with uniform effort.
  • Identify the hardest mineral that produces no more than one scratch.
  • For variable hardness, report the lowest Mohs hardness.

• Test Report Must Include:

  • Tile description.
  • Mohs hardness value for each specimen.

Additional Notes from IS 13630 (Part 12):

• Scratch volume (V) in mm³ and chord length (l) in mm are measured for grooves.
• Use Table 1 (Clause 8.2) for equivalent values of volume vs chord length.

Summary Table Extract (Volume V vs Chord l):

(Refer to full Table 1 for detailed values.)

flowchart TD
    A[Select Mineral] --> B[Scratch Tile Surface]
    B --> C{Scratch Count ≤ 1?}
    C -- Yes --> D[Record Mohs Hardness]
    C -- No --> E[Try Softer Mineral]
    D --> F[Report Hardness]

This method ensures standardized, reproducible scratch hardness values for ceramic tiles per IS 136

Moisture Expansion (IS 13630 Part 1-5 & ISO 10545-10:1995)

• Formula for moisture expansion (mm/m):
  [ \text{Moisture Expansion} = \frac{I}{L} \times 1000 ]
  where:

  • (I) = Change in length (mm)
  • (L) = Original length (mm)

• Report must include:

  • Tile description
  • Moisture expansion value for each specimen

Crazing Resistance (IS 13630 Part 9:2006)

• Test procedure:

  • Examine specimens visually for crazing (fine cracks on glaze)
  • Avoid confusing crazing with scratches or cracks

• Report must include:

  • Tile description
  • Number of specimens tested
  • Number showing crazing
  • Description of crazing (text, drawing, photo)

• Crazing classification (visual inspection)

Frost Resistance (IS 13630 Part 10:2006)

• Classes of resistance:

  Class	Description
  AA	No visible effect
  A	Slight change in appearance
  B	Definite change in appearance
  C	Partial loss of original surface
  D	Total loss of original surface

• Test: 50 freeze-thaw cycles between +15°C and -15°C with water impregnation.

flowchart LR
  A[Start: Tile Specimen] --> B[Measure initial length (L)]
  B --> C[Expose to moisture]
  C --> D[Measure length change (I)]
  D --> E[Calculate Moisture Expansion = (I/L)*1000]
  E --> F[Visual inspection for crazing]
  F --> G{Crazing?}
  G -- Yes --> H[Describe crazing]
  G -- No --> I[No crazing]
  H & I --> J[Report results]

Summary: Use the length change ratio for moisture expansion, visually inspect for crazing, and classify frost resistance per IS 13630 guidelines.

IS 13630 Part 14 (2006) — Impact Resistance by Coefficient of Restitution

Key Specifications:

• Test Units: 5 specimens of unglazed Bla tiles, thickness 8 ± 0.5 mm, water absorption ≤ 0.08.
• Test Setup: Drop height (h₀) = 72.5 ± 1.5 cm.
• Coefficient of Restitution (e):
  [ e = \sqrt{\frac{h_r}{h_0}} ] where:
  • ( h_r ) = rebound height
  • ( h_0 ) = initial drop height

Requirements:

Test Report Must Include:

• Tile description
• Coefficient of restitution for each specimen
• Average coefficient of restitution
• Any visible indentation or cracking

Summary Diagram:

flowchart LR
    A[Drop Tile from height h₀ (72.5 cm)] --> B[Measure rebound height hᵣ]
    B --> C[Calculate e = sqrt(hᵣ / h₀)]
    C --> D{Is e ≥ required value?}
    D -- Yes --> E[Pass]
    D -- No --> F[Fail]

This method (aligned with ISO 10545-5:1996) provides a reliable quantitative measure of tile impact resistance via the coefficient of restitution.

IS 13630 Part 1-5: Basis for Acceptance and Sampling Plans

Key Clauses Summary:

• Clause 9.1.1:
  • If non-conforming units ≤ Ac1 (Acceptance number from Table 1, col 4), lot is acceptable.
• Clause 9.1.5:
  • If non-conforming units ≤ Ac (Acceptance number from Table 1, col 6), lot is acceptable.
• Clause 9.2.1:
  • If average test value (X) of initial samples meets specs, lot is acceptable.
• Clause 9.2.3:
  • If average test value (X2) of combined initial + second samples meets specs, lot is acceptable (see Table 1, col 10).

Sampling Plan Table Extract (Example Format)

Note: Actual values must be taken from IS 13630 Table 1.

Acceptance Criteria Formula:

• Acceptance if:
  [ \text{Non-conforming units} \leq Ac1 \quad \text{(initial sample)}
  ] or
  [ \text{Non-conforming units} \leq Ac \quad \text{(re-sample or combined)}
  ]

• Acceptance if average test value:
  [ X \geq \text{Specified limit} \quad \text{(initial)}
  ] [ X_2 \geq \text{Specified limit} \quad \text{(combined samples)}
  ]

Summary:

• Use Table 1 acceptance numbers (Ac1, Ac, Ac2) for decision.
• Evaluate average values for quality parameters.
• Sampling plans ensure statistical confidence in lot acceptance.

flowchart TD
    Start[Start Sampling] --> SampleInitial[Initial Sample]
    SampleInitial -->