Specification for fibre insulation boards

IS 3348: Scope - Key Specifications & Tables

1. Scope Overview (Clause 2.0)

• Defines types of fibre insulation boards covered: ordinary, flame-retardant, bitumen-bonded.
• Applicable for thermal insulation in buildings.

2. Dimensions & Tolerances (Clause 3.1, Table 1)

3. Mechanical Properties (Clause 4.2, Table 2)

4. **Sampling & Test Unit Sizes (Clause 8.1, Table

IS 3348 - Definitions & Key Specifications

1. Definitions (Clause 2.0)

• Standard definitions apply for fibre insulation boards (ordinary, flame-retardant) and bitumen-bonded fibre insulation boards.
• Boards are rectangular with square edges unless specified otherwise.

2. Dimensions & Tolerances (Clause 3.1, Table 1)

3. Mechanical Properties (Clause 4.2, Table 2)

4. Thickness Determination (Appendix A, Clause 8.2)

• Mean thickness is measured per Appendix A method.
• Ensures compliance with tolerances in Table 1.

Summary:

• Thickness tolerance: ±0.75 mm (fibre boards), ±0.50 mm (bitumen-bonded).
• Dimensional tolerance: ±3 mm for ≤120 cm, ±6 mm for >120 cm.
• Breaking load and modulus of rupture increase

IS 3348: Dimensions and Tolerances for Fibre Insulation Boards

1. Dimensions (Clause 3.1)

• Length (mm): 3600, 3000, 2700, 2400, 2100, 1800, 1500, 1200, 1000, 900, 600, 450, 300
• Width (mm): 1800, 1500, 1200, 1000, 900, 600, 450, 300
• Boards are rectangular with square edges (unless specified otherwise).

2. Tolerances on Nominal Sizes (Clause 3.3)

3. Thickness Tolerances by Type (Table 1)

4. Mean Thickness Determination

IS 3348: Key Requirements Summary

1. Dimensions and Tolerances (Clause 3.1, Table 1)

2. Minimum Mean Breaking Load (Clause 4.2, Table 2)

IS 3348: Flame-Retardant Treatment for Fibre Insulation Boards

Key Specifications:

• Flame-Retardant Treated Board: Insulation board treated to reduce flame spread (Clause 2.3).
• Maximum Char Area: When tested by Appendix E (surface spread of flame), the average maximum char area ≤ 75 cm² (Clause 5.1).
• Treated Face Identification: For boards treated on one face only, the treated face must be clearly marked (Clause 5.1.1).
• Manufacturer's Certificate must include:
  • Treated face(s) identification
  • Board size and thickness (Clause 5.1.1 d, e)

Important Notes:

• Flame-retardant treatment may require special primers/sealers before decoration.
• Such coatings might reduce flame-retardant effectiveness.
• Consult manufacturers for effects on sound absorption or other physical properties.

Flame Spread Test (Appendix E Summary):

• Boards are subjected to a flame source.
• Measure charred area after exposure.
• Acceptable char area ≤ 75 cm².

Summary Table: Flame-Retardant Fibre Insulation Board

flowchart LR
    A[Flame-Retardant Treatment] --> B[Test as per Appendix E]
    B --> C{Char Area ≤ 75 cm²?}
    C -->|Yes| D[Pass]
    C -->|No| E[Fail]
    D --> F[Mark Treated Face]
    F --> G[Manufacturer's Certificate]

This ensures flame-retardant fibre boards meet safety and quality standards per IS 3348.

Manufacturer's Certificate - IS 3348 Key Points

• Clause 6.1: Manufacturer's certificate confirms board conformity to IS 3348.
• Certificate can be replaced by regular test records if shared with purchaser.
• Certificate not needed if board has ISI Certification Mark (Clause 7.1.1).

Key Tables from IS 3348

Testing & Sampling (Clause 1.1 & 3.1)

• Test length & width accuracy: ±1.5 mm.
• Weight accuracy: ±0.5%.
• Three specimens (30x30 cm) from three boards tested for strength.

Summary: Manufacturer’s certificate ensures compliance; alternatively, periodic test records or ISI mark suffice. Dimensions, tolerances, and strength parameters are strictly defined for quality assurance.

IS 3348 - Marking: Key Points & Specifications

1. Marking & Cutting of Test Units (Clauses 8.2, 9.1.2):

   • Test pieces must be marked and cut as per Fig. 1A, 1B, and 1C depending on the width of the test unit.
   • These figures provide the recommended layout for obtaining test specimens for various tests (Appendices A to E).

2. Dimensions of Test Units (Table 4):

   • Specifies standard dimensions for test units to ensure uniformity in testing.
   • Exact dimensions depend on the test type and product form.

3. BIS Certification Marking (Clause 7.2):

   • Products may carry the BIS Standard Mark indicating compliance with IS 3348.

4. Reporting (Clause 5.2):

   • Report the average area of char and duration of flaming by averaging results from three specimens.

Summary Table for Marking & Cutting

Diagram Concept (Simplified)

flowchart LR
    A[Test Unit] --> B{Width?}
    B -->|Narrow| C[Mark & Cut as per Fig. 1A]
    B -->|Medium| D[Mark & Cut as per Fig. 1B]
    B -->|Wide| E[Mark & Cut as per Fig. 1C]
    C & D & E --> F[Obtain Test Pieces]
    F --> G[Conduct Tests (Appendices A-E)]

Note: For exact dimensions and marking details, refer to Figures 1A, 1B, 1C and Table 4 in IS 3348.

IS 3348 - Sampling for Particle Boards

Sampling Procedure (Clause 8.1)

• Minimum sample: At least 6 boards randomly selected per lot.
• Alternative: Follow sampling in IS 3129-1965 Clause 7.
• From each board, cut a length based on board width (see Table below).
• From this length, cut a rectangular test unit avoiding edges by 15 cm minimum.

Table 8.1: Sampling Dimensions

Notes:

• Test units are conditioned, weighed, and measured for density before further cutting.
• Number of units can be increased by agreement.
• Test units form the sample for strength and property tests.

Appendix A (Clause 8.2)

• Thickness and density determination methods apply to these units before testing.

flowchart LR
    A[Select 6 Boards Randomly] --> B[Cut Length per Table 8.1]
    B --> C[Cut Test Unit (Avoid 15 cm edges)]
    C --> D[Condition & Measure Density]
    D --> E[Perform Strength & Property Tests]

This ensures representative sampling and reliable test results per IS 3348.

IS 3348: Key Formulas, Tables & Specifications for Tests

1. Test Piece Dimensions (Table 4)

• Test units are cut as per Fig. 1A, 1B, 1C.
• Example sizes:
  • Thermal Conductivity (TC): 30 x 30 cm (4 pieces per test unit)
  • Transverse Strength: 20 x 10 cm (36 pieces total)
  • Width for boards ≥18 mm thick: 5 cm (load corrected to 10 cm width)

2. Transverse Strength Test (Appendix B)

• Support: Two parallel rollers (diameter 18-25 mm), spaced 15 cm apart.

• Load applied at mid-span by a rounded bar (radius 9-12 cm).

• Load application duration: 0.5 to 4 minutes to reach breaking load.

• Load correction formula for width:

  [ P_{10cm} = P_{5cm} \times 2 ]

3. Thermal Conductivity Test (Clause 9.4 & Appendix D)

• Prepare 30 x 30 cm specimens marked 'TC'.
• Three specimens from three different boards are tested.
• Test setup includes brass tubing, plates, and steel rod supports (see Fig. 3).

4. Surface Spread of Flame Test (Fig. 3)

• Uses brass tubing (16 mm OD), brass plates (0.8 mm thick), steel rods (3 mm diameter).
• Specimens prepared as per dimensions in Fig. 3.

Summary Table:

flow

IS 3348: Method of Test for Thermal Conductivity — Key Points

Formula for Thermal Conductivity (Clause 2.2)

[ K = \frac{q \times L}{A \times (T_1 - T_2)} ]

• K = Thermal conductivity (kcal·cm/cm²·h·°C)
• q = Heat flow rate (kcal/h)
• L = Thickness of specimen (cm)
• A = Area normal to heat flow (cm²)
• T₁ = Temperature of hot surface (°C)
• T₂ = Temperature of cold surface (°C)

Test Specimen (Clause 9.4)

• Size: 30 cm × 30 cm
• Prepared from each of four test units
• Marked 'TC' as per Fig. 1A, 1B, 1C

Method Summary (Appendix D)

• Two methods allowed:
  • D-2: Calculation method (heat flow, temperature difference)
  • D-3: Guarded Hot-Plate Method using a single slab

Thermal Conductivity Limit (Clause 4.4)

• Maximum allowed: 5.6 kcal·cm/m²·h·°C or 0.65 mW/cm·°C

Notes:

• Ensure uniform temperature difference and steady-state heat flow.
• Area A is measured center-to-center between separations on the specimen.

flowchart LR
    A[Heat Source] -->|Heat Flow q| B[Specimen (thickness L)]
    B -->|Heat Flow q| C[Heat Sink]
    B --> D[Measure T1 (hot surface)]
    B --> E[Measure T2 (cold surface)]
    F[Calculate K] -->|K = qL / A(T1-T2)| G[Thermal Conductivity]

This concise summary covers the essential formulas, specimen specs, and limits per IS 3348 for thermal conductivity testing.

IS 3348: Method of Test for Surface Spread of Flame (Appendix E)

Key Specifications:

• Specimen size: 30 cm × 30 cm
• Number of specimens: Minimum 3 from 3 different boards
• Maximum char area allowed: 75 cm² (for flame-retardant treated fibre insulation board)

Test Procedure Highlights:

• Specimens are exposed to flame following the setup in Appendix E.
• The charred area after burning is measured.
• Average char area from 3 specimens is calculated.

Equipment Details:

• Brass tubing: 16 mm outer diameter
• Brass plate thickness: 0-8 mm
• Steel rod diameter: 3 mm (welded to upright frame)
• Support: Cup support as per Fig. 3

Acceptance Criteria:

[ \text{Average maximum char area} \leq 75 \text{ cm}^2 ]

Summary Table:

flowchart LR
    A[Prepare 3 specimens (30x30 cm)] --> B[Mount on test rig (Appendix E)]
    B --> C[Expose to flame]
    C --> D[Measure charred area]
    D --> E[Calculate average char area]
    E --> F{Average char area ≤ 75 cm²?}
    F -- Yes --> G[Pass]
    F -- No --> H[Fail]

This test ensures flame-retardant fibre boards limit flame spread effectively per IS 3348.

IS 3348: Method of Test for Sound Absorption (Clause 4.5 & 9.5)

• Test Method: Standing wave method as per Appendix C of IS 3308* (under preparation).
• Test Specimen Size: 30 cm × 30 cm (same as thermal conductivity test pieces).
• Frequency vs Minimum Absorption Coefficient:

• Notes:
  • Until IS 3308 is published, testing details are subject to agreement between purchaser and supplier.
  • Sound absorption coefficient α is dimensionless, ranging from 0 (total reflection) to 1 (total absorption).

Summary Diagram of Test Setup (Standing Wave Method)

flowchart LR
    A[Sound Source] --> B[Test Specimen (30x30 cm)]
    B --> C[Microphone Probe]
    C --> D[Frequency Analyzer]
    D --> E[Calculate Absorption Coefficient α]

Key:

• Use standing wave method to measure α at specified frequencies.
• Ensure specimen size and test conditions per IS 3308 Appendix C.
• Compare results against minimum α values in the table for compliance.