Method of test for length distribution (wet classification of fibre length) of chrysotile asbestos fibre using Turner and Newall classifier

IS 11267: Scope - Key Specifications & Tables

Scope:
IS 11267 covers asbestos cement products, detailing material specifications, testing methods, and quality control.

Key Specifications:

• Material: Asbestos cement composites.
• Testing: Particle size distribution via sieves.
• Units: SI Units as per IS 2-1960 (e.g., length in meters, mass in kg, force in Newtons).

Important Tables:

Calculation Example (Appendix A):

Percentage retained = (Mass retained / Total sample mass) × 100

Rounding Off:

• Values rounded per IS 2-1960.
• Maintain significant digits as per specified values.

This ensures consistent quality and compliance in asbestos cement product manufacturing.

IS 11267 - Apparatus Description: Key Points

Accessories Required (Clause 2.2)

• 63 µm IS Sieve disc: For drying 75 µm fractions.
• Fraction collector or suction arrangement: E.g., Buchner funnel.
• Drying oven: Convection/mechanical draught type or infra-red drying unit.
• Balance: Sensitivity of 0.001 g.

Sieve Discs (Clause 2.1.1)

• IS Sieve designations: 2.36 mm, 1.18 mm, 600 µm, 300 µm, 75 µm.

Sampling & Specimen Preparation (Clause 4.1)

• Draw two specimens of ~15 g.
• Reduce by coning and quartering to 2 ± 0.005 g for testing.

Calculation Table (Clause 1.18)

• Percentage retained and percentage passing 75 µm fractions are calculated to analyze particle size distribution.

Summary Table: Accessories & Specifications

Conceptual Diagram: Sample Preparation Flow

flowchart TD
    A[Sampling (~15 g)] --> B[Coning & Quartering]
    B --> C[Final Specimen (2 ± 0.005 g)]
    C --> D[Sieve Analysis with IS Sieves]
    D --> E[Drying (Oven or IR)]
    E --> F[Weighing (Balance 0.001 g)]

This setup ensures precise particle size analysis per IS 11267 standards.

IS 11267: Sampling Key Points

Sampling Procedure (Clause 3.1)

• Sampling must follow IS 4844-1968 standards.

Test Sample Preparation (Clause 4.1)

• Draw two specimens, each ~15 g.
• Reduce each specimen by coning and quartering to 2 ± 0.005 g for testing.

Sample Test Data & Calculations (Appendix A, Clause 7.1)

Percentage Retained & Passing (Clause 2.36)

Notes:

• Coning and quartering is a standard method to reduce sample size while maintaining representativeness.
• Mass retained on each sieve is used to calculate percentage retained and percentage passing.
• Percentage passing is calculated as:
  [ % \text{Passing} = 100 - % \text{Retained} ]

flowchart TD
    A[Sampling as per IS 4844-1968] --> B[Draw 2 specimens (~15g each)]
    B --> C[Coning & Quartering]
    C --> D[Reduce to 2 ± 0.005 g]
    D --> E[Sieve Analysis]
    E --> F[Calculate % Retained & Passing]

This concise summary covers the essential sampling and sample prep steps per IS 11267.

IS 11267: Preparation of Test Sample - Key Points

1. Sampling (Clause 3.1)

   • Follow IS 4844-1968 for initial sampling.

2. Specimen Preparation (Clause 4.1)

   • Draw two specimens, each ~15 g.
   • Reduce each specimen by coning and quartering to 2 ± 0.005 g.

3. Test Sample Mass

   • Final test sample mass: 2 g.

4. Sieve Analysis (Appendix A, Clause 7.1)

   • Mass retained on sieves and % retained calculated as:

5. Calculations
   • % Retained = (Mass retained on sieve / Total sample mass) × 100
   • % Passing = 100% - Cumulative % Retained

Summary Formula:

[ \text{Mass of sample} = 2 \pm 0.005 \text{ g} ]

[ % \text{Retained} = \frac{\text{Mass retained on sieve}}{\text{Mass of sample}} \times 100 ]

[ % \text{Passing} = 100 - \sum % \text{Retained} ]

flowchart TD
    A[Sampling per IS 4844-1968] --> B[Draw 2 specimens (~15g each)]
    B --> C[Reduce by coning & quartering]
    C --> D[Test sample: 2 ± 0.005 g]
    D --> E[Sieve Analysis]
    E --> F[Calculate % Retained & % Passing]

This ensures representative, accurate test samples for particle size analysis as per IS 11267.

IS 11267: Adjustment and Calibration of Turner and Newall Classifier

Key Specifications & Setup (Clauses 2.1, 5.4, 6.2)

• Classifier vessels: Four rotating plastic vessels, each 127 mm diameter with 98 mm diameter screens arranged vertically by decreasing mesh size.
• Sieve discs: IS sieve sizes: 2.36 mm, 1.18 mm, 600 µm, 300 µm, and 75 µm.
• Base sieve: 75 µm IS sieve, 203.2 mm diameter at the base.
• Water flow rate: Adjust water valve to 80 ml/s or 64 graduation on flowmeter (top of float).
• Water jet position: Water jet must impinge 3 mm from the inner edge of the lower bevelled part of the plastic vessel screen.
• Leak check: Ensure no leaks at sieve disc clamping; if leaks occur, reclamp after repositioning sieve discs.
• Sieve preparation: Wet all sieve discs and test sieve thoroughly before fitting.
• Daily check: Verify tare mass of each sieve disc daily.

Calibration Procedure (Clause 5.4)

1. Open water valve, start motor.
2. Adjust flow to 80 ml/s (64 graduation).
3. Check water jet position on screen (3 mm from inner edge).
4. Inspect for leaks; reclamp sieve discs if needed.
5. Ensure stirrers operate to prevent blinding.

Diagram of Classifier Setup

flowchart TB
    A[Water Control Valve] --> B[Drive Motor]
    B --> C[Rotating Plastic Vessels (4)]
    C --> D[Sieve Discs: 2.36,1.18,600,300,75 µm]
    D --> E[75 µm IS Sieve (203.2 mm)]
    C -. Water Jet (3 mm from inner edge) .-> D
    C --> F[Stirrers to prevent blinding]

This ensures accurate particle size separation per IS 11267.

IS 11267: Test Procedure Key Formulas & Tables

1. Sample Preparation & Sieve Analysis (Clause 7.1, Appendix A)

• Sample mass: Typically 2 g for Group 4 (Q.S. classification).
• Sieve sizes: 2.36 mm, 1.18 mm, 600 µm, 300 µm, 75 µm.
• Mass retained on each sieve is recorded.

2. Calculation of Percentage Retained (Clause 1.18, 2.36)

[ \text{Percentage retained} = \frac{\text{Mass retained on sieve}}{\text{Total sample mass}} \times 100 ]

3. Rounding Off (Clause 0.6)

• Follow IS 2-1960 for rounding test results.
• Retain significant figures as per specified standard values.

Summary:

• Test involves weighing sample retained on standard IS sieves.
• Calculate % retained and % passing for particle size distribution.
• Use IS 2-1960 for rounding off results.

flowchart TD
    A[Start: Sample Preparation] --> B[Weigh total sample (2g)]
    B --> C[Pass through IS Sieves]
    C --> D[Record mass retained on each sieve]
    D --> E[Calculate % retained = (mass retained/2g)*100]
    E --> F[Calculate %

IS 11267: Reporting of Results – Key Formulas & Tables

1. Percentage Retained & Passing (Clause 1.18, 2.36, 7.1)

• Percentage Retained on a Sieve:

[ \text{Percentage Retained} = \frac{\text{Mass retained on sieve}}{\text{Total mass of sample}} \times 100 ]

• Percentage Passing a Sieve:

[ \text{Percentage Passing} = 100 - \sum \text{Percentage Retained on all larger sieves} ]

2. Sample Calculation Example (Clause 7.1, Appendix A)

• Total sample mass = 2 g
• Calculate % retained for each sieve:

[ % \text{Retained} = \frac{\text{Mass retained}}{2} \times 100 ]

3. Reporting Guidelines (Clause 7)

• Report mass retained and percentage retained on each sieve.
• Report percentage passing the 75 µm sieve as a key fineness indicator.
• Ensure samples are dried and cooled for at least 15 minutes before weighing (Clause 6.9).

4. Units (SI Units per IS 11267)

flowchart TD
    A[Sample Preparation] --> B[Sieving on Standard IS Sieves]
    B --> C[Weigh Mass Retained on Each Sieve]
    C --> D[Calculate % Retained]
    D --> E[Calculate % Passing]
    E --> F[Report Results]

Summary: Use mass retained data to calculate % retained and % passing. Report these clearly, following drying and cooling protocols for accuracy. The 75

IS 11267 - Accuracy and Reproducibility Key Points

• Water Temperature for Testing (Clause 8.3):
  Maintain water temperature at 27 ± 2°C to ensure better accuracy and reproducibility of test results.

• Rounding Off Results (Clause 0.6):
  Final test values must be rounded according to IS 2-1960.

  • Retain the same number of significant figures as specified in the standard.
  • Ensures consistency and comparability of results.

• General Precautions (Clause 8.1):
  Follow the precautions in Clauses 8.2 to 8.6 for desired accuracy (details not provided here).

Rounding Off (IS 2-1960) - Summary

Recommended Test Environment

Conceptual Flow for Accuracy & Reproducibility

flowchart TD
    A[Start Test] --> B[Check Water Temp: 27±2°C]
    B --> C[Follow Precautions (Clauses 8.2-8.6)]
    C --> D[Conduct Test]
    D --> E[Calculate Result]
    E --> F[Round Off Result (IS 2-1960)]
    F --> G[Report Final Value]

Summary: Maintaining controlled temperature and following IS rounding rules are critical for reproducible and accurate test results per IS 11267.

IS 11267: Limitations and Applicability - Key Points

1. Applicability:

• IS 11267 covers asbestos cement products.
• It specifies test methods, material grading, and quality control.
• Applicable for manufacturing and testing of asbestos cement sheets and related products.

2. Limitations:

• Material grading depends on particle size distribution tested via IS sieves.
• Percentage retained and passing on various sieve sizes (2.36 mm to 75 µm) are critical for compliance.
• Final test results must be rounded off as per IS 2-1960 rules for significant figures.

Key Table: Particle Size Distribution (Example from Clause 2.36)

Important Formula:

Rounding off test results (IS 2-1960):

• Round off the final value to the same number of decimal places as specified.
• Example: If specified value is 13.5, round test result to one decimal place.

Units (SI system as per IS 11267):

flowchart TD
    A[Raw Material] --> B[Sieving as per IS 11267]
    B --> C{Particle Size Distribution}
    C -->|Meets limits| D[Proceed to Manufacturing]
    C -->|Does not meet| E[Reject or Reprocess]
    D --> F[Final Product Testing]
    F --> G{Results Rounded as per IS 2-1960}
    G --> H[Compliance Check]

Summary: IS 11267 limits material grading by sieve analysis and