Glossary of terms relating to asbestos

IS 11707: Scope Overview

IS 11707 covers specifications for asbestos cement products, harmonizing with international standards while addressing Indian field practices.

Key Points on Scope:

• Applies to asbestos cement products used in construction.
• Ensures quality, durability, and safety in manufacturing and application.
• Aligns with international standards and Indian practices.
• Includes definitions and terminology related to asbestos (refer IS Glossary).

Typical Specifications (Generalized):

Important Formulas:

• Water-cement ratio (w/c):
  [ w/c = \frac{\text{Weight of water}}{\text{Weight of cement}} ]

• Flexural strength (modulus of rupture):
  [ \sigma = \frac{3PL}{2bd^2} ] Where:

  • ( P ) = Load at fracture
  • ( L ) = Span length
  • ( b ) = Width of specimen
  • ( d ) = Depth of specimen

flowchart TD
    A[IS 11707 Scope] --> B[Asbestos Cement Products]
    A --> C[International Coordination]
    A --> D[Indian Field Practices]
    B --> E[Material Composition]
    B --> F[Mechanical Properties]
    B --> G[Durability & Safety]

For detailed product-specific tables and test methods, refer to the full IS 11707 document.

IS 11707 primarily provides definitions and terminology related to asbestos rather than formulas or tables.

Key Points from Clause 1.1 and Glossary:

• Asbestos: Naturally occurring fibrous silicate minerals.
• Chrysotile: White asbestos, serpentine group.
• Amosite: Brown asbestos, amphibole group.
• Crocidolite: Blue asbestos, amphibole group.
• Asbestos Cement: Composite material with asbestos fibers and cement.
• Asbestos Fiber: Thin, elongated mineral particle with high tensile strength and resistance.

Usage:

• These definitions standardize communication in design, testing, and safety related to asbestos-containing materials.
• No structural formulas or tables are provided here; the focus is on clear terminology.

If you need design or safety parameters involving asbestos cement products, please specify, and I can provide relevant IS codes and formulas.

IS 11707 - Asbestos Mineral Varieties: Key Formulas & Specifications

1. Asbestos Mineral Definition (Clause 2.1)

• Acicular silicate minerals with silicon-oxygen tetrahedral structure.

2. Varieties & Chemical Formulas:

Note: Colour variations are indicative; actual colours may vary within each variety.

3. Structural Note:

• All formulas are based on silicon-oxygen tetrahedra (SiO₄) units linked in chains, characteristic of asbestos minerals.

Summary Table (Simplified):

If you want, I can provide a mermaid diagram illustrating the silicon-oxygen tetrahedra chain structure typical of asbestos minerals.

IS 11707 - Cross-Fibre: Key Points & Definitions

• Cross-Fibre (Clause 2.5): Asbestos fibres oriented perpendicular (at right angles) to the plane of veins or seams in the material.

• Fibre Characteristics (Clause 2.10):

  • Length to transverse dimension ratio ≥ 10:1
  • Max cross-sectional area: 5.06 × 10⁻² mm²
  • Max transverse dimension: 0.254 mm (diameter if circular)

• Fibre Spicules (Clause 2.13):

  • Rod-like asbestos pieces ≤ 10 mm length, ≤ 1 mm transverse dimension
  • Fibres in parallel, natural orientation giving rigidity

• Fibre Cohesion (Clause 2.12):

  • Resistance to fibre separation; affects ease of fibre opening

Summary Table: Fibre Dimensions

Conceptual Diagram of Cross-Fibre Orientation

graph LR
    A[Vein/Seam Plane] -->|Fibres aligned parallel| B(Fibres in plane)
    A -->|Cross-Fibre| C(Fibres at 90° to plane)

Note: Cross-fibre orientation affects mechanical properties and fibre cohesion in asbestos-containing materials, critical for processing and safety considerations.

IS 11707 - Crude Asbestos (Clause 2.6)

• Definition: Crude asbestos is asbestos extracted manually by hammer impact (hand cobbed), consisting of cross-vein asbestos in its natural, unfiberized state.

• Key Characteristics:

  • Not yet processed or fiberized.
  • Contains natural impurities and mineral matrix.
  • Used as raw material for further processing.

• Specifications & Quality Checks (General Practice):

  • Moisture Content: Should be minimal to avoid degradation.
  • Fiber Content: Low fiber separation; fibers are embedded in matrix.
  • Impurities: Presence of rock, soil, and other minerals.
  • Physical Appearance: Lumpy, irregular chunks.

• No direct formulas or tables are provided in IS 11707 for crude asbestos, as it is a raw material stage.

Additional Notes:

• Crude asbestos is the starting point before fiberization and grading.
• Subsequent IS codes (e.g., IS 6994 for asbestos fiber) cover fiber quality and testing.

flowchart LR
    A[Asbestos Ore] --> B[Hand Cobbed (Crude Asbestos)]
    B --> C[Fiberization Process]
    C --> D[Graded Asbestos Fiber]

For detailed testing and grading, refer to related IS standards on asbestos fibers.

IS 11707 - Key Specifications for Crudy (Crude Asbestos Quality)

• Crudy (Clause 2.8):

  • Processed asbestos with low specific surface area and low fiberization.
  • Contains a significant portion of unfiberized agglomerates.
  • Term derived from "crude asbestos."

• Crudiness (Clause 2.7):

  • Measures how close asbestos fibers are to their natural crude state.

• Crudy Bundle (Clause 2.9):

  • Heavy fiber assemblage with a transverse dimension ≥ 8 mm.
  • Fibers are parallel-packed, may be partially crushed.

• Crude Asbestos (Clause 2.6):

  • Asbestos in natural, unfiberized form, obtained by manual hammer impact (hand cobbed).

Important Notes:

• Crudy asbestos has lower fiber quality and is less suitable for applications requiring fine fiberization.
• The degree of crudiness affects processing and end-use properties.

Visual Summary:

flowchart LR
    A[Crude Asbestos] --> B[Crudy (Processed, Low Fiberization)]
    B --> C[Crudy Bundle (≥8mm, parallel fibers)]
    A --> D[Hand cobbed, natural form]
    B --> E[Contains unfiberized agglomerates]

This clarifies the gradation from crude to processed asbestos as per IS 11707.

IS 11707 - Fibre Specifications & Definitions

• Fibre (Clause 2.10):

  • Minimum length to max transverse dimension ratio: ≥ 10:1
  • Max cross-sectional area: 5.06 × 10⁻² mm²
  • Corresponding max diameter (circular cross-section): 0.254 mm
  • Max transverse dimension: 0.254 mm

• Fibre Spicules (Clause 2.13):

  • Rod-like asbestos fibre pieces
  • Length: ≤ 10 mm
  • Transverse dimension: ≤ 1 mm
  • Close-packed parallel orientation with natural relative positions imparting rigidity

• Fibre Cohesion (Clause 2.12):

  • Resistance when fibres separate from each other
  • Ranges from low to high; affects ease of fibre opening

• Fibre Adhesion (Clause 2.11):

  • Resistance when fibres separate from seam wall (host rock)
  • Ranges from low to high

Summary Table:

This ensures fibres meet dimensional and mechanical criteria for asbestos material quality control.

IS 11707: Fibre Adhesion Key Points

• Fibre Adhesion (Clause 2.11):
  Resistance encountered when fibres separate from the seam wall (host rock). Adhesion varies from low to high, influencing fibre extraction and processing.

• Fibre Cohesion (Clause 2.12):
  Resistance when fibres separate from each other, affecting how easily fibres open or separate.

• Fibre Dimensions (Clause 2.10):

  • Length to max transverse dimension ratio ≥ 10:1
  • Max cross-sectional area = 5.06 × 10⁻² mm²
  • Max transverse dimension = 0.254 mm diameter (circular cross-section)

• Fibre Spicules (Clause 2.13):
  Rod-like fibre bundles ≤ 10 mm length and 1 mm transverse dimension, with natural fibre alignment imparting rigidity.

Practical Notes:

• Adhesion and cohesion affect fibre extraction efficiency and quality.
• No explicit formula is given in IS 11707 for adhesion; it is characterized qualitatively (low to high).
• Testing methods usually involve mechanical separation tests or microscopic analysis.

Summary Table:

flowchart LR
    A[Fibre Adhesion] --> B[Resistance to separation from host rock]
    A --> C[Varies Low to High]
    D[Fibre Cohesion] --> E[Resistance to fibre-fibre separation]
    D --> F[Varies Low to High]
    G[Fibre] --> H[Length:Width ≥ 10:1]
    G --> I[Max Diameter: 0.254 mm]
    J[Fibre Sp

IS 11707 - Fibre Cohesion Key Points

• Definition (Clause 2.12):
  Fibre cohesion is the resistance encountered when fibres separate from each other. It varies from low to high, indicating how easily fibres can be opened or separated.

• Related Terms:

  • Fibre Adhesion (Clause 2.11): Resistance to fibre separation from the seam wall (host rock).
  • Soft Fibres (Clause 2.29): High flexibility and low fibre cohesion.

• Fibre Dimensions (Clause 2.10):

  • Length to transverse dimension ratio ≥ 10:1
  • Max cross-sectional area = 5.06 × 10⁻² mm²
  • Max transverse dimension = 0.254 mm

Practical Notes on Fibre Cohesion

• High cohesion fibres require more energy to separate, affecting processing and handling in mining or material extraction.
• Low cohesion fibres (soft fibres) are easier to open but may release more airborne fibres, impacting safety.

No explicit formula in IS 11707, but cohesion relates to fibre separation force (F) and contact area (A):

[ \text{Fibre Cohesion} \propto \frac{F}{A} ]

Where:

• (F) = force to separate fibres
• (A) = contact area between fibres

flowchart LR
    Fibre_Cohesion["Fibre Cohesion"] -->|High| Difficult_to_Separate
    Fibre_Cohesion -->|Low| Easy_to_Separate
    Fibre_Properties --> Fibre_Cohesion
    Fibre_Properties["Fibre Properties"] --> Fibre_Dimensions
    Fibre_Dimensions --> Length_to_Diameter["Length:Diameter ≥ 10:1"]
    Fibre_Dimensions --> Max_Transverse["Max Transverse Dimension = 0.254 mm"]

For detailed testing, refer to IS 11707 test methods for fibre separation resistance.

IS 11707 Key Specifications for Fibre Spicules

• Fibre Spicules (Clause 2.13):

  • Rod-like asbestos fibre pieces
  • Length ≤ 10 mm
  • Transverse dimension ≤ 1 mm
  • Fibres in close-packed parallel orientation
  • Natural relative positions undisturbed to impart rigidity

• Fibre (Clause 2.10):

  • Length to transverse dimension ratio ≥ 10:1
  • Max cross-sectional area = 5.06 × 10⁻² mm²
  • Max transverse dimension = 0.254 mm

• Non-Fibrous Spicule (Clause 2.24):

  • Acicular particles ≥ 0.1 mm transverse dimension
  • Composed of non-fibrous/semi-fibrous minerals (e.g., picrolite)

• Pencil (Clause 2.26):

  • Rod-like asbestos fibre assemblage
  • Uniform diameter, fibrizable
  • Dimensions > fibre spicule size (longitudinal >10 mm or transverse >1 mm)

Summary Table

flowchart LR
    Fibre -->|Length:Transverse ≥10:1| FibreSpicule
    FibreSpicule -->|Length ≤10mm & Transverse ≤1mm| Pencil
    NonFibrousSpicule -.-> FibreSpicule

This clarifies fibre spicule dimensional limits and their relation to fibres and pencils per IS 11707.

IS 11707: Key Specifications for Floats

• Definition (Clause 2.16):
  Floats are the air-floated fibrous fraction recovered from the air filtration system of an asbestos mill.

• Fibre Characteristics (Clause 2.10):

  • Minimum length to diameter ratio: 10:1
  • Max cross-sectional area: 5.06 × 10⁻² mm²
  • Max transverse dimension: 0.254 mm

• Loftiness (Clause 2.20):

  • Loftiness = Measure of loose specific volume of asbestos fibre
  • Inversely proportional to dry bulk density

Practical Notes:

Conceptual Relation:

graph LR
    A[Dry Bulk Density] -- Inverse --> B[Loftiness]
    B -- High loftiness --> C[Better insulation & lightness]

Floats are characterized by their fibrous nature and loftiness, critical for their performance in asbestos products.

IS 11707 Key Specifications for Mass Fibre

• Fibre Definition (Clause 2.10):

  • Length to max transverse dimension ratio ≥ 10:1
  • Max cross-sectional area = 5.06 × 10⁻² mm²
  • Max transverse dimension = 0.254 mm (circular diameter)

• Mass Fibre (Clause 2.21):

  • Asbestos fibres randomly arranged in host rock
  • Do not occur as seams or veins

• Fibre Spicules (Clause 2.13):

  • Rod-like bundles of fibres ≤ 10 mm length, ≤ 1 mm transverse
  • Parallel orientation, impart rigidity

• Loftiness (Clause 2.20):

  • Loftiness ∝ 1 / Dry Bulk Density
  • Measures loose specific volume of fibres

Summary Table

Visual Concept: Fibre Dimensions

graph LR
A[Fibre Length] -->|≥ 10x| B[Max Transverse Dimension (0.254 mm)]
B --> C[Cross-sectional Area ≤ 5.06×10⁻² mm²]

This ensures fibres have a high aspect ratio and controlled size for material properties.

IS 11707 - Milled Asbestos: Key Points

• Definition (Clause 2.22):
  Milled asbestos is the primary consumer derivative of asbestos ore, processed by beating and washing. It may or may not be graded by sieving. Also called raw asbestos.

• Processing:
  Further treatment involves opening fibers free from unfiberized agglomerates for specific product manufacture.

Specifications & Properties (General Industry Practice)

Usage Notes:

• Milled asbestos is the raw input for manufacturing asbestos cement, friction materials, and textiles.
• Quality depends on fiber opening and removal of agglomerates.
• No direct formula in IS 11707, but milling aims to maximize fiber separation and purity.

flowchart LR
    A[Asbestos Ore] --> B[Milling (Beating & Washing)]
    B --> C[Milled Asbestos (Raw)]
    C --> D{Further Processing?}
    D -->|Yes| E[Opened Fibers (Free from Agglomerates)]
    D -->|No| F[Used as Raw Milled Asbestos]

For detailed mechanical/physical properties, refer to product-specific standards or testing protocols.

IS 11707 - Milling of Asbestos: Key Points & Specifications

• Milling Definition (Clause 2.23):
  Mechanical treatment of asbestos ore by beating and washing, producing a primary consumer derivative called milled asbestos.

• Milled Asbestos (Clause 2.22):
  Raw asbestos obtained after milling, may be further processed to separate fibers free from agglomerates for specific end uses.

• Fibre Specifications (Clause 2.10):

  • Length to width ratio ≥ 10:1
  • Max cross-sectional area = 5.06 × 10⁻² mm²
  • Max transverse dimension = 0.254 mm (diameter for circular cross-section)

Important Notes:

• Milling is primarily a physical process (beating + washing).
• No direct formulas are provided in IS 11707 for milling operations.
• Quality control focuses on fiber dimensions and cleanliness after milling.

Summary Table for Fibre Dimensions

flowchart LR
    A[Asbestos Ore] --> B[Beating]
    B --> C[Washing]
    C --> D[Milled Asbestos (Raw)]
    D --> E[Further Opening]
    E --> F[Separated Fibres]

This flow shows the milling process from raw ore to usable fibres.

IS 11707 Key Points on Silky Fibres

• Silky fibres (Clause 2.27) are asbestos fibres characterized by:

  • Low fibre cohesion
  • Soft feeling to touch
  • High flexibility (similar to "Soft" fibres, Clause 2.29)

• Fibre dimensions (Clause 2.10):

  • Length to diameter ratio ≥ 10:1
  • Max cross-sectional area: 5.06 × 10⁻² mm²
  • Max transverse dimension: 0.254 mm diameter (circular cross-section)

• Fibre spicules (Clause 2.13):

  • Rod-like bundles of fibres ≤ 10 mm length and 1 mm transverse dimension
  • Parallel orientation maintaining natural fibre positions

Summary Table: Fibre Characteristics

flowchart LR
    Fibre[Asbestos Fibre]
    Fibre -->|Length/diameter ≥ 10| Dimension
    Dimension -->|Max dia 0.254 mm| CrossSection
    Fibre --> Silky[Silky Fibre]
    Silky -->|Low cohesion| Property1
    Silky -->|Soft feel| Property2
    Silky -->|High flexibility| Property3

This defines silky fibres as flexible, soft, low-cohesion asbestos fibres within specified dimensional limits.