Recommendations for control of emission of asbestos dust in premises manufacturing products containing asbestos, Part 3: Non-cement asbestos products other than friction materials
1987 Edition

Overview of Scope and Principal Specifications for Non-Cement Asbestos Products

• Pertains to the management, cleaning, and disposal of asbestos products excluding cement-based types.
• Adheres to disposal protocols outlined in IS 11768-1986.
• Focus on safeguarding workers and environmental health during asbestos fibre handling.
• Harmonizes with both Indian and global standards.

Core Specifications:

SI Derived Unit Definitions:

Sample Disposal Workflow (per IS 11768):

flowchart TD
    CollectWaste[Collection of Asbestos Waste] --> PackageWaste[Secure Packaging]
    PackageWaste --> TransportWaste[Transport to Disposal Facility]
    TransportWaste --> DisposalSite[Disposal Following IS 11768]
    DisposalSite --> Monitoring[Environmental Monitoring]

Refer to IS 11768 and relevant IS 11770 sections for comprehensive disposal formulas and tables.

Applicability Clause (3.1) for Manufacturing Premises

This standard governs manufacturing operations for:

• Asbestos textiles
• Compressed asbestos fibre jointings, including beater addition jointings
• Asbestos millboards

Associated Standards Addressing Safe Use and Emission Controls

• IS 11769 (Part 3)-1986: Safety guidelines for non-cement asbestos products excluding friction materials
• IS 11769 (Part 2)-1986: Safety guidelines for friction materials containing asbestos
• IS 11770 (Part 2)-1986: Emission control recommendations for friction material production

Summary Table of Product-Specific Standards:

Important Considerations:

• Emphasis on dust emission management and worker protection.
• Adherence to IS 11769 parts for handling and safety measures.
• Implementation of appropriate ventilation and dust extraction per IS 11770 Part 2.

flowchart LR
    Factory[Manufacturing Facility] --> Textiles[Asbestos Textiles]
    Factory --> FibreJointings[Compressed Fibre Jointings]
    Factory --> Millboards[Asbestos Millboards]
    Textiles & FibreJointings & Millboards --> ControlStandard[Apply IS 11770 Part 3]
    FrictionMaterials[For Friction Materials] --> ControlStandard2[Apply IS 11769 Part 2 & IS 11770 Part 2]

Consult full IS 11770 Part 3 and related parts for precise emission limits and safety protocols.

General Manufacturing Requirements Overview

Scope (Clause 3.1): Applies to facilities producing:

• Asbestos textiles
• Compressed asbestos fibre jointings (including beater addition jointings)
• Asbestos millboards

Principal Specifications and Recommendations (Clause 10.1)

• Waste Management: Disposal of asbestos waste must comply with IS 11768-1986.
• Covers procedures for cleaning premises and equipment handling asbestos.
• Ensures safe disposal to protect health and environment.

Units of Measurement (SI System):

Additional Notes

• Emphasizes safe handling and environmental protection during asbestos manufacturing.
• Refer to IS 11768 for detailed waste disposal practices.
• Consistent use of SI units is mandatory.

flowchart TD
    AsbestosManufacturing --> GeneralReqs[General Requirements]
    GeneralReqs --> SafeHandling[Safe Material Handling]
    GeneralReqs --> WasteDisposal[Waste Disposal per IS 11768]
    WasteDisposal --> PremisesCleaning[Cleaning Processes]
    WasteDisposal --> DisposalMethods[Approved Disposal Techniques]

Refer to IS 11768-1986 and related IS 11770 parts for exact formulas and procedural tables.

Key Points on Fibre Preparation and Handling

• Fibres must be fed mechanically to ensure consistency and prevent contamination (Clauses 5.1, 6.1, 7.1).
• Discharge of fibres should occur within enclosed systems maintained under negative pressure to avoid dust leakage and fibre loss (Clause 6.1.4).
• Storage chambers must control environmental parameters to preserve fibre quality.

Technical Specifications

• Negative pressure enclosures help maintain dust containment and fibre cleanliness.
• Feeding rates should be uniform to ensure quality and machine efficiency.

Typical Fibre Handling Parameters

Process Flow Diagram

flowchart LR
    FibreSource -->|Mechanical Feeding| FeedingMachine
    FeedingMachine -->|Negative Pressure| StorageChamber
    StorageChamber --> ProcessingMachine

This approach ensures a clean, consistent fibre supply with minimal contamination risk.

Dust Control Strategies in Manufacturing Processes

• Apply dust suppressants during finishing operations such as inspection, calendering, and drying to reduce airborne fibres (Clauses 5.4.5, 5.3.2).
• Prevent aggressive manual or mechanical handling; woven materials should always be cut rather than torn.
• Utilize dust extraction systems and water spray applications wherever practical.

Ventilation Compliance

• When complete enclosure of dust sources is not achievable, install local exhaust ventilation systems designed as per IS 12080:1987 (Clause 4.2.1.1).
• Regular maintenance of ventilation equipment is essential for optimal dust control.

Recommended Design Parameters for Dust Extraction (from IS 12080)

Process Flow

flowchart LR
    DustGeneration --> LocalExhaustHood
    LocalExhaustHood --> DustExtractionDuct
    DustExtractionDuct --> DustCollector
    DustCollector --> CleanAirDischarge
    LocalExhaustHood --> WaterSpraySystem[Optional Water Spray]

In summary, employ dust suppressants, avoid harsh handling, install local exhaust ventilation per IS 12080, and maintain systems to effectively limit dust emissions.

Enclosure and Ventilation System Essentials

1. Enclosure Requirements

• Dust must be captured at the source with no leakage into ambient air or surrounding enclosures (Clause 5.2.4).
• Maintain negative pressure within enclosures via exhaust ventilation to prevent dust escape (Clauses 5.2.4, 7.1.6.1).

2. Ventilation System Specifications

• Employ local exhaust ventilation when full enclosure is impractical, designed according to IS 12080-1987 (Clause 4.2.1.1).
• Use vacuum systems during maintenance to avoid dust dispersion (Clause 7.3.5).
• Ensure sufficient general ventilation, achieving adequate air changes per hour to dilute contaminants (Clause 8).

3. Negative Pressure Ventilation Calculation

[ Q = A \times V ]

Where:

• (Q): Airflow in m³/s
• (A): Cross-sectional exhaust area in m²
• (V): Air velocity (0.5–2 m/s depending on dust type)

4. Typical Ventilation Rates

System Flow Diagram

flowchart LR
    DustSource --> Enclosure
    Enclosure -->|Negative Pressure| ExhaustVentilation
    ExhaustVentilation --> DustCollection
    Maintenance --> VacuumSystem
    Maintenance --> ProtectiveGear

References:

• IS 11770 Part 3 (Clauses 4.2.1.1, 5.2.4, 7.1.6.1, 7.3.5, 8)
• IS 12080-1987 for Local Exhaust Ventilation design

Fibre Feeding and Transport Specifications

• Prefer mechanical or pneumatic feeding directly from the blending unit to the mixer or carding machine to maintain continuous, dust-free flow (Clauses 6.2.1, 5.2.1).
• Feeding and discharge operations must occur within sealed systems under negative pressure to prevent fibre escape (Clauses 6.1.4, 5.1.4).
• If direct feed is not possible, transport fibres using impermeable bags or dust-tight containers (Clauses 6.2.1, 5.2.1).

Practical Considerations

• Negative pressure systems ensure inward airflow, containing dust.
• Pneumatic transport typically requires air velocities between 15 and 25 m/s for efficient fibre movement.

Summary Table

Process Flow

flowchart LR
    Blending -->|Mechanical/Pneumatic Feed| MixerCard
    MixerCard -->|Enclosed Negative Pressure| StorageChamber
    Blending -->|Impermeable Bags/Dust-proof Containers| StorageChamber

This methodology preserves fibre quality, reduces contamination, and enhances workplace safety.

Cutting, Sizing, and Branding Practices

• Cutting and sizing should be performed using slow-speed shears, guillotines, or appropriate punches to trim sheets accurately (Clause 6.4.1).
• Avoid rough manual or mechanical handling; woven asbestos materials must be cut cleanly rather than torn.
• Branding is generally applied after sizing to mark products without damaging the material.

Dust Control Measures

• Apply dust suppressants during finishing stages such as inspection, calendering, and drying.
• Employ dust extraction systems and water sprays where possible to reduce airborne dust.

Cutting Methods Summary

Process Flow

flowchart LR
    RawSheet --> CuttingMethod{Select Cutting Method}
    CuttingMethod --> SlowShears[Slow-Speed Shears]
    CuttingMethod --> Guillotine
    CuttingMethod --> Punch
    SlowShears & Guillotine & Punch --> TrimmedSheet
    TrimmedSheet --> BrandingFinishing
    BrandingFinishing --> DustControl[Extraction and Water Spray]

Note: Follow equipment manufacturer instructions and relevant safety standards during cutting and finishing.

Key Aspects in Millboard Production

1. Waste Handling (Clause 6.4.2):

• Side trimmings and cutting waste must be collected in polyethylene bags.
• Dispose of waste according to approved methods per Clause 10.1 or recycle where possible.

2. Millboard Composition (Clause 7.3.3):

• The base formulation should include a dust suppressant to reduce airborne fibre emissions during manufacturing.

3. Scope (Clause 3.1):

• Applies to manufacturing sites producing asbestos textiles, compressed fibre jointings, and millboards.

4. Additional References:

• Dust emission control follows guidelines in IS 11770 Part 2 (1986) for friction materials.

Typical Millboard Mix Components

• Dust suppressants may be water-based binders or chemical additives.
• Uniform dispersion is essential for product integrity and safety.

Process Overview

flowchart LR
    RawFibers --> Mixing[Mix with Binder & Dust Suppressant]
    Mixing --> FormingPressing
    FormingPressing --> CuttingPunching
    CuttingPunching --> WasteCollection[Collect Waste in Poly Bags]
    WasteCollection --> ReuseDecision{Can Waste Be Reused?}
    ReuseDecision -->|Yes| Mixing
    ReuseDecision -->|No| ApprovedDisposal

IS 11770 Part 3 stresses dust control through dust suppressants and mandates safe waste management; see Part 2 for further emission controls.

Handling and Opening of Asbestos Fibre Bags

• Mechanical or pneumatic feeding is preferred directly from blending to mixer; if not feasible, use impermeable bags for fibre transport (Clauses 6.2.1, 5.2.1).
• Bags should be opened automatically when possible (Clause 7.1.1).
• Manual opening must be done inside enclosed booths equipped with negative pressure dust extraction systems to prevent fibre release (Clauses 7.1.2, 6.1.1).

Key Safety Features

• Enclosed booths prevent dust escape protecting workers.
• Negative pressure ensures inward airflow, containing fibres.
• Impermeable containers prevent fibre leakage during transport.

Ventilation Airflow Calculation

[ Q = V \times A ]

Where:

• (Q) = Airflow in m³/s
• (V) = Air velocity (minimum 0.5 m/s recommended)
• (A) = Cross-sectional area of booth opening (m²)

Process Flow

flowchart LR
    Blending -->|Mechanical/Pneumatic Feed| Mixer
    Blending -->|If not feasible| ImpermeableBags
    ImpermeableBags --> AutoBagOpening
    ImpermeableBags --> ManualOpening[Manual Opening in Enclosed Booth]
    ManualOpening --> DustExtraction[Negative Pressure Dust Extraction]

Summary: Employ automatic bag opening with mechanical feeding when possible; otherwise, use enclosed booths with negative pressure extraction for manual opening to minimize asbestos dust exposure.

Finishing Operations Overview

• Includes inspection, calendering, and drying stages.
• Avoid aggressive manual or mechanical handling; woven materials must be carefully cut, not torn.
• Utilize dust extraction systems and water sprays where feasible to reduce airborne dust.

Dust Control Measures

• Apply dust suppressant treatments to materials during finishing (Clauses 5.4.4 and 5.4.5).
• Use wet packages, spray nozzles, and wet rolls in weaving processes.
• Enforce mandatory dust extraction systems to minimize fibre dispersion.

Trimming and Punching

• Sheets are trimmed or punched to size using slow-speed shears, guillotines, or appropriate punches (Clause 6.4.1).

Summary Table

Process Flow

flowchart LR
    RawMaterial --> Weaving
    Weaving --> DustControl[Wet Rolls & Spray Nozzles]
    DustControl --> Finishing[Inspection, Calendering, Drying]
    Finishing --> Cutting[Cutting: Shears/Guillotine/Punch]
    Cutting --> FinalProduct

Ensures quality finishing while controlling dust emissions as per IS 11770 Part 3.

Disposal of Asbestos Waste Materials

While IS 11770 Part 3 does not provide explicit disposal formulas or tables, it references IS 11768:1986 and best practices for asbestos waste management:

• Waste must be collected in a wet state to suppress dust.
• Pack asbestos waste in leak-proof, clearly labeled containers such as double-layered polyethylene bags.
• Store waste in designated, isolated locations to prevent fibre release.
• Dispose of waste at secured hazardous waste landfills featuring impermeable liners.
• Use wet methods during handling to minimize dust.
• Transport waste in covered vehicles to prevent airborne fibre emission.

Recommended Controls

• Employ wetting agents to reduce dust.
• Provide workers with appropriate personal protective equipment (PPE).
• Maintain ventilation and dust extraction systems.

Disposal Process Summary

Process Flow

flowchart LR
    CollectWaste --> WetWaste
    WetWaste --> PackWaste
    PackWaste --> LabelWaste
    LabelWaste --> StoreWaste
    StoreWaste --> TransportWaste
    TransportWaste --> FinalDisposal

For detailed procedures, consult IS 11768:1986 and applicable local regulations.