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

IS 11770 Part 3 (1987) — Scope & Key Specifications

Scope Summary:

• Covers handling, cleaning, and disposal of asbestos cement products and waste.
• Emphasizes safe disposal per IS 11768-1986.
• Focus on safety in asbestos fiber handling and environmental protection.
• Aligns with international standards and Indian practices.

Key Specifications:

Important Derived Units (SI):

Disposal Flow (per IS 11768):

flowchart TD
    A[Asbestos Waste Collection] --> B[Safe Packaging]
    B --> C[Transport to Disposal Site]
    C --> D[Disposal as per IS 11768]
    D --> E[Site Monitoring & Environmental Safety]

Note: For detailed formulas and tables on handling and disposal, refer directly to IS 11768 and related parts of IS 11770.

IS 11770 Part 3: Applicability to Asbestos Products

Applicability (Clause 3.1)

This standard applies to premises manufacturing:

• Asbestos textiles
• Compressed asbestos fibre jointings and beater addition jointings
• Asbestos millboards

Related Standards for Safe Use & Emission Control

• IS 11769 (Part 3)-1986: Guidelines for safe use of non-cement asbestos products (excluding friction materials)
• IS 11769 (Part 2)-1986: Guidelines for safe use of friction materials containing asbestos
• IS 11770 (Part 2)-1986: Recommendations for controlling asbestos dust emissions in friction materials manufacturing

Key Specifications Summary:

Important Notes:

• Dust emission control and worker safety are emphasized.
• Follow related IS 11769 parts for handling and safety.
• Use proper ventilation and dust extraction systems per IS 11770 Part 2.

flowchart LR
    A[Manufacturing Premises] --> B[Asbestos Textiles]
    A --> C[Compressed Fibre Jointings]
    A --> D[Asbestos Millboards]
    B & C & D --> E[Apply IS 11770 Part 3]
    F[For Friction Materials] --> G[Apply IS 11769 Part 2 & IS 11770 Part 2]

For detailed emission limits and safety measures, refer to the full IS 11770 Part 3 and related parts.

IS 11770 Part 3 — General Requirements Summary

Scope (Clause 3.1):
Applies to manufacturing premises for:

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

Key Specifications & Recommendations (Clause 10.1)

• Waste Disposal:
  All asbestos waste must be disposed of per IS 11768-1986.
  This standard covers:
  • Cleaning procedures for premises and plants handling asbestos
  • Safe disposal methods to minimize environmental and health hazards

Units and Symbols (International System of Units - SI)

Important Notes

• The standard emphasizes safe handling and environmental control in asbestos product manufacturing.
• Refer to IS 11768 for detailed waste management procedures.
• Use SI units consistently for all measurements.

flowchart TD
    A[Asbestos Product Manufacturing] --> B[General Requirements]
    B --> C[Safe Handling]
    B --> D[Waste Disposal per IS 11768]
    D --> E[Cleaning Premises]
    D --> F[Disposal Methods]

For detailed formulas or tables, refer to IS 11768-1986 and related parts of IS 11770 series.

IS 11770 Part 3: Fibre Preparation and Handling Key Points

Fibre Preparation (Clauses 5.1, 6.1, 7.1)

• Mechanical feeding: Fibre must be fed mechanically to ensure uniformity and avoid contamination.
• Enclosed handling: Fibre discharge should occur under negative pressure in enclosed systems to prevent dust escape and fibre loss (Clause 6.1.4).
• Storage: Fibre is stored in chambers maintaining controlled conditions to preserve fibre integrity.

Specifications

• Negative pressure environment: Ensures dust control and fibre cleanliness.
• Uniform feed rate: Maintains consistent fibre quality and machine efficiency.

Typical Fibre Handling Parameters (General Engineering Practice)

Summary Diagram

flowchart LR
    A[Fibre Source] -->|Mechanical Feed| B[Feeding Machine]
    B -->|Negative Pressure| C[Storage Chamber]
    C --> D[Processing Machine]

This ensures clean, uniform fibre supply with minimal contamination per IS 11770 Part 3.

IS 11770 Part 3: Manufacturing Processes & Dust Control Key Points

Dust Control Measures (Clauses 5.4.5, 5.3.2)

• Apply dust-suppressant treatments on materials during finishing (inspection, calendering, drying).
• Avoid violent manual/mechanical handling; woven materials must be cut, not torn.
• Use dust extraction systems and water sprays where feasible.

Ventilation Requirements (Clause 4.2.1.1)

• If total enclosure of dust sources is impossible, provide local exhaust ventilation per IS 12080:1987.
• Maintain ventilation equipment regularly to ensure effectiveness.

Additional Recommendations

• Follow IS 12080-1987 for design and maintenance of dust extraction.
• Refer to Indian Standards for asbestos dust emission control in asbestos product manufacturing.

Typical Dust Extraction Design Parameters (from IS 12080)

flowchart LR
    A[Dust-producing process] --> B[Local Exhaust Hood]
    B --> C[Dust Extraction Duct]
    C --> D[Dust Collector/Filter]
    D --> E[Clean Air Discharge]
    B --> F[Water Spray System (optional)]

Summary:
Use dust suppressants, avoid harsh handling, employ local exhaust ventilation per IS 12080, and maintain equipment to control dust effectively in manufacturing processes.

IS 11770 Part 3: Enclosure and Ventilation Systems - Key Points

1. Enclosure Requirements

• Dust containment: Dust must be collected at the source; escape into enclosures or atmosphere is prohibited (Clause 5.2.4).
• Negative pressure: Maintain negative pressure inside enclosures using exhaust ventilation to prevent dust leakage (Clauses 5.2.4, 7.1.6.1).

2. Ventilation Specifications

• Local Exhaust Ventilation (LEV): Required when total enclosure is not feasible (Clause 4.2.1.1). Follow IS 12080-1987 for LEV design.
• Vacuum systems: Use during maintenance to avoid dust spread (Clause 7.3.5).
• General ventilation: Ensure adequate air changes per hour (ACH) to dilute airborne contaminants (Clause 8).

3. Key Formula for Negative Pressure Ventilation

[ Q = A \times V ]

Where:

• ( Q ) = Airflow rate (m³/s)
• ( A ) = Cross-sectional area of exhaust opening (m²)
• ( V ) = Air velocity to maintain negative pressure (m/s), typically 0.5 to 2 m/s depending on dust type

4. Typical Ventilation Rates (Reference)

5. Summary Diagram

flowchart LR
    Dust_Source --> Enclosure
    Enclosure -->|Negative Pressure| Exhaust_Ventilation
    Exhaust_Ventilation --> Dust_Collection_System
    Maintenance --> Vacuum_System
    Maintenance --> Protective_Equipment

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

IS 11770 Part 3 – Feeding and Transport of Fibres: Key Specifications

• Mechanical or Pneumatic Feeding:

  • Prefer direct mechanical or pneumatic feed from blending to mixer/card input (Clauses 6.2.1, 5.2.1).
  • Ensures continuous, dust-free fibre flow and minimizes contamination.

• Enclosed Negative Pressure Conditions:

  • Fibre feeding and discharge must occur within enclosed systems under negative pressure to prevent fibre loss and dust escape (Clauses 6.1.4, 5.1.4).

• Transport Containers:

  • When direct feed is not feasible, use impermeable bags or dust-proof containers for fibre transport (Clauses 6.2.1, 5.2.1).

Practical Notes:

• Negative Pressure Systems maintain air flow inward, avoiding fibre dust leakage.
• Pneumatic systems use air velocity to move fibres efficiently; design air velocity typically ranges 15–25 m/s for fibre transport.

Summary Table

flowchart LR
    Blending -->|Mechanical/Pneumatic feed| Mixer/Card
    Mixer/Card -->|Enclosed negative pressure| Storage Chamber
    Blending -->|Impermeable bags/Dust-proof containers| Storage Chamber

This ensures fibre integrity, reduces contamination, and maintains workplace safety.

IS 11770 Part 3 — Cutting, Sizing, and Branding (Clause 6.4)

• Cutting & Sizing (6.4.1):

  • Use slow speed shears, guillotine, or a suitable punch for trimming sheets to size.
  • Avoid violent manual/mechanical handling to prevent damage.
  • Woven materials must be cut, not torn.

• Branding:

  • Branding details are typically applied post-sizing, ensuring clear identification without damaging the material.

• Dust Control (5.4.5 & 7.3):

  • Apply dust-suppressant treatments during finishing (inspection, calendering, drying).
  • Employ dust extraction systems and water sprays where feasible to minimize airborne dust.

Summary Table: Cutting Methods

flowchart LR
    A[Raw Sheet] --> B{Cutting Method}
    B --> C[Slow Speed Shears]
    B --> D[Guillotine]
    B --> E[Suitable Punch]
    C --> F[Trimmed Sheet]
    D --> F
    E --> F
    F --> G[Branding & Finishing]
    G --> H[Dust Control: Extraction & Water Spray]

Note: Always follow manufacturer recommendations and safety standards during cutting and finishing.

IS 11770 Part 3: Asbestos Millboard Manufacturing – Key Points

1. Material Handling & Waste (Clause 6.4.2)

• Side trimmings and waste from cutting/punching must be:
  • Collected in polyethylene bags.
  • Disposed of per Clause 10.1 (approved methods).
  • Or reprocessed for reuse if possible.

2. Millboard Composition (Clause 7.3.3)

• The basic mix of asbestos millboard should include a dust suppressant to minimize airborne fibers during manufacturing.

3. Scope (Clause 3.1)

• Applies to premises manufacturing:
  • Asbestos textiles,
  • Compressed asbestos fibre jointings,
  • Asbestos millboards.

4. Additional References

• For dust emission control, refer IS 11770 Part 2 (1986) for friction materials, applicable for asbestos dust control.

Typical Formulation Considerations (General Engineering Knowledge)

• Dust suppressants may include water-based binders or chemical additives.
• Ensure uniform dispersion for product integrity and safety.

flowchart LR
    A[Raw Asbestos Fibers] --> B[Mixing with Binder & Dust Suppressant]
    B --> C[Forming & Pressing]
    C --> D[Cutting & Punching]
    D --> E[Waste Collection in Poly Bags]
    E --> F{Reuse Possible?}
    F -->|Yes| B
    F -->|No| G[Approved Disposal]

Summary: IS 11770 Part 3 emphasizes dust control via dust suppressants in millboard mix and mandates safe waste handling. Refer Part 2 for emission controls.

IS 11770 Part 3: Handling and Opening of Fibre Bags (Asbestos Fibre)

Key Specifications from Clauses:

• 6.2.1: Prefer direct mechanical/pneumatic feed from blending to mixer; if not, use impermeable bags for fibre transport.
• 7.1.1: Bags should be opened and emptied automatically wherever possible.
• 7.1.2: If opened manually, it must be in an enclosed booth with a negative pressure dust extraction system.
• 6.1.1: Bags must be opened either automatically or in an enclosed booth with dust extraction.

Important Points:

• Enclosed Booth: Prevents fibre dust escape, protecting workers.
• Negative Pressure System: Ensures air flows into the booth, not out, containing dust.
• Impermeable Bags: Prevent fibre leakage during transport.

No direct formulas or tables are provided in IS 11770 Part 3 for this process, but design of dust extraction booths typically follows:

[ Q = V \times A ]

Where:

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

flowchart LR
    A[Blending Operation] -->|Mechanical/Pneumatic Feed| B[Mixer]
    A -->|If not possible| C[Impermeable Bags]
    C --> D[Automatic Bag Opening] 
    C --> E[Manual Opening in Enclosed Booth]
    E --> F[Negative Pressure Dust Extraction System]

Summary: Use automatic opening of fibre bags with mechanical feed when possible; if manual, use enclosed booths with negative pressure extraction to minimize asbestos dust exposure.

IS 11770 Part 3 — Finishing Operations: Key Points

1. Finishing Operations (Clause 7.3)

• Operations include inspection, calendering, drying.
• Avoid violent manual/mechanical handling.
• Woven materials must be cut, not torn.
• Use dust extraction and water sprays where possible.

2. Dust Control (Clauses 5.4.4 & 5.4.5)

• Use dust-suppressant treatments on materials.
• Employ wet packages, spray nozzles, wet rolls in weaving.
• Dust extraction systems are mandatory to minimize airborne dust.

3. Trimming and Punching (Clause 6.4.1)

• Sheets trimmed/punched to size using:
  • Slow speed shears
  • Guillotine
  • Suitable punch

Summary Table

flowchart LR
    A[Raw Material] --> B[Weaving]
    B --> C[Dust Control: Wet rolls, Spray nozzles]
    C --> D[Finishing: Inspection, Calendering, Drying]
    D --> E[Cutting: Slow speed shears / Guillotine / Punch]
    E --> F[Final Product]

This ensures quality finish and dust control per IS 11770 Part 3.

IS 11770 Part 3 does not provide explicit formulas or tables for asbestos waste disposal. However, based on IS 11768:1986 and general good practices, key points for disposal of asbestos waste are:

Key Specifications for Disposal of Asbestos Waste

• Waste Packaging: Asbestos waste must be sealed in leak-proof, labeled containers or bags (e.g., double-layered polythene bags).
• Labeling: Clearly mark containers as "Hazardous Asbestos Waste."
• Storage: Store in a designated, isolated area to prevent fiber release.
• Disposal Site: Waste should be disposed of in a secured landfill designed for hazardous waste, with a clay or synthetic liner to prevent leachate.
• Handling: Use wet methods to suppress dust during handling.
• Transport: Transport in covered vehicles to avoid airborne fiber release.

Recommended Control Measures (from emission control standards)

• Use wetting agents to suppress dust.
• Provide personal protective equipment (PPE) to workers.
• Maintain ventilation and dust extraction systems.

Summary Table (Typical Disposal Steps)

flowchart LR
    A[Collect Asbestos Waste] --> B[Wet to Suppress Dust]
    B --> C[Seal in Leak-proof Bags]
    C --> D[Label as Hazardous]
    D --> E[Store in Isolated Area]
    E --> F[Transport in Covered Vehicles]
    F --> G[Dispose in Secure Landfill]

For detailed procedures, refer to IS 11768:1986 and local hazardous waste regulations.