Recommendations for control of emission of asbestos dust in premises manufacturing products containing asbestos, Part 2: Friction materials
2006 Edition

Overview of IS 11770 Part 2 Scope

• Scope Definition: Details handling, packaging, transportation, storage, and safety requirements related to asbestos-cement friction materials.
• References complementary IS standards for thorough safety and environmental management:

Summary of Key Points:

• Adhere to personal protection protocols (IS 12078).
• Employ correct packaging and transport methods (IS 12079).
• Ensure safe asbestos waste disposal (IS 11768).
• Maintain proper ventilation standards in production areas (IS 12080).

Tabular Summary of Safety and Handling References:

This framework ensures comprehensive adherence to health, safety, and environmental norms for asbestos-cement friction products.

Summary of Referenced IS Codes in IS 11770 Part 2

This part incorporates key Indian Standards that support its safety and handling provisions:

Important Notes:

• These standards underpin the requirements of IS 11770 Part 2.
• They address health, safety, environmental controls, and handling protocols related to asbestos.
• Users should consult the latest versions for the most current safety practices.

This section serves as a bibliographic reference critical for compliance in asbestos friction material production.

Though IS 11770 Part 2 (2006) primarily deals with asbestos-cement friction materials, its Definitions section clarifies terminology associated with asbestos cement products and handling safety.

Key Terms (Typical):

• Asbestos Cement: A composite made from asbestos fibers bonded with cement.
• Fiber Content: The proportion of asbestos fibers by weight within the product.
• Density: The mass per unit volume of the asbestos cement material.
• Water Absorption: The increase in weight after immersion in water, expressed as a percentage.
• Tensile Strength: The maximum tensile stress the product can endure before failure.

Related IS Standards (per Table 2):

• IS 11767: Cleaning asbestos fibre-contaminated areas.
• IS 11768: Asbestos waste disposal.
• IS 12078: Personal protection for asbestos handlers.
• IS 12079: Packing, transport, and storage.
• IS 12080: Local exhaust ventilation systems.

Typical Parameters (Indicative):

For detailed mechanical properties or specific formulations, refer to product-specific IS parts.

Overview of General Requirements in IS 11770 Part 2 (2006)

This section emphasizes adherence to safety and handling standards related to asbestos products rather than specific design formulas.

Referenced Standards (Table 2):

Highlights:

• Compliance with referenced IS codes for health, safety, and environmental safeguards is mandatory.
• Provide appropriate personal protective equipment (PPE) and ventilation.
• Implement safe disposal and cleaning methods to reduce asbestos exposure.

Process Flow Diagram:

flowchart LR
    A[Start: Asbestos Handling] --> B[Use PPE per IS 12078]
    B --> C[Ensure Ventilation per IS 12080]
    C --> D[Clean Premises per IS 11767]
    D --> E[Dispose Waste per IS 11768]
    E --> F[Pack & Transport per IS 12079]
    F --> G[End: Safe Handling & Compliance]

Summary: The part focuses on environmental and safety controls referencing vital IS codes rather than structural or design calculations.

IS 11770 Part 2: Measures to Control Asbestos Dust Emission

Principal Measures (Clauses 4.1, 4.2, 4.3.2):

• Source Control (Clause 4.2.1):

  • Enclose dust-producing processes to prevent dispersion.
  • Localize dust emissions to minimize contamination.

• Engineering Controls (Clause 4.2):

  • Implement engineering solutions to prevent airborne asbestos fibers.
  • Techniques include containment, ventilation, and wetting.

• Wet Suppression (Clause 4.3.2):

  • Apply fine water sprays directly at dust generation points like cutting and drilling.
  • Spraying should not itself create dust.
  • Collect and dispose of the dampened material following IS 11768.
  • Avoid wetting if local exhaust ventilation is in operation.

Recommended Control Methods:

Control Flow:

flowchart TD
    A[Dust Generation Point] --> B{Control at Source?}
    B -- Yes --> C[Enclosure]
    B -- No --> D[Engineering Controls]
    C --> E[Apply Wet Methods]
    D --> E
    E --> F[Collect and Dispose Wet Material]
    F --> G[Reduce Workplace Dust Levels]

Note: The standard emphasizes procedural engineering controls rather than providing specific formulas.

IS 11770 Part 2: Control Strategies at Dust Source

Core Principles (Clause 4.2.1):

• Implement dust control as close to the emission point as possible for maximal effectiveness.
• Enclose dust sources physically to contain emissions.

Wet Suppression (Clause 4.3.2):

• Use fine water sprays targeting dust generation points such as cutting or drilling tools.
• Ensure spraying does not cause dust generation.
• Collect and appropriately dispose of wetted materials (refer IS 11768).
• Refrain from wetting if local exhaust ventilation is active.

Operational Recommendations (Clause 4.3.1):

• Maintain machinery, tools, and ventilation systems properly.
• Apply wetting techniques where beneficial.
• Perform frequent cleaning of waste.
• Use PPE as specified in IS 12078.

Control Methods Table:

flowchart LR
    A[Dust Source] --> B[Enclosure]
    B --> C[Local Exhaust Ventilation]
    C --> D[Wet Spray Application]
    D --> E[Waste Collection & Disposal]
    E --> F[Safe Workplace Environment]
    F --> G[PPE Usage]

Note: Engineering controls take precedence over administrative controls such as PPE.

IS 11770 Part 2: Local Exhaust Ventilation (LEV) System Design (Clause 4.2.2)

Components (Clause 4.2.2.1):

• Hood/Enclosure: Captures dust at its release point.
• Ductwork: Connects hoods to dust collectors; designed per IS 12080 for adequate airflow.
• Dust Collector: Separates dust particles from air stream.
• Fan: Ensures movement of dust-laden air through the system.

Design Criteria (Clause 4.2.2.3):

• Ducts must effectively transport all contaminated air without leaks.
• Follow IS 12080 guidelines for duct sizing and air velocity.

Key Parameters:

System Diagram:

flowchart LR
  Hood/Enclosure --> Ductwork --> Fan --> Dust Collector --> Exhaust

Note: Ensure airtight systems with HEPA filters for asbestos dust; maintenance is critical to prevent leaks.

IS 11770 Part 2: Design and Function of Hoods and Enclosures

Purpose (Clauses 4.2.2.1 & 4.2.2.2.1):

• Capture hoods collect airborne dust effectively at source.
• Enclosures contain dust, directing it to dust collectors.
• Typical system includes hood/enclosure, ducting, dust collector, and fan.

Design Guidelines (Clause 5.6.2):

• Maintain adequate capture velocity at hood openings for effective dust collection.
• Use fully enclosed systems wherever feasible (Clause 5.3.1).
• Common hoods feature open grill shelves, shredders, and hopper with screw feeds.

Capture Velocity Ranges (Typical Values):

Ventilation System Layout:

flowchart LR
    Hood/Enclosure --> Ductwork --> Dust Collector --> Fan --> Clean Air Outlet

• Hoods capture dust.
• Ducts transport contaminated air.
• Dust collectors remove particles.
• Fans maintain airflow.

Summary: Design hoods to maintain capture velocities, enclose dust sources, and connect via ductwork to dust collectors for effective asbestos dust control.

IS 11770 Part 2: Work Practices to Minimize Asbestos Dust Exposure

Key Recommendations (Clauses 4.3 & 4.3.1):

• Use and maintain appropriate machinery, tools, and local exhaust ventilation systems (per IS 12080).
• Employ wetting techniques to suppress dust where applicable.
• Conduct regular cleaning using approved methods (refer IS 11767 and IS 11768).
• Provide and enforce use of personal protective equipment (PPE) as specified in IS 12078.

Associated IS Standards:

Practical Summary:

• Design LEV systems to capture dust at source with proper airflow.
• Use water sprays or misting to reduce airborne fibers.
• Ensure workers wear respirators, gloves, and protective clothing.
• Clean work areas with HEPA-filtered vacuums or wet methods; avoid dry sweeping.

flowchart TD
    A[Begin Work] --> B[Inspect Machinery & LEV]
    B --> C[Apply Wetting]
    C --> D[Wear PPE]
    D --> E[Perform Task]
    E --> F[Clean Waste Regularly]
    F --> G[Dispose Waste per IS 11768]
    G --> H[End Work]

This framework minimizes asbestos fiber release, safeguarding worker health.

IS 11770 Part 2: Recommended Dust Control for Different Manufacturing Processes

Key Controls:

1. Wet Suppression (Clause 4.3.2):

• Use fine water sprays at dust generation points such as cutting and drilling.
• Sprays must not produce additional dust.
• Collect and dispose of wetted material in line with IS 11768.
• Refrain from wetting if local exhaust ventilation is active.

2. Work Practices (Clause 4.3.1):

• Maintain machinery, tools, and ventilation systems.
• Apply wetting where suitable.
• Conduct regular cleaning of dust and waste.
• Use PPE as recommended in IS 12078.

3. Local Exhaust Ventilation (Clause 5.6.2):

• Utilize properly designed hoods.
• Maintain sufficient capture velocity to collect dust effectively.

Typical Capture Velocity Values:

Process Flow Diagram:

flowchart LR
    A[Dust-Generating Operation] --> B[Apply Wet Spray]
    A --> C[Local Exhaust Ventilation]
    B --> D[Collect and Dispose Wet Material]
    C --> E[Maintain Capture Velocity]
    D --> F[Regular Cleaning]
    E --> F
    F --> G[PPE Usage]

Note: Coordinate wet suppression and ventilation to prevent inefficiencies or dust dispersion.

IS 11770 Part 2: Guidelines for Debagging and Fibre Preparation

Debagging (Clause 5.2.1):

• Prefer automatic debagging machines for effective dust control.
• When manual debagging is necessary, provide a specially designed hood:
  • Hood covers all sides except a front opening with a removable cover.
  • Features include interior lighting, shredder chamber, open grill work shelf, and hopper connected to a screw feed chute.

Fibre Preparation and Mixing (Clause 5.2):

• Ensure fibrization occurs under dust-controlled conditions.
• Mixing should promote uniform fibre dispersion.

Compound Transfer (Clauses 5.3 & 5.3.1):

• Utilize fully enclosed systems where possible to transfer compounds from mixing to processing machinery to prevent dust escape.

Debagging Hood Features Summary:

flowchart LR
    Fibre Bags --> Shredder Chamber --> Work Shelf --> Hopper --> Screw Feed Chute --> Mixing Machine

Note: Emphasizes dust control by enclosure and containment rather than specific formulations.

IS 11770 Part 2: Specifications for Fibre Preparation and Mixing

Fibre Preparation and Mixing (Clauses 5.2 & 5.3):

• Weigh powder materials under effective ventilation.
• Use dust control systems during mixing to prevent fibre release.
• Store and transport mixes in sealed containers.
• Perform dry mixing within enclosed negative pressure systems.
• For wet or plasticized mixes in open environments, remove residues using vacuum or dustless methods.

Transfer to Moulding/Forming (Clause 5.3):

• Employ fully enclosed transfer systems to minimize contamination.
• Equipment such as debagging hoods, shredders, hoppers with screw feeds help maintain dust control.

Equipment Layout:

flowchart LR
    Fibre Bags --> Shredder Chamber --> Hopper --> Screw Feed Chute --> Moulding Machine
    Shredder Chamber -. Dust Control .-> Interior Lighting
    Hopper --> Open Grill Work Shelf

Summary:

• Enclosed systems and dust suppression are essential for health and product quality.
• Negative pressure and vacuum cleaning are used appropriately.
• Sealed transfer systems prevent dust emissions.

IS 11770 Part 2: Guidelines for Transferring Mixed Compounds to Moulding/Forming Machines

Key Requirements (Clause 5.3):

• Use fully enclosed systems whenever feasible for compound transfer to control contamination.
• Typical components include:
  • Internal lighting within hoods
  • Shredder chamber for fibre bags
  • Open grill work shelf
  • Hopper connected to screw feed and chute

Specifications:

• Minimize manual handling to reduce contamination and maintain uniform quality.
• Handle preforms carefully when transferring to hot presses to avoid defects.

Enclosed System Diagram:

flowchart LR
    Fibre Bags --> Shredder Chamber
    Shredder Chamber --> Hopper
    Hopper --> Screw Feed
    Screw Feed --> Chute
    Chute --> Processing Machine
    subgraph Enclosure
        Interior Lighting
        Open Grill Shelf
    end

Recommendations:

• Ensure airtight connections between hopper, screw feeder, and chute.
• Maintain cleanliness and adequate ventilation within the enclosure.
• Employ automated feeding to ensure consistent flow.

This method aligns with IS 11770 Part 2 to optimize safety and product integrity.

IS 11770 Part 2: Procedures for Handling and Cleaning Asbestos Spillage

Vacuum Systems (Clause 5.4.2):

• Install vacuum systems designed for immediate spill cleanup to contain dust.

Work Practices (Clause 4.3.1):

• Maintain proper machinery, tools, and effective ventilation.
• Apply wetting techniques where feasible to suppress dust.
• Perform regular cleaning using approved methods.
• Use PPE as specified in IS 12078.

Wet Methods (Clause 4.3.2):

• Apply fine water sprays at dust sources.
• Sprays should not create dust.
• Collect and dispose of wetted materials per IS 11768.
• Avoid wetting if local exhaust ventilation is operational.

Cleaning Methods Summary:

flowchart LR
    A[Spill Occurrence] --> B{Is Vacuum Available?}
    B -- Yes --> C[Use Vacuum Cleaning]
    B -- No --> D{Is Wetting Appropriate?}
    D -- Yes --> E[Apply Fine Spray]
    D -- No --> F[Manual Cleaning with PPE]
    E --> G[Collect and Dispose of Wet Material]
    C --> G
    F --> G

Note: Always comply with PPE and disposal standards for safety.

IS 11770 Part 2: Hot Press and Curing Process Controls

Key Points (Clauses 5.5, 5.4.3):

• Handle preforms cautiously during transfer to hot presses to prevent damage.
• Conduct pressing under negative pressure with properly designed hoods to control dust.
• Immediately transfer pressed materials to curing sections.

Typical Parameters (Engineering Practice):

Process Flow:

flowchart LR
    A[Preform Preparation] --> B[Careful Handling]
    B --> C[Hot Pressing under Negative Pressure]
    C --> D[Transfer to Curing Section]
    D --> E[Curing Process]

Summary: Proper handling, dust control during pressing, and timely curing ensure product quality and safety.

IS 11770 Part 2: Controls for Finishing Operations

Operations (Clause 5.6):

• Cutting and shaping moulded pieces to precise dimensions.
• Grinding to achieve required thickness.
• Drilling holes for fastening components.

Quality Control (Clause 5.6.3):

• Conduct inspections on tables equipped with dust extraction systems to maintain cleanliness.

Dust Suppression (Clause 4.3.2):

• Apply fine water sprays at dust generation points during cutting and drilling.
• Sprays should not cause dust generation.
• Collect and dispose of wet material per IS 11768.
• Avoid wetting when local exhaust ventilation is active.

Control Measures Overview:

flowchart LR
    A[Begin Finishing] --> B[Cut to Specification]
    B --> C[Grind to Desired Thickness]
    C --> D[Drill Fastening Holes]
    D --> E[Inspect on Dust Extraction Table]
    E --> F[Complete Finishing]

Note: Follow dust control measures consistently to ensure safety.

IS 11770 Part 2: Material Reclamation and Handling

• Enclosed system transfer is mandatory for reclaimed material to prevent contamination and dust release (Clause 5.7.2).
• Dispose of leftover reclaimed material according to IS 11768 to ensure environmental safety (Clause 5.7.3).
• Operations like disintegration, milling, or grinding must occur in enclosed booths with proper ventilation to control dust and fumes (Clause 5.7.1).

Summary Table:

Process Flow:

flowchart LR
    A[Reclaimed Material] --> B[Automatic Enclosed Transfer]
    B --> C[Processing Plant]
    C --> D[Disintegrator/Milling/Grinding]
    D --> E[Enclosed Booth with Ventilation]
    F[Leftover Material] --> G[Disposal per IS 11768]

This ensures dust containment, worker safety, and environmental compliance.

IS 11770 Part 2: General Ventilation Guidelines (Clause 6.1)

• Purpose: Supply sufficient fresh air beyond exhaust needs to maintain safe air quality.
• Fresh air must keep contaminant concentrations below permissible exposure limits.
• Ventilation rates depend on space volume, occupancy, and contaminant generation rates.

Fresh Air Supply Formula:

[ Q = \frac{N \times G}{C_{max} - C_{out}} ]

Where:

• ( Q ): ventilation rate (m³/min)
• ( N ): number of occupants or sources
• ( G ): contaminant generation rate per source (mg/min)
• ( C_{max} ): maximum allowable concentration (mg/m³)
• ( C_{out} ): outdoor contaminant concentration (mg/m³)

Additional Notes:

• Local Exhaust Ventilation (LEV) design is covered under Clause 4.2.2.
• LEV systems for asbestos should include HEPA filtration and maintain negative pressure.
• Asbestos waste disposal must follow IS 11768.

Typical Ventilation Rates:

flowchart LR
    A[Contaminant Source] --> B[Contaminated Air]
    B --> C[Local Exhaust Ventilation]
    C --> D[Filtered Exhaust]
    E[Fresh Air Supply] --> F[Work Area]
    F -->|Dilution| B

Proper ventilation design per IS 11770 Part 2 and related standards is critical for occupational safety.

IS 11770 Part 2: Cleaning Protocols for Plant and Premises

Clause 7: Cleaning Operations

• Aim to maintain environments free from asbestos dust and residues.
• Employ vacuum cleaning or wet methods (e.g., moistening before/during sweeping) to minimize airborne dust.
• Avoid dry sweeping techniques.
• Clean all surfaces including machinery, ventilation systems, and interior structures.
• Comply with IS 11767 for cleaning specifics.

Clause 6.2: Air Pollution Controls

• Install necessary pollution control equipment as per regulations.

Clause 4.3.1: Work Practices

• Maintain tools, machinery, and ventilation systems.
• Use wetting methods when applicable.
• Perform routine waste cleaning.
• Enforce PPE use according to IS 12078.

Clause 8: Waste Disposal

• Dispose waste following IS 11768 guidelines.

Cleaning Summary Table:

flowchart TD
    A[Asbestos Dust & Waste] --> B[Vacuum/Wet Cleaning]
    B --> C[Clean Plant & Machinery]
    B --> D[Clean Ventilation & Premises]
    C --> E[Use PPE (IS 12078)]
    D --> E
    E --> F[Dispose Waste (IS 11768)]
    F --> G[Air Pollution Control Compliance]

Note: Following IS 11767 and IS 11768 ensures safe and compliant cleaning.

IS 11770 Part 2: Procedures for Disposal of Asbestos Waste

Key Points:

• Per Clause 8, all asbestos waste must be disposed of following IS 11768 standards.
• Cleaning methods per Clause 7.1 include wet cleaning and vacuuming, avoiding dry sweeping, as detailed in IS 11767.
• Leftover reclaimed materials must also be managed as per IS 11768 (Clause 5.7.3).

Disposal Steps (per IS 11768):

Disposal Flowchart:

flowchart TD
    A[Generation of Asbestos Waste] --> B[Collection in Leak-Proof Containers]
    B --> C[Label Containers as Asbestos Waste]
    C --> D[Transport in Sealed Vehicles]
    D --> E[Disposal at Approved Landfill]
    E --> F[Site Isolation & Monitoring]

Always comply with environmental laws and consult IS 11768 and IS 11767 for comprehensive procedures.