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

IS 11770 Part 2: Scope Overview

• Scope: Specifies requirements for handling, packaging, transport, storage, and safety measures related to asbestos-cement products.
• It references related IS standards for comprehensive safety and environmental practices:

Key Specifications:

• Follow personal protection guidelines (IS 12078).
• Use proper packaging and transport methods (IS 12079).
• Ensure safe disposal of asbestos waste (IS 11768).
• Maintain ventilation standards in manufacturing areas (IS 12080).

Summary Table: Safety and Handling References

This ensures holistic compliance covering environmental, health, and safety aspects of asbestos-cement products.

IS 11770 Part 2 References Summary

This standard references key IS codes related to asbestos handling and safety, which are integral to its provisions:

Key Notes:

• These referenced standards form part of IS 11770 Part 2’s framework.
• They cover health, safety, environmental controls, and handling procedures for asbestos materials.
• Users should consult the latest editions for updated safety and handling practices.

No specific formulas or tables are given in this clause; it serves as a bibliographic reference list essential for compliance and safety in friction material manufacturing involving asbestos.

IS 11770 Part 2 (2006) focuses on asbestos cement products, but the Definitions section typically clarifies terms related to asbestos cement materials, handling, and safety.

Key Points on Definitions (General IS Practice):

• Asbestos Cement: Composite material of asbestos fibers and cement binder.
• Fiber Content: Percentage of asbestos fibers by weight in the product.
• Density: Mass per unit volume of the asbestos cement product.
• Water Absorption: Percentage increase in weight after water immersion.
• Tensile Strength: Maximum stress the product can withstand while being stretched.

Related IS References (per Table 2):

• IS 11767: Cleaning asbestos fiber premises.
• IS 11768: Disposal of asbestos waste.
• IS 12078: Personal protection for asbestos handlers.
• IS 12079: Packing, transport, and storage.
• IS 12080: Local exhaust ventilation systems.

Typical Specification Parameters:

If you need detailed formulas or mechanical properties, please specify the product type (e.g., sheets, pipes).

IS 11770 Part 2 (2006) - General Requirements Summary

This part of IS 11770 primarily references safety and handling standards related to asbestos products. It does not specify design formulas but emphasizes compliance with related IS codes for safe handling.

Key References (Table 2):

General Requirements Highlights:

• Follow all referenced IS standards for health, safety, and environmental protection.
• Ensure proper personal protective equipment (PPE) and ventilation.
• Maintain safe disposal and cleaning methods to minimize asbestos exposure.

Note:

For structural design or product specifications, refer to other parts of IS 11770 or related IS codes.

flowchart LR
    A[Start: Handling Asbestos] --> 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: IS 11770 Part 2 focuses on safe handling and environmental controls, referencing key IS codes for asbestos-related safety practices rather than structural formulas.

IS 11770 Part 2: Control Measures for Asbestos Dust

Key Specifications & Measures (Clauses 4.1, 4.2, 4.3.2)

• Control at Source (4.2.1)

  • Enclose dust-generating processes to prevent spread.
  • Localize dust emission to reduce workplace contamination.

• Engineering Controls (4.2)

  • Use engineering methods to prevent dust emission.
  • Minimize airborne asbestos fibers by containment, ventilation, or wetting.

• Wet Methods (4.3.2)

  • Apply fine water spray directly at dust source (cutting, drilling).
  • Spray must not generate dust.
  • Collect and dispose wet material per IS 11768.
  • Avoid wetting if local exhaust ventilation is used.

Recommended Approach

Summary Flow

flowchart TD
    A[Dust Source] --> B{Control at Source?}
    B -- Yes --> C[Enclosure]
    B -- No --> D[Engineering Controls]
    C --> E[Use Wet Methods]
    D --> E
    E --> F[Collect & Dispose Wet Material]
    F --> G[Minimize Workplace Dust]

Note: No explicit formulas are given; focus is on procedural engineering controls per IS 11770 Part 2.

IS 11770 Part 2: Control at the Source – Key Points

1. Control Principles (Clause 4.2.1)

• Control dust as close to the source as possible to maximize efficiency and minimize spread.
• Enclosure of the source is the preferred first step to contain dust.

2. Wet Methods (Clause 4.3.2)

• Use fine spray directed at dust sources (cutting tools, saws, drilling points).
• Spray must not generate dust.
• Collect and dispose of wet material properly (refer IS 11768).
• Avoid wetting if local exhaust ventilation is in use.

3. Recommended Work Practices (Clause 4.3.1)

• Maintain proper machinery, tools, and ventilation.
• Use wetting where applicable.
• Regularly clean waste generated.
• Use personal protective equipment (see IS 12078).

Summary Table: Control at Source Methods

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

Note: Engineering controls (enclosure, ventilation) are prioritized over administrative controls (PPE).

For detailed design formulas or tables, IS 11770 primarily focuses on qualitative control measures rather than quantitative formulas. For ventilation design, refer to IS 11821 or IS 12078.

IS 11770 Part 2 — Local Exhaust Ventilation System (Clause 4.2.2)

Key Components (Clause 4.2.2.1)

• Hood/Enclosure: Captures airborne dust at the source.
• Duct Work: Connects hoods to dust collector; sized per IS 12080.
• Dust Collector: Separates dust from air.
• Fan: Moves dust-laden air through the system.

Design Guidelines (Clause 4.2.2.3)

• Ducts must be designed to remove all dust-laden air effectively.
• Follow IS 12080 for duct sizing and airflow velocity.

Important Parameters for Duct Design (from IS 12080 & general practice)

Summary Diagram of Local Exhaust Ventilation System

flowchart LR
  Hood[Hood/Enclosure] --> Duct[Duct Work]
  Duct --> Fan[Fan]
  Fan --> DustCollector[Dust Collector]
  DustCollector --> Exhaust[Exhaust Air]

Note: For asbestos-containing premises, ensure airtight systems and HEPA filtration in dust collectors as per additional safety guidelines.

IS 11770 Part 2 (2006) – Hoods and Enclosures Key Points

1. Purpose of Hoods & Enclosures (Clauses 4.2.2.1 & 4.2.2.2.1)

• Capture-type hoods collect dust at the source.
• Enclosures ensure airborne dust is contained and directed to dust collectors.
• Systems include: Hood/enclosure → Ductwork → Dust collector → Fan.

2. Design Specifications (Clause 5.6.2)

• Maintain required capture velocity at hood openings to ensure dust capture.
• Use totally enclosed systems wherever practicable (Clause 5.3.1).
• Typical hoods include features like open grill shelves, hopper connected screw feeds, and shredder chambers.

3. Capture Velocity Guidelines

• Though IS 11770 Part 2 does not specify exact velocities, typical capture velocities for dust hoods are:

4. Typical Ventilation System Elements (Fig.1)

flowchart LR
    Hood/Enclosure --> Ductwork --> DustCollector --> Fan --> CleanAirDischarge

• Hood/Enclosure: Captures dust.
• Ductwork: Transports dust-laden air.
• Dust Collector: Separates dust.
• Fan: Drives air through system.

Summary: Design hoods to maintain capture velocity, use enclosures to contain dust, and connect to dust collectors via ductwork with a fan to ensure safe dust disposal.

IS 11770 Part 2: Work Practices for Asbestos Handling

Key Specifications (Clause 4.3 & 4.3.1)

• Machinery & Equipment: Use and maintain proper process machinery, installations, tools, local exhaust ventilation (LEV) systems (see IS 12080).
• Wetting: Apply wetting methods to suppress asbestos dust where applicable.
• Cleaning: Regularly clean waste from manufacturing by approved methods (see IS 11767 for cleaning, IS 11768 for waste disposal).
• Personal Protective Equipment (PPE): Use PPE as per IS 12078 to protect workers.

Important Related IS Codes

Practical Summary:

• LEV Design: Ensure airflow captures dust at source; maintain airflow velocity as per IS 12080.
• Wetting: Use water sprays or mist to reduce airborne fibers.
• PPE: Respirators, gloves, and protective clothing mandatory.
• Cleanup: Use HEPA-filtered vacuums or wet methods; avoid dry sweeping.

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

This ensures minimal asbestos fiber release and worker safety per IS 11770 Part 2.

IS 11770 Part 2: Recommended Control for Different Operations

Key Specifications & Controls

1. Use of Wet Methods (Clause 4.3.2)

• Apply fine spray directly at dust sources (cutting tools, saws, drilling).
• Spray must not generate dust.
• Collect and dispose of wet material per IS 11768.
• Avoid wetting if local exhaust ventilation (LEV) is used simultaneously.

2. Work Practices (Clause 4.3.1)

• Maintain proper machinery, tools, LEV systems.
• Use wetting methods where applicable.
• Perform regular cleanup of waste.
• Use personal protective equipment (PPE) as per IS 12078.

3. Local Exhaust Ventilation (Clause 5.6.2)

• Use properly designed hoods.
• Maintain capture velocity to ensure all dust is collected.

Capture Velocity Guidelines (Typical values)

Summary Diagram: Dust Control Flow

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

Note: Always coordinate wet methods and ventilation to avoid inefficiency or increased dust dispersion.

IS 11770 Part 2: Debagging and Fibre Preparation Key Points

1. Debagging Methods (Clause 5.2.1)

• Automatic debagging machines are preferred for effective dust control.
• If manual debagging is used, a properly designed hood must be provided:
  • Hood covers all sides except a front opening.
  • Front opening has a removable cover that remains closed during fibrization.
  • Typical hood features (Fig. 2):
    • Light inside hood
    • Shredder chamber for fibre bags
    • Open grill work shelf under hood
    • Hopper connected to screw feed chute

2. Fibre Preparation and Mixing (Clause 5.2)

• Fibre preparation should ensure proper fibrization under dust-controlled conditions.
• Mixing should be done in a manner that facilitates uniform fibre dispersion.

3. Transfer of Mixed Compound (Clause 5.3 & 5.3.1)

• Use totally enclosed systems wherever practicable for transferring compounds from mixing to processing machinery.
• This minimizes contamination and dust escape.

Summary Table: Debagging Hood Features

flowchart LR
    A[Fibre Bags] --> B[Shredder Chamber]
    B --> C[Open Grill Work Shelf]
    C --> D[Hopper]
    D --> E[Screw Feed Chute]
    E --> F[Mixing Machinery]

Note: IS 11770 Part 2 focuses on dust control and enclosed systems rather than specific formulas. For fibre preparation quality, follow standard fibrization and mixing practices ensuring uniform fibre dispersion.

IS 11770 Part 2: Fibre Preparation and Mixing (Clauses 5.2 & 5.3)

Key Specifications:

• Fibre Preparation & Mixing (Clause 5.2):

  • All powder materials must be weighed under effective ventilation.
  • Mixing should use dust control systems to prevent dust escape.
  • Mixes must be stored and transported in closed containers.
  • Dry mixing done only in enclosed, negative pressure systems.
  • For wet/plasticized mixes in open systems, residues cleared by vacuum or dustless methods.

• Transfer to Moulding/Forming (Clause 5.3):

  • Use totally enclosed systems wherever practicable.
  • Equipment like debagging hoods, shredders, hoppers with screw feed ensure dust control (see Fig. 2 in IS).
  • Closed transfer systems prevent contamination and dust release.

Typical Equipment Setup (Fig. 2):

flowchart LR
    FibreBags --> ShredderChamber --> Hopper --> ScrewFeedChute --> MouldingMachine
    ShredderChamber -. Dust Control .-> LightInsideHood
    Hopper --> OpenGrillWorkShelf

Summary:

• Enclosed systems and effective dust control are mandatory for health and quality.
• Use negative pressure and vacuum cleaning for dry and wet mixes respectively.
• Transfer systems must be sealed to prevent dust escape.

This ensures safe, clean, and efficient fibre mixing and transfer operations per IS 11770 Part 2.

IS 11770 Part 2 - Transfer of Mixed Compound to Moulding and Forming (Clause 5.3)

Key Points:

• Clause 5.3 mandates the use of totally enclosed systems wherever practicable for transferring mixed compounds to moulding/forming machines to ensure contamination control and safety.
• Typical enclosed system components include:
  • Light inside hood
  • Shredder chamber for fibre bags
  • Open grill work shelf under the hood
  • Hopper connected to screw feed and chute

Specifications:

• Transfer systems should minimize manual handling to avoid contamination and ensure uniform compound quality.
• Preforms must be handled carefully (Clause 5.5.2) when moving into the hot press to prevent defects.

Typical Setup (Fig. 2 - Debagging Hood):

flowchart LR
    FibreBags --> ShredderChamber
    ShredderChamber --> Hopper
    Hopper --> ScrewFeed
    ScrewFeed --> Chute
    Chute --> ProcessingMachine
    subgraph EnclosedSystem
        LightInsideHood
        OpenGrillShelf
    end

Practical Tips:

• Ensure airtight connections between hopper, screw feed, and chute.
• Maintain cleanliness and ventilation inside the hood.
• Use automated feeding to maintain consistent compound flow.

This approach aligns with IS 11770 Part 2 to optimize compound transfer efficiency and product quality.

IS 11770 Part 2: Handling and Cleaning Spillage – Key Points

1. Vacuum Provision (Clause 5.4.2)

• Vacuum systems must be installed to immediately clean asbestos spillage.
• Ensures dust containment without dispersal.

2. Work Practices (Clause 4.3.1)

• Maintain proper machinery, tools, local exhaust, and ventilation.
• Use wetting methods where applicable to suppress dust.
• Conduct regular cleanups using approved methods.
• Use Personal Protective Equipment (PPE) per IS 12078.

3. Wet Methods (Clause 4.3.2)

• Apply fine spray at dust sources (cutting, drilling).
• Spray must not generate dust.
• Collect and dispose wet material properly (see IS 11768).
• Avoid wetting if local exhaust ventilation is active.

Summary Table: Cleaning Method vs. Conditions

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

Note: Always follow PPE guidelines (IS 12078) and disposal procedures (IS 11768) for safety and compliance.

IS 11770 Part 2 – Hot Press and Curing Operations Key Points

From Clause 5.5 (Hot Pressing and Curing):

• 5.5.2: Preforms must be handled carefully during transfer into the hot press to avoid damage.
• 5.5.3: After hot pressing, materials are immediately transferred to the curing section to complete the process.

From Clause 5.4.3 (Pressing Operations):

• Pressing must be done under negative pressure to control dust.
• Use properly designed hoods connected directly to the press to prevent dust escape.

Typical Hot Press and Curing Parameters (General Engineering Practice):

Process Flow (Mermaid Diagram):

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:

• Handle preforms carefully.
• Use negative pressure and dust control hoods during pressing.
• Transfer immediately to curing after hot pressing for optimal material properties.

IS 11770 Part 2 — Finishing Operations Key Points

1. Finishing Operations (Clause 5.6)

• Cutting & Shaping: Mould pieces are trimmed to exact dimensions.
• Grinding: Achieve required thickness.
• Drilling: Holes made for fastening to brake shoes.

2. Quality Control (Clause 5.6.3)

• Inspection must be done on tables with dust extraction systems to maintain cleanliness and safety.

3. Dust Control - Wet Methods (Clause 4.3.2)

• Use fine spray at dust source (cutting, drilling).
• Spray must not generate dust.
• Collect and dispose of wet material per IS 11768.
• Avoid wetting when local exhaust ventilation is active.

Summary Table: Finishing Operations Control

flowchart LR
    A[Start Finishing] --> B[Cut to dimensions]
    B --> C[Grind to thickness]
    C --> D[Drill fastening holes]
    D --> E[Inspect on dust extraction table]
    E --> F[End]

Note: Always follow dust control guidelines to ensure safety and compliance.

IS 11770 Part 2 – Reclamation of Materials (Clause 5.7)

• Enclosed System Transfer (5.7.2):
  Reclaimed materials must be transferred automatically within an enclosed system to prevent contamination and loss.

• Disposal of Leftover Material (5.7.3):
  Any leftover reclaimed material should be disposed of per IS 11768 guidelines, ensuring environmental safety.

• Ventilation Requirements (5.7.1):
  Disintegrators, milling, or grinding plants must operate inside an enclosed booth with a proper ventilation system to control dust and fumes.

Key Specifications Summary

Practical Notes:

• Enclosed transfer reduces dust and contamination.
• Ventilation ensures worker safety and compliance with air quality.
• Disposal per IS 11768 avoids environmental hazards.

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

IS 11770 Part 2 — General Ventilation (Clause 6.1)

• Objective: Provide adequate fresh air beyond exhaust requirements to ensure safe air quality.

• Key Specification:

  • Fresh air supply must maintain contaminant concentration below permissible limits.
  • Ventilation rate depends on room volume, occupancy, and contaminant generation.

• Typical Formula for Fresh Air Supply Rate (Q):

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

  Where:

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

• Additional Notes:

  • Clause 4.2.2 covers Local Exhaust Ventilation (LEV) design to capture contaminants at source.
  • Leftover asbestos material disposal must follow IS 11768.
  • For asbestos, LEV systems should have HEPA filters and maintain negative pressure.

Summary Table: Ventilation Rates (Indicative)

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

Ensure ventilation design complies with IS 11770 Part 2 and related IS codes for health safety.

IS 11770 Part 2: Cleaning of Plant and Premises - Key Points

Clause 7: Cleaning of Plant and Premises

• Objective: Keep premises free from asbestos waste and dust.
• Methods:
  • Use vacuum cleaning or dustless methods (e.g., wetting before/during sweeping).
  • Avoid dry sweeping to minimize airborne dust.
• Surfaces to clean: Plant, machinery, exhaust ventilation equipment, and all internal building surfaces.
• Reference: Cleaning shall comply with IS 11767 (specific asbestos cleaning practices).

Clause 6.2: Air Pollution Control

• Install necessary air pollution control equipment to meet regulatory requirements.

Clause 4.3.1: Work Practices for Cleaning

• Use and maintain proper machinery, tools, local exhaust, and ventilation.
• Apply wetting methods where applicable.
• Regularly clean waste generated during manufacturing.
• Use personal protective equipment as per IS 12078.

Clause 8: Disposal of Waste

• Dispose of all waste as per IS 11768.

Summary Table: Cleaning Practices

flowchart TD
    A[Asbestos Waste & Dust] --> B[Vacuum Cleaning / Wetting]
    B --> C[Clean Plant & Machinery]
    B --> D[Clean Ventilation & Building Surfaces]
    C --> E[Use PPE (IS 12078)]
    D --> E
    E --> F[Dispose Waste (IS 11768)]
    F --> G[Comply with Air Pollution Control (Clause 6.2)]

Note: Always follow IS 11767 for cleaning specifics and IS 11768 for waste disposal to ensure safety and regulatory compliance.

IS 11770 Part 2: Disposal of Waste (Asbestos)

Key Points:

• Clause 8 (Disposal of Waste):
  All asbestos waste must be disposed of as per IS 11768 (Indian Standard for disposal of asbestos waste).

• Clause 7.1 (Cleaning):
  Use vacuum cleaning or wet methods to avoid dust. Cleaning should comply with IS 11767.

• Clause 5.7.3 (Reclaimed Material):
  Leftover reclaimed asbestos materials must also be disposed of according to IS 11768.

Summary of Disposal Requirements (per IS 11768):

Important Notes:

• Disposal must prevent airborne asbestos fibers.
• Follow all local environmental and safety regulations.
• Refer to IS 11768 for detailed procedures and specifications.

flowchart TD
    A[Asbestos Waste Generation] --> B[Collection in Leak-proof Containers]
    B --> C[Labeling as Asbestos Waste]
    C --> D[Transport in Sealed Containers]
    D --> E[Disposal at Designated Landfill]
    E --> F[Site Isolation & Monitoring]

For detailed procedures, consult IS 11768 and IS 11767 alongside IS 11770 Part 2.