Recommendations for control of emission of asbestos dust in premises manufacturing products containing asbestos, Part 1: Asbestos cement products
1987 Edition

Overview of IS 11770 Part 1 - Scope and Essential Details

Scope:

• Focused on manufacturing of asbestos cement products.
• Aims to ensure control and safety regarding asbestos dust emissions.
• Conforms with international guidelines such as the 1984 ILO Codes of Practice.

Essential Specifications:

• Waste Management:
  All asbestos-related waste must be handled following IS 11768:1986.

• Dust Emission Control (2005 Amendment):
  Processes emitting dust above allowed limits are required to be isolated and enclosed.

• Empty Bag Handling:
  Bags should be shredded and either recycled or disposed according to IS 11768:1986.

Units and Symbols (SI Units)

Process Flow Diagram: Dust Emission Control

flowchart LR
    P[Dust-Generating Operation] --> Q{Is Dust Level Above Limit?}
    Q -- Yes --> R[Isolate Process]
    R --> S[Provide Enclosure]
    S --> T[Control Dust Emission]
    Q -- No --> U[Continue Normal Operation]

Refer to IS 11770 Part 1 full text and IS 11768:1986 for detailed tables and formulas.

Definitions and Core Specifications in IS 11770 Part 1 (1987)

Scope:

• Provides terminology and recommendations for controlling asbestos dust emissions in asbestos cement manufacturing.
• Aligns with global standards, particularly the ILO's 1984 Codes of Practice.

Key Definitions & SI Units

Essential Guidelines

• Waste Disposal: Must comply with IS 11768:1986.
• Dust Control: Dust-generating operations exceeding limits should be enclosed.
• Bag Management: Empty asbestos bags to be shredded and recycled or disposed as per IS 11768.

Process Flow: Dust Control

flowchart TD
    M[Asbestos Cement Product Manufacturing] --> N{Dust Level}
    N -->|Within Limit| O[General Ventilation]
    N -->|Exceeds Limit| P[Isolation and Enclosure]
    P --> Q[Dust Extraction and Filtration]
    Q --> R[Safe Dust Levels]

For exposure limits and detailed procedures, consult IS 11768:1986 and relevant amendments.

IS 11770 Part 1: Principal Guidance on Controlling Asbestos Dust

This section concentrates on asbestos cement product manufacturing, aiming to reduce workers’ exposure to hazardous asbestos dust.

Key Recommendations:

• Continuous monitoring of airborne asbestos dust concentration per IS 11450:1986.
• Control measures include:
  • Installation of effective ventilation systems, prioritizing local exhaust ventilation.
  • Application of dust suppression tactics such as wetting and enclosure.
  • Utilization of appropriate personal protective equipment (PPE).
• Regular health check-ups and medical surveillance for exposed personnel.
• Secure packaging, transport, and disposal methods to prevent dust release.

Summary of Control Measures:

Basic Dust Concentration Formula:

[ C = \frac{M}{V} ] Where:

• ( C ) = asbestos dust concentration (fibers/cm³)
• ( M ) = mass of asbestos fibers collected
• ( V ) = volume of air sampled

flowchart LR
    X[Raw Asbestos Handling] --> Y[Wet Processing]
    Y --> Z[Local Exhaust Ventilation]
    Z --> AA[Airborne Dust Monitoring (IS 11450)]
    AA --> AB[Use of PPE & Health Monitoring]
    AB --> AC[Safe Packaging and Transport]
    AC --> AD[Waste Disposal Procedures]

This framework ensures effective reduction of asbestos dust emissions in manufacturing environments.

IS 11770 Part 1 (1987) - Recommended Control Techniques for Asbestos Dust

Primary Control Measures

Engineering Controls (Clause 3.2)

• Dust Suppression:
  Apply wetting methods at the dust source to reduce airborne fibers.

• Dust Dilution:
  Redesign dust-producing systems, separate processes, and automate operations. Ensure general ventilation supplies clean air.

• Dust Extraction:
  Utilize enclosures or booths; design effective hoods. Employ vacuum cleaning systems to limit dust dispersion.

• Dust Conveyance:
  Implement balanced duct systems with appropriate air velocities (typically 15-20 m/s) for dust transport.

• Dust Collection:
  Fit efficient filters such as HEPA units.

• Workplace Separation:
  Isolate operations generating dust beyond permissible levels.

Work Practices (Clause 3.3)

• Regular maintenance of machinery and ventilation systems.
• Routine cleaning using methods recommended in IS 11767-1986.
• Consistent use of PPE as outlined in IS 12078-1987.

Recommended Air Velocity for Dust Transport

Control Measure Flowchart

flowchart TD
    D[Dust Generation] --> E[Engineering Controls]
    E --> E1[Wet Suppression]
    E --> E2[Dust Dilution]
    E --> E3[Dust Extraction]
    E --> E4[Dust Conveyance]
    E --> E5[Dust Collection]
    E --> E6[Workplace Isolation]
    D --> F[Operational Procedures]
    F --> F1[Equipment Maintenance]
    F --> F2[Regular Cleaning]
    F --> F3[PPE Use]

References:

• IS 11767:1986 - Cleaning methods for asbestos fibers
• IS 12078:1987 - Personal protective equipment for asbestos handling

IS 11770 Part 1: Essential Points on General Ventilation

• Clause 5.2: Ventilation rates must ensure adequate air exchange to maintain a safe and healthy environment.

• Air Change Rate (ACH): Typically, 6 to 12 air changes per hour are recommended based on specific operations and contaminant levels.

• Ventilation Flow Rate (Q) Calculation:

  [ Q = V \times N ]

  Where:

  • ( Q ) = ventilation flow rate (m³/hr)
  • ( V ) = volume of workspace (m³)
  • ( N ) = number of air changes per hour

• Dust Control Measures (Clauses 4.7.1 & 3.2.1.5):

  • Employ exhaust hoods or booths to capture dust at source.
  • Ensure airflow is directed downward to minimize inhalation.
  • Design ventilation to avoid turbulence or eddies which reduce dust removal efficiency.

Summary Table: Ventilation Specifications

flowchart LR
    V[Workspace Volume] --> W[Calculate Flow Rate: Q = V × ACH]
    W --> X{Ventilation System}
    X --> Y[General Ventilation (6-12 ACH)]
    X --> Z[Local Exhaust Hood]
    Z --> AA[Downward Airflow to Trap Dust]
    AA --> AB[Minimized Turbulence]

Summary: Provide sufficient air exchange, direct airflow downward in dusty zones, and design exhaust systems to effectively remove asbestos dust.

Maintenance and Cleaning of Facilities (IS 11770 Part 1)

Key Points:

• Clause 5.3: Exhaust air must be filtered efficiently; recirculating air containing asbestos dust back into work areas is prohibited.

• Clause 6.1:

  • Premises should be kept clean and free of asbestos residues.
  • All machinery, equipment, and surfaces including ventilation systems and building interiors must be dust-free.
  • Cleaning procedures must follow IS 11767-1986 standards.

• Clause 7.1 (Waste Disposal):

  • Waste must be disposed of according to IS 11768-1986 guidelines.

Cleaning and Disposal Standards Overview

Notes:

• Use wet cleaning or vacuum systems equipped with HEPA filters to minimize airborne fibers.
• Exhaust air must be passed through HEPA filters.
• Asbestos waste should be sealed, labeled, and disposed in accordance with IS 11768.

flowchart TD
    P[Asbestos Processing Facility] --> Q[Exhaust Ventilation]
    Q --> R[HEPA Filtration]
    R --> S[Filtered Air Release]
    P --> T[Cleaning via Wet and Vacuum Methods]
    T --> U[Asbestos Waste Collection]
    U --> V[Sealed Disposal per IS 11768]

References:

• IS 11767-1986: Cleaning protocols for asbestos
• IS 11768-1986: Asbestos waste disposal
• IS 11770 Part 1: Air filtration and maintenance requirements

Waste Disposal Guidelines as per IS 11770 Part 1 (1987)

Primary References:

• Waste management must adhere strictly to IS 11768-1986.
• Clause 7.1 specifies that all waste disposal conforms to IS 11768-1986 protocols.

Critical Details:

1. Recycling of Waste (Clause 4.6)

• Dry Waste Recycling (4.6.1):

  • Pulverize dry asbestos cement waste within enclosed systems fitted with exhaust ventilation.
  • Alternatively, wet grinding (e.g., ball mill) can be used to suppress dust.

• Green Waste Recycling (4.6.2):

  • Manufacturing side cuttings must be completely recycled back into production.

2. Disposal of Empty Bags (2005 Amendment)

• Empty bags should be shredded and either recycled or disposed of per IS 11768:1986.

Waste Disposal Summary

Additional Notes:

• Dust control through isolation and enclosures is vital (2005 Amendment).
• Utilize closed systems to prevent airborne fiber escape.
• Follow IS 11768-1986 for detailed waste disposal processes.

flowchart TD
    W[Asbestos Cement Waste] --> X{Waste Type}
    X -->|Dry Waste| Y[Pulverize in Enclosed System]
    X -->|Dry Waste| Z[Wet Ball Mill Grinding]
    X -->|Green Waste| AA[Recycle into Production]
    X -->|Empty Bags| AB[Shred and Recycle/Dispose as per IS 11768]
    Y --> AC[Exhaust Dust Control]
    Z --> AC

Refer to IS 11768-1986 and IS 11770 Part 1 for comprehensive procedures.

IS 11770 Part 1 refers to IS 12078-1987 for PPE standards related to asbestos handling.

Key PPE Recommendations:

• PPE is mandatory when asbestos dust exposure cannot be entirely eliminated by engineering controls.
• PPE components include:
  • Respirators or masks suitable for filtering asbestos fibers.
  • Protective clothing to prevent skin contamination.
  • Gloves for hand protection.
  • Eye protection such as goggles.
• PPE must be regularly inspected, maintained, and cleaned.
• Work protocols should ensure proper PPE use and hygiene, including cleaning of equipment and work areas per IS 11767-1986.
• Local exhaust ventilation (as per IS 12080-1987) should be implemented where full enclosure is not feasible.

PPE Summary Table

Additional Notes:

• No explicit formula for PPE in IS 11770 Part 1; emphasis is on correct selection, maintenance, and usage.
• Ventilation standards per IS 12080-1987 complement PPE usage.

flowchart LR
    D[Dust-Producing Operation] -->|If enclosure insufficient| E[Local Exhaust Ventilation (IS 12080)]
    E --> F{Dust Exposure Controlled?}
    F -- Yes --> G[Minimal PPE]
    F -- No --> H[Use PPE: Respirators, Clothing, Gloves]
    H --> I[Regular PPE Maintenance & Cleaning (IS 11767, IS 12078)]

Summary: Employ PPE as prescribed by IS 12078-1987 where engineering controls fall short, ensuring diligent maintenance and combined with proper ventilation and work practices.

Airborne Asbestos Concentration Measurement per IS 11770 Part 1

• Air sampling and fiber counting follow IS 11450:1986.
• The method involves membrane filtration and light microscopy to count fibers.
• Steps include:
  • Pumping air through a membrane filter.
  • Microscopic fiber counting.
  • Calculating fiber concentration in fibers per cubic centimeter (f/cc).

Concentration Calculation Formula:

[ C = \frac{N}{V} ] Where:

• ( C ): asbestos fiber concentration (fibers/cm³)
• ( N ): number of fibers counted
• ( V ): volume of air sampled (cm³)

Specifications:

• Minimum fiber length: 5 micrometers
• Aspect ratio (length to diameter): at least 3:1
• Sampling flow rates typically between 1-2 liters/minute
• Counting performed by phase contrast microscopy

Parameter Summary

Consult IS 11450:1986 for detailed procedures.

flowchart LR
    A[Air Sampling Pump] --> B[Membrane Filter]
    B --> C[Microscopic Fiber Analysis]
    C --> D[Count Fibers ≥ 5μm & Aspect Ratio ≥ 3:1]
    D --> E[Calculate Fiber Concentration]

Key Points on Packaging, Transport, and Storage (IS 11770 Part 1)

Packaging and Handling (Clauses 4.1.2 & 4.3)

• Palletized loads should be arranged to prevent damage and facilitate mechanized handling.
• Finished products must be handled carefully to avoid breakage and dust emission.

Transportation

• Ensure packaging is secure to prevent spillage and damage during transit.
• Mechanized handling is recommended as per Clause 4.1.2.

Storage

• Store products in dry, well-ventilated, covered areas to prevent moisture damage.
• Stack bags or pallets to avoid crushing or deformation.

Waste Disposal (Clause 7.1)

• Dispose asbestos waste following IS 11768:1986.
• Empty bags must be shredded and either recycled or disposed according to IS 11768.

Waste Disposal Summary (Clause 7.1)

Relevant Units & Definitions

• Force: Newton (N) = 1 kg·m/s²
• Pressure/Stress: Pascal (Pa) = 1 N/m²
• Energy: Joule (J) = 1 N·m

Flow Diagram of Handling Process

flowchart LR
    P[Finished Products] --> Q[Palletized Packaging]
    Q --> R[Mechanized Handling]
    R --> S[Transportation]
    S --> T[Storage (Dry, Covered)]
    T --> U[Usage or Disposal]
    U --> V[Waste Disposal per IS 11768]

Note: Compliance with dust control and safety regulations, including enclosure of dust-generating processes, is essential.

IS 11770 Part 1 emphasizes occupational health and safety in asbestos handling, aligning with international standards such as the ILO Codes of Practice and IS 11451-1986.

Health Monitoring and Supervision Highlights

• Regular medical examinations for workers exposed to asbestos.
• Periodic air sampling to verify exposure remains within permissible limits.
• Exposure limits generally follow threshold limit values (TLVs) or permissible exposure limits (PELs) specified in IS 11451 and ILO guidelines.
• Medical surveillance includes chest X-rays, lung function tests, and symptom questionnaires to detect early signs of asbestos-related diseases.

Typical Exposure Limits

Monitoring Frequency

• Air quality: Monthly or quarterly depending on risk level.
• Medical exams: Annual or biannual.

flowchart LR
  W[Worker Exposure] --> X[Air Sampling]
  X --> Y{Exposure Within Limits?}
  Y -- Yes --> Z[Continue Monitoring]
  Y -- No --> AA[Implement Control Measures]
  W --> AB[Medical Examination]
  AB --> AC{Health Status}
  AC -- Normal --> Z
  AC -- Abnormal --> AD[Medical Intervention]

For more detailed information, refer to IS 11451-1986 and ILO Codes of Practice. IS 11770 Part 1 adopts these protocols for health supervision.

IS 11770 Part 1: Guidelines on Recycling Asbestos Cement Waste

1. Dry Waste Recycling (Clause 4.6.1)

• Pulverize dry asbestos cement waste inside enclosed systems equipped with exhaust to prevent dust dispersal.
• Alternatively, perform wet grinding (e.g., ball mill) to suppress dust emissions.
• Objective: Minimize airborne asbestos fibers and environmental contamination.

2. Green Waste Recycling (Clause 4.6.2)

• Side cuttings generated during sheet manufacturing must be fully reincorporated into the production process.

3. Dust Reuse (Clause 4.6.3)

• Dust collected from bag filters and cement pulverizers should be recycled without compromising product quality.

4. Waste Disposal (Clause 7.1)

• Maximize recycling of asbestos cement waste.
• Dispose residual waste according to IS 11768:1986.

Recycling Summary Table

Important Notes:

• For low-density products (density below 1.20), consult Clauses 4.4.3 and 4.4.4 for specific recycling instructions.

flowchart TD
    R[Asbestos Cement Waste] --> S{Waste Category}
    S -->|Dry Waste| T[Pulverize in Enclosed System]
    S -->|Green Waste| U[Recycle Entirely into Process]
    S -->|Collected Dust| V[Recycle into Production]
    T --> W[Use Exhaust System to Control Dust]
    T --> X[Alternatively, Wet Ball Mill Grinding]
    W & X --> Y[Safe Recycling]
    U & V --> Y