asbestos cement pressure pipes (light duty)

IS 9627: Scope Key Formulas, Tables & Specifications

1. Scope Overview

• Applies to pipes with nominal diameters 50 to 200 mm.
• Specifies thickness, diameters, tolerances, and pressure relationships.

2. Thickness & External Diameter (Clause 4.2.1)

3. Tolerance on External Diameter (Clause 4.1.3.1)

4. Pressure Relationships (Clause 3.2.2, Table 2)

5. Rounding Off (Clause 0.6)

• Final values must be rounded per **IS: 2-1960

IS 9627 Key References:

1. Rounding Off (Clause 0.6)

• Final values from tests/analysis must be rounded as per IS:2-1960.
• Retain the same number of significant digits as the specified value.

2. Pipe Thickness & External Diameter (Clause 4.2.1)

3. Tolerance on External Diameter (Clause 4.1.3.1)

This summary provides essential dimensional specifications and tolerances for pipes under IS 9627. For detailed design or testing, refer to the full standard and IS 2-1960 for rounding rules.

IS 9627: Classification of Asbestos Cement Pressure Pipes

Key Points from Clause 3.1 & 3.2 and Table 1

• Classification is based on Hydraulic Test Pressure (N/mm²):

• Hydraulic Working Pressure should be ≤ 50% of the test pressure of the respective class.

Additional Notes:

• Tolerances on pressure values are free (no extra allowance).
• Pipe dimensions vary by class and nominal diameter (see Table 3 in the code).
• Length of pipe, L, is measured in meters.

Summary Formula:

[ P_{working} \leq 0.5 \times P_{test} ]

Where:

• (P_{working}) = Hydraulic working pressure (N/mm²)
• (P_{test}) = Hydraulic test pressure for the class (N/mm²)

Visual Summary:

flowchart TD
    A[Classification] --> B[Class 5: 0.5 N/mm² Test Pressure]
    A --> C[Class 10: 1.0 N/mm² Test Pressure]
    A --> D[Class >10 to 15: 2.0 N/mm² Test Pressure]
    B --> E[Working Pressure ≤ 0.25 N/mm²]
    C --> F[Working Pressure ≤ 0.5 N/mm²]
    D --> G[Working Pressure ≤ 1.0 N/mm²]

This classification ensures safety and durability of asbestos cement pipes under specified pressures.

IS 9627: Dimensions and Tolerances Key Points

1. Tolerances on External Diameter (Clause 4.1.3.1)

• Measured 100 mm from the ends.
• For Nominal Diameter 50 to 200 mm:
  Tolerance = ± 0.6 mm

2. Tolerances on Thickness at Finished Ends (Clause 4.2.3.1)

3. Tolerances on Nominal Length (Clause 4.3.1)

• Refer to the specific clause for length tolerances; typically ± a defined value depending on length and application.

Summary Table

This ensures dimensional accuracy for structural steel tubes per IS 9627, critical for fit and structural integrity.

flowchart TD
    A[Start: Tube Production] --> B{Measure Diameter @ 100mm from ends}
    B -->|50-200 mm| C[Check ±0.6 mm tolerance]
    A --> D{Measure Thickness at finished ends}
    D -->|≤10 mm| E[Thickness tolerance: -1.5 mm]
    D -->|>10 to 15 mm| F[Thickness tolerance: -2.0 mm]
    A --> G{Check Length}
    G --> H[Apply length tolerance as per Clause 4.3.1]

IS 9627: Material Requirements - Key Points

1. Thickness & Diameter (Clause 4.2.1, Table 4.2)

2. Rounding Off (Clause 0.6)

• Final test/analysis values must be rounded as per IS: 2-1960.
• Retain the same number of significant digits as specified in the standard.

3. Physical Properties (Clause 2.2)

• Refer to the standard for specific mechanical and physical property requirements of materials.

4. Testing & Acceptance (Clause 8.1)

• Additional tests beyond manufacturer's certificate can be requested.
• Cost borne by:
  • Manufacturer if material fails specs.
  • Purchaser if material passes specs.

This ensures compliance with dimensional and quality requirements for cast iron detachable joints and related materials under IS 9627.

IS 9627: Key Specifications & Formulas for Tests

1. Rounding Off Test Results (Clause 0.6)

• Final test values must be rounded per IS:2-1960.
• Retain the same number of significant digits as specified in the standard.

2. Test Cost Responsibility (Clause 8.1)

• Manufacturer bears cost if material fails the test.
• Purchaser bears cost if material passes the test.
• Tests may be conducted in presence of purchaser or representative if specified in order.

3. Classification & Hydraulic Test Pressure (Clause 3.1, Table 1)

4. Physical Properties Testing (Clause 6.3)

• Conduct tests as per IS:5913-1970 for physical properties (Clauses 2.2.1 to 2.2.3).

Summary Diagram of Test Procedure Responsibility

flowchart TD
    A[Test Required?] -->|Yes| B[Specify in Order]
    B --> C{Test Result}
    C -->|Pass| D[Purchaser Pays]
    C -->|Fail| E[Manufacturer Pays]

This ensures clarity on testing and acceptance criteria for asbestos cement pressure pipes per IS 9627.

IS 9627: Key Points on Joints for Asbestos Cement Pressure Pipes

• Types of Joints (Clause 7.1):

  • a) Asbestos cement couplings with rubber sealing rings.
  • b) Cast iron detachable joints with rubber sealing rings, bolts, and nuts.

• Flexibility & Pressure Resistance (Clause 7.5):

  • Joints must be flexible.
  • Must withstand specified hydraulic pressure (see Clauses 3.1 & 6.2).
  • Allow angular deviation up to 8° or less depending on pipe diameter.
  • For pipes with external diameter ≤ 1170 mm, angular deviation ≤ 8°.

• Dimensional Specifications (Clause 7.4 & 5.3):

  • Dimensions and tolerances on internal diameters must be as per manufacturer.
  • Finished pipe ends shaped to suit joint type (manufacturer-defined).

Typical Joint Design Parameters:

Important Notes:

• Always consult manufacturer’s data for exact joint dimensions and tolerances.
• Rubber sealing rings ensure watertight and flexible joints.
• Bolted joints allow easy dismantling and maintenance.

graph LR
A[Pipe End Shape] --> B[Joint Type]
B --> C[Coupling with Rubber Seal]
B --> D[Cast Iron Detachable Joint]
C & D --> E[Flexibility & Pressure Resistance]
E --> F[Max Angular Deviation ≤ 8°]
E --> G[Hydraulic Pressure Capacity]

This ensures joints are both flexible and pressure-tight per IS 9627 requirements.

IS 9627 - Marking of Pipes: Key Specifications

Per Clause 12.1, pipes must be legibly and indelibly marked with:

• Manufacturer's name or trade-mark
• Date of manufacture
• Nominal diameter
• Class of pipe with suffix 'LD'

Additional Notes:

• Marking ensures traceability and quality control.
• Marking must be durable to withstand handling and environmental exposure.
• Verification of marking is part of inspection (Clause 9.1.1).
• Dimensions and tolerances of pipes and joints are verified as per Clauses 4 and 7.4.
• Rounding of test results follows IS 2-1960 guidelines (see Clause 0.6).

Summary Table for Marking Requirements:

flowchart LR
    A[Pipe] --> B{Marking}
    B --> C[Manufacturer's Name/Trade-mark]
    B --> D[Date of Manufacture]
    B --> E[Nominal Diameter]
    B --> F[Class of Pipe + 'LD']

This marking system ensures clear identification and quality traceability as per IS 9627 standards.

IS 9627: Inspection and Acceptance Key Points

1. Inspection by Sampling (Clause 9.2)

• Sampling follows IS 7639-1975 (Methods of sampling asbestos cement products).
• Inspection lots must be uniform in diameter and class.
• Lot size limits:
  • Pipes ≤ 100 mm dia: max 800, min 200 pipes.
  • Pipes 125–200 mm dia: max 400, min 100 pipes.

2. Inspection of Each Item (Clause 9.1)

• Each item in the consignment must be inspected for compliance.

3. Test Costs (Clause 8.1)

• Tests beyond manufacturer's certificate are done in purchaser’s presence if specified.
• Cost borne by:
  • Manufacturer if material fails.
  • Purchaser if material passes.

4. Acceptance Criteria (Clause 11.1)

• Sampling, inspection, and acceptance per IS 7639-1975.
• Inspection lot uniformity essential.

Summary Table: Inspection Lot Size

This ensures consistent quality control and fair cost allocation for testing.

IS 9627: Manufacturer's Certificate - Key Points

• Clause 10.1:
  The manufacturer must ensure pipes meet the standard requirements and provide a certificate confirming compliance, including the pipe class.

• Clause 9.2.2:
  If the purchaser does not witness the hydraulic pressure tightness test (per 9.1.3), they may request additional tests on selected pipe samples (see 6.2 & 11).

• Clause 8.1:

  • Additional tests in purchaser's presence must be specified in the order.
  • Cost responsibility:
    • Manufacturer pays if material fails specification.
    • Purchaser pays if material passes specification.

• Rounding off results:
  Use IS 2-1960 for rounding test values to the same significant figures as the specified values.

Summary Table for Manufacturer's Certificate

This ensures traceability and accountability in pipe quality per IS 9627.

IS 9627: Sampling and Inspection Key Points

1. Inspection Methods

• Clause 9.1: Inspection of each item in the consignment may be carried out.
• Clause 9.2: Sampling inspection follows IS 7639-1975 (Methods of sampling asbestos cement products).

2. Inspection Lots

• Items in a lot must be of same diameter and class.
• Lot size limits:

3. Acceptance Criteria & Cost Responsibility (Clause 8.1)

• Tests beyond manufacturer's certificate are done in purchaser presence if specified.
• Cost borne by:
  • Manufacturer if material fails specification.
  • Purchaser if material passes specification.

Summary Table for Sampling and Inspection

flowchart LR
    A[Consignment] --> B{Same Diameter & Class?}
    B -- Yes --> C[Form Inspection Lot]
    B -- No --> D[Separate Lots]
    C --> E{Lot Size}
    E -- ≤100 mm --> F[200 to 800 pipes]
    E -- 125 to 200 mm --> G[100 to 400 pipes]
    F & G --> H[Sampling per IS 7639-1975]
    H --> I{Test Results}
    I -- Pass --> J[Cost borne by Purchaser]
    I -- Fail --> K[Cost borne by Manufacturer]

This ensures standardized quality checks and fair cost distribution per IS 9627.

IS 9627 - Certification Mark Key Points

• ISI Certification Mark (Clause 12.1.1) may be applied on each pipe to certify compliance with the standard.
• The ISI Mark assures:
  • Production under a strict quality control system.
  • Continuous inspection, testing, and supervision by ISI.
  • Ongoing conformity checks by ISI.
• Use of the ISI Mark is governed by the Indian Standards Institution (Certification Marks) Act.
• Manufacturers must obtain a license from ISI to use the mark.
• Details on licensing conditions can be obtained directly from ISI.

Additional Notes:

• No direct formulas or tables are provided in IS 9627 related to the Certification Mark.
• The mark represents compliance, not a calculated value.
• Testing costs (Clause 8.1) are borne by:
  • Manufacturer if material fails.
  • Purchaser if material passes.

flowchart LR
    A[Manufacturer Produces Pipes] --> B[Quality Control & Testing]
    B --> C{Complies with IS 9627?}
    C -- Yes --> D[Apply ISI Certification Mark]
    C -- No --> E[Reject or Rework]
    D --> F[Continuous ISI Surveillance]

Summary: The ISI Certification Mark under IS 9627 is a mark of quality assurance, not a numeric specification. It requires licensing and ongoing compliance verified by ISI.