Asbestos Cement Pressure Pipes and Joints

IS 1592 - Scope: Key Formulas, Tables & Specifications

1. Tolerances on Pipes (Clause 1.5)

2. External Diameter of Finished Ends (Clause 2.5)

• Nominal diameter ( d = ) specified nominal diameter.
• For pipes > 500 mm, internal diameter checked at 3 points per end (60° apart), accuracy ±1 mm.
• None of six measured diameters < allowed by formula.

3. Nominal Wall Thickness Tolerances (Clause 2.5c)

• Plus tolerance is free (no upper limit).
• Thickness at any point ≥ nominal - tolerance.
• Average thickness ≥ nominal; max 10% samples with negative tolerance.

4. Length Tolerances (Clause 2.5d)

• Length tolerance: +3 mm / -0 mm.

5. Straightness Deviation (Optional Test, Clause 2.5e)

6. Dimensions & Weight of AC Couplings (Clause 4

Classification of Pipes as per IS 1592

1. Classes Based on Works Hydraulic Test Pressure (Table 1)

• Pipes up to 1000 mm nominal diameter are classified by TP.
• Hydraulic working pressure (WP) ≤ 50% of TP.
• Total WP including surge ≤ 75% of TP.

2. Pressure Relationships (Table 2)

• BP = Bursting Pressure
• TP = Works Hydraulic Test Pressure
• WP = Hydraulic Working Pressure

3. Nominal Diameters (Table 3)

4. Pipes Over 1000 mm Diameter

• Not classified by standard classes.
• Designed per purchaser's data and specific pipeline requirements.
• Must account for crushing loads per relevant IS guidelines.

Summary:

• Select pipe class based on Table 1 TP values.
• Ensure WP ≤ 0.5 TP and total WP including surge ≤ 0.75 TP.
• Use Table 2 for pressure safety factors (BP/TP and BP/WP).
• For pipes > 1000 mm, design is project-specific.

IS 1592: Dimensions & Tolerances Summary

1. Tolerances on Pipe Dimensions (Clause 1.5 & 2.5)

• For wall thickness at jointing surfaces, negative tolerances vary by thickness:

• Plus tolerance is free (no upper limit).

2. External Diameter Tolerances at Pipe Ends (Clause 3.4.1.4)

3. Straightness Deviation Limits (Optional Test, Clause 2.5 e)

l = length of pipe segment tested

4. **AC Couplings Dimensions & Weights

IS 1592: Physical and Mechanical Characteristics Summary

1. Tolerances (Clause 1.5)

2. Mechanical Characteristics (Clause 3.4.3)

• Unit strength from tests (3.5(a)(2), (3), (4)) must meet or exceed specified values.
• For non-immersed specimens, minimum unit bursting strength = 24 N/mm² (based on manufacturing diameter if different from nominal).

3. Geometrical Characteristics (Clause 4.2.1)

• Specifies dimensional accuracy and shape requirements (not detailed here).

Key Formula:

Bursting Strength (σ_b) = Load at failure / Cross-sectional area

Where:

• Cross-sectional area = π × (d_o × t) (approximate for thin-walled pipes)
• d_o = outer diameter
• t = thickness

flowchart LR
    A[Manufacturing] --> B[Dimensional Tolerances]
    B --> C[Mechanical Testing]
    C --> D[Unit Strength ≥ Specified Values]
    D --> E[Acceptance / Rejection]

Summary: Ensure dimensional tolerances as per Clause 1.5, and verify mechanical strength ≥ 24 N/mm² for non-immersed specimens per Clause 3.4.3. Use manufacturing diameter for calculations if different from nominal.

IS 1592: Joints and Sealing Requirements - Key Points

1. Sealing Characteristics (Clause 4.2.2)

• Joints must withstand the specified hydraulic test pressure even at the maximum angular deviation recommended.
• Test pressure as per Clause 3.5(a)(1) (typically the design pressure or higher for safety).

2. Fluid Considerations (Clause 7.1)

• Manufacturer must be informed of the fluid type to ensure compatibility of joint rings.
• Special tests for chemical resistance may be required depending on fluid nature.

3. Verification by Sampling (Clause 5.2.1)

• Sealing and mechanical properties can be verified by sampling tests upon request.

4. Dimensional Tolerances (Clause 3.4.1.4)

• The pipe section with rubber rings must meet external diameter tolerances.
• Ends must be free from irregularities to maintain water tightness.
• End shapes are manufacturer-defined to suit joint type.

Typical Joint Sealing Test (Hydraulic Pressure)

Summary Diagram: Joint Sealing Test Setup

flowchart LR
    A[Pipe with Rubber Ring] --> B[Assembled Joint]
    B --> C[Apply Hydraulic Pressure]
    C --> D{Max Angular Deviation?}
    D -->|Yes| E[Test for Leakage]
    D -->|No| F[Adjust Angle]
    E --> G{Leakage?}
    G -->|No| H[Pass]
    G -->|Yes| I[Fail - Redesign/Repair]

Note: Always refer to manufacturer specs for angular deviation and ring material compatibility per fluid conveyed.

IS 1592: Marking and Identification Key Points

1. Marking Requirements (Clause 3.6.1)

Each pipe must be legibly and indelibly marked with:

• Source of manufacture
• Date of manufacture and batch number
• Nominal diameter
• Class of pipe
• Pictorial warning sign as per IS 12081 (Part 2)

2. BIS Certification (Clause 3.6.2)

• Pipes may carry the BIS Standard Mark indicating compliance.

3. Tolerances on Dimensions (Clause 1.5)

4. Verification (Clause 5.1.2)

• Appearance, geometry, and marking must be verified on each consignment item.

Summary Diagram: Marking Information on Pipe

graph TD
    A[Pipe] --> B[Source of Manufacture]
    A --> C[Date & Batch Number]
    A --> D[Nominal Diameter]
    A --> E[Class of Pipe]
    A --> F[Pictorial Warning (IS 12081 Pt.2)]
    A --> G[BIS Mark (optional)]

This ensures traceability, quality control, and safety compliance.

IS 1592: Acceptance Tests and Inspection Key Points

1. Measurement Specifications (Clause 6.0)

• Internal Diameter: Average of measurements at 3 places.
• Thickness: Average of 3 places excluding groove section.
• Weight: Weight per piece in kg.

2. Acceptance Tests (Annex C)

• Test Types: Specified by purchaser at order (e.g., internal hydraulic pressure tightness).
• Test Scheduling: By mutual agreement; tests must complete before delivery and within 4 weeks of sampling.
• Access: Purchaser has right to inspect/testing at manufacturer's premises.
• Cost Responsibility:
  • Manufacturer pays for compulsory and initially ordered optional tests.
  • Purchaser pays for additional optional tests by agreement.
• Inspection:
  • Can be 100% or by sampling.
  • If sampling indicates failure, 100% inspection may be required.
• Certificates:
  • Manufacturer issues test certificates if purchaser is absent during testing.

3. Summary Table for Inspection & Testing

flowchart TD
    A[Order Placement] --> B{Tests Required?}
    B -- Yes --> C[Schedule Tests]
    C --> D[Conduct Tests]
    D --> E{Tests Passed?}
    E -- Yes --> F[Delivery]
    E -- No --> G[Re-inspection or 100% Inspection]
    G --> D
    F --> H[Manufacturer Issues Certificate]

This ensures quality compliance and traceability per IS 1592 requirements.

IS 1592: Sampling Procedures & Specifications Summary

Sampling & Inspection (Clause 5.2 & 5.2.3)

• Sampling follows IS 7639 procedure for inspection and acceptance.
• Each inspection lot must have items of same diameter and class.
• For diameters > 1000 mm, purchaser-manufacturer agreement is mandatory.

Tolerances (Clause 1.5)

Measurement Notes (Clause 6.0)

• Internal diameter: Average of 3 places.
• Thickness: Average of 3 places (excluding groove section).
• Weight: Per piece in kg.

Acceptance Tests (Annex C)

• Tests agreed at ordering; purchaser informs manufacturer.
• Purchaser access to test sites and stock for inspection.
• Manufacturer bears cost of compulsory and order-specified tests.
• Sampling inspection can replace 100% inspection, but failing lots require full inspection.
• All tests completed before delivery and within 4 weeks of sampling.
• Manufacturer provides a certificate after testing.

flowchart TD
    A[Order Placement] --> B[Sampling as per IS 7639]
    B --> C{Diameter > 1000 mm?}
    C -- Yes --> D[Agreement between purchaser & manufacturer]
    C -- No --> E[Proceed with sampling]
    E --> F[Tests as agreed]
    F --> G{Pass?}
    G -- Yes --> H[Lot Accepted]
    G -- No --> I[100% inspection on failing characteristics]
    I --> J{Pass?}
    J -- Yes --> H
    J -- No --> K[Lot Rejected]

This summary ensures compliance with IS 1592 sampling and acceptance criteria.

IS 1592: Manufacturing Requirements Summary

1. Dimensional Tolerances (Clause 1.5 & 2.5)

Wall Thickness Tolerances:

• Plus tolerance is free.
• Thickness at any point ≥ nominal thickness minus tolerance.
• Average thickness of samples ≥ nominal thickness; max 10% can have negative tolerance.

2. Internal Diameter Measurement (Clause 6.0 & 2.5)

• Average internal diameter measured at 3 places per end, spaced ~60° apart.
• Accuracy ±1 mm.
• None of the six measured diameters shall be smaller than allowed by the formula.

3. Straightness (Optional Test, Clause 2.5)

L = length of the pipe

4. **Acceptance Tests

IS 1592: Guidelines for Selection and Installation of Asbestos Cement Pipes

Key Specifications and Tolerances

1. Pipe Dimensions

• External Diameter (d): Nominal diameter as per clause 2.5.
• Internal Diameter Check (for pipes > 500 mm):
  Measure 3 diameters at each end at 60° apart; none should be smaller than allowed by formula with ±1 mm accuracy.

2. Wall Thickness Tolerances

• Plus tolerance is free.
• Thickness at any point ≥ nominal thickness minus tolerance.
• Average thickness of samples ≥ nominal thickness; max 10% with negative tolerance.

3. Length Tolerances

• At least 90% pipes must be standard length (± tolerance).
• Remaining pipes ≥ 2 m.
• Total length supplied ≥ length ordered.
• Short length pipes tested same as standard length.

4. Straightness Deviation (Optional Test)

l = length considered for straightness

Additional Guidelines

• Special Applications: Specify aggressive water/soil conditions to manufacturer for material/treatment advice.
• Safety: Delivery must include safety rules sheet as per IS 11769 (Part 1).
• Acceptance Tests: Internal hydraulic pressure test mandatory for acceptance.
• Short Length Pipes: Additional joints supplied free if short pipes are delivered.

IS 1592: Safety and Compliance Key Points

1. Tolerances on AC Couplings (Clause 1.5)

2. Dimensions & Weight of AC Couplings (Annex B, Clause 4.1.3)

(Refer to full table in Clause 4.1.3 for all sizes)

3. Mechanical Characteristics (Clause 3.4.3)

• Couplings must meet specified mechanical strength and dimensional accuracy.
• Compliance with ICS 23.040.50; 91.100.40 ensures durability and safety.

Summary:

• Dimensional tolerances ensure proper fit and performance.
• Weight and size tables guide selection and quality control.
• Mechanical specs guarantee safety under operational loads.

flowchart TD
    A[AC Coupling] --> B{Check Dimensions}
    B -->|Within Tolerance| C[Accept]
    B -->|Out of Tolerance

IS 1592 - Annexes & References Summary

Key Tables & Specifications:

Tolerances (Clause 1.5):

Annex B: Dimensions & Weight of AC Couplings (Sample)

(Refer to Annex B for full table)

Annex C: Acceptance Tests

• Tests must be agreed upon at order.
• Internal hydraulic pressure test per 3.5(a)(1).
• Purchaser access for inspection.
• Manufacturer bears costs for compulsory and agreed optional tests.
• Sampling inspection allowed, with 100% inspection if lot tends to reject.
• Tests completed before delivery, max 4 weeks post-sampling.
• Manufacturer’s certificate required.

Annex A: Referenced Indian Standards (Sample)