Fabricated PVC-U Fittings for Potable Water Supplies - Specification, Part 12: Specific Requirements for 22 ½o Bends

IS 10124 (Part 12): Scope & Key Specifications for 22½° Bends

Scope:

• Covers dimensions and minimum wall thickness for 22½° bends in pipes.
• Applies to plain ends and elastomeric sealing ring joint bends.
• Dimensions and thickness vary by nominal pipe size and working pressure class (0.4 to 1.25 MPa).

Key Formulas & Notes:

• Y_min (offset length) = 22½° × 2 × π × R
• R_min (bend radius) = 3 × Nominal Outside Diameter (D)
• Minimum wall thickness (t) is based on 90% of the pipe thickness for the corresponding size and pressure class, rounded to the next 0.1 mm.

Table Summary (Excerpt for Plain Ends):

For Elastomeric Sealing Ring Joint Bends:

| Nominal Size (mm) | Y_min (mm) | L (mm) | R_min (mm) | Min Wall Thickness (mm) for Working

IS 10124 (Part 12) : 2009 — Key Formulas, Tables & Specifications

References (Table 2)

• IS 4985:2000 — Unplasticized PVC pipes for potable water.
• IS 10124 (Part 1):2009 — Fabricated PVC-U fittings, General requirements.

Dimensions of 22½° Bends (Clause 3.2.2)

Table 1: 22½° Bend Dimensions (Plain Ends)

Table 2: 22½° Bend Dimensions (Elastomeric Sealing Ring Joint)

| Nominal Size (mm) | Y Min (mm) | L Min (mm) | R Min (mm) | Min Wall Thickness (mm) for Pressure

IS 10124 Part 12: Manufacture - Key Specifications

1. Manufacture Clause (3.2)

• Specifies dimensions and wall thickness for 22½° bends.
• Two types of bends covered:
  • Plain Ends (Table 1, Fig. 1)
  • Elastomeric Sealing Ring Joint (Table 2, Fig. 2)

2. Key Dimensions & Wall Thickness (Tables 1 & 2)

3. Minimum Wall Thickness (t)

• Varies with Nominal Size and Working Pressure Class (MPa):

4. Notes

• Minimum wall thickness calculated as 90% of pipe thickness, rounded to next 0.1 mm.
• Radius ( R_{min} = 3D ) ensures proper bend curvature.
• Certification and marking follow BIS Act 1986 (Clause 4.2.1).

Example: For 90 mm nominal size (Plain Ends, Table 1)

• ( Y_{min} = 106 ) mm
• ( L_{min} = 90 ) mm
• ( R_{min} = 270 ) mm
• Wall thickness varies from 1.9 mm (0.6 MPa) to 5.5 mm (1.25 MPa)

flowchart TD
    A[Nominal Size (D)] --> B[R_min = 3 × D]
    B --> C[Calculate Y_min (bend length)]
    C --> D[Select Wall Thickness (t) based on Pressure Class]
    D --> E[Manufacture Bend as per Table Dimensions]

**Summary

IS 10124 Part 12: Marking of 22 1/2° Bends

Key Marking Requirements (Clause 4.1): Each 22 1/2° bend must be marked with:

• Manufacturer's name or ID mark
• Size of the bend and corresponding IS 4985 class (working pressure)
• Degree of the bend (22 1/2°)
• Colour code indicating class of fitting:

BIS Certification Mark (Clause 4.2):

• Use of BIS Standard Mark is governed by BIS Act, 1986.
• Manufacturer must obtain license for use.

Dimensional & Thickness Specifications (Table 1 & 2)

• Minimum bend radius (R_min) = 3 × Nominal Outside Diameter (D)
• Y_min = 22.5° × 2 × π × R_min / 360 (arc length formula for bend)
• Minimum wall thickness varies with size and pressure class; refer tables below.

For full details, refer to Tables 1 & 2 in the standard.

Summary Diagram of Marking Elements

IS 10124 Part 12: Dimensions for 22½° Bends

Key Parameters:

• Y Min: Minimum offset length, calculated as
  [ Y = 2 \times R \times \sin(22.5^\circ) ]
• R Min: Minimum bend radius = 3 × Nominal Outside Diameter (D)
• L (Plain Ends): Minimum length for plain ends (varies per size)
• Minimum Wall Thickness (t): Depends on working pressure class (MPa)

Table 1: Dimensions of 22½° Bends (Plain Ends)

(Refer to full Table 1 for intermediate sizes)

Table 2: Dimensions for 22½° Bends with Elastomeric Sealing Ring Joint

| Nominal Size (mm) | Y Min (mm) | L Min (

IS 10124 Part 12: Material Requirements Summary

Key Formulas & Specifications:

• Minimum Wall Thickness (t):
  Calculated as 90% of the minimum wall thickness of corresponding pipe size & pressure class, rounded to next 0.1 mm.

• Bend Radius (R, Min):
  [ R_{min} = 3 \times D ]
  where (D) = nominal outside diameter.

• Y Minimum (Y, Min):
  [ Y_{min} = 22.5^\circ \times 2 \pi R ]

Table: Dimensions of 22.5° Bend for Elastomeric Sealing Ring Joint (excerpt)

Note: Refer to IS 10124 Part 1 for general material, size, test, and conformity requirements.

flowchart LR
    A[Nominal Pipe Diameter (D)] --> B[Calculate R_min = 3D]
    B --> C[Calculate Y_min = 22.5° × 2πR]
    C --> D[Determine Min

IS 10124 Part 12: Pressure Classes & Color Coding for 22½° PVC-U Bends

Pressure Classes & Corresponding Colors (Clause 4.1)

Key Dimensions & Wall Thickness (Table 1 & 2)

• Minimum bend radius (R_min) = 3 × Nominal outside diameter (D)
• Y_min = 2 × 22½° × π × R (arc length for bend)
• Wall thickness varies with nominal size and pressure class; e.g., for 110 mm nominal size:
  • Class 2 (0.4 MPa): 2.3 mm
  • Class 3 (0.6 MPa): 3.4 mm
  • Class 4 (0.8 MPa): 4.4 mm
  • Class 5 (1.0 MPa): 5.5 mm
  • Class 6 (1.25 MPa): 6.8 mm

Marking Requirements on Each Bend

• Manufacturer's ID
• Size & Class (pressure rating per IS 4985)
• Degree of bend (22½°)
• Color coding as per class

Summary Formulae:

• R_min = 3 × D
• Y_min = (22.5° / 360°) × 2π × R_min = 2 × 22½° × π × R_min

flowchart TD
    A[22½° Bend] --> B{Marking}
    B --> C[Manufacturer's ID]
    B --> D[Size & Class]
    B --> E[Degree of Bend]
    B --> F[Color Coding]
    F --> G[Blue (Class 2)]
    F --> H[Green (Class 3)]
    F --> I[Brown (Class 4)]
    F --> J[Yellow

IS 10124 Part 12: Design for Elastomeric Sealing Ring Joints – Key Details

1. Bend Geometry & Dimensions

• Bend angle: 22½°
• Minimum radius (R_min): 3 × Nominal Outside Diameter (D)
• Y_min: Calculated as ( 22.5^\circ \times 2 \pi R ) (Clause 1.25)
• Plain end length (L): Provided per nominal size in Table 2

2. Minimum Wall Thickness (t)

• Calculated as 90% of the minimum wall thickness of the corresponding pipe size and pressure class, rounded up to nearest 0.1 mm.
• Varies with working pressure class (0.4 to 1.25 MPa)

3. Table 2: Dimensions for 22½° Bend (Elastomeric Sealing Ring Joint)

IS 10124 Part 12: Testing and Sampling - Key Points

• Rounding Off Results:
  Follow IS 2:1960 for rounding numerical values.

  • Retain the same number of significant figures as the specified value.
  • Ensures consistency and comparability of test results.

• General Requirements:
  Refer to IS 10124 Part 1 for:

  • Material specifications
  • Size tolerances
  • Testing procedures
  • Sampling methods
  • Criteria for conformity

• Testing & Sampling:
  While Part 12 focuses on specific tests, the overall methodology aligns with Part 1, which includes:

  • Sampling Plan: Random sampling from batches for representative testing.
  • Test Types: Mechanical, chemical, dimensional, and visual inspections.
  • Acceptance Criteria: Based on batch conformity and test results within specified limits.

Summary Table: Rounding Off (IS 2:1960)

For detailed sampling and testing procedures, always cross-check with IS 10124 Part 1 and relevant test standards referenced therein.

IS 10124 Part 12: Conformity Criteria - Key Points

• General conformity requirements (materials, sizes, tests, sampling) refer to IS 10124 Part 1 (Clause 3.1).

• Rounding off results: Final test values must be rounded as per IS 2:1960 rules, keeping the same significant figures as the specified values (Clause None).

• Dimensions for 22½° bends:

  • For standard bends, refer to Table 1 + Fig. 1.
  • For elastomeric sealing ring joint bends, refer to Table 2 + Fig. 2 (Clause 3.2.2).

Example: Rounding Off (IS 2:1960)

• Specified value: 12.5
• Calculated value: 12.47 → Rounded to 12.5

Typical Dimensional Table Format (from IS 10124 Part 12)

(Refer to actual IS tables for precise values)

flowchart LR
    A[Material & Size] --> B[Tests & Sampling per IS 10124 Part 1]
    B --> C[Dimension Check]
    C --> D{Bend Type}
    D -->|Standard| E[Table 1 + Fig. 1]
    D -->|Elastomeric Joint| F[Table 2 + Fig. 2]
    E & F --> G[Conformity Decision]
    G --> H[Rounding off as per IS 2:1960]

For exact dimensions and test criteria, always consult IS 10124 Part 1 and Part 12 tables and figures.

BIS Certification Marking (IS 10124 Part 12 - Clause 4.2 & 4.2.1)

• Certification Mark: Each 22½° bend may be marked with the BIS Standard Mark.
• License: Use governed by Bureau of Indian Standards Act, 1986.
• Details & Conditions: Obtained from BIS for license to use the Standard Mark.

Key Dimensions & Specifications for 22½° Bends (Clause 3.2.2)

Table: Minimum Wall Thickness (t) for 22½° Bend (Plain Ends)

Refer to the full table for all sizes and classes.

Table: Minimum Wall Thickness (t) for 22½° Bend with Elastomeric Sealing Ring Joint

IS 10124 Part 12 refers to general requirements as per IS 10124 Part 1 for fabricated PVC-U fittings for potable water supplies.

Key Points from IS 10124 Part 1 (General Requirements):

• Material: PVC-U (Unplasticized Polyvinyl Chloride) conforming to IS 4985.
• Sizes: Standard nominal sizes as per IS 4985.
• Tests:
  • Dimensional checks (OD, ID, wall thickness)
  • Hydrostatic pressure test (typically at 6 bar for 1 hour)
  • Impact resistance test
  • Flattening test
  • Leak test
• Sampling: Random sampling as per IS 10124 Part 1 guidelines.
• Criteria for conformity:
  • Dimensional tolerances within ±2%
  • No leakage under test pressure
  • No cracks or visible defects after tests

Reference Table of Standards:

Typical Dimensional Tolerances (Example):

Hydrostatic Test Pressure:

• Test pressure = 1.5 times the working pressure (usually 6 bar for potable water fittings)

flowchart LR
A[Material: PVC-U] --> B[Dimensional Checks]
B --> C[Hydrostatic Pressure Test]
C --> D[Impact Resistance Test]
D --> E[Flattening Test]
E --> F[Leak Test]
F --> G[Conformity Criteria]

For detailed values and procedures, refer directly to IS 10124 Part 1: 2009.