GRP pipes joints and fittings for use in sewerage, industrial waste and water (other than potable)

IS 14402 Scope - Key Specifications & Tables

1. Pipe Dimensions & Tolerances

Refer to Clause 7.1.1 & 7.1.2 for full tables.

2. Pipe Stiffness at 5% Deflection (kPa)

Clause 10.1

3. Visual Acceptance Levels for Defects

*Clause 6.5, Table 3

IS 14402 Type Tests Summary

Purpose (Clause 3.6.1):
Type tests verify pipe suitability and performance after significant design or manufacturing changes or at specified intervals.

Key Specifications:

• Sampling (Clause G-2.1):

  • Not mandatory unless agreed between manufacturer & purchaser.
  • Test certificates must be provided on request for:
    • Long-term hydrostatic design pressure test (Clause 15)
    • Long-term chemical requirement test (Clause 16)

• Test Pieces (Clause D-2.3):

  • Samples must represent the actual pipe material and manufacturing process.

• Test Temperature (Clause F-9.1.4):

  • Tests are conducted at specified temperatures relevant to service conditions.

Important Tests & Parameters:

Typical Formula for Hydrostatic Design Pressure:

[ P = \frac{2 \times \sigma_t \times t}{D} ]

Where:

• (P) = Design pressure
• (\sigma_t) = Allowable tensile stress
• (t) = Pipe wall thickness
• (D) = Outside diameter

flowchart TD
    A[Design/Process Change] --> B[Type Test Required]
    B --> C{Sampling Agreed?}
    C -- Yes --> D[Sample Test Pieces]
    C -- No --> E[No Sampling]
    D --> F[Conduct Hydrostatic & Chemical Tests]
    F --> G[Provide Test Certificates]

Summary: Type tests ensure pipe reliability under design conditions, with sampling and testing protocols defined for pressure and chemical resistance.

IS 14402: Key Formulas, Tables & Specifications for Stiffness Classes

1. Pipe Stiffness (Clause 10.1)

• Pipe Stiffness (F/Ay) is the load per unit length divided by vertical deflection:

  [ \text{Pipe Stiffness} = \frac{F}{A_y} ]

  Where:

  • (F) = Load per unit length (kN/m)
  • (A_y) = Vertical deflection (m)

2. Pipe Stiffness Classes & Minimum Stiffness (Table 4)

3. Deflection Levels & Limits (Clause 10.1.1, Table 10)

Note: Visual inspection only; recommended max in use is 5% deflection.

4. Minimum Chemical Requirements: Strain vs Time (Table 9)

IS 14402: Size Designation & Nominal Diameter Key Data

1. Inside Diameter (ID) - Clause 7.1.1 & Table 1

• Specified inside diameter must be within the range and tolerances below:

(For full table, refer to IS 14402 Clause 7.1.1)

2. Outside Diameter (OD) - Clause 7.1.2 & Table 2

• Specified outside diameter and tolerances:

IS 14402: Key Materials Specifications & Formulas

1. Visual Acceptance Levels for Defects (Clause 6.5, Table 9)

2. Pipe Stiffness at 5% Deflection (Clause 10.1, Table 4)

3. Minimum Strain (EScv) at Various Times (Clause 16.2.1.2, Table 9)

[ \text{EScv} = \text{strain fraction} \times \frac{t}{d} ]

Where:

• ( t ) = nominal wall thickness
• ( d ) = mean diameter (inside diameter + ( t ))

IS 14402: Dimensions and Tolerances for Pipes

1. Outside Diameter (OD) & Tolerances (Table 2, Clause 7.1.2)

• OD is specified with positive tolerance only.
• Larger diameters have higher tolerances.

2. Inside Diameter (ID) & Tolerances (Table 1, Clause 7.1.1)

• ID tolerances are ± values around declared ID.
• Some sizes have no explicit tolerance listed (refer to code for details).

3. Measurement (Clause 7.3, Annex A)

• Diameters measured as per specified procedures ensuring compliance with tolerances.
• OD and ID checked to confirm pipe size designation.

Summary Formula for Tolerance Check:

[ \text{Measured OD} \leq \text{Specified OD} + \text{Tolerance} ] [ \text{Specified ID} - \text{Tolerance} \leq \text{Measured ID} \leq \text{Specified ID} + \text{Tolerance} ]

This ensures pipes meet dimensional accuracy for fit and function per IS 14402.

IS 14402 - Joints: Key Formulas, Tables, and Specifications

1. Types of Joints (Clause 8.2.1 & 8.2.2)

• Joints similar to Clause 8.1.1 but with supplemental restraining elements.
• Butt Joint with Laminated Overlay: Provides enhanced strength by layering additional laminate over the joint area.

2. Workmanship and Visual Acceptance (Clause 6.5, Table 9)

3. Pipe Stiffness at 5% Deflection (Clause 10.1, Table 4)

4. General Notes

• Joints and fittings per IS 14402 are guidance only; detailed design may require additional calculations.
• Ensure supplemental restraining elements to improve joint integrity.
• Visual defects must be within acceptance limits to maintain structural and hydraulic performance.

flowchart LR
    A[Pipe Sections] --> B[Joints]
    B --> C[Butt Joint]
    B --> D[Butt Joint with Laminated Overlay]
    C --> E[Supplemental

IS 14402 - Workmanship: Key Specifications & Acceptance Criteria

Workmanship must follow good practices per Clause 9.1 and meet acceptance criteria in Table 3 for defects in laminated plastics.

Allowable Defects & Visual Acceptance Levels (Summary)

IS 14402 Mechanical Properties Summary

1. Pipe Stiffness & Minimum Strain (Clause 16.2.1.2)

• t = nominal total wall thickness
• d = mean diameter (inside diameter + t)

2. Pipe Stiffness Classes (Clause 10.1)

3. Long Term Hydrostatic Design Pressure (Clause 15)

IS 14402 – Key Specifications & Formulas for Fittings

1. Fabrication (Clause 11.2)

• Fittings must be made from complete or portions of straight pipes complying with pipe classification.
• Mitre cuts are mandatory and must be overwrapped externally and, if possible, internally with woven roving/chopped strand mat.
• This ensures longitudinal and circumferential tensile strength ≥ pipe strength.

2. Tolerances (Clause 11.4)

• Length tolerance (excluding socket): ±25 mm from intersection point to fitting end.
• Angle tolerance for bends/tees/junctions: ±1º deviation allowed.
• For flanged pipework, tighter tolerances may apply.

Summary Table

This ensures fittings maintain strength and dimensional accuracy compatible with the pipe system.

flowchart LR
    A[Straight Pipe] --> B[Mitre Cut]
    B --> C[External Overwrap]
    B --> D[Internal Overwrap (if practicable)]
    C & D --> E[Fitting with Strength ≥ Pipe]
    E --> F[Length ±25 mm]
    E --> G[Angle ±1º]

IS 14402: Hydraulic Test Key Points

1. Hydrostatic Test Pressure (Clause 12.2, Table 5)

Each pipe (DN ≤ 1400 mm) must withstand without leakage/cracking:

For DN > 1400 mm, test frequency is as agreed.

2. Longitudinal Strength (Clause 13, Table 6)

• Pipes DN ≤ 600: Beam load test (kN) and minimum longitudinal tensile strength (kN/m circumference).
• Pipes DN > 600: Tensile tests on pipe wall specimens.

Example for DN 300, PN 9:

• Beam Load = 7.1 kN
• Min Longitudinal Tensile Strength = 102 kN/m

3. Hoop Tensile Strength (Clause 14, Table 7)

Minimum hoop tensile strength (kN/m width of circumference) by size and pressure class.

Example for DN 300:

• PN 3: 182 kN/m
• PN 15: 910 kN/m

4. Long-Term Hydrostatic Design Pressure (Clause 15, Table 8)

5. Formula for Longitudinal Tensile Strength (Clause 15)

[ T = \frac{F}{w} ]

• T = Longitudinal tensile strength (kN/m)
• F = Failure force (N)
• w = Width of test piece (mm)

Summary Diagram: Hydraulic Test Flow

flowchart TD
    A[Pipe Sample] --> B[Hydrostatic Test at Pressure (Table 5)]
    B -->|Pass| C[

IS 14402 - Chemical Resistance Test Method (Annex F)

Key Points & Specifications

• Test Purpose: Determine chemical resistance of fiberglass pipe under deflection (Clause F-1.1).
• Specimen: Minimum length = 1 nominal pipe diameter or 300 mm, whichever is less (Clause F-5).
• Test Condition: Ambient temperature (Clause F-6).
• Apparatus: Two parallel steel plates with a 6 mm elastomeric (rubber) pad between plates and pipe to ensure uniform strain (Clause F-3.2). Load applied vertically to maintain constant deflection (Fig. 7).
• Chemical Exposure: Specimen is immersed in test solution within 30 minutes of locking apparatus; exposure time noted (Clause F-7.9).
• Safety: Use spacers to contain leaks due to catastrophic failure (Clause F-7.9).

Long-Term Resistance Evaluation

• Method: Log-log linear regression of initial strain vs. time.
• Extrapolation: To 100,000 hours (approx. 11.4 years) or 50 years, whichever applicable (Clause F-3.2).

Summary of Method A (F-7) - Key Formula for Extrapolation

[ \log(\varepsilon) = m \log(t) + c ]

• (\varepsilon) = Initial strain level
• (t) = Time (hours)
• (m, c) = Regression constants from test data

Use this to predict strain at long durations.

Apparatus Diagram (Fig. 7)

graph LR
A[Steel Plate (Channel)] -- 6 mm Rubber Pad --> B[Test Specimen (Pipe)]
B -- 6 mm Rubber Pad --> C[Steel Plate (Channel)]
D[Vertical Load] --> B

This test ensures reliable chemical resistance data for design life prediction of fiberglass pipes under strain.

IS 14402: Sampling, Frequency, and Criteria for Conformity

Sampling Procedure (Annex G)

• Minimum samples: 18 to determine regression line & lower confidence level (Clause 7.12)
• Failure points distribution:

Inspection Frequency (Clause 7.13)

Criteria for Conformity

• Record time to endpoint for each specimen.
• Use control test procedures (Clause 16.2.1.6) as alternative to reconfirmation.
• Ensure data points are well-distributed across life hours for valid regression.

This ensures statistically reliable durability and conformity assessment per IS 14402.

IS 14402: Marking and Licensing Key Points

1. BIS Certification Marking (Clause 18.2)

• Pipes may be marked with the Standard Mark as per BIS regulations.
• Use of the Standard Mark is governed by the BIS Act, 1986.
• Licensing details for the Standard Mark are available from the Bureau of Indian Standards.

2. Pipe Stiffness & Minimum Strain (Clause 16.2.1.2)

• t = nominal wall thickness, d = mean diameter (inside diameter + t).

3. Pipe Stiffness Classes at 5% Deflection (Clause 10.1)