Code of practice for laying glazed stoneware pipes

IS 4127: Scope - Strength and Loading of Pipes (Appendix A, Clause 5.10)

Key Formula: Marston’s Load Calculation

[ W = C \times w \times B ]

Where:

• W = Load on pipe (kg/m length)
• C = Coefficient based on trench depth/width ratio and soil type (from Table 1)
• w = Weight of filling material (kg/m³) (from Table 2)
• B = Width of trench (m)

Table 1: Coefficient (C) for Different Soil Types and Depth-to-Width Ratios

(Refer to full table in IS 4127 for intermediate values)

Table 2: Weight of Common Filling Materials

Additional Specifications

• Superimposed load limit: 1600 kg/m length (minimum crushing strength per IS

IS 4127: Definitions & Key Formulas for Strength and Loading of Pipes

1. Load on Pipe (Marston's Formula)

[ W = C \times w \times B ]

• W = Load on pipe (kg/m)
• C = Coefficient (depends on trench depth/width ratio and soil type, see Table 1)
• w = Weight of filling material (kg/m³, see Table 2)
• B = Width of trench (m)

2. Coefficient ( C ) (Table 1 excerpt)

3. Weight of Filling Materials (Table 2)

4. Additional Dimensions for Loading Calculations

• ( W = D + X )
  • ( D ) = External diameter of pipe
  • ( X = \begin{cases} 300,mm & \text{if trench depth} \leq 1.20,m \ 400,mm & \text{if trench depth} > 1.20

IS 4127: Excavation and Preparation of Trench - Key Points

1. Trench Dimensions (Clause 1.20)

• For depth ≤ 1.20 m:
  [ \text{Trench width} = \text{Pipe diameter} + 300 \text{ mm} ]
• For depth > 1.20 m:
  [ \text{Trench width} = \text{Pipe diameter} + 400 \text{ mm} ]
• Minimum trench width for depths > 0.9 m:
  [ \geq 0.75 \text{ m} ]

2. Depth and Cover (Clause 3.1)

• Minimum cover under roadways: 90 cm (modifiable per local conditions)
• Trench depth must allow pipe laying at required alignment and depth.

3. Safety & Work Conditions (Clause 3.1)

• Trenching by manual or approved mechanical means.
• Trench must be shored and drained for safe working.
• Dewatering discharge to drainage or natural drains.

Summary Table for Trench Width

flowchart TD
    A[Start Excavation] --> B{Depth ≤ 1.20 m?}
    B -- Yes --> C[Width = Pipe dia + 300 mm]
    B -- No --> D[Width = Pipe dia + 400 mm]
    D --> E{Width < 0.75 m?}
    E -- Yes --> F[Width = 0.75 m minimum]
    E -- No --> G[Use calculated width]
    C --> G
    F --> G
    G --> H[Ensure min cover 90 cm under road]
    H --> I[Shore & drain trench]
    I --> J[Lay pipe]

This ensures safe, efficient pipe laying per IS 4127.

IS 4127: Bedding, Haunching, Surrounding & Encasing of Pipes

Key Formulas:

• Width of bedding/surround (W):
  [ W = D + X ]
  where,

  • (D) = External diameter of pipe
  • (X = \begin{cases} 300 \text{ mm} & \text{if trench depth} \leq 1.20 \text{ m} \ 400 \text{ mm} & \text{if trench depth} > 1.20 \text{ m} \end{cases})

• Thickness of bedding/haunching (T):
  [ T = \begin{cases} 100 \text{ mm} & \text{for pipes } < 150 \text{ mm nominal diameter} \ \max\left(150, \min\left(\frac{ID}{4}, 300\right)\right) & \text{for pipes } \geq 150 \text{ mm} \end{cases} ]
  where (ID) = Internal diameter of pipe.

Specifications:

• Bedding:
  Concrete bedding is mandatory if the water table is at invert level or soil is soft (Clause 4.1). Precast concrete sleepers or sand cushion may be used for swelling soils.

• Haunching:
  Concrete haunching provided as per Fig. 2, with thickness (T) as above.

• Surrounding/Encasing:
  Concrete surround or encasing as per Fig. 3, width (W) and thickness (T) as above.

• Additional Support:
  Wooden struts fixed horizontally at mid-depth to distribute loads (Fig. 5, Clause 4.2).

Summary Table:

IS 4127: Key Specifications & Formulas for Laying Pipes

1. Load on Pipe (Marston's Formula)

[ W = C \times w \times B ]

• W = Load on pipe (kg/m)
• C = Coefficient (depends on trench depth/width ratio & soil type, see Table 1)
• w = Weight of filling material (kg/m³, see Table 2)
• B = Width of trench (m)

2. Coefficient ( C ) (Table 1 excerpt)

3. Weight of Filling Materials (Table 2)

4. Trench Dimensions (Clause 1.20)

• W = D + X
  • (D) = External pipe diameter
  • (X = 300 \text{ mm}) (trench depth ≤ 1.20 m)
  • (X = 400 \text{ mm}) (trench depth > 1.20 m)
• T (Haunching thickness):
  • 100 mm for pipes < 150 mm diameter
  • ¼ internal diameter for pipes > 150 mm (min 150 mm, max 300 mm)

5. Bedding & Surround (Clause 4.1)

• Concrete bedding required if water table at pipe invert.
• Precast concrete

IS 4127: Jointing of Pipes – Key Formulas & Specifications

1. Cement Quantity for Cement Joints (Clause 6.1.2.4)
Approximate cement required per joint for glazed stoneware pipes:

2. Jointing Procedure (Clause 6.3)

• Socket and spigot must be thoroughly wetted before making the joint.
• Use ordinary, low heat, Portland slag, or Portland pozzolana cement as per relevant IS specifications.
• Use tarred gasket or spun yarn soaked in neat cement slurry for sealing.

3. Typical Cement Joint Detail (Fig. 4)

• Socket length = X (as per pipe size)
• Joint filled with cement mortar around the spigot and socket.

4. Types of Joints (Clause 6.1)

• Cement joints or bituminous joints as approved by the Authority.

Summary Diagram: Cement Joint Components

flowchart LR
    A[Spigot End] -->|Insert into| B(Socket)
    B --> C[Cement Mortar]
    C --> D[Tarred Gasket / Spun Yarn soaked in Cement Slurry]
    D --> E[Sealed Joint]

Note: Always follow IS specifications for cement types and sand quality (IS 269, IS 455, IS 3812, IS 1542). Ensure proper curing for joint strength.

IS 4127: Testing of Pipelines - Key Formulas & Specifications

1. Test Pressure (Clause 7.1)

• Minimum test pressure = 2.5 m head of water at the highest point of the pipeline section.
• Leakage tolerance: 2 litres per cm diameter per km over 10 minutes.

2. Load Calculation on Pipes (Clause 5.10, Appendix A)

• Marston's Formula for superimposed load on pipe:

  [ W = C \times w \times B ]

  Where:

  • (W) = Load on pipe (kg/m)
  • (C) = Coefficient (depends on trench depth/width ratio & soil type, see Table 1)
  • (w) = Weight of filling material (kg/m³), see Table 2
  • (B) = Width of trench (m)

3. Coefficient (C) Values (Table 1)

(Refer full table for detailed values)

4. Weight of Filling Materials (Table 2)

IS 4127 - Backfilling Key Points

Backfilling Zones & Methods:

• Zone A (Clause 2.5.1):

  • Backfill by hand using sand, fine gravel, or approved material.
  • Place in 80 mm layers, compact by tamping.
  • Deposit material simultaneously on both sides of pipe/fittings for full trench width.

• Zone C (Clause 8.5.3):

  • Backfill by hand or approved mechanical means.
  • If by hand, use 300 mm layers, compact well before next layer.

Use of Excavated Material (Clause 8.7):

• Allowed if compliant with Clause 8.3.
• Suitable for Zone C where settlement is not critical.
• Allowed if material is loam, clay, sand, fine gravel, or approved by Authority.

Backfill Material Specification (Clause 8.3.1):

• Sand must be natural, graded from fine to coarse.
• Should comply with industrial sieve standards (IS Part 1 - wire cloth sieves).

Summary Table for Backfilling Layers

Notes:

• Always compact each layer thoroughly before next.
• Excavated material use depends on Authority approval and material type.
• Follow industrial sieve standards for grading sand.

flowchart TD
    A[Start Backfilling] --> B{Zone?}
    B -->|Zone A| C[Hand place 80mm layers]
    C --> D[Compact by tamping]
    B -->|Zone C| E[Place 300mm layers]
    E --> F{Method?}
    F -->|Hand| G[Compact well before next layer]
    F -->|Mechanical| H[Approved mechanical compaction]
    D & G & H --> I[Backfilling Complete]

This ensures proper compaction and pipe protection per IS 4127.

IS 4127: Strength and Loading of Pipes (Clause 5.10, Appendix A)

Key Formula: Marston's Load on Pipe

[ W = C \times w \times B ]

• W = Load on pipe (kg/m length)
• C = Coefficient (depends on trench depth/width ratio & soil type, see Table 1)
• w = Weight of filling material (kg/m³, see Table 2)
• B = Width of trench (m)

Table 1: Coefficient ( C ) Values (Sample)

Table 2: Weight of Filling Materials

Important Notes:

• Max superimposed load should not exceed 1600 kg/m length (minimum crushing strength per IS 651-1980).
• Surface (traffic) loads on pipes are calculated as per IS 783-1959, Clause 5.4.
• For higher loading capacity, refer to measures in Appendix A

Hydraulic Testing of Stoneware Pipe Sewer Lines (IS 4127 - Appendix B, Clause 7.2)

Key Points:

• Objective: Ensure pipe integrity and leak-tightness after laying.
• Test Medium: Usually water.
• Test Pressure: Should not exceed the pipe's safe crushing strength (min. crushing strength = 1600 kg/m length per IS 651-1980).

Load Calculation (Marston's Formula)

[ W = C \times w \times B ]

• W: Load on pipe (kg/m length)
• C: Coefficient (depends on trench depth/width ratio and soil type) — see Table 1
• w: Weight of filling material (kg/m³) — see Table 2
• B: Width of trench (m)

Table 1: Coefficient ( C ) Values (Sample)

(Refer full table in IS 4127 Appendix A)

Table 2: Weight of Common Filling Materials

Testing Procedure Summary:

• Fill pipe with water.
• Apply test pressure gradually (not exceeding crushing strength).
• Maintain pressure for specified duration (usually 30 minutes).
• Check for leakage or pressure drop.

flowchart TD
    A[Pipe laid in trench] --> B[Backfill with selected material]
    B --> C[Calculate Load W = C × w × B]
    C --> D[Apply Hydraulic Test]
    D --> E