Code of practice for laying cast iron pipes

IS 3114: Scope & Key Specifications Summary

Scope (Clause 1.3):
This code covers standard pipe jointing and installation but excludes:

• Piping through rigid walls
• Subaqueous piping
• Piping requiring insulation
• Plant or pump station piping

Key Tables & Formulas:

Note: Quantities may be adjusted on-site by the Engineer-in-Charge.

Cleaning Up (Clause 10.4):

• Remove all surplus materials, tools, and temporary structures.
• Clear dirt, rubbish, and excess earth to leave site clean as per Authority.

Referenced IS Standards (Annex A):

• IS 456: Plain & Reinforced Concrete
• IS 638: Sheet Rubber Jointing
• IS 782: Caulking Lead
• IS 1536/1537: Iron Pressure Pipes
• IS 5330: Anchor Blocks Design

flowchart TD
    A[Scope Exclusions] -->|Exclude| B[Piping through rigid walls]
    A --> C[Subaqueous piping]
    A --> D[Piping requiring insulation]
    A --> E[Plant or pump station piping]
    F[Lead Wool & Spun Yarn Quantities] --> G[Table by Nominal Diameter]
    H[Cleaning Up] --> I[Remove surplus materials]
    H --> J[Site left clean to Authority's satisfaction]

This summary provides essential scope and material quantities for pipe jointing per IS 3114.

IS 3114: Terminology & Key Specifications Summary

• Rock Excavation (Clause 3.9):
  Definition of 'rock' follows IS 1200 (Part 1):1974.

• Lead for Pipe Joints (Clause 6.1.3.2, Table 1):
  Lead quantity and depth depend on pipe nominal size.
  Example:

  Nominal Size (mm)	Lead per Joint (kg)	Depth of Lead Joint (mm)
  80	1.8	45
  150	3.4	50
  300	7.2	55
  600	19.0	60
  1500	66.5	75

  Note: ±20% variation in lead quantity allowed.

• Materials & Methods:

  • Spun yarn centers spigot, prevents lead flow into bore, reduces lead quantity, ensures watertight joint.
  • Spun yarn must be disinfected or sterilized.
  • Alternatives: shredded lead, lead wire/strip, lead-covered yarn.
  • Caulking tools: pneumatic or hand hammer (≥2 kg).
  • Lead run joints finish 3 mm behind socket face.

• Lead Wool & Spun Yarn Quantities for Single Collar Joints (Clause 6.1.3.6, Table 2):

  Nominal Internal Dia (mm)	Lead Wool Mass (kg)	Spun Yarn Mass (kg)
  80	1.30	0.17
  150	2.41	0.34
  400	7.00	1.33
  900	18.80	4.25
  1200	28.44	6.01

Summary Diagram of Lead Joint Components

graph LR
A[

IS 3114: Key Specifications for Trenching and Excavation

1. Trench Width (Clause 3.2)

• Minimum clearance 200 mm on each side of the pipe between sheeting faces.
• Extra width as needed for timber supports, strutting, planking, and handling specials.
• Exception: For rock excavation, clearance may differ.

2. Sheeting and Bracing (Clause 3.11 & 3.11.1)

• Sheeting and bracing must comply with state laws and municipal regulations.
• Close sheeting must prevent soil ingress below or through the sheeting.
• The Authority may require sheeting to be driven to full trench depth or deeper for protection.
• If soil stability at trench bottom is adequate, sheeting may stop above bottom as approved.

3. Excavation Method (Clause 3.1.1)

• Hand excavation where specified by Authority.
• Elsewhere, hand or machine excavation allowed.

Typical Trench Width Formula:

[ \text{Trench Width} = \text{Pipe Diameter} + 2 \times 200,mm + \text{Extra for supports} ]

Summary Table:

flowchart TD
    A[Start Excavation] --> B{Location?}
    B -->|Specified by Authority| C[Hand Excavation]
    B -->|Elsewhere| D[Hand or Machine Excavation]
    C --> E[Trench Width: Pipe + 400 mm + Extra]
    D --> E
    E --> F{Sheeting Required?}
    F -->|Yes| G[Drive sheeting full depth or as directed]
    F -->|No| H[Proceed with excavation]
    G --> I[Bracing & Supports Installed]
    I --> J[Complete Trenching]
    H --> J

This ensures safe, compliant trenching with adequate space and protection.

IS 3114: Key Specifications & Formulas for Laying of Pipes

1. Trench Excavation (Clause 1.0)

• Minimum cover under roadways: 1.0 m (modifiable per local conditions).
• Trench depth & alignment must match pipe requirements.
• Trench must be braced and drained for safe working.
• Dewatering discharge must be directed to drainage channels or natural drains, not near site.

2. Number of Pipes Laid Before Jointing (Clause 4.6)

• Pipes should be laid in manageable lengths before jointing to avoid damage and ease handling.
• Exact number depends on site conditions and pipe size (refer to Authority instructions).

3. Laying Pipe (Clause 4.5)

• No debris, tools, clothing, or other materials inside pipes during operations.
• Pipes must be handled carefully to avoid damage.

4. Permissible Deflection at Socket & Spigot Joints (Clause 4.9)

Summary Diagram of Deflection Limits:

graph LR
A[Pipe Joint] --> B[Lead Joint: 2°20']
A --> C[Rubber Joint]
C --> D[80-300 mm: 5°]
C --> E[350-400 mm: 4°]
C --> F[450-750 mm: 3°]

For detailed pipe laying, always consult the Authority and follow site-specific instructions.

IS 3114: Anchorage and Restraint Key Points

1. Anchor/Thrust Blocks Design

• Design per IS 5330:1984.
• Thrust resistant design pressure = test pressure of the pipeline.

2. Usage of Anchors (Clause 5.3)

Anchors are required:

• At bends or points with unbalanced pressure.
• On step gradients where joint shear resistance is inadequate.
• To control expansion/contraction due to temperature changes.

3. Materials for Restraint (Clause 5.5)

• Reaction backing (vertical/horizontal) must be M15 concrete (IS 456:1978).

Typical Thrust Force Calculation (from IS 5330 & general practice):

[ F = P \times A = P \times \frac{\pi}{4} \times (D^2 - d^2) ]

Where:

• (F) = Thrust force (N)
• (P) = Internal pressure (N/mm²)
• (D) = Outside diameter of pipe (mm)
• (d) = Inside diameter of pipe (mm)

Summary Table: Anchor Block Design Parameters

flowchart LR
    A[Pipeline] --> B[Points of Unbalanced Pressure]
    B --> C[Anchor/Thrust Block]
    C --> D[Resists Thrust Force]
    D --> E[Made of M15 Concrete]
    C --> F[Designed per IS 5330:1984]

For detailed dimensions and reinforcement, refer to IS 5330:1984.

IS 3114: Jointing of Pipes - Key Formulas, Tables, and Specifications

1. Number of Pipes Laid Before Jointing

• Refer Clause 4.6 for permissible limits on pipes laid before jointing to ensure proper handling and alignment.

2. Direction of Laying of Socket End

• See Table 4.8 (Clause 4.9) for correct orientation of the socket end during laying.

3. Permissible Deflection at Socket and Spigot Joints (Clause 4.9)

Deflection helps avoid obstructions or create curves without stressing the joint.

4. Jointing Materials (Clause 6.1)

• Molten lead (dry conditions)
• Lead wool (wet conditions)
• Tarred yarn (for sewers, if necessary)

5. Quantity of Lead for Joints (Clause 6.1.3.2)

• Refer Table 1 (IS 3114) for lead quantity per pipe size.
• Example (typical values):

(Exact values must be taken from IS 3114 Table 1.)

Summary Diagram: Joint Deflection Limits

graph LR
A[Socket & Spigot Joint] --> B[Lead Joint: 2°20']
A --> C[Rubber Joint 80-300mm: 5°]
A --> D[Rubber Joint 350-400mm: 4°]
A --> E[Rubber Joint 450-750mm: 3°]

IS 3114: Testing of Pipes – Key Points

Types of Tests (Clause 7.1)

• Pressure Test: At pressure specified in Clause 7.2.
• Leakage Test: At pressure specified by the Authority, for 2 hours.

Leakage Test Details (Clause 7.3.1)

• Conducted concurrently with pressure test.
• Leakage is the water volume supplied to maintain pressure within 0.035 N/mm² of leakage test pressure after air expulsion and filling.

Time for Testing

• Cement Jointed Pipes (Clause 7.4.4): Testing time as specified (usually minimum 2 hours).
• Lead Jointed Pipes (Clause 7.4.3): Testing time as specified (usually minimum 2 hours).

Summary Table

Notes:

• Ensure air is expelled before testing.
• Testing is done on newly laid and jointed pipes or valved sections.
• Leakage test pressure is slightly less than pressure test pressure by 0.035 N/mm².

flowchart LR
    A[New Pipe Laid & Jointed] --> B[Expel Air & Fill Water]
    B --> C[Pressure Test @ Clause 7.2 Pressure]
    C --> D[Leakage Test @ Authority Specified Pressure]
    D --> E[Duration: 2 Hours]
    E --> F{Leakage ≤ 0.035 N/mm²?}
    F -- Yes --> G[Pass]
    F -- No --> H[Fail - Repair Required]

This ensures pipe integrity and leak tightness as per IS 3114 standards.

IS 3114 - Back-Filling Key Points

1. Back-Fill Material and Layering

• Zone A (Clause 8.4):

  • Use sand, fine gravel, or approved material.
  • Place in 150 mm layers by hand.
  • Compact each layer by tamping.
  • Material must cover the full width on both sides of pipe and fittings simultaneously.

• Zone B (Clause 8.5):

  • Back-fill by hand or approved mechanical methods.
  • Also in 150 mm layers.
  • Avoid pipe damage during placement.
  • Material and method as prescribed by the Authority.

2. Partial Back-Filling Before Testing (Clause 7.4.2)

• Allowed only with Authority permission.
• Avoid back-filling at joints before testing.

Summary Table for Back-Filling Layers

Notes:

• Always ensure simultaneous placement on both sides of pipe to prevent displacement.
• Compact each layer thoroughly to avoid settlement and pipe damage.

flowchart TD
    A[Start Back-Filling] --> B{Zone}
    B -->|Zone A| C[Use sand/fine gravel]
    B -->|Zone B| D[Use approved material]
    C --> E[Place 150 mm layers by hand]
    D --> F[Place 150 mm layers by hand or machine]
    E --> G[Compact each layer by tamping]
    F --> H[Compact as per authority]
    G --> I[Full width on both sides simultaneously]
    H --> I
    I --> J[Complete Back-Filling]

This ensures proper back-filling per IS 3114.

IS 3114: Disinfection of New Mains – Key Points & Formulas

1. Sources of Contamination

• Sewer drainage, contaminated soil, workmen/equipment, foreign materials.

2. Disinfection Methods

3. Procedure Summary

• Inject chlorine solution (hypochlorite or liquid chlorine) at constant rate.
• Maintain chlorine residual by periodic checks.
• Prevent backflow of strong chlorine solution into supply line.
• After contact period, flush chlorinated water until chlorine residual matches system levels.
• Conduct bacteriological tests; repeat disinfection if standards not met.

4. Important Specifications

• Continuous Feed:
  Chlorine concentration: 20–50 mg/l
  Contact time: ≥ 24 hours
  Residual chlorine after contact: ≥ 10 mg/l

• Slug Method:
  Chlorine concentration: ≥ 300 mg/l
  Contact time: ≥ 3 hours

flowchart LR
    A[Start: New Main Installation] --> B{Select Disinfection Method}
    B -->|Continuous Feed| C[Inject 20-50 mg/l Chlorine]
    B -->|Slug Method| D[Inject ≥300 mg/l Chlorine Slug]
    C --> E[Maintain Chlorine Residual ≥10 mg/l for 24 hrs]
    D --> F[Maintain Chlorine Slug Contact for 3 hrs]
    E --> G[Operate Valves & Hydrants]
    F --> G
    G --> H[Flush Chlorinated Water to System Levels]
    H --> I[Bacteriological Testing]
    I --> J{Pass Test?}
    J -->|Yes| K[Main Ready for Service]
    J -->|No| B

Summary: Proper disinfection requires maintaining specified

IS 3114 Key Points on Pavement Removal and Restoration

1. Allowable Removal of Pavement (Clause 10.1)

• Only remove pavement as necessary.
• Preserve sound materials like granite blocks, bricks, asphalt blocks for reuse.

2. Restoration of Pavement and Structures (Clause 10.3)

• Restore all disturbed pavements, footpaths, curbs, gutters, fences, poles, shrubbery, etc. to original condition.
• Use original sound materials where possible.
• Permanent pavement restoration only after back-fill is properly compacted and approved by Authority.

3. Restoration of Damaged Surfaces (Clause 10.2)

• Repair or replace any damaged property or surface structures after work completion.

4. Back-Fill Under Permanent Pavement (Clause 8.7)

• Back-fill under permanent pavements/curbs must be sand as per Clause 8.2.1.
• Consolidation method to be approved by Authority.
• Non-permanent pavements (broken stone, gravel, slag, cinders) do not require sand back-fill.

Typical Back-fill Specification (from Clause 8.2.1)

Summary Flow Diagram for Pavement Restoration

flowchart TD
    A[Excavation] --> B{Pavement Type?}
    B -->|Permanent| C[Back-fill with Sand]
    B -->|Non-Permanent| D[Back-fill with original material]
    C --> E[Compaction & Approval]
    D --> E
    E --> F[Restore pavement with sound materials]
    F --> G[Repair damaged property]
    G --> H[Final Inspection & Approval]

Note: Always follow Authority’s instructions for consolidation and material reuse.

IS 3114: Recommended Quantities of Lead and Yarn for Joints

1. Quantity of Lead for Different Pipe Sizes (Clause 6.1.3.2, Table 1)

Note: ±20% variation in lead quantity is permissible.

2. Quantity of Lead Wool and Spun Yarn (Clause 6.1.3.6, Table 2)

Note: Quantities may vary with site conditions as per Engineer-in-Charge.

Additional Specifications

• Spun Yarn: Used to center spigot, prevent lead flow into bore, reduce lead quantity, and ensure watertightness.
• Disinfection: Yarn must be disinfected or use sterilized brands to avoid bacterial contamination.
• **Caul

Committee Responsible for Preparation (IS 3114:1994)

• The Water Supply and Sanitation Sectional Committee, CED 24 prepared this standard.
• The committee includes experts from government departments, public health engineering, consulting engineers, research institutes, and industry.
• Key roles:
  • Chairman: Shri V. B. Patel (Personal capacity)
  • Members: Representatives from PHE departments, municipal corporations, engineering institutions, and industry.
  • Member Secretary: Hemant Kumar
• The committee ensures coordination with related Indian Standards (see Annex A) such as IS 456 (Concrete), IS 638 (Rubber jointing), IS 1536 (Cast iron pipes), etc.
• The standard reflects best practices in pipe laying, safety, and material specifications, harmonized with international standards.

Summary Table: Committee Composition (Excerpt)

This committee ensures the standard covers technical, safety, and practical aspects of laying cast iron pipes, referencing appropriate IS codes and international practices.