Code of practice for water supply and drainage in high altitudes and sub-zero temperature regions
1986 Edition

Overview of Scope

• Objective: To guide the design and operation of water supply and drainage systems in cold, high-altitude areas.

• Applicability: Focuses on engineering challenges in mountainous regions with harsh climates, ensuring:

  • Reliable water delivery
  • Safe and nuisance-free sanitary waste management

• Temperature Coverage: From 0°C to 10°C, relevant for high elevation zones.

• Physical Property Data:

  Temperature (°C)	Kinematic Viscosity (100×V) in Stokes (cm²/s)	Density (g/cm³)
  0	1.792	1.0
  5	1.519	1.0
  10	1.308	1.0

• Rounding Guidelines: Final values are rounded following IS 2:1960, matching the precision of specified data.

This document ensures the creation of frost-resilient water infrastructure tailored for cold and elevated regions.

flowchart LR
    A[High Altitude & Cold Regions] --> B[Water Supply Design]
    A --> C[Drainage and Sanitation]
    B --> D[Viscosity & Density Parameters]
    C --> E[Sanitary Waste Management]
    D --> F[Design Considerations]
    E --> F

Definitions and Reference Tables

1. Terminology (Clause 2.0)

• Test or analytical values must be rounded as per IS 2:1960.
• The count of significant digits in results should correspond with the given data.

2. Water Viscosity and Density at Low Temperatures (Appendix A, Clause 3.2.1)

• Viscosity decreases as temperature rises from 0 to 10°C.
• Density remains nearly constant at 1 g/cm³ in this temperature range.

3. Atmospheric Pressure at Elevated Altitudes (Appendix B, Clause 3.3)

• Atmospheric pressure decreases with altitude.
• Seasonal variations are slight but significant for design.

Summary:

• Utilize Table 1 for cold climate water properties.
• Refer to Table 2 for altitude-based atmospheric pressure corrections.
• Adhere to IS 2:1960 for data rounding compliance.

flowchart TD
    A[Water Temperature (0-10°C)] --> B[Decreasing Viscosity with Temp]
    A --> C[Stable Density ~1 g/cm³]
    D[Increasing Altitude] --> E[Decreasing Atmospheric Pressure]
    E --> F[Adjust Hydraulic Design Parameters]

Environmental Parameters for High Altitude and Sub-Zero Conditions

Essential Parameters:

• Temperature Limit: Below 4°C (Clause 3.1)
• Atmospheric Pressure Threshold: Below 0.86 N/mm² (~860 millibar)

1. Water Viscosity and Density at Low Temperatures (0°C to 10°C) (Appendix A, Table 1)

Note: Viscosity declines as temperature increases, density remains nearly 1 g/cm³.

2. Barometric Pressure Variation with Altitude (1500 to 5100 geopotential meters) (Appendix B, Table 2)

Pressure decreases with height and shows slight seasonal changes.

Design Implications:

• Account for increased viscosity at low temperatures in hydraulic calculations.
• Reduced atmospheric pressure impacts fluid flow and pressure heads.
• Use seasonal atmospheric pressure data for precise design in mountainous regions.

flowchart LR
    A[Temperature <4°C] --> B[Higher Viscosity]
    B --> C[Increased Flow Resistance]
    D[Altitude >1500 gpm] --> E[Lower Atmospheric Pressure]

Water Supply Systems for Cold and Elevated Regions

Core Guidelines:

• Scope: Provides instructions for water and sanitation systems in mountainous cold zones (Clauses 0.2, 1.1).
• Pipe Materials:
  • Centrifugally cast iron pressure pipes for water, gas, and sewage.
  • Unplasticized PVC pipes for drinking water supply.
• Thermal Insulation:
  • Use waterproof wrapping over insulation to prevent freezing.
  • Insulate service connections as shown in typical diagrams (Fig. 1).
• Atmospheric Pressure Effects:
  • Limits on pump suction head due to reduced pressure at altitude (Clause 3.3).
  • Refer to Appendix B for altitude-specific atmospheric pressures (e.g., Srinagar).

Important Design Formulas:

[ H_s = H_a - H_v - H_f ]

Where:

• (H_s) = Net available suction head

• (H_a) = Atmospheric pressure head (decreases with altitude)

• (H_v) = Vapor pressure head of water (temperature-dependent)

• (H_f) = Frictional losses in suction piping

• Insulation Measures:

  • Apply lagging with waterproof covering.
  • Ensure service connections are insulated to avoid freeze damage.

System Flow Diagram

flowchart LR
    Source[Water Source]
    Pump[Pump with altitude-adjusted suction head]
    Pipes[Spun Iron / uPVC Pipes]
    Insulation[Waterproof Wrapping & Lagging]
    Connection[Service Connection]
    Consumer[End User]

    Source --> Pump --> Pipes --> Insulation --> Connection --> Consumer

Refer to IS 6295 tables and Appendix B for pipe sizes, pressure classes, and insulation thickness details.

Key Points on Waste Disposal Systems in Cold Climates

1. Waste Disposal Techniques (Clauses 5.2 - 5.4)

• Utilized primarily when water-based sewage systems are not viable.
• Biological and chemical breakdown slows significantly at low temperatures; therefore, insulation is critical for functionality.

2. Waterborne Sanitation (Clause 5.5)

• Preferred where possible.
• Sewage pipes should be insulated to preserve heat.
• When sewers and water pipes share a utilidor:
  • Maintain at least 300 mm vertical clearance between water pipe bottoms and sewer tops to avoid contamination.

3. Pipe Standards

• Centrifugally cast iron pressure pipes are specified for water, gas, and sewage networks.
• Unplasticized PVC pipes are specified for potable water supply.

4. Insulation of Service Connections (Clause 4.4.6)

• House service connections should be insulated beneath the frost line.
• Typical insulation wrapping and lagging are illustrated in Fig. 1.

Clearance Requirements in Utilidors

flowchart TB
    A[Waterborne Sewage System] --> B[Insulated Sewage Pipes]
    B --> C{Shared Utilidor?}
    C -->|Yes| D[Maintain 300 mm clearance]
    C -->|No| E[Separate Trenches]
    D --> F[Prevent Cross-Contamination]
    E --> F

Ensuring insulation and proper separation is vital for system integrity and hygiene.

Guidelines for Fire Hydrants in Cold Regions

Freeze Protection Measures (Clauses 6.1 & 6.4)

• Fire hydrants should be housed within easily removable insulated enclosures to prevent freezing.
• Incorporate drain valves to enable complete water removal after use, avoiding freeze damage.

Design Considerations:

• Hydrants must remain accessible and clearly visible.
• Ensure proper drainage slope and valve installation to prevent water retention.
• Use centrifugally cast iron or uPVC pipes compliant with relevant IS standards for hydrant connections.

Drain Valve Arrangement

flowchart LR
    Fire Hydrant --> Valve --> Drain Valve --> Drain Outlet

Additional Notes:

• Clause 5.5.5 recommends heating lavatories and bathrooms to prevent freezing water traps, a principle extendable to fire hydrant pits.
• Apply insulation and waterproof coverings to service connections as per Fig. 1 in IS 6295.

Refer to IS 1536 and IS 4985 for detailed dimensions of pipes and valves used in hydrant systems.

Economic Considerations for Water Infrastructure at Elevated Altitudes

1. Atmospheric Pressure Variation (Srinagar Example)

• Atmospheric pressure decreases with increased altitude, values measured in millibars for elevations between 1500 and 5100 geopotential meters.
• Conversion factor: [ 1 \text{ millibar} = 10.1972 \text{ kgf/m}^2 ]
• Sample pressures:

2. Water Physical Properties at Low Temperatures (0-10°C)

Practical Implications:

• Lower atmospheric pressure impacts combustion efficiency, ventilation, and material properties.
• Increased water viscosity at low temperatures affects pumping and flow characteristics.
• Employ local atmospheric data for accurate design in mountainous regions.

flowchart TD
    Altitude Increase --> Lower Atmospheric Pressure
    Lower Atmospheric Pressure --> Reduced Oxygen Levels
    Lower Atmospheric Pressure --> Decreased Air Density
    Altitude Increase --> Decreasing Temperature
    Decreasing Temperature --> Higher Water Viscosity
    Higher Water Viscosity --> Hydraulic Design Modifications
    Decreased Air Density --> Structural and Economic Impacts

Summary: For safe and cost-effective design, utilize tabulated data on atmospheric pressure and water properties for cold, high-altitude environments.