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

IS 6295: Scope Summary

• Purpose: Provides guidance for water supply & drainage systems in high altitude and sub-zero temperature regions.

• Application: Addresses engineering challenges in mountainous areas with harsh climates, focusing on:

  • Adequate water supply
  • Sanitary waste disposal without nuisance or danger

• Temperature Range Covered: 0°C to 10°C (low temperatures relevant to high altitudes)

• Key Physical Properties Provided:

  Temperature (°C)	Kinematic Viscosity (100×V) Stokes (cm²/s)	Density (g/cm³)
  0	1.792	1
  5	1.519	1
  10	1.308	1

• Rounding Off: Final test/analysis values are rounded per IS 2:1960, matching significant figures of specified values.

This standard is essential for designing water systems resilient to cold and altitude effects, ensuring functionality and safety.

flowchart LR
    A[High Altitude & Sub-zero Regions] --> B[Water Supply Systems]
    A --> C[Drainage & Sanitation]
    B --> D[Kinematic Viscosity & Density Data]
    C --> E[Sanitary Waste Disposal]
    D --> F[Design Parameters]
    E --> F

IS 6295 - Definitions & Key Tables

1. Definitions (Clause 2.0)

• Values from tests or analysis shall be rounded off as per IS:2-1960.
• The number of significant digits in the rounded value should match the specified value.

2. Kinematic Viscosity & Density of Water at Low Temperatures (Appendix A, Clause 3.2.1)

• Viscosity decreases with temperature rise from 0 to 10°C.
• Density is approximately constant at 1 g/cm³ in this range.

3. Barometric Pressures at High Altitudes (Appendix B, Clause 3.3)

• Pressure decreases with altitude.
• Monthly variation is minor but important for high-altitude design considerations.

Summary:

• Use Table 1 for water viscosity/density in cold climates.
• Use Table 2 for barometric pressure adjustments at altitude.
• Round values as per IS:2-1960 for compliance.

flowchart TD
    A[Water Temperature (0-10°C)] --> B[Kinematic Viscosity ↓ with Temp]
    A --> C[Density ≈ 1 g/cm³]
    D[Altitude ↑] --> E[Barometric Pressure ↓]
    E --> F[Adjust design parameters for pressure]

This ensures accurate design inputs for hydraulic and structural systems in cold/high-altitude regions.

IS 6295: High Altitude & Sub-Zero Temperature Conditions

Key Specifications:

• Low Temperature Range: Below 4°C (Clause 3.1)
• Low Barometric Pressure: Below 0.86 N/mm² (approx. 860 millibar)

1. Kinematic Viscosity & Density of Water at Low Temperatures (0°C to 10°C)

(Appendix A, Table 1)

Kinematic viscosity decreases with temperature rise; density remains approx. 1 g/cm³.

2. Barometric Pressures at High Altitudes (1500 to 5100 geopotential meters)

(Appendix B, Table 2)

Barometric pressure decreases with altitude and varies seasonally.

Application Notes:

• Design water supply and drainage considering increased viscosity at low temps.
• Reduced barometric pressure affects fluid flow and pressure head calculations.
• Use seasonal barometric values for accurate hydraulic design in mountainous regions.

flowchart LR
    A[Low Temperature (<4°C)] --> B[Kinematic Viscosity ↑]
    B --> C[Flow Resistance ↑]
    D[High Altitude (>1500 gpm)] -->

IS 6295 - Water Supply Systems in High Altitude & Sub-Zero Regions

Key Points & Specifications:

• Scope: Guidance for water supply and sanitation in mountainous, cold regions (Clause 0.2, 1.1).
• Material Specifications:
  • Centrifugally cast (spun) iron pressure pipes for water, gas, sewage.
  • Unplasticized PVC pipes for potable water.
• Thermal Protection:
  • Waterproof wrapping over lagging to prevent freezing.
  • Insulation details at service connections (Fig. 1).
• Low Barometric Pressure Effects:
  • Limits pump suction head (Clause 3.3).
  • Refer Appendix B for barometric pressures at high altitudes (e.g., Srinagar).

Important Design Considerations:

• Pump Suction Head Adjustment:

  [ H_s = H_a - H_v - H_f ]

  Where:

  • (H_s) = Net suction head available
  • (H_a) = Atmospheric pressure head (reduced at high altitudes)
  • (H_v) = Vapor pressure head of water (temperature-dependent)
  • (H_f) = Friction losses in suction pipe

• Thermal Insulation:

  • Use lagging with waterproof wrapping.
  • Insulate service connections to prevent freezing.

Summary Diagram: Water Supply System Components

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

    Source --> Pump --> Pipe --> Insulation --> Service --> Consumer

For detailed pipe dimensions, pressure ratings, and insulation thickness refer to IS 6295 tables and Appendix B.

IS 6295: Waste Disposal Systems - Key Points & Specifications

1. Waste Disposal Methods (Clauses 5.2 - 5.4)

• Used only when water carriage systems are impractical.
• Biological and chemical degradation of waste slows at low temperatures; insulation is critical.

2. Water Borne Sanitation (Clause 5.5)

• Preferred method where feasible.
• Sewage collection systems must retain maximum heat via insulation.
• When placing sewers and water pipes in the same utilidor:
  • Maintain a minimum vertical clearance of 300 mm between the bottom of water pipes and the top of sewer lines to prevent contamination.

3. Pipe Specifications

• Centrifugally cast (spun) iron pressure pipes: For water, gas, sewage (per IS 6295 second revision).
• Unplasticized PVC pipes: For potable water supply (first revision).

4. Insulation & Service Connections (Clause 4.4.6)

• House service connections must be insulated below frost line.
• Refer to Fig. 1 for typical insulation wrapping and lagging details.

Summary Table: Sewer & Water Pipe Clearance in Utilidor

flowchart TB
    A[Water Borne Sanitation System] --> B[Insulated Sewage Pipes]
    B --> C{Utilidor?}
    C -->|Yes| D[Maintain 300 mm clearance]
    C -->|No| E[Separate trenches]
    D --> F[Prevent contamination]
    E --> F

Note: Always ensure insulation and separation to maintain system integrity and hygiene.

IS 6295 - Fire Hydrants: Key Specifications & Guidelines

Protection Against Freezing (Clause 6.1 & 6.4)

• Hydrant Protection: Fire hydrants should be housed in a quickly removable insulated box to prevent freezing.
• Drain Valve: Incorporate a drain valve to allow complete drainage of water, avoiding freeze damage.

Key Design Considerations:

• Location: Hydrants must be accessible and visible.
• Drainage: Ensure proper drainage slope and valve to prevent water stagnation inside.
• Material: Typically, centrifugally cast iron pipes or uPVC pipes per IS standards are used for hydrant connections.

Typical Fire Hydrant Drain Valve Setup:

flowchart LR
    A[Fire Hydrant] --> B[Valve]
    B --> C[Drain Valve]
    C --> D[Drain Outlet]

Additional Notes:

• Clause 5.5.5 emphasizes heating lavatories and bathrooms to prevent freezing in water traps, a principle extendable to hydrant pits.
• Use insulation and waterproof wrapping (see Fig.1 in IS 6295) for service connections in cold regions.

For detailed pipe and valve dimensions, refer to IS 1536 (centrifugally cast iron pipes) and IS 4985 (uPVC pipes).

IS 6295: Economic Factors at High Altitude Regions

1. Barometric Pressure at Altitudes (Srinagar Region)

• Barometric pressure decreases with altitude; values in millibar (mb) for 1500–5100 geopotential meters (gpm) are tabulated monthly.
• Conversion:
  [ 1 \text{ millibar} = 10.1972 \text{ kgf/m}^2 ]
• Example values at 1500 gpm: Jan = 858 mb, Jul = 840 mb; at 5100 gpm: Jan = 549 mb, Jul = 547 mb.

2. Kinematic Viscosity & Density of Water (0–10°C)

• Important for hydraulic calculations in cold climates.

Practical Notes:

• Reduced barometric pressure affects combustion, ventilation, and material properties.
• Water viscosity increases at low temperatures, affecting flow and pumping efficiency.
• Use local barometric data for design adjustments in high altitude projects.

flowchart TD
    A[Altitude Increase] --> B[Barometric Pressure Decrease]
    B --> C[Reduced Oxygen Availability]
    B --> D[Lower Air Density]
    A --> E[Lower Temperature]
    E --> F[Increased Water Viscosity]
    F --> G[Hydraulic Design Adjustments]
    D --> H[Structural & Economic Impact]

Summary: Use Table 2 for barometric pressure at altitude and Table 1 for water properties at low temperature to adapt designs economically and safely in