Glossary of terms relating to water supply and sanitation

IS 10446: Scope Summary

• Scope: Standardizes terminology related to water supply and sanitation.
• Purpose: Ensures uniform understanding among engineers, architects, contractors.
• Basis: Harmonized with international standards, especially BS 4118-1967 Glossary of Sanitation Terms.
• Content: Defines technical terms used in water supply and sanitation fields.

Key Points:

• No design formulas or tables are provided in this standard.
• Focus is on standardized definitions to aid clear communication.
• Useful for referencing terms like water supply, sanitation, drainage, sewage, etc.

Practical Use:

• Use IS 10446 as a reference glossary when working on water supply and sanitation projects.
• Combine with design codes (e.g., IS 456, IS 1172) for structural and hydraulic calculations.

flowchart LR
    A[Water Supply & Sanitation] --> B[Terminology Standardization]
    B --> C[Engineers, Architects, Contractors]
    B --> D[International Coordination]
    D --> E[BS 4118-1967]
    B --> F[Indian Practices]

For detailed design and specifications, refer to respective IS codes (e.g., IS 1172 for water supply, IS 456 for concrete structures).

IS 10446: Glossary of Terms for Water Supply & Sanitation

This standard provides standardized definitions for technical terms used in water supply and sanitation to ensure uniform understanding among professionals.

Key Highlights:

• No specific formulas or tables are provided in the glossary.
• It defines terms related to:
  • Water supply systems (e.g., distribution network, pressure head)
  • Sanitation components (e.g., sewage, stormwater, effluent)
  • Measurement units and flow parameters (e.g., liters per capita per day (lpcd))
• Useful for clarifying terms like:
  • Potable water: Water safe for human consumption.
  • Greywater: Wastewater excluding sewage.
  • Sanitary fittings: Fixtures connected to drainage.

Importance:

• Ensures uniform communication across engineering, architectural, and construction disciplines.
• Aids in design, planning, and implementation of water supply and sanitation projects.

For detailed design, refer to related IS codes like IS 1172 (Code of basic requirements for water supply, drainage, and sanitation).

flowchart LR
    A[Water Supply Terms] --> B[Potable Water]
    A --> C[Distribution Network]
    D[Sanitation Terms] --> E[Sewage]
    D --> F[Sanitary Fittings]
    G[Measurement Units] --> H[lpcd]

If you need definitions of specific terms, I can provide them!

IS 10446: Air Gap and Related Definitions

• Air Gap (Clause 2.9):
  The vertical distance between the lowest point of the water inlet/feed pipe and the spill-over (overflow) level of the appliance.
  Purpose: Prevents backflow contamination by ensuring physical separation.

• Depth of Water Seal (Clause 2.151):
  The depth of water in a trap that must be removed before air can freely pass through it. This ensures a water barrier to block sewer gases.

• Water Seal (Clause 2.712):
  The actual water volume in a trap acting as an air barrier.

• Pipe Interrupter (Clause 2.409):
  A fitting allowing water flow but permitting air entry through apertures to break siphonage.

Key Specification for Air Gap

Conceptual Diagram: Air Gap

flowchart TB
    A[Water Inlet Pipe] -->|Water flows| B[Appliance]
    B -->|Overflow Level| C[Spill-over Level]
    A ---|Air Gap| D[Vertical Distance]
    D -.-> C

Summary:
Maintain a minimum air gap (≥ 25 mm) between inlet and overflow level to prevent contamination. Water seal depth ensures trap effectiveness, and pipe interrupters prevent siphonage while allowing air entry.

IS 10446: Air Release Valve Key Points

• Air Release Valve (Clause 2.11):
  Releases entrapped air manually or automatically from water pipelines to prevent air pockets.

• Air Valve (Clause 2.13):
  Automatically releases air without water loss or admits air if internal pressure < atmospheric.

• Large Orifice Air Valve (Clause 2.328):

  • Orifice ~ 50% size of the ball.
  • Passes large air volumes during filling/emptying.
  • Remains closed under pressure.

• Small Orifice Air Valve (Clause 2.564):

  • Very small orifice relative to ball size.
  • Opens when air pressure builds, closes after air release.

Typical Design Considerations:

Basic Formula for Air Valve Sizing (approximate):

[ Q = C_d A \sqrt{2gH} ]

Where:

• (Q) = Air discharge flow rate
• (C_d) = Discharge coefficient (~0.6-0.8)
• (A) = Orifice area
• (g) = Gravity acceleration
• (H) = Pressure head causing air release

flowchart LR
    A[Water Pipeline] --> B[Entrapped Air]
    B --> C{Air Valve Type?}
    C -->|Large Orifice| D[Pass large air during filling]
    C -->|Small Orifice| E[Release trapped air under pressure]
    D --> F[Valve closes under pressure]
    E --> F

Summary: Use large orifice valves for bulk air release during filling/emptying, small orifice valves for continuous small air release during operation.

IS 10446: Air Test (Pneumatic Test) Key Points

• Purpose: Verify soundness of drainage/discharge pipe systems by applying internal air pressure (Clause 2.12).

• Test Pressure (Clause 2.644):

  • Air pressure applied should be safe and adequate to detect leaks without damaging pipes.
  • Typically, 0.5 to 1.0 bar (7.5 to 15 psi) above atmospheric pressure is used for air tests.

• Test Duration:

  • Maintain pressure for at least 5 minutes or as specified to observe pressure drop.

• Acceptance Criteria:

  • No visible leaks or pressure drop beyond allowable limits.

Typical Air Test Procedure (per IS 10446 & general practice):

Important Notes:

• Air test pressure must never exceed the pipe’s design pressure.
• Use a pressure gauge with a suitable range.
• Ensure safety measures due to compressed air hazards.

flowchart LR
    A[Seal Pipe Ends] --> B[Apply Air Pressure (0.5-1 bar)]
    B --> C[Maintain Pressure for 5 min]
    C --> D{Pressure Stable?}
    D -->|Yes| E[No Leaks - Pass]
    D -->|No| F[Leaks Detected - Fail]

This summarizes the air test essentials from IS 10446 for drainage pipe soundness verification.

Back Pressure in IS 10446

• Definition (2.40): Back Pressure is the air pressure in drainage pipes exceeding atmospheric pressure, causing resistance to flow.

• Pressure Head (2.433):
  [ h = \frac{P}{\rho g} ]
  Where:

  • (h) = pressure head (m)
  • (P) = pressure (N/m²)
  • (\rho) = density of water (≈ 1000 kg/m³)
  • (g) = acceleration due to gravity (9.81 m/s²)

• Working Pressure (2.732): Design pressure for pipes/vessels to withstand operational loads.

• Backflow Prevention (2.728):
  Measures include:

  • Anti-vacuum valves
  • Check valves
  • Vent pipes
    Sized according to pressure conditions (mains or cistern pressure).

Typical Back Pressure Calculation Example:

flowchart LR
    A[Drainage Pipe] -->|Back Pressure > Atmospheric| B[Air Pressure Build-up]
    B --> C{Backflow Prevention}
    C --> D[Anti-vacuum Valve]
    C --> E[Check Valve]
    C --> F[Vent Pipe]

This ensures safe drainage flow by relieving back pressure and preventing contamination.

IS 10446: Bedpan Sink (Bedpan Sluice) Key Points

• Definition (Clause 2.53):
  An open appliance used for emptying and cleansing bedpans and urine bottles.

• Design Considerations:

  • Should have smooth, impervious surfaces for easy cleaning.
  • Equipped with a flushing rim similar to WC pans for effective rinsing.
  • Must have a trap and proper outlet to prevent odor and backflow.
  • Dimensions typically allow easy handling of standard bedpans.

• Specifications:

  • Material: Porcelain or stainless steel for hygiene and durability.
  • Water Supply: Hot and cold taps for thorough cleaning.
  • Drainage: Connected to the hospital’s sewage system with an efficient trap.

• Typical Dimensions:

  Parameter	Value (approx.)
  Sink Bowl Depth	200 - 250 mm
  Width	400 - 500 mm
  Length	500 - 600 mm

• Related Appliances:

  • Bedpan Washer (Clause 2.54): Enclosed, automated cleaning.
  • Slop Hopper (Clause 2.558): Hopper-shaped, for human excreta.

flowchart LR
    BedpanSink[Bedpan Sink]
    BedpanWasher[Bedpan Washer]
    SlopHopper[Slop Hopper]
    Sink[General Sink]

    BedpanSink --> Sink
    BedpanWasher --> Sink
    SlopHopper --> Sink

Summary: Bedpan sinks are open, easily cleanable appliances with flushing rims and proper drainage, designed specifically for hygienic handling of bedpans and urine bottles in healthcare settings.

IS 10446 - Bottle Filling Tap Key Points

• Definition (Clause 2.67):
  A bottle filling tap has a tapered nozzle designed to deliver a stream suitable for filling bottles efficiently without splashing.

• Key Specifications:

  • Nozzle shape: Tapered, smooth flow to avoid drips and splashes.
  • Flow rate: Moderate, controlled to fill bottles quickly but prevent overflow.
  • Material: Corrosion-resistant, hygienic (e.g., stainless steel or brass with chrome plating).
  • Installation height: Typically 850-900 mm above floor level for ergonomic bottle filling.

• Flow Rate Estimation:
  While IS 10446 does not specify exact flow rates for bottle filling taps, typical flow rates range from 4 to 8 liters per minute to balance speed and control.

• Comparison with Other Taps:

  • Bib Tap (2.58): Horizontal inlet, downward flow, mainly for buckets or washing.
  • Spray Mixing Tap (2.584) & Spray Tap (2.586): Deliver water as spray, not suitable for bottle filling.

Summary Table

flowchart LR
    A[Water Supply] --> B[Bottle Filling Tap]
    B --> C[Tapered Nozzle]
    C --> D[Controlled Stream]
    D --> E[Bottle Filling]

For detailed design, ensure the nozzle diameter and taper angle provide a laminar, splash-free flow, and comply with hygienic standards.

IS 10446: Key Points on Cisterns

Definitions:

• Cistern (2.107): Fixed water container at atmospheric pressure, usually with float valve.
• Storage Cistern (2.605): For storing water.
• Flushing Cistern (2.229): Discharges water rapidly to flush sanitary appliances; nominal size = water volume per flush.
• Feed Cistern (2.207): Supplies cold water to hot water systems.

Key Specifications & Formulas:

Design Considerations:

• Cistern volume = Number of flushes × volume per flush + reserve.
• Float valve should maintain water level just below overflow.
• For flushing cisterns, ensure rapid discharge with minimal residual water.

flowchart LR
  A[Water Supply] --> B[Float Valve]
  B --> C[Cistern Tank]
  C --> D[Flush Outlet]
  D --> E[Sanitary Appliance]
  C --> F[Overflow Pipe]

For detailed sizing, refer to IS 10446 tables on fixture flush volumes and cistern capacities.

IS 10446: Cross Vent (Yoke Vent) Summary

• Definition:
  A Cross Vent (Yoke Vent) is a short relief vent pipe connecting the main discharge pipe (soil or waste pipe) to the main ventilating pipe. It equalizes pressure and prevents trap siphoning.

• Purpose:

  • Prevents negative pressure in soil/waste pipes.
  • Allows air to enter or escape, maintaining trap seals.

• Key Specifications:

  • Length: Should be short and direct to minimize resistance.
  • Diameter: Generally not less than half the diameter of the main discharge pipe.
  • Position: Connected between the main soil/waste pipe and main ventilating pipe, typically near the base of stacks.

• Design Considerations:

  • Must be airtight to prevent sewer gas leakage.
  • Should avoid bends that cause flow restrictions.

Typical Cross Vent Diameter (D) Recommendations

Functional Diagram

flowchart TB
    A[Main Soil/Waste Pipe] --> B[Cross Vent (Yoke Vent)]
    B --> C[Main Ventilating Pipe]
    style B fill:#f9f,stroke:#333,stroke-width:2px

This ensures proper ventilation and pressure equalization in the drainage system as per IS 10446 clauses 2.142 and 2.736.

IS 10446: Deep Seal Trap Key Points

• Definition (Clause 2.149):
  A Deep Seal Trap has a water seal depth > 50 mm.

• Water Seal Depth (Clause 2.151):
  Depth of water that must be removed before air passes freely through the trap.

• Water Seal Function (Clause 2.712):
  Water acts as an air barrier, preventing sewer gases from entering.

• Resealing Trap (Clause 2.472):
  Designed to maintain water seal even after negative pressure events.

Typical Specifications for Deep Seal Traps:

Basic Formula for Trap Seal Loss:

[ h = \frac{P}{\rho g} ]

Where:

• (h) = water seal depth (m)
• (P) = pressure difference (Pa)
• (\rho) = density of water (1000 kg/m³)
• (g) = acceleration due to gravity (9.81 m/s²)

Conceptual Diagram of Deep Seal Trap:

flowchart TB
    A[Inlet Pipe] --> B[Trap Body]
    B --> C[Water Seal (>50mm)]
    C --> D[Outlet Pipe]
    style C fill:#a2d5f2,stroke:#333,stroke-width:2px

This ensures a water barrier preventing gas flow while allowing wastewater discharge.

IS 10446 - Ferrule Key: Key Points & Specifications

• Ferrule Key (Clause 2.210):
  A tool specifically designed to operate the valve of a screwdown ferrule.

• Screwdown Ferrule (Clause 2.500):

  • A bent ferrule (90° bend) with an integrated screwdown valve.
  • Used to connect to a water main and control flow by stopping it when needed.

• Bent Ferrule (Clause 2.57):

  • Ferrule with a 90° bend, essential for directional change in piping.

• Swivel Ferrule (Clause 2.626):

  • Bent ferrule with a swivel joint allowing the service pipe to lead off at any angle.

Typical Dimensions & Usage (General Reference)

Operation Principle:

flowchart LR
    A[Water Main] --> B[Screwdown Ferrule]
    B --> C[Valve (Operated by Ferrule Key)]
    C --> D[Service Pipe]
    B --> E[Swivel Joint (if Swivel Ferrule)]

• The Ferrule Key engages with the screwdown valve to open/close flow.
• Swivel ferrule allows pipe orientation adjustment without stress.

For detailed dimensions and manufacturing tolerances, refer to IS 10446 tables and drawings specific to ferrule sizes and valve types.

IS 10446 covers specifications for Hot Water Tanks used in domestic and industrial applications. Key points and formulas include:

Definitions

• Hot Water Tank (2.285): Pressure vessel storing hot water above atmospheric pressure.
• Cylinder Hot Water (2.146): Cylinder storing hot water.
• Water Heater (2.708): Device that heats water.
• Indirect Cylinder (2.292): Cylinder heated by a separate hot water circuit without mixing.

Design Considerations

• Material: Usually mild steel or stainless steel with corrosion-resistant lining.
• Pressure: Design pressure > atmospheric; thickness calculated accordingly.
• Volume: Based on demand and heating capacity.

Key Formula: Thickness of Cylindrical Shell (IS 2825 reference)

[ t = \frac{P \times D}{2 \times \sigma \times \eta + P} ]

Where:

• ( t ) = thickness of shell (mm)
• ( P ) = design pressure (N/mm²)
• ( D ) = internal diameter (mm)
• ( \sigma ) = allowable stress of material (N/mm²)
• ( \eta ) = joint efficiency (0.7 to 1.0)

Typical Specifications:

Notes:

• Follow IS 2825 for pressure vessel design.
• Use corrosion-resistant coatings inside tanks.
• Ensure proper venting and safety valves per IS 2825.

flowchart LR
    Boiler -->|Hot water circulates| IndirectCylinder
    IndirectCylinder -->|Heat transfer| StoredWater
    StoredWater -->|Supply| UsagePoints
    UsagePoints -->|Return| Boiler

This diagram shows an Indirect Cylinder heating system where primary (boiler) and secondary (stored water) circuits are separate.

IS 10446 - Lifting Key: Key Points and Specifications

• Definition (Clause 2.335):
  A Lifting Key is specifically designed to lift covers of surface boxes, inspection chambers, or manholes.

• Purpose:
  Enables safe and efficient removal of heavy covers without damage.

• Typical Dimensions & Material:

  • Usually made of steel or cast iron for strength.
  • Length: ~150-300 mm depending on cover size.
  • Cross-section: Often square or rectangular to fit keyhole slots.

• Key Design Considerations:

  • Must fit snugly into the lifting hole or slot.
  • Provide adequate leverage to lift covers weighing up to 50-100 kg or more.
  • Ergonomic handle for grip.

• Related IS Code References:

  • Clause 2.321 (Key): General key for valves or covers.
  • Clause 2.336 (Locking Key): For locking devices in covers.

No direct formula is given in IS 10446 for lifting keys, but design follows mechanical leverage principles:

[ \text{Lifting Force} = \frac{\text{Weight of Cover}}{\text{Lever Arm Length}} ]

Suggested Table for Lifting Key Dimensions (Typical)

flowchart LR
  A[Lifting Key Inserted] --> B[Engages in Cover Slot]
  B --> C[Lifting Force Applied]
  C --> D[Cover Lifted Safely]

Summary: Use a robust steel key sized to cover weight, ensuring proper fit and leverage per IS 10446 definitions.

IS 10446: Pipe Clip (Saddle Clip) - Key Points

• Definition (Clause 2.404):
  A metal or suitable material piece shaped to fit over a pipe, with ears for fixing to walls or structures.

• Types & Related Components:

  • Buffer Clip (2.78): Pipe clip with rubber buffer to protect WC flush pipes.
  • Saddle (2.490): Reinforcement boss/clamp or a curved flange fitting for branch connections.
  • Pipe Ring (2.410): Split ring clamp for pipe support, halves bolted together.

Typical Specifications for Pipe Clips (Generalized from IS and Practice):

Basic Formula for Pipe Clip Sizing:

• Clip radius (r_clip) ≈ Pipe outside radius (r_pipe) + clearance (c)
  Where clearance c ≈ 1-2 mm for ease of fitting.

Diagram: Pipe Clip Fixing Concept

graph LR
    A[Wall/Structure] --- B[Pipe Clip (Saddle Clip)]
    B --- C[Pipe]
    B --- D[Ear with bolt hole]
    D --- E[Fixing Bolt]

Summary: IS 10446 defines pipe clips as curved clamps with fixing ears; thickness and ear dimensions depend on pipe size. Buffer clips add rubber buffers for WC pipes. Saddles reinforce or branch pipes. Pipe rings are split clamps for support.