The Uses of Valves and Pipe Fittings in Daily Life

Valves and pipe fittings (elbows, tees, connectors, flanges, etc.) essentially serve as connection components and flow controllers for piping systems. They are found wherever there is water, gas, or heating; many are concealed within walls or beneath cabinets, remaining out of sight during daily use.
I. Tap Water Systems (Most common in the home)
Main Shut-off Valve: The gate valve or ball valve on the main water supply line entering the home; used to cut off water to the entire house during repairs or faucet replacements.
Angle Valve: Small valves located beneath toilets, washbasins, and water heaters; they control the water supply to a specific fixture, allowing for maintenance without shutting off water to the entire house.
Pipe Fittings: Straight connectors, elbows, and tees used to change direction, split the flow, and route water to various points of use.
Check Valve: Installed at water heaters or booster pumps to prevent backflow (e.g., preventing water from flowing back into the mains during a supply outage).
II. Gas Piping (Natural Gas)
Main Gas Ball Valve: The primary shut-off switch for the home's gas supply; it can be turned off when the home is left vacant for extended periods.
Gas Hose Connectors and Tees: Fittings used to connect appliances such as stoves and water heaters.
Gas valves and fittings are classified as specialized equipment; unauthorized modification is strictly prohibited.
III. Heating / Hot Water Systems (Underfloor heating, radiators, wall-hung boilers)
Ball Valves and Butterfly Valves: Switches for heating circuit branches, allowing individual heating loops to be shut off separately.
Filter Ball Valve: A valve with an integrated filter installed at the inlet of a wall-hung boiler to trap sediment and debris.
Air Vent Valve: Automatically bleeds air from the piping to ensure efficient heating performance.
Pipe Fittings: Manifolds, elbows, and unions; underfloor heating manifolds are essentially assemblies of multiple valves and fittings.
IV. Kitchen and Bathroom Equipment
Water Heater: Inlet valve and pressure relief valve (automatically drains water if pressure becomes excessive to protect the inner tank).
Washing Machine: Inlet angle valve.
Water Purifier: Pre-filter housing valve and tee connector; used to divert a portion of the tap water supply to the purifier.
V. Residential Community Common Areas (Public Utilities)
Fire Safety: Fire hydrants and fire-rated butterfly valves; supply water for firefighting and are located in corridors and basements. Secondary water supply pump room: Large-diameter gate valves and check valves for supplying water to high-rise buildings.
Rainwater and sewage piping networks: Municipal pipeline gate valves and manhole fittings.
VI. Other residential applications
Central air conditioning / Air-source heat pumps: Valves and unions for circulating water piping; facilitates maintenance of water circuits.
Rooftop water tanks: Inlet float valves; automatically shut off when full to prevent overflow.
Car washers and garden irrigation: Quick-connect hose fittings and small ball valves.