Each fixture in a water supply system represents a certain demand of water. Supply requirement for common fixtures:
|Fixture||Flow rate||Minimum Supply Pressure|
|Dish washing machine||4||15||8||55|
|Drinking fountain jet||0.75||3||8||55|
|Hose bib or sillcock, 1/2"||5||19||8||55|
|Laundry faucet 1/2"||5||19||8||55|
|Lavatory faucet, ordinary||2||7.5||8||55|
|Lavatory faucet, self closing||2.5||10||8||55|
|Shower, temperature controlled||3||10||20||138|
|Sink faucet 3/8", 1/2"||4.5||17||8||55|
|Sink faucet 3/4"||6||23||8||55|
|Urinal flush valve||15||56||15||110|
|Water closet with flush valve||35||132||25||170|
|Water closet with gravity tank||2.5||10||8||55|
|Water closet with close coupled tank, ballcock||3||11||8||55|
Adding up the numbers to cover all fixtures in a system would give the total demand if all fixtures were used at the same time. This is almost never realistic for a supply system. Reasonable estimates must be made based on simultaneously demand from the fixtures.
Example - Required Water Supply
For a water supply system the summarized theoretical water flow for all fixtures is 10 l/s. The largest fixture in the system requires 0.4 l/s.
Based on the diagram above the expected total water flow in the system will be aprox. 1.1 l/s.
Hot and cold water service systems - design properties, capacities, sizing and more.
Required cold water dwelling storage capacity - commonly used fixtures and types of buildings.
Cold water storage for occupants in common types of buildings as factories, hospitals, houses and more
Farming and animals required water supply.
Content of hot water in some common used fixtures - basins, sinks and baths.
Hot water can be circulated through a return pipe if it's instantly required at the fixtures.
Design hot water consumption of fixtures - basins, showers, sinks and baths.
Plumbing or sanitation codes are a set of rules and regulations imposed by cities, counties or states.
Maximum Drainage Fixture Unit - DFU - loads in sanitary piping systems.
Activity and average water consumption
Calculating expected demand for water supply service lines.
Converting WSFU - Water Supply Fixture Units - to GPM.
Required water supply to public buildings.
Free online tool for designing water supply systems in buildings.
Water consumption in garden fixtures.