1. WATER DEMAND (Chapter 24)
Types of demand
Average daily demand
Building type
Types of plumbing fixtures
Hours of operation
Measured in gallons per person per day
Peak demand
Demand during critical periods of the day
Maximum momentary demand
Demand by individual plumbing fixtures
Measured in gallons per minute

2. WATER DISTRIBUTION Municipal street main Static pressure (static head)
Depth 2 – 7 ft. from grade
Pressure ranges from 50 to 70 psi
Usually adequate for lowrise buildings
Static pressure (static head)
Pressure exerted by water standing in vertical piping
Pressure exerted by a 1-sq. in. column of water, 1 ft. in height = psi

3. WATER DISTRIBUTION Upfeed distribution Downfeed distribution
Simple upfeed
Water fed to fixtures in a building only by the incoming pressure of the supply water. This method is good for buildings up to 5 to 6 stories high.
Pumped upfeed
Water fed to the fixtures in a building by increasing the pressure of the supply water using additional pumps.
Hydro-pneumatic upfeed
Downfeed distribution
Uses pumps to deliver water to a rooftop storage tank of the building.
The water in the storage tank feeds fixtures below due to the force of gravity.
Cross-connection and backflow
Connection between supply system and any system containing non-potable water
Backflow prevention
Air gap
Atmospheric Vacuum breaker
Pressure Vacuum breaker

4. SUPPLY PIPING MATERIALS (Chapter 24)
Steel and galvanized steel
Copper
Plastic
Water supply accessories and controls
Valves
Gate valve
Globe valve
Check valve
Ball valve
Butterfly valve
Water hammer arrestor
Insulation
Pipe expansion
Pipe support

5. SUPPLY PIPING MATERIALS (Chapter 24)(Additional information)
Need for piping
To transport water from source to the locations of use
Requirements
Efficient
Low maintenance
Non-corrosive

6. SUPPLY PIPING MATERIALS (Chapter 24)
Steel: inexpensive, used only where water is non-corrosive
Brass, red: expensive, corrosion resistant to a certain extent
Copper: Less expensive than brass, corrosion resistant
Plastic: Corrosion resistant, special types required for hot water
Galvanized steel: Moderately corrosion resistant

7. SIZING OF SUPPLY PIPES Some definitions (additional information)
Fixture pressure : Pressure required to operate a fixture; varies from 5 to 15 psi
PSI: pound(s) per square inch
gpm: gallon(s) per minute
Fixture unit: An index of water demand by a fixture
DL: Actual linear distance of pipe from street main to the remotest fixture
EL: Additional length of piping (in terms of friction loss) equivalent to fittings, 50% of DL
TEL: Total Equivalent Length, DL+EL
Static pressure: Pressure loss due to height (Height*0.433)

8. SIZING OF SUPPLY PIPES Pressure components in an upfeed supply system
Pflh = Pressure loss due to friction in piping
Psm = Street or municipal main pressure
Pf = Pressure required to operate a fixture (use the highest figure)
Pht = Pressure loss due to height (static pressure): psi/ft.
Pm = Pressure loss due to water flow through meter
(Pflh+Pf+Pht+Pm) should be equal to Psm
Friction loss equation
Pflh/100 = [Psm-(Pf+Pht+Pm)]*100/TEL

9. SIZING OF SUPPLY PIPES Total water demand Pipe size
Calculated in gpm using Hunter's curve (or the algorithm provided by the instructor)
Curve 1 (if Hunter's curve is used) to be used if there is any FV operated fixture in the system
Curve 2 (if Hunter's curve is used) to be used, if otherwise
Demand for hot and cold supply to be calculated separately
Pipe size
To be determined using the sizing graph or
By using this formula: Pf = (4.52*Q1.85)/C1.85*ð4.87)
Both friction loss and demand calculations will be required to find sizes
Velocity of water in supply pipes
Should not exceed 10 fps
Pipe size should be increased if velocity exceeds this limit

10. PRESSURE TANK (Additional information)
Sizing pressure tank: Q = Qm/[1-(P1/P2)]
Q = tank volume (gal)
Qm = 15 minutes of storage at peak usage rate (gal)
P1 = min. allowable operating pressure psi
P2 = max. allowable operating pressure psi
The additional 14.7 psi added to maximum and minimum operating pressures of fixtures is atmospheric pressure. The sum of gauge pressure in the pumping system and atmospheric pressure is called absolute pressure.