Water Distribution in Buildings

Hydro-pneumatic tank high water levels &withdrawals

Size of Food Waste Grinders

Tank fill Pumps

pressure range (kPa)

high water level propor-tion of total tank capacity

withdrawal 0.96 total tank capacity

persons served

pot washer

kW

dish washer

kW

Location

number of fixture

litres/second per fixture

minimum pump capacity (litre/second)

140 - 275

43

33

up to 200

1.45

2.24

Adminis tration building

1 - 25

0.08

1.5

275 - 415

34

24

200 to 500

2.24

3.73

51 - 100

0.045

3.2

205 - 380

42

32

501 to 1000

3.73

5.6

151 - 250

0.03

6.3

415 - 590

32

22

over 1000

5.6

7.46

501 - 750

0.02

15

Water Service Temperatures

1000 - up

0.02

20

Service

°C

Apart ments

26 - 50

0.03

0.9

general use as showers, sinks, family housing, administration facilities, etc.

49

101 - 200

0.02

2.5

commercial type dishwashers with internal boosters

60

401 - 800

0.015

4.1

commercial type dishwashers without internal boosters

82

Hospitals

1 - 50

0.06

1.6

commercial type laundries

82

51 - 100

0.05

3.5

Water Distribution Systems

201 - 400

0.03

7.9

Steam Distribution System

Hot Water Distribution System

Industrial buildings

1 - 25

0.1

1.6

Advantages

Disadvantages

Advantages

Disadvantages

51 - 100

0.05

3.8

smaller return pipe sizes are required

fast uniform response to instantaneous load changesusing minimum pipe sizes

251 - up

0.04

10.5

pumping costs for maintaining circulation are lower.

piping may be installed level or at any pitch

Schools

1 - 10

0.09

0.06

motor size is a fraction of that required for water, as is operating time in some cases

larger supply piping sizes are required

smaller supply pipe sizes are used

larger motor sizes are required for circulating pumps

11 - 25

0.06

0.9

maintenance costs are lower. The small difference of pressure under which the system components operate reduces wear and maintenance expense to a minimum

larger expansion loops, joints and swing connections are required

forced circulation provides in the total water mass, the desirable inertia effect which helps to diversify system load requirement contributing to uniform input at fuel burners

larger return pipe sizes are required

51 - 100

0.03

2.8

convectors and radiators must be installed in a pitched position

requires fewer specialty items

expansion tanks and air vents are required

when the condensate is repeatedly recycled through the boiler & system, makeup water requirements &corrosion are negligible & equipment life is lengthened

additional specialty items such as traps, lifts and in some cases pressure reducing valves are required

permits practical air elimination to minimize corrosion & maintenance

more maintenance is required due to increased equipment wear caused by longer operating times

condensate systems fail frequently causing significant losses of heat

resetting of system supply water temperature to meet changing loads permits more efficient energy usage

more intricate controls may be required to compensate for areas with frequent load variations in order to keep system in balance

Distribution Loads and Fluids Conditions in Buildings

Fluid

Use

Capacity

Pressure

Demand Factor

Comments

steam

auxiliary power

determined by heat balance

boiler steam

1

feed water & fuel-oil heating

steam

heating & snow melting

14 - 69 kPa

1 for heating radiation

steam

waterfront demand

1035 kPa

1 single berths

high purity steam for nuclear ships

0.8 multiple berths

steam

process

laundry

690 kPa

0.65

7hr/day, 5d/w

steam

process

kitchen

69 - 276 kPa

1

2-8hr/day,7d/w

steam

process

bakery

69 kPa

1

2-8hr/day,7d/w

steam

dry cleaning

480 kPa

0.65

7hr/day, 5d/w

steam

hospital

276 - 414 kPa

0.65

steam

laundry hot water

34 - 310 kPa

0.65

steam

refrigeration

domestic hotwater: DM-3

34 - 310 kPa

0.65

steam

refrigeration

tons.steam rate/ton

boiler steam 3.( -3.75kPa

1

turbine driven centrifugal compressor

steam

refrigeration

tons.steam rate/ton

1.6 kPa

1

absorption machine

condensate return

distribution loss boiler feed

losses: condensate blow-down or blow-off: determined by amount &analysis of makeup

138 - 414 kPa

1 for continuous operation of condensate pumps

check economics of returning codensate

condensate return

distribution loss boiler feed

process depends on usage. Distribution 10%

1.5 to 3 intermittent operation of condensate pumps

hot water (supply & return)

heating & snow melting process

same criteria as for steam

69 - 690 kPa

same asfor steam

chilled water supply and return

refrigeration

gpm =

500(t

supply 5-7°C , return 11 - 15°C

pressure depends on friction & static head

1

condenser water

refrigeration

3 gpm/tom

supply 30 - 40°C

1

condenser water

power system

gpm = steam. 950 , lbs/hour Btu/lb

pressure depends on friction & static heads

1

fuel gas

process fuel, gas burner

Presure vapor - temperatures

Hot water (40°C)

compressed air

low pressure

°C

kPa

sink

10 l /day

medium pressure

0

0.61

private toilet

100

high pressure

10

1.23

public toilet

150

25

3.17

bidet

7.5

50

12.34

private shower

30

Boiler size

dimensions (m)

power kW

public shower

75

2.2 x 1.4 x 1.2

580

private laundery

3 l / pers

2.72 x 1.70 x 1.5

1160

washing machine

100 / unit

4.0 x 1.85 x 1.83

2325

4.4 x 2.2 x 2.1

3485