Hot Water and Steam

1
Hot Water and Steam

• Plumbing Systems
• CNST 305
• Environmental Systems 1
• Dr. Berryman

2
Hot Water Considerations

• Hot Water Burns People
• Hot water is corrosive
• Every 20o F double corrosive qualities
• Electrolysis develops between dissimilar
  materials highly temperature dependant

3
Hot Water Considerations

• Bacteria can breed (i.e. Legionella)
• Dormant at 68o F
• Highest point of reproduction 110 120o F
• Recirculation
• Hot water on demand
• Recovery vs Storage
• Tank storage (70 usable)
• Tankless

4
Hot Water Heaters

• Classified by fuel sources
• Natural gas
• Propane
• Fuel oil
• Electric
• Steam

5
Steam

• Phase change from water
• Liquid to gas
• Increases it volume 1700 times this expansion
  allows moves heat through pipe
• One pound of steam releases about 1000 BTU
• Safety devices
• Pressure relief valves (set at 150 210oF)
• Gas shutoff valves

6
Domestic Hot Water Heaters
7
Commercial Heaters

• Semi-Instantaneous
• Instantaneous
• Heat exchanger

8
Design Considerations for Hot/Cold Systems

• Noise
• Water Hammer (shock wave)
• Caused by quick closing valves (water)
• Caused by condensate in steam pipes
• Dampening/prevention devices
• Shock absorber and air chambers
• Steam traps
• Steam system start up

9
Design Considerations for Hot/Cold Systems

• Pressure loss
• Factors that affect pressure loss
• Starting pressure
• Booster pump
• City main
• Ending pressure
• Needed at fixture (i.e. tank water closets 15
  psi)
• Friction loss in pipe, fittings, and valves
• Pressure needed to lift water
• Water weighs 62.4 lbs per cubic feet

• 1 psi lifts water 2.307
• Static pressure 0.433 psi per foot of pipe

10
Class Exercise

• A multi-story building has access to a water
  main. Ignoring friction, how many floors will
  this system effectively serve?
• Given
• 50 psi main
• 12 per floor
• Ignore affects of pipe and fitting friction

• Fixture requirements 25 psi for Flush Tank

• 25 psi available (less flush tank requirement)
• (12)(0.433)5.2 psi loss per floor
• 25/5.2 4.8 or 4 stories

11
Next Time

• Sizing Water Systems