PLUMBING SYSTEMS Flashcards
pH levels: anything above 7 is ___ and anything below 7 is ____.
Above 7: alkaline.
Below 7: acidic
What is an aquifer?
Large region of subsurface water
What causes hardness? How do you soften it?
Calcium and magnesium. Treat it with an ion exchange process with a water softener like zeolite where cal and mag ions are exchanged for sodium ions in the zeolite
What causes acid rain?
Increased sulphur and nitrogen compounds in the atmosphere
What causes turbidity in water?
Suspended material like silt, clay, organic material.
How do you correct odor problems in water?
Run it through activated carbon filter
How do you correct biological contamination in water?
Chlorination
Name three examples of private water supplies
Well, spring, collected rainwater
What are the two considerations when drilling a well?
Depth and yield
How shallow is a shallow well?
Less than 25 feet
What is the yield of a well measured it and what is the minimum for a private residence?
Gallons per minute. A private residence would need at least 5-10 gpm… If there isn’t enough you can include a storage tank
Name 3 types of pumps for wells and what they are suitable for.
Suction pumps. For water tables less than 25 ft deep.
Deep-well jets. For depths of 25-100 ft.
Turbine pumps. High capacity and deep.
Submersible pump. Used a lot for medium to deep residences b/c it has a waterproof motor and pump below the water line and pump to a pressure tank.
What is the pressure of water pumped through mains (average and full range)?
50psi, 40-80psi
Water-wise what are the first things you have to determine in a building project? What makes it super expensive?
Determine the location of the water main, it’s size, it’s pressure, and the cost to tap it, all available from the local water company. When you have to pipe a long way to meet the main it becomes expensive.
What is static head? What is the static head of water?
The pressure required to push water vertically (or the pressure causes at te bottom of a column of water). You need .443 psi to lift water 1ft…. Or 1psi to lift water 2.3ft.
What is an upfeed system?
Uses pressure in the main directly to supply water fixtures.
Why use a downfeed system and how does it work?
Use or because a building is too tall for upfeed. You pump water from the main to a storage tank on the top of the building or top of a zone… then use the pressure of gravity to supply to fixtures.
What is the max. pressure on a fixture and what limits does this place on downfeed systems?
Max. 45-60psi. This means that zones can’t be more than 138ft high.
What can you do if your downfeed zones are so high they feed too much pressure to fixtures?
Use pressure-reducing valves
What is (and what is another name for) a direct upfeed pumping system?
Tankless system. Several pumps used together with a pressure sensor. When demand is light you only use one pump and then next ones kick in automatically.
What is the most common steel for piping?
Schedule 40
What is the only type of plastic piping you can use with hot water?
PVDC
In piping, what is a union?
Connects 2 sections of rigid pipe
What do you need to connect small kitchen and bathroom pipes to supply lines?
Compression fittings
What do you use to control water flow?
Valves
Name three common valve types and describe their purposes.
Globe valve. Used for water that is frequently and variable controlled (like faucets and hose bibs). A lot of friction loss to (2) 90° turns.
Gate valve. Seats metal wedge against 2 metal parts. Turns on and off completely.
Check valve. Works automatically allowing water flow from only one direction (no back flow)
What is water hammer?
Noise caused by abrupt valve closure forcing water to move in the system and rattle the pipes.
Name two things you can do to avoid water hammer.
Air chamber. Length of pipe installed above the connection to the faucet to cushion surges.
Shock absorber. Expansion device that performs the same service.
Too much pressure on fixtures can lead to_____. Use what?
Wear and tear. Use pressure reducers, also called pressure regulators.
Name the (4) values that must add up or be less than the total street water main pressure.
- Pressure at most remote fixture
- pressure loss from static head
- pressure loss by friction in piping and fittings
- pressure loss through water meter
Calculate the pressure loss by static head by multiplying ____ by ____?
Multiply the total height by 0.434.
Above ___ ft/sec water in pipes is too noisy.
10
PVC expands how many times more than copper piping?
3.5
How do you solve the problem of having to wait for all the cold water in the piping to run through the fixture until hot water is pumped from water heaters or boilers?
Use a two-pipe circulating system, which keeps water slowly circulating, then cooling and falling down to the water heater to be reheated and continuing to circulate.
What does the recovery rate mean in reference to a water heater?
This is the number of gallons per hour of cold water that they heater can raise to the desired temperature.
What are the three basic types of water heaters?
Storage tank, tankless, and circulating.
When does indirect hot water heating not work very well?
When it’s heated indirectly by boiler or furnace that only works when space heating as needed.
In solar water heating what is the difference between a direct and indirect system? Or “open–loop system” versus “closed–loop system”? What is the one advantage of each?
An open–loop / direct system (efficiency but subject to freezing) uses the same water that is heated in the solar collectors while the indirect /closed-loop system (uses antifreeze) uses a separate fluid for collecting heat.
Passive circulation systems rely on what to operate and are therefore less expensive? But active circulation systems use what to operate under therefore more reliable but my expensive?
gravity versus pumps
How does the batch system solar heating system work? What are the disadvantages?
Also known as a breadbox heater, it heats water directly in a black – painted tank inside a glazed box. Subject to freezing and night time he lost.
How does a thermosiphon solar heating system work? What can you do to keep it from freezing?
It uses the natural movement of heated water to circulate in a passive, open – loop system. But to avoid freezing you can also use a closed – system with anti-freeze.