If your plumbing experience has been limited to turning a faucet on and off, you may be pleasantly surprised at the simplicity of the system behind that faucet.
Home plumbing is largely a network of pipes and the fittings that connect them, carrying water in and out of the house by two basic forces of nature: pressure and gravity. Water fixtures'sinks, tubs, showers and toilets'and such appliances as dishwashers and washing machines tap into this system, receiving fresh water from one set of pipes and discharging used water through another.
Here's a first look at the basic terms and concepts you'll need to know when evaluating, repairing, or extending your home's plumbing system.
The water cycle
Plumbing is closely tied to both weather and geography. Water that enters your home starts way up in the sky, falling to earth as rain or snow. It flows in a stream or river to a lake or manmade reservoir or percolates down into the water table'which is like a river or lake, only underground. The water then travels through a treatment plant, pumping station, and/or local water tower to a water main and meter or from a private well that taps into the local water table. Fresh water enters the house via a main cold water pipe and flows, under pressure, out of whatever faucet has been turned on.
Where does used water go? So-called 'gray water' and waste leave the house and head for the city sewer or a private septic system. This sewage moves by gravity'each point in the system is at a lower slope than the one preceding. From the city sewer, water goes to a treatment plant, which removes waste from water, or to a septic tank, which does the same thing. Water evaporates back ino the sky, where things start all over again.
Three plumbing systems
Now let's peek inside the house. There are really three separate but interdependent pipe systems: supply, drain-waste, and vent. (Drain-waste-vent systems are interconnected and therefore often referred to as the 'DWV system.')
The supply system carries pressurized water from a utility main or private well into your house and around to all the water-using fixtures and appliances. What drives this pressure? There's either an initial 'fall' (such as from a water tower) or a 'push' from a pumping station; displacement does the rest. Because the water is in a closed supply pipe system, it has nowhere to go but along the same path, pushed along by the water behind it. When you open a faucet or valve, water flows out; when you close it, the flow stops until the next time you open it.
The drain-waste system transports gray water and waste out of the house into a city sewer or septic tank outside the house perimeter. Tub and sink drains flow by gravity only; toilets use a combination of pressure (falling water) and gravity. If waste needs to flow uphill at any point, such as from a basement bathroom, an electric pump helps push it up.
The vent system carries away noxious sewer gasses. When a drainpipe is empty, sewer gasses rise up the vent pipe and out the roof. P- or S-shaped pipe bends, called traps, below each drain remain filled with just enough water to prevent sewer gasses from seeping out the drain into your home. The vent system also helps maintain atmospheric pressure in the drain system to help wastes flow downhill. It works on the same principle as the second hole on a gas can.
By : HomeTips.com
Visiting your local hardware store prior to doing your own plumbing can be a confusing experience. Which type of pipe should you choose? You'll find that the answer isn't as clear as it may have been in the past--when there were much fewer plumbing pipe choices. Here are the main types of plumbing supplies you will use:
PVC Pipe - Polyvinyl Chloride
PVC pipe has been a very big deal in the plumbing industry in the last few decades, because it is lighter and easier to work with than traditional galvanized steel pipe. You will mainly be using PVC pipe for drain or waste pipes, or stacks (those pipes you often see sticking up out of the roofline), and not as supply pipes. PVC pipe is easy to install, and requires little more than a hacksaw, miter box, and solvents which essentially "glue" the pipe together. Diameters are clearly marked on the white surface of the pipe. If not easy to read, diameters can be determined with a sizing tool such as Pi-Piper.
Rigid Copper Pipe
This is your water supply pipe. Rigid copper is easily cut with a hacksaw or Skilsaw, or with a special copper tube cutter. Connection is a different matter, as it requires a practiced hand to solder copper pipe together (advice: buy extra copper pipe to practice on). Rigid copper pipe is great for water supply because it resists corroding, and does not carry the health risks that PVC has.
ABS Pipe
ABS pipe looks very much like PVC pipe, except it is black. ABS is basically the "older version" of PVC, and is often not allowed anymore by plumbing codes. Like PVC, ABS pipe is used for drain and vent pipes. If working with ABS, the best advice is to replace with PVC.
Flexible Copper Tubing
Flexible copper is used for short runs. You have probably seen it leading up to your water heater, or for cold water supply in tight spots. Flexible copper tubes can be cut with ease with a hacksaw, and bent to fit around corners. Because it does not stand up well against extreme temperatures, flexible copper is not recommended for exterior use.
Galvanized Iron Pipe
Galvanized iron pipe is the pipe of popular imagination: it is what we think of when we think about plumbing pipe. It is made of galvanized steel, with each end of the pipe threaded. Individual pipes are screwed into each other with connecting joints. While extremely strong, galvanized pipe is rarely used for new home construction, and is not recommended for the home renovator.
