Plumbing
Basics
Understanding how your plumbing system functions will take some of the
guess work out of planning your next renovation, or, at the very least,
allow you to ask the right questions the next time you call a plumber
to fix a leaky faucet.
The topic of indoor plumbing is one that
homeowners rarely concern themselves with--until they discover a leak,
run out of hot water, or begin to remodel the house. While the temptation
may be to call a plumbing contractor to handle things, a little patience
and a willingness to experiment may make plumbing repairs more straightforward
than you think.
System Basics
Water pressure is fuel for the plumbing system. Distributing, manipulating,
and preserving water pressure is the plumber's stock in trade. All plumbing
fixtures, from simple laundry hoses to toilets to the nozzles on an expensive
hot tub, are designed to operate within a fixed range of pressure, and
it is the plumber's job to ensure that each receives that pressure--no
more, no less. The plumber and the plumbing designer rely on the internal
diameter of the water delivery pipes to control water pressure. The smaller
the pipe diameter, the lower the pressure and the greater the velocity
of the water moving through it.
Plumbers rely on gravity to drive the
drainage and waste removal portion of the plumbing system. The plumbing
system must be properly vented to release all air pressure, or it will
lose its flow. For that reason, the drainage and waste system is referred
to as the "DWV" (drainage, waste, and vent) system.
Codes
Plumbing is both an art and a science. Most of what plumbers do when designing
or repairing a system is dictated by local, state and federal codes. Codes
specify the internal diameter of pipe that must be used for a particular
plumbing section or function. In the water supply system, for example,
pipe of increasingly smaller diameter is called for as the supply pipes
branch out from the water main that enters the house. Water in the main
is under tremendous pressure — far more than can be safely handled by
the individual sinks, toilets and appliances in the home. The successive
drop in pressure as the water moves from main, to primary supply lines
to secondary supply lines ensures that each appliance receives an appropriate
amount of pressure.
Codes also prescribe where shutoff valves
should be placed, what pipe materials can be used for given functions,
what kinds of fittings are needed to safely join pipes or create branches,
and the amount of slope or downward drop that drain pipes need to function
properly.
Plumbing Renovations
Homeowners need to understand that the limitations of their system will
likely impact their plumbing projects. You might plan to use an existing
drain line to catch the flow from a new sink or toilet only to find that
it doesn't have enough capacity to handle the additional volume. Or, after
purchasing a laundry tub for the basement you might discover that it can't
be connected because the main sewage or septic outlet is located above
the basement floor. While you or your plumbing contractor may find solutions
to such problems, its important to anticipate how plumbing can complicate
your renovation plans and budget.
System Design
Laying out an efficient, well-designed system requires craftsmanship and
experience. On the water supply side, the plumber must decrease water
pressure as it enters the home from the water main, and preserve enough
pressure throughout various parts of the system to provide adequate flow,
even when several appliances are turned on at the same time. This manipulation
of pressure is achieved entirely by varying the internal diameters of
the pipes.
On the DWV side of things, calculating
for downward slope, the correct internal diameter of a waste pipe, or
adequate venting will determine how well your system sends waste water
to the sewer or septic. What's more, plumbing design requires an understanding
of how to safely integrate a complex maze of pipes with the wires and
ducts that travel through your walls.
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Quick
Tips |
Old
homes, old pipes
When you are planning renovations to an older home, don't be surprised
if your plumbing contractor wants to do a thorough investigation
before taking the job. Plumbers must be familiar with the properties
of outdated plumbing components, such as iron or brass pipes,
which they might encounter on a renovation job. At the same time
they must know how to take advantage of the latest developments
in plumbing technology, such as flexible plastic pipe.
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