PEX Plumbing - Trunk &
Branch Plumbing - Residential PEX Manifold Plumbing - Home Run Plumbing Layouts
Residential plumbing
system layouts come in a variety of shapes and sizes, with a number of different
types of plumbing layouts, and piping materials.
Trunk and Branch
Residential Plumbing Layouts
For decades,
trunk and branch (T&B) plumbing layouts have been used by plumbers and home
builders for water distribution using iron pipe, copper pipe, and rigid pipe.
Trunk and branch plumbing layouts use a main trunk line to supply various branch
take-offs to specific fixtures.
The trunk
line services numerous branch lines, each branch lines serving generally one
to three
closely grouped outlets, such as in a bathroom where there may be one or two
sinks, a toilet and a shower.
With trunk
and branch plumbing the plumber usually uses rigid pipe, and generally follows
the beams and trusses when installing the piping. This means extensive use of
elbows and longer pipe runs than if the pipe was run directly from the water
heater to the fixture.
Recirculating systems don’t work will with trunk and branch plumbing layouts,
since they don’t include the branch lines in the circulating loop. (See Fig 1)
Demand hot water systems suffer similar problems, although one could use
multiple demand pumps.
Residential PEX Manifold Plumbing Systems
A relative
newcomer to the residential plumbing system is the PEX manifold plumbing
layout. A manifold system is similar in a way to the trunk and branch system in
that it has a single trunk line leading to a manifold which in turn sends a
single branch line to each fixture or closely spaced group of fixtures such as
in a bathroom. (Fig 2)
In some
situations the manifold type plumbing layout can work well with recirculating
systems and demand hot water systems. For example, if the trunk lines are long,
a pump could be placed at the manifold to rapidly fill the trunk lines. The
branch lines being much smaller in diameter hold a much smaller volume of water
and thus have a high flow rate. With high flow rates the deliver is rapid and
wastes only a small amount of water.
These
systems are sometimes referred to as remote manifold systems. These systems are
sometimes combined into a hybrid system, for instance, it could have two or
three trunk lines with a remote manifold at the end of each trunk. All kinds of
combinations are possible. A single trunk line could have several flow-through
manifolds and one at the end of the trunk line.
With PEX
manifold systems shut off valves are often located at each outlet on the
manifold allowing you to turn off individual fixtures for repair or replacement
without shutting off the water to the whole house.
Home
Run Plumbing Layouts
PEX piping
systems make it ideal for use in home-run plumbing systems. In this design, all
fixtures are fed from dedicated piping that runs directly from central
manifolds. The hot water manifold should be located in close proximity to the
hot water source to ensure fast and efficient delivery. (Fig 3)
Because
inline fittings are eliminated, pressure losses along the line are reduced,
allowing the piping size to be reduced for certain fixtures. Three-eighths-inch
piping may be used for lower flow applications and 1/2-inch piping is
recommended for higher flow applications.
If the
manifold is installed using a valve at each outlet, many plumbing codes do not
require a second valve at the fixture. This speeds installation and adds
convenience.
Chilipepper Sales 1380 Greg St., # 221 Sparks Nevada, 89431 PH (775)-359-1223
