=Plumbing Pipes=
=The House Drain.=--All waste and soil matter in the house is carried
from the receptacles into the waste and soil pipes, and from these
into the house drain, the main pipe of the house, which carries all
waste and soil into the street sewer. The house drain extends from the
junction of the soil and waste pipes of the house through the house to
outside of the foundations two to five feet, whence it is called
"house sewer." The house drain is a very important part of the
house-plumbing system, and great care must be taken to make its
construction perfect.
_Material._--The material of which house drains are manufactured is
extra heavy cast iron. Lighter pipes should never be used, and the use
of vitrified pipes for this purpose should not be allowed.
_Size._--The size of the house drain must be proportional to the work
to be performed. Too large a pipe will not be self-cleansing, and the
bottom of it will fill with sediment and slime. Were it not for the
need of carrying off large volumes of storm water, the house drain
could be a great deal smaller than it usually is. A three-inch pipe
is sufficient for a small house, though a four-inch pipe is made
obligatory in most cities. In New York City no house drains are
allowed of smaller diameter than six inches.
[Illustration: FIG. 22.
SYSTEM OF HOUSE DRAINAGE, SHOWING THE PLUMBING OF A HOUSE. (H.
BRAMLEY.)]
_Fall._--The fall or inclination of the house drain depends on its
size. Every house drain must be laid so that it should have a certain
inclination toward the house sewer, so as to increase the velocity of
flow in it and make it self-flushing and self-cleansing. The rate of
fall should be as follows:
For 4-inch pipe 1 in 40 feet
" 5 " " 1 " 50 "
" 6 " " 1 " 60 "
_Position._--The house drain lies in a horizontal position in the
cellar, and should, if possible, be exposed to view. It should be hung
on the cellar wall or ceiling, unless this is impracticable, as when
fixtures in the cellar discharge into it; in this case, it must be
laid in a trench cut in a uniform grade, walled upon the sides with
bricks laid in cement, and provided with movable covers and with a
hydraulic-cement base four inches thick, on which the pipe is to rest.
The house drain must be laid in straight lines, if possible; all
changes in direction must be made with curved pipes, the curves to be
of a large radius.
_Connections._--The house drain must properly connect with the house
sewer at a point about two feet outside of the outer front vault or
area wall of the building. An arched or other proper opening in the
wall must be provided for the drain to prevent damage by settling.
All joints of the pipe must be gas-tight, lead-calked joints, as
stated before. The junction of the vertical soil, waste, and
rain-leader pipes must not be made by right-angle joints, but by a
curved elbow fitting of a large radius, or by "Y" branches and 45 deg.
bends.
When the house drain does not rest on the floor, but is hung on the
wall or ceiling of the cellar, the connection of the vertical soil and
waste pipes must have suitable supports, the best support being a
brick pier laid nine inches in cement and securely fastened to the
wall.
Near all bends, traps, and connections of other pipes with the house
drain suitable hand-holes should be provided, these hand-holes to be
tightly covered by brass screw ferrules, screwed in, and fitted with
red lead.
"No steam exhaust, boiler blow-off, or drip pipe shall be connected
with the house drain or sewer. Such pipes must first discharge into a
proper condensing tank, and from this a proper outlet to the house
sewer outside of the building must be provided."
_Main Traps._--The disconnection of the house pipes from the street
sewer is accomplished by a trap on the house drain near the front
wall, inside the house, or just outside the foundation wall but
usually inside of the house. The best trap for this purpose is the
siphon or running trap. This trap must be constructed with a cleaning
hand-hole on the inside or house side of the trap, or on both sides,
and the hand-holes are to be covered gas-tight by brass screw
ferrules.
_Extension of Vertical Pipes._--By the main trap the house-plumbing
system is disconnected from the sewer, and by the traps on each
fixture from the air in the rooms; still, as the soil, waste, and
drain pipes usually contain offensive solids and liquids which
contaminate the air in the pipes, it is a good method to ventilate
these pipes. This ventilation of the soil, waste, and house drain
pipes prevents the bad effects on health from the odors, etc., given
off by the slime and excreta adhering in the pipes, and it is
accomplished by two means: (1) by extension of the vertical pipes to
the fresh air above the roof, and (2) by the fresh-air inlet on the
house drain.
By these means a current of air is established through the vertical
and horizontal pipes.
Every vertical pipe must be extended above the roof at least two feet
above the highest coping of the roof or chimney. The extension must be
far from the air shafts, windows, ventilators, and mouths of chimneys,
so as to prevent air from the pipes being drawn into them. The
extension must be not less than the full size of each pipe, so as to
avoid friction from the circulation of air. The use of covers, cowls,
return bends, etc., is reprehensible, as they interfere with the free
circulation of air. A wire basket may be inserted to prevent foreign
substances from falling into pipes.
_Fresh-air Inlet._--The fresh-air inlet is a pipe of about four inches
in diameter; it enters the house drain on the house side of the main
trap, and extends to the external air at or near the curb, or at any
convenient place, at least fifteen feet from the nearest window. The
fresh-air inlet pipe usually terminates in a receptacle covered by an
iron grating, and should be far from the cold-air box of any hot-air
furnace. When clean, properly cared for, and extended above the
ground, the fresh-air inlet, in conjunction with the open extended
vertical pipe, is an efficient means of ventilating the air in the
house pipes; unfortunately most fresh-air inlets are constantly
obstructed, and do not serve the purpose for which they are made.
=The Soil and Waste Pipes.=--The soil pipe receives liquid and solid
sewage from the water-closets and urinals; the waste pipe receives all
waste water from sinks, washbasins, bath tubs, etc.
The material of which the vertical soil and waste pipes are made is
cast iron.
The size of main waste pipes is from three to four inches; of main
soil pipes, from four to five inches. In tenement houses with five
water-closets or more, not less than five inches.
The joints of the waste and soil pipe should be lead calked. The
connections of the lead branch pipes or traps with the vertical lines
must be by Y joints, and by means of brass ferrules, as explained
above.
The location of the vertical pipes must never be within the wall,
built in, nor outside the house, but preferably in a special
three-foot square shaft adjacent to the fixtures, extending from the
cellar to the roof, where the air shaft should be covered by a
louvered skylight; that is, with a skylight with slats outwardly
inclined, so as to favor ventilation.
The vertical pipes must be accessible, exposed to view in all their
lengths, and, when covered with boards, so fitted that the boards may
be readily removed.
Vertical pipes must be extended above the roof in full diameter, as
previously stated. When less than four inches in diameter, they must
be enlarged to four inches at a point not less than one foot below the
roof surface by an "increaser," of not less than nine inches long.
All soil and waste pipes must, whenever necessary, be securely
fastened with wrought-iron hooks or straps.
Vertical soil and waste pipes must not be trapped at their base, as
the trap would not serve any purpose, and would prevent a perfect flow
of the contents.
=Branch Soil and Waste Pipes.=--The fixtures must be near the vertical
soil and waste pipes in order that the branch waste and soil pipes
should be as short as possible. The trap of the branch soil and waste
pipes must not be far from the fixture, not more than two feet from
it, otherwise the accumulated foul air and slime in the waste and soil
branch will emit bad odors.
The minimum sizes for branch pipes should be as follows:
Kitchen sinks 2 inches
Bath tubs 1-1/2 to 2 "
Laundry tubs 1-1/2 to 2 "
Water-closets not less than 4 "
Branch soil and waste pipes must have a fall of at least one-quarter
inch to one foot.
The branch waste and soil pipes and traps must be exposed, accessible,
and provided with screw caps, etc., for inspection and cleaning
purposes.
Each fixture should be separately trapped as close to the fixture as
possible, as two traps on the same line of branch waste or soil pipes
will cause the air between the traps to be closed in, forming a
so-called "cushion," that will prevent the ready flow of contents.
"All traps must be well supported and rest true with respect to their
water level."
=Vent Pipes and Their Branches.=--The purpose of vent pipes, we have
seen, is to prevent siphoning of traps and to ventilate the air in the
traps and pipes. The material of which vent pipes are made is cast
iron.
The size of vent pipes depends on the number of traps with which they
are connected; it is usually two or three inches. The connection of
the branch vent to the trap must be at the crown of the trap, and the
connection of the branch vent to the main vent pipe must be above the
trap, so as to prevent friction of air. The vent pipes are not
perfectly vertical, but with a continuous slope, so as to prevent
condensation of air or vapor therein.
The vent pipes should be extended above the roof, several feet above
the coping, etc.; and the extension above the roof should not be of
less than four inches diameter, so as to avoid obstruction by frost.
No return bends or cowls should be tolerated on top of the vent pipes.
Sometimes the vent, instead of running above the roof, is connected
with the soil pipe several feet above all fixtures.
[Illustration: FIG. 23.
LEADER PIPE.]
=Rain Leaders.=--The rain leader serves to collect the rain water from
the roof and eaves gutter. It usually discharges its contents into the
house drain, although some leaders are led to the street gutter, while
others are connected with school sinks in the yard. The latter
practice is objectionable, as it may lead the foul air from the school
sink into the rooms, the windows of which are near the rain leader;
besides, the stirring up of the contents of the school sink produces
bad odors. When the rain leader is placed within the house, it must be
made of cast iron with lead-calked joints; when outside, as is the
rule, it may be of sheet metal or galvanized-iron pipe with soldered
joints. When the rain leader is run near windows, the rules and
practice are that it should be trapped at its base, the trap to be a
deep one to prevent evaporation, and it should be placed several feet
below the ground, so as to prevent freezing.