It shall be the duty of every person owning
or constructing any drain, soil pipe, passage or connection between
a sewer and any ground, building or establishment served thereby,
as well as every person owning or in control or in possession of any
such ground, building or establishment, to cause and require such
drain, soil pipe, passage or connection to be adequate for its purpose
and such that all material entering the same shall at all times pass
freely through the same.
A.
General. The service line from the curbline to the
building shall be laid at the expense of the property owner, but shall
be subject at all times to the inspection and approval of the Town
or its duly authorized representatives who shall have supervision
and control over the same.
B.
Size. Service lines shall be not less than four inches
in diameter. Where multiple homes are permitted to be served with
a common service line because the sewage facilities are not separated
for each home, double homes may be served with a four-inch line, and
other multiple home units must be served larger lines as required
by the Town.
C.
Material.
(1)
Extra-heavy or medium-weight cast-iron pipe. This
pipe shall be bell-and-spigot-type pipe with caulked joints packed
firmly with oakum or hemp and filled with molten lead not less than
three-fourths of an inch deep and extending not less than one-eighth
of an inch below rim or hub.
(2)
Standard-strength vitrified clay pipe. Standard-strength
vitrified pipe shall have either joints packed with hemp and poured
with hot bituminous compound in one pour or shall have preformed joints
as may be approved by the Plumbing Inspector. Vitrified clay pipe
shall be used in trenches which provide good support and shall have
a minimum cover of two feet.
(3)
Asbestos-cement nonpressure pipe. Asbestos-cement
nonpressure pipe shall conform to the requirements of Federal Specification
1500, having a minimum crushing strength for applied loads of 1,500
pounds per linear foot. Joints shall be made of couplings of the same
strength and material as the pipe with the necessary rubber sealing
rings or gaskets to provide a watertight connection.
D.
Slope. Service lines shall be laid on a grade of not
less than one-fourth of an inch per foot for four-inch pipes and one-eighth
of an inch per foot for six-inch pipes or larger.
E.
Installation. Service lines must be as direct as possible.
Changes in direction must be made with Y's, combination Y-and-eighth
bends or half Y's or one-eighth bend. Changes in size where the lateral
or house drain is connected to the service line shall be made only
with fittings. Ditches shall be promptly backfilled after inspection
and approval by the Plumbing Inspector. Care shall be taken to prevent
damage to the pipe in backfilling and to secure a well-compacted and
firm trench.
On existing construction, as distinguished from
new buildings erected after passage of this Part 3, it is permitted
to vent, trap and clean out the house drain by providing these services
beyond the building and installing them on the service line.
A.
Vents. A vent shall be placed as close to the house
as possible. In case there is an existing septic tank or cesspool,
the vent may be placed in a position immediately after these facilities
are bypassed. However, subject to the approval of the Plumbing Inspector,
the house-trap cleanout opening may be used to serve as a part of
the vent. Vent risers shall extend a minimum of 12 inches above the
ground surface and shall be capped with a dome or double bend. Vents
shall be at least four inches in diameter.
B.
Cleanouts. Cleanouts shall be spaced a maximum distance
of 45 feet apart, except that existing lines need not be disturbed
to provide this maximum spacing. The cleanout shall consist of a Y-branch,
with an inclined riser reaching above the surface, where it is to
be securely capped and provided with a leaded-in ferrule for cleaning
purposes.
A.
Rock. Where rock is encountered, pipes are to be laid
on a six-inch deep cushion of earth.
B.
Shoring. Ditches are to be shored in accordance with
the rules and regulations of the Maryland Department of Health and
all other state or local regulatory bodies having jurisdiction over
this type of work. Ditches which are 30 inches in width and over six
feet in depth must be shored. Twenty-inch-wide ditches in excess of
4 1/2 feet in depth must likewise be shored.
C.
Excavate for bells. The subgrade upon which pipes
are laid shall be excavated to receive bells and couplings in order
to ensure a uniform and even bearing for the entire length of the
barrel of the pipe. The subgrade shall be finished off by hand and
evenly tamped and compacted true to the line and grade of the finished
pipe.
All pipes are to be backfilled by hand for a
distance of six inches over the top of the bell using approved loose
soil. The sides of the pipe are to be tamped at the haunches. The
hand fill over the pipe is to be compacted thoroughly by tamping with
approved tampers. Above the band tamping, the fill must be placed
carefully so as not to injure the pipe. Where pipes are laid in drilled
holes rather than in dug trenches, fine-stone backfill is to be blown
into the holes and securely packed from both ends.
Abandoned cesspools must be left in a safe condition,
preferably by filling with compacted material. Where service lines
pass over cesspools, they shall be bridged with a full length of cast-iron
pipe (not less than 16 feet), consisting of Class 150 AWWA-Specification.
The ends of the pipe are to be firmly bedded on both sides of the
cesspool to secure firm bearing in order to develop the full flexural
strength of the pipe.
Upon completion of each service installation
and/or house drain, the Town office is to be notified and an appointment
made for inspection. Inspections should be arranged for as soon as
the work is completed in order to minimize the chance of cave-ins.
Where they do occur, all caved-in material must be removed and required
repairs, if any, made to the pipe. All pipes and pipe joints must
be visible and accessible to the Plumbing Inspector. If the work is
satisfactory, the permit, which must be on hand at the time of the
inspection, will be endorsed and returned to the owner.
For new construction, the following regulations
shall apply:
A.
Materials.
(1)
Soil and waste piping for a drainage system within
a building shall be of extra-heavy or medium-weight cast iron galvanized
steel or copper tubing (Type L).
(2)
Drains within buildings, when underground, shall be
of cast-iron soil pipe. For buildings four stories in height, the
pipe may be of medium weight. For buildings five stories or more in
height, the pipe shall be of extra-heavy weight.
(3)
Fittings on the drainage system shall conform to the
type of piping used. Fittings on screwed pipe shall be of the recessed
drainage type. Fittings for copper tubing shall be of the drainage
type.
(4)
Calked points for cast iron bell-and-spigot soil pipe
shall be firmly packed with oakum or hemp and filled with molten lead
not less than three-fourths deep and not more than one-eighth inch
below the rim of the hub when firmly caulked.
(5)
Threaded joints shall be made with a standard tapered
pipe thread with pipe joint compound applied to the male thread before
assembly.
(6)
Soldered or sweat joints for tubing shall be made
with drainage fittings with male and female fittings cleaned bright.
The joints shall be properly fluxed and made with 50-50 grade solder.
B.
Drainage piping installation.
(1)
Horizontal drainage piping shall be installed at a
uniform slope, but at slopes not less than the following:
(2)
Cleanouts.
(a)
A Y-branch cleanout shall be installed immediately
inside or outside the building wall to provide access to the service
line on the downstream side of the house trap.
(b)
A Y-branch cleanout shall be provided at the
base of each stack where it empties into an underground line. Where
lines run above ground, a cleanout may be placed at the end of the
house drain. Where the house drain is more than 45 feet long, an additional
Y-branch cleanout shall be provided for each additional forty-five-foot
run. All cleanouts shall be of full size pipe and shall be provided
with a plug which shall be watertight. All plugs shall be removable
for servicing access to the drain line.
(3)
Backwater valves. Where the lowest drain in a building
is six feet or less from the top of the public sewer main, a backwater
valve shall be installed on the downstream side of all waste lines
or drains which empty into the house drain. The exception to this
rule will be where the backwater valve can be placed on a drain line
which carries waste from drains on a higher level. Provisions shall
be made to service the backwater valve in the future.
(4)
Fresh air vent. A fresh air vent shall be installed
either on the vent fitting of the house trap or on a T-fitting immediately
adjacent to the house trap on the upstream side. The vent shall be
of cast iron. It shall lead to 12 inches above the surface of the
ground and shall be provided with a gooseneck or mushroom-type vent.
The vent shall be no less than three inches for four-inch house drains
and no less than four inches for five-inch and six-inch drains.
(5)
Changes in direction.
(a)
When changing from vertical to horizontal in
lines three inches and larger, a short sweep or 90° long-turn
drainage elbow may be used.
(b)
When changing from horizontal to vertical in
lines three inches and larger, a quarter-bend or a 90° short-turn
drainage elbow may be used.
(c)
When changing from vertical to horizontal in
lines less than three inches, a long sweep or an extra-long-turn drainage
elbow must be used.
(d)
When changing from horizontal to vertical in
lines less than three inches, a quarter-bend or a 90° short-turn
drainage elbow may be used.
(e)
For venting in any direction and for any size
line, a quarter-bend or a 90° short-turn fitting may be used.
(f)
When changing direction of horizontal lines,
only long-sweep, 1/8 bends or 1/16 bends shall be used.
(g)
A heel- or side-inlet quarter bend shall not
be used as a vent unless the inlet is placed in the vertical position.
All side inlets may be used as branch waste connections in any position.
(h)
Branch lines shall enter a horizontal drainage
line by using a wye or combination Y-and-one-eighth-bend fitting.
(i)
Floor flanges shall be provided for water closets
or similar connections.
(j)
A closet bend or 1/4 bend may be used directly
beneath a closet.
C.
Venting and plumbing fixtures.
(1)
On all new constructions, plumbing fixtures shall
be properly vented in accordance with the following minimum standards.
Where deviations are required, they shall be made to conform to the
minimum standards of the National Plumbing Code and be subject to
the approval of the Plumbing Inspector.
(a)
Extensions or vent pipes through a roof shall
be terminated at least six inches above the roof.
(b)
Where a roof is to be used for any purpose other
than weather protection, the vent extensions shall be run at least
five feet above the roof.
(c)
No vent terminal from a drainage system shall
be directly beneath any door or window or other ventilating opening
of the building.
(d)
Traps serving sinks which are part of the equipment
of bars, soda fountains and counters need not be vented when the location
and construction of such bars, soda fountains and counters are such
as to make it impossible to do so. When such conditions exist, such
sinks shall discharge into a safe waste receptacle which is properly
trapped and vented.
(e)
Two fixtures set back-to-back within the distance
allowed between a trap and its vent may be served with one continuous
soil or waste vent pipe, provided that each fixture wastes separately
into an approved double fitting having inlet openings at the same
level. Fixtures set side-by-side will be treated the same as back-to-back.
(f)
Trap to vent table.
[1]
The following table shows the permitted distance
from trap to vent. Drain lines between trap and vent shall be limited
to one-fourth-inch per foot to give a lower flow rate and reduce the
possibility of self-siphoning of the trap.
|
Fixture Size
(inches)
|
Distance of Drain Line Between Trap and
Vent
(feet)
| |
|---|---|---|
|
1 1/4
|
2 1/2
| |
|
1 1/2
|
3 1/2
| |
|
2
|
5
| |
|
3
|
6
| |
|
4
|
10
|
[2]
The horizontal drain from a fixture may enter
a vertical drain line through a sanitary T or Y-and-one-eighth-bend
combination.
(2)
Sizes and lengths of vents.
(a)
The following table shows the size vent required
for certain fixtures and fixture groups and the maximum developed
length of each vent. Twenty percent of the total length of a vent
may be installed in a horizontal position. All horizontal vent lines
shall have a minimum grade toward the drain line of one-half-inch
per foot.
|
Individual Fixture or Group
|
Fixture Units
|
Trap Size
(inches)
|
Vent Size
(inches)
|
Vent Length
(feet)
| |
|---|---|---|---|---|---|
|
Lavatory
|
1
|
1 1/4
|
1 1/4
|
30
| |
|
Bathtub
|
2
|
1 1/2
|
1 1/4
|
30
| |
|
Bathtub
|
3
|
2
|
1 1/4
|
30
| |
|
Tank closet
|
4
|
3
|
1 1/2
|
30
| |
|
Valve closet
|
8
|
3
|
1 1/2
|
20
| |
|
Sink, double and single
|
2
|
1 1/2
|
1 1/2
|
30
| |
|
Dishwasher
|
2
|
1 1/2
|
1 1/2
|
30
| |
|
Sink with disposal
|
3
|
1 1/2
|
1 1/2
|
30
| |
|
Shower stall
|
2
|
2
|
1 1/4
|
30
| |
|
Urinal
|
4
|
2
|
1 1/2
|
30
| |
|
Automatic washer
|
-
|
-
|
1 1/2
|
30
| |
|
Closet, lavatory, tub
|
-
|
-
|
2
|
15
| |
|
Closet and lavatory
|
-
|
-
|
2
|
20
| |
|
Closet, 2 lavatories, tub
|
-
|
-
|
2
|
15
| |
|
Sink and dishwasher
|
-
|
-
|
1 1/2
|
20
| |
|
Sink, dishwasher, automatic washer
|
-
|
-
|
2
|
20
| |
|
Sink and automatic washer
|
-
|
-
|
2
|
20
| |
|
Laundry tray
|
-
|
-
|
1 1/2
|
30
| |
|
Floor drains
|
-
|
-
|
None
|
(b)
Where distance from trap to stack is greater than shown in the table in Subsection C(2)(a) of this section, the fixture shall be back-vented. Where back-venting is required, the vent shall enter stack above overflow of highest fixture on stack.
(c)
Vent on sink and automatic washer combination
may be run 1 1/2 inches if the drain line is increased to two
inches.
(d)
Where more than one bathroom group vent into
a common stack, the vent stack shall be a minimum of three-inch-pipe.
