(2)
Fixture
Traps.
(a)
Separate
Traps for Each Fixture.
1.
Separate Trapping Required.
a. Individual plumbing fixtures shall be
separately trapped by a water seal trap placed as close as possible to the
fixture outlet.
Exception: To the separate trapping
requirements are as follows:
i. Fixtures
having integral traps.
ii. A
combination plumbing fixture may be installed on one trap provided one
compartment is not more than six inches deeper than the other and the waste
outlets are not more than 30 inches apart.
iii. One trap may be installed for not more
than three single compartment sinks or lavatories, immediately adjacent to each
other, and in the same room. The trap is to be centrally located when three
such fixtures are installed. The center-to-center measurement of the waste
outlets shall not exceed 30 inches apart.
iv. The waste for a domestic dishwasher may
be separately trapped, connected to the manufactured inlet side opening of a
food waste disposer or connected between the outlet of the kitchen sink and the
inlet of the trap using a "wye" fitting.
b. The vertical distance from the fixture
outlet to the trap weir shall not exceed 24 inches.
See 10.08:
Examples 1 and
2.
10.08: Example 1 - Vertical Distance from Fixture Outlet
to Trap Weir
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10.08: Example 2 - Vertical Distance from Fixture Outlet
to Trap Weir
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(b)
Size of Fixture
Traps.
1. The size of the fixture
trap shall be sufficient to drain the fixture rapidly and in no case less than
outlined in
248
CMR
10.08:
Table 1:
Minimum Size of Fixture Traps.
2. The fixture trap shall be the same pipe
size as the drain into which it discharges.
Table 1
Minimum Size of Fixture Traps
|
PLUMBING FIXTURE
|
Trap Size in
Inches
|
|
Bathtub (with or without overhead
shower)
|
11/2
|
|
Bidet
|
11/2
|
|
Clothes washing machine connection
|
2
|
|
Combination sink and wash tray
|
11/2
|
|
Combination sink and wash tray with food waste
disposer unit
|
11/2
|
|
Dental unit or cuspidor
|
11/2
|
|
Dental Lavatory
|
11/2
|
|
Drinking Water Station, with Drain
|
11/4
|
|
Dishwasher, commercial
|
2
|
|
Dishwasher, domestic
|
11/2
|
|
Floor drain
|
2
|
|
Food waste disposer
|
11/2
|
|
Kitchen sink, domestic, with food waste disposer
unit
|
11/2
|
|
Kitchen sink (two compartments)
|
11/2
|
|
Kitchen sink, domestic
|
11/2
|
|
Lavatory, common
|
11/2
|
|
Lavatory (barber shop, beauty parlor or
surgeon's)
|
11/2
|
|
Lavatory, (multiple type) (wash fountain or wash
sink)
|
11/2
|
|
Laundry sink (one or two
compartments)
|
11/2
|
|
Shower stall
|
2
|
|
Sink (surgeon's)
|
11/2
|
|
Sink (flushing rim type with flushometer
valve)
|
3
|
|
Sink (service type with floor outlet trap
standard)
|
3
|
|
Sink (service trap with P trap)
|
2
|
|
Sink, commercial (pot, scullery, or similar
type)
|
2
|
|
Sink, commercial (with food disposer
unit)
|
2
|
(c)
Prohibited
Traps. The following type traps are prohibited.
1. Traps which depend upon moving parts to
maintain their seal.
2. Bell
traps.
3. Crown vented
traps.
4. Separate fixture traps
which depend on interior partitions for their seal.
5. Full "S" traps.
(d)
Design of Traps.
1. Fixture traps shall be self-scouring and
shall have no interior partitions except where such traps are integral with the
fixture.
2. Slip or ground joints
that are part of a trap shall meet the requirements on
248
CMR
10.07(6).
3. Each fixture trap shall have an accessible
cleanout plug of ample size that is protected by the water seal.
Exception:
a. Traps which are cast integrally or in
combination with the fixture in which the trap seal is readily accessible or
except when a portion of the trap is readily removable for cleaning
purposes.
b. Traps for floor outlet
and similar fixtures including bathtubs and showers where a cleanout would not
be accessible. A cleanout shall be installed in the nearest accessible
location.
(e)
Trap Seal. Each fixture trap shall have a liquid seal
of not less than two inches and not more than four inches, except where for
special conditions, a deeper seal may be required.
See 10.08:
Example 3. The protection of trap seals from siphonage,
aspiration, momentum, oscillation, back pressure, evaporation, or capillary
action shall be accomplished by the appropriate use of soil or waste stacks,
vents, re-vents, dry vents, wet vents, loop vents, circuit, or continuous
vents, or combinations thereof, installed in accordance with the requirements
of 248 CMR
10.16, so that at no
time shall the trap be subjected to a pressure differential of more than one
inch of water.
10.08: Example 3 - Minimum Liquid Trap Seal
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(f)
Trap Setting and Protection. Traps shall be set level
with respect to their water seals and wherever necessary, shall be protected
from freezing.
(g)
Building and Running Traps.
1. Building and running traps shall not be
installed unless in the opinion of the Inspector they are deemed necessary.
Exception: Where a trap in compliance
with 248 CMR
10.08(2)(d) may be subject
to freezing temperatures, a running trap may be installed in an area not
subject to freezing but as close as possible to the fixture it
serves.
2. Each building
trap when installed shall be provided with an accessible cleanout and with a
relieving vent or fresh air intake which need not be larger than 1/2 the
diameer of the drain to which it connects.
3.
Open Parking
Garages. Parking garages containing openings in exterior walls on
two or more sides of each level of not less than 20% of the total perimeter
wall space on that level.
a. Installation of
traps for floors drains which are located on the open level(s) shall not be
required.
b. A running trap shall
be installed on the sanitary drain prior to entering the separation or
containment system as required in
248
CMR
10.09(1)(a) and equipped
with:
i. an accessible cleanout;
ii. a vent four-inch in size run
independently through the roof.
c. Stacks shall be installed in intervals not
exceeding 60 feet and in accordance with
248
CMR
10.16(3)(a).
(h)
Acid Resistant
Trap. Where a vitrified-clay or other brittle ware, acid-resistant
trap is installed underground, it shall be embedded in concrete extending six
inches beyond the bottom and sides of the trap.
(3)
Drainage Pipe
Cleanouts.
(a)
Location: Cleanouts shall be placed no more than 50
feet apart in all horizontal drainage piping and branch drain piping which is
four-inch in diameter or less. On horizontal piping which is over four inch in
diameter, cleanouts shall not be more than 100 feet apart.
See
10.08:
Example 4.
10.08: Example 4 - Maximum Cleanout Distance on
Horizontal Drain
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(b)
Cleanout plugs shall meet the following requirements.
1. Shall be composed of brass or
plastic.
2. Shall meet the latest
testing standards.
3. Shall have
raised or countersunk square or hexagon heads.
4. If a tripping hazard may exist, only a
countersunk head shall be used.
5.
Plastic cleanout plugs shall be of the same material to which it
connects.
(c)
Underground Drainage. Cleanouts, when installed on
underground drainage piping, shall be:
1.
extended vertically to or above the finished grade level; or
2. extended to an accessible location
immediately outside the building. See 10.08: Example
9.
(d)
Change of Direction. Accessible cleanouts shall be
installed:
1. at each change of direction of
the building drain; or
2. at each
change of direction of horizontal waste or soil lines and branch lines, that
are greater than 45 °.
(e)
Concealed
Piping. Cleanouts on concealed piping shall be extended through
and terminate flush with the finished wall or floor. Cleanouts located in
floors, walls, pits, and chases may be left in the wall or floor provided an
access panel of sufficient size to allow removal of the cleanout plug and
proper cleaning of the system.
See 10.08:
Example
5.
10.08: Example 5
Concealed Cleanout in Floor
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Concealed Cleanout in Wall
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(f)
Base of Stacks. A cleanout shall be provided at or
near the base of each vertical storm water conductor, waste, or soil stack.
See 10.08:
Example 6.
10.08: Example 6 - Cleanout at the Base of a
Stack
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(g)
Building Drain at Foundation Wall.
1. There shall be a clean-out installed on
the building drain so located as to provide accessibility in direct line
through the building drain to building sewer.
2. If necessary, a pit or manhole shall be
provided.
3. Piping configuration
shall be installed as diagramed in 10.08: Example 7 and in
compliance with 10.06: Table 1 and consistent with the
materials being installed.
4. An
additional full-sized cleanout may be installed outside of the building but not
more than five feet beyond the foundation wall.
10.08: Example 7 - Piping Configurations of Building
Drains at Foundation Wall
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(h)
Inaccessible
Cleanouts. For buildings with concrete floors (slabs) or with less
than 36 inches of crawl space under the floor, or where a cleanout is not
easily accessible, the cleanout for the building drain may be installed outside
of the building but not more than five feet beyond the foundation wall.
10.08: Examples 8 and
9
10.08: Example 8
Inaccessible Cleanout at The Base of A
Stack
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10.08: Example 9
Building Drain Cleanout Installed Outside
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(i)
Direction of Flow. Every cleanout shall be installed
so that the cleanout opens in the direction of the flow of the drainage line or
at right angles thereto.
(j)
Cleanout Size: Cleanouts shall be of the same nominal
size as the pipes up to four inches and not less than four inches for larger
piping.
(k)
Cleanout
Clearances.
See 10.08:
Example
10.
1.
Large Pipe - 18
Inch Clearance: Cleanouts on three inch or larger pipes shall be
so installed that there is a clearance of not less than 18 inches for the
purpose of clearing stoppages.
2.
Small Pipe - 12 Inch Clearance: Cleanouts smaller than
three inches shall be so installed that there is a 12-inch clearance for the
purpose of clearing stoppages.
10.08: Example 10 - Cleanout Clearances
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(l)
Cleanouts Shall Be Kept
Uncovered and Accessible.
1.
Cleanout plugs shall not be covered with cement, plaster, or any other
permanent finishing material.
2.
Where it is necessary to conceal a cleanout plug, a covering plate or access
door shall be provided which will allow ready access to the plug for removal.
See 10.08: Example 5.
(m)
Cleanout
Equivalent: The cleanout equivalent may be satisfied by one of the
following methods:
1. a fixture trap that
incorporate a union connection;
2.
a fixture with an integral trap; or
3. roof drain covers that are readily
removable without disturbing concealed rough piping.
(n)
Connections to Cleanouts
Prohibited. Cleanout openings shall not be used for the
installation of any new or additional plumbing except where another
end-cleanout of equal access and capacity is provided.
(o)
Manholes for Large
Pipes.
1. For underground and
"dedicated system" piping that is over ten inches in diameter and is outside a
building, manholes shall be provided and located at every change of size in
diameter, alignment grade or elevation and at intervals of not more than 350
feet except when the total developed length of the drain is less than 150 feet,
cleanouts may be installed at 75 intervals.
2. Manholes shall conform to current
standards and engineering practices.
