Each fixture, and all outlets for chemical or
experimental laboratory tables, or any fixture having a waste-pipe
specified, defined herein or not, shall be furnished with a trap,
which shall be placed as close as practical to the fixture it serves,
or integral therewith and in no case shall trap be more than one foot
from said fixture. The waste from one fixture must not connect with
the trap of another, except that a residential dishwasher or a two
to five part laundry tray may be connected with a single trap. The
size of traps for a given fixture shall be as computed in Subsection
A.
A. Size of fixture traps.
(1) Fixture trap size (nominal diameter) shall be sufficient
to drain the fixture rapidly and in no case less than given in Table
Fixture Traps for Different Type Plumbing Fixtures. No trap shall
be larger than the drainage pipe into which it discharges.
|
Table 860-97A
Fixture Traps for Different Type Plumbing
Fixtures
|
---|
|
Plumbing Fixture
|
Minimum Trap Size In Inches
|
Fixture Unit Value
|
---|
|
Automatic Clothes Washer (when connected to
drainage system)
|
2
|
3
|
|
Bathtub (with or without overhead shower)
|
1 1/2
|
2
|
|
Bedpan washer
|
3
|
8
|
|
Bidet
|
1 1/2
|
2
|
|
Combination sink & tray (separate traps
for each compartment)
|
1 1/2
|
3
|
|
Combination sink & tray with food waste
grinder (separate traps for each compartment)
|
1 1/2
|
4
|
|
Dental unit for cuspidor
|
1 1/2
|
1
|
|
Dental lavatory
|
1 1/4
|
1
|
|
Drinking fountain
|
1 1/4
|
1
|
|
Dishwasher — commercial
|
2 or 3
|
3 or 5
|
|
Dishwasher — domestic
|
1 1/2
|
2
|
|
Floor drain (above ground)
|
3
|
4
|
|
Floor drain (below ground)
|
4
|
5
|
|
Floor drain (car wash or similar functions)
|
4
|
6
|
|
Kitchen sink — domestic
|
1 1/2
|
2
|
|
Kitchen sink — domestic, with food waste
grinder
|
1 1/2
|
3
|
|
Kitchen sink — domestic, double bowl (separate
traps for each compartment)
|
1 1/2
|
3
|
|
Kitchen sink — domestic, double bowl with
food waste grinder (separate traps for each compartment)
|
1 1/2
|
4
|
|
Kitchen sink — domestic, double bowl with
food waste grinder
|
|
|
|
(separate traps for each compartment)
|
1 1/2
|
4
|
|
Lavatory, common
|
1 1/4
|
1
|
|
Lavatory (barber shop, beauty parlor or surgeons)
|
1 1/2
|
2
|
|
Lavatory, multiple type (wash fountain or wash
sink)
|
2
|
2
|
|
Laundry tray (1 or 2 compartments)
|
1 1/2
|
2
|
|
Laundry tray (3 to 5 compartments)
|
2
|
3
|
|
Shower stall (single)
|
2
|
2
|
|
Shower stalls (group or gang type, above ground)
|
3 or 4
|
2 per head
|
|
Shower stalls (group or gang type, below ground)
|
4
|
2 per head
|
|
Sink — surgeons
|
1 1/2
|
3
|
|
Sink — flushing rim type, flush valve
supplied
|
3
|
6
|
|
Sink — service type with trap combined
|
3
|
4
|
|
Sink — service type, ordinary
|
2
|
2
|
|
Sink — service, janitors style, floor
receptor above ground
|
2, 3 or 4
|
4
|
|
Sink — service, janitors style, floor
receptor below ground
|
4
|
4
|
|
Sink — commercial (pot, scullery, or similar
type)
|
2
|
4
|
|
Sink — commercial (with food grinder unit)
|
2
|
4
|
|
Urinal — (pedestal, syphon jet)
|
3
|
8
|
|
Urinal — (wall hung blowout type, flush
valve supplied)
|
2-3
|
6-8
|
|
Urinal — (trough — each two ft.
section)
|
1 1/2
|
2
|
|
Urinal — (wall hung siphon jet)
|
2
|
4
|
|
Urinal — (wall lip type, flush tank or
self closing valve)
|
1 1/2
|
2
|
|
Urinal — (stall type — existing
only)
|
2
|
4
|
|
Water closet tank operated
|
3
|
4
|
|
Water closet valve operated
|
3
|
8
|
(2) Trap size for plumbing fixtures not listed above will
be sized as determined by the Administrative Authority, based on GPM
discharge.
B. Prohibited traps. The following traps are prohibited:
(1) Traps which depend upon moving parts to maintain their
seal.
(4) Separate fixture traps which depend on interior partitions
for their seal.
(6) Manufactured traps 1 1/4 inches and larger with
an area serving as the top and bottom dip not constructed of a one
piece 180° bend.
(7) Running trap with double cleanouts (except where trap
is exposed and accessible).
C. Design of traps. Fixture traps shall be self scouring
and shall have no interior partitions except where such traps are
integral with the fixture. Slip joints or coupling may be used on
the trap inlet or within the trap seal.
D. Drum traps.
(1) Drum traps shall be three or four inches in diameter
and shall be provided with a water seal of not less than two inches.
(2) The trap screw shall be one size less than the trap
diameter.
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 deep seal may be required by the Administrative
Authority.
F. Trap cleanouts. Each fixture trap, except those cast
integral or in combination with fixtures in which the trap seal is
readily accessible or except when a portion of the trap is removable
for cleaning purposes, shall have an accessible brass or plastic trap
screw of ample size protected by this water seal.
G. Trap settings and protection. Traps shall be set level
with respect to their water seals and, when necessary, shall be protected
from freezing.
H. Traps underground. Traps for floor drains shall have
a water seal of three inches and shall be provided with removable
strainers. Underground traps except "P" traps into which floor drains
or similar fixtures with removable strainers discharge, shall be provided
with accessible and removable clean outs.
I. Provision for evaporation. Where floor drains are
subject to evaporation, they shall be provided with a water supply
by means of a faucet located not more than three feet above the floor
area drain through an approved automatic priming device, or other
approved means.
J. Building (house) traps.
(1) Each house or building drain shall be provided with
a horizontal intercepting trap, which shall be the same size as the
building drain in which it is installed. The trap shall be provided
with an accessible cleanout and a fresh air grill or inlet, which
shall terminate in a location acceptable to the Administrative Authority.
(2) Relieving vents or fresh air intakes shall be no less
than four inches in diameter for building drains up to and including
eight inches in diameter. For drains larger than eight inches, the
fresh air intake shall be one-half the diameter of the drain. Openings
in grill of fresh air inlet shall equal the area of the inlet pipe.
The fresh air inlet shall not be used as an area drain.
(3) Cleanouts for intercepting traps shall be no less
than four inches in diameter for trap sizes up to and including 10
inches. For traps larger than 10 inches the cleanout shall be no less
than six inches in diameter.
(4) It is recommended that the trap shall be placed inside
the cellar or basement wall or as close thereto as practical allowing
for construction circumstances. Where house or building traps are
placed outside of buildings, it shall be placed as close as practical
to the outside of the foundation wall and the fresh air shall be extended
above ground, in addition, on traps installed below four feet in depth,
a wye and one eighth bend, combination wye or two way cleanout tee
shall be installed on the down stream or sewer side of trap with a
pipe extending to grade and finished with a cleanout. Also, no trap
shall be placed outside of a building if the depth is greater than
six feet below finished grade except that in commercial applications,
traps may be installed greater than six feet deep provided they are
placed in a manhole.
(5) Refer to illustration in Chapter 22 for trap assembly
dimensions.
K. Protection of brittleware traps. Where the use of
vitrified clay or brittleware traps installed underground, is approved
by the Administrative Authority, the traps shall be embedded in concrete
encasement extending four inches beyond the bottom and sides of the
trap.