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  1. Plumbing fixtures shall be separately trapped by a liquid seal trap placed as close as possible to the fixture outlet.
  2. The vertical distance from the fixture outlet to the trap weir shall not exceed 24 inches.
  3. Fixtures shall not be double-trapped unless a relief vent is provided between the two traps.
EXCEPTIONS:
  1. Fixtures that have integral traps.
  2. Interceptors in Chapter 6 that provide the required trap seal. Interceptors in Chapter 6 that do not provide the required trap seal shall be provided with a separate trap.
  3. A multi-compartment sink with up to 3 compartments may be installed on one trap provided that no compartment is more than 6 inches deeper than another and the waste outlets are not more than 30 inches from the trap inlet.
  4. One trap may be installed for up to three (3) sinks or lavatories in the same room with their waste outlets no more than 30 inches from the trap, and where the trap is centrally located when three such fixtures are installed.
  5. No clothes washer or laundry sink shall be discharged to a trap serving a kitchen sink.
  6. As otherwise permitted by this Code.
See Figures 5.1-A through 5.1-D
Figure 5.1 - A
THE VERTICAL DISTANCE FROM A FIXTURE OUTLET TO ITS TRAP WEIR
Figure 5.1 - B
A FIXTURE WITH AN INTEGRAL TRAP
Figure 5.1 - C
A CONTINUOUS WASTE WITH END OUTLET
Figure 5.1 - D
A CONTINUOUS WASTE WITH CENTER OUTLET
Fixture trap size (nominal diameter) shall be sufficient to drain the fixture rapidly and in no case less than given in Table 5.2. No trap shall be larger than the drain pipe into which it discharges. Integral traps shall conform to appropriate standards.
Comment: A drain pipe that is smaller than the trap to which it is connected could create an obstruction to flow through the trap.
Table 5.2
MINIMUM SIZE OF NON-INTEGRAL TRAPS
Plumbing Fixture Trap Size in inches
Bathtub (with or without overhead shower) 1-1/2
Bidet 1-1/4
Clothes washing machine standpipe 2
Combination kitchen sink, domestic dishwasher, and food waste disposer 1-1/2
Dental unit or cuspidor 1-1/4
Dental lavatory 1-1/4
Drinking fountain 1-1/4
Dishwasher, commercial 2
Dishwasher, domestic (non-integral trap) 1-1/2
Floor drain 2
Food waste disposer, commercial use 2
Food waste disposer, domestic use 1-1/2
Kitchen sink, domestic, with food waste disposer unit 1-1/2
Kitchen sink, domestic 1-1/2
Lavatory, common (private and public) 1-1/4
Lavatory (barber shop, beauty parlor or surgeon's) 1-1/2
Laundry tray (1 or 2 compartments) 1-1/2
Shower stall or shower drain (single shower head) 1-1/2
Shower stall or shower drain (multiple shower heads) 2
Sink (surgeon's) 1-1/2
Sink (flushing rim type, flush valve supplied) 3
Sink (service type with floor outlet trap standard) 3
Sink (service type with P trap) 2
Sink, commercial (pot, scullery, or similar type) 2
Sink, commercial (with food disposer unit) 2
Wash Fountain (4 rated users or less) 1-1/2
Wash Fountain (8 rated users or less) 2
Wash Sink 1-1/2
Fixture traps shall be self-scouring and shall have no interior partitions except where such traps are integral with the fixture or where corrosion-resistant materials of plastic or glass are used. Solid connections, slip joints, or couplings may be used on the trap inlet, trap outlet, or within the trap seal. See Figures 5.3.1-A through 5.3.1-C. Refer to Sections 4.2.15 and 7.3.7 for slip joints and their required access.
Figure 5.3.1 - A
A FIXTURE TRAP WITH SOLID CONNECTIONS
Figure 5.3.1 - B
A FIXTURE TRAP WITH SLIP JOINTS
Figure 5.3.1 - C
A FIXTURE TRAP WITH THREE DIFFERENT TYPES OF JOINTS
Each fixture trap shall have a liquid seal of not less than two inches and not more than four inches.
EXCEPTIONS:
  1. Interceptors in Chapter 6 that provide the required trap seal.
    Note: Interceptors in Chapter 6 that do not provide the required trap seal shall be provided with a separate trap.
  2. Special conditions such as accessible fixtures, a deeper seal may be required by the Authority Having Jurisdiction in accordance with N.J.A.C. 5:23-3.3. See Figure 5.3.2
Figure 5.3.2
TRAP SEAL DEPTH
Traps shall be set level with respect to their water seals and, where necessary, shall be protected from freezing. See Figure 5.3.3
Figure 5.3.3
TRAPS MUST BE LEVEL AND PROTECTED FROM FREEZING
Building traps shall not be installed except where required by the Authority Having Jurisdiction in accordance with N.J.A.C. 5:23-3.3. Each building trap when installed shall be provided with a cleanout and with a relieving vent or fresh air intake on the inlet side of the trap that shall be at least one-half the diameter of the drain to which it connects. Such relieving vent or fresh air intake shall be carried above grade and terminate in a screened outlet located outside the building.
Comment: Building traps are no longer installed in modern plumbing systems. They provide a collection point for solids and other waste that may cause line stoppages. Building traps also prevent the building vent system from venting the building sewer. The Authority Having Jurisdiction may require building traps if the sewer gas in the municipal sewage system is particularly corrosive or aggressive and could damage the drain, waste, and vent piping in the building.
  1. The following types of traps shall be prohibited:
    1. Traps that depend upon moving parts to maintain their seal.
    2. Bell traps.
    3. Crown vented traps.
    4. Separate fixture traps that depend on interior partitions for their seal, except if made from plastic, glass or other corrosion resistant materials.
    5. "S" traps, of uniform internal dimension.
    6. Drum traps, except drum trap solids interceptors that are permitted in Section 5.3.7.
      See Figure 5.3.5
Figure 5.3.5
PROHIBITED TRAPS
  1. Traps that could lose their seal due to evaporation because of infrequent use shall have accessible means to replenish the trap seal or be connected to a trap primer conforming to ASSE 1018 or ASSE 1044.
  2. Floor drains that comply with ASME A112.6.3 shall be permitted to be fitted with a barrier type floor drain trap seal protection device complying with ASSE 1072. The device shall have an application designation marking for the type of floor and environment it has been designed and tested for (AF, AF-GW, SF, CF, CT, WF).
  1. Drum trap solids interceptors shall be permitted for lavatories and sinks in beauty salons, dental offices, jewelry stores, hotel and motel guest rooms, dormitories and other areas that require interception of hair, solids, and valuables.
  2. Solids interceptors of the drum trap type shall comply with Section 6.5.
  3. The depth of trap seals shall comply with Section 5.3.2.
  1. Cleanouts for horizontal drain piping shall be spaced at intervals not exceeding the following values:
    4" pipe size or less: 75 feet
    5" size and larger: 100 feet
  2. The distances referred to in Section 5.4.1.a shall include the developed length from a cleanout opening to the connection of the next downstream cleanout or cleanout pipe.
See Figure 5.4.1
Figure 5.4.1
CLEANOUT SPACING ON HORIZONTAL DRAIN LINES
Cleanouts, when installed on an underground building sewer, shall be extended vertically to or above the finished grade level. See Figure 5.4.2
Figure 5.4.2
A SEWER CLEANOUT EXTENDED TO FINISHED GRADE
  1. Where required, cleanouts shall be installed at changes of direction in drain piping made with 60°, 72°, and 90° fittings. EXCEPTION: Where there are multiple changes of direction in a run of piping, one cleanout shall be permitted for up to forty total feet of offset piping. See Figure 5.4.3
  2. Cleanouts shall not be required where changes of direction are made with one or more 22-1/2° or 45° fittings.
Figure 5.4.3
WHERE CLEANOUTS ARE REQUIRED AT CHANGES IN DIRECTION
Cleanouts for concealed piping in finished walls or ceilings shall be accessible through access doors or cover plates which provide clearance for removal of the cleanout plug and insertion of the drain cleaning equipment. See Figure 5.4.4
Figure 5.4.4
ACCESS TO CONCEALED CLEANOUTS
  1. A cleanout shall be provided near the base of each vertical drain stack and located not less than 6 inches above the lowest flood level rim of the fixtures served on that level. If there are no fixtures served on that level, the cleanout shall be installed above the base of the stack.
  2. For buildings with a crawl space of less than 18 inches clear height, or where a stack cleanout would not be accessible from within the building, the cleanout may be installed not more than five feet outside the building wall.
  3. Where cleanouts are below grade, the cleanout opening shall be installed in an accessible location flush with the finished floor or terminated above the floor.
  4. Rain leaders and conductors connected to a building storm drain or storm sewer shall have a cleanout installed at or above the base of the outside leader or inside conductor before it connects to the building drain or sewer.
See Figures 5.4.5-A through 5.4.5-C
Figure 5.4.5 - A
A CLEANOUT NEAR THE BASE OF A STACK
Figure 5.4.5 - B
A CLEANOUT EXTENDED TO OUTSIDE OF THE BUILDING FOR ACCESS
Figure 5.4.5 - C
A CLEANOUT NEAR THE BASE OF A RAIN LEADER
  1. There shall be a cleanout near the junction of a building drain and building sewer either inside or outside the building wall.
  2. Cleanouts shall be placed in the building sanitary sewer and the building storm sewer at the property line and brought to the surface. See Figures 5.4.6-A and 5.4.6-B
Figure 5.4.6 - A
A CLEANOUT AT THE JUNCTION OF THE BUILDING DRAIN AND BUILDING SEWER
Figure 5.4.6 - B
A CLEANOUT AT THE PROPERTY LINE
Cleanouts shall be installed so that the opening of the cleanout connection is in the direction of the flow within the drain line or at right angles thereto. See Figure 5.4.7
Figure 5.4.7
THE FLOW DIRECTION OF CLEANOUTS
  1. Cleanout plug openings in other than drainage pattern fittings shall not be used for the installation of fixtures or floor drains.
  2. If a cleanout fitting or cleanout plug opening is removed from a drainage pattern fitting in order to extend the drain, another cleanout of equal access and capacity shall be provided in the same location.
Cleanout size shall conform with Table 5.4.9.
Table 5.4.9
SIZE OF CLEANOUTS
Nominal Drain Pipe Size Nominal Size of Cleanout
1-1/4" 1-1/4"
1-1/2" 1-1/2"
2" 2"
3" 3"
4", 5", 6" 4"
8" & 10" 6"
12" & 15" 8"
NOTES FOR TABLE 5.4.9
  1. See Section 5.4.10 for sizes 12" or larger for building sewers.
  2. See Section 5.4.13 for cleanout equivalents.
  1. Manholes shall be provided as cleanouts for building sewers 12" size and larger. Manholes shall be provided at every change of size, alignment, direction, grade, or elevation. The distance between manholes shall not exceed 300 feet.
  2. Manholes may be provided in lieu of cleanouts in underground building sewers, building drains, and branches thereof, 8" size and larger. Such manholes shall comply with the requirements of Section 5.4.10.a.
  3. If manholes are installed indoors, they shall have a bolted, gas-tight cover.
  4. DELETED
Cleanouts on 3" and larger piping shall be so installed that there is a clearance of not less than 18" for the purpose of rodding. Cleanouts on piping smaller than 3" shall be so installed that there is a 12" clearance for rodding. See Figures 5.4.11-A and 5.4.11-B
Figure 5.4.11 - A
CLEANOUT CLEARANCE ABOVE THE BASE OF A STACK
Figure 5.4.11 - B
CLEANOUT CLEARANCE AT THE BASE OF A STACK
Cleanout plugs shall not be covered with cement, plaster, or any other permanent finishing material. Where it is necessary to conceal a cleanout plug, a covering plate or access door shall be provided that will permit access to the plug.
Where drain piping is concealed, a fixture trap or a fixture with integral trap, removable without disturbing the concealed piping, shall be accepted as a cleanout equivalent, provided the opening to be used as a cleanout opening is the size required by Table 5.4.9. See Figure 5.4.13
EXCEPTIONS:
  1. A removable fixture trap may be used as a cleanout equivalent for drain piping that is no more than one size larger than the drain pipe for the removed trap.
  2. A floor drain with a removable strainer or grate may be used as a cleanout equivalent based on the pipe size of its outlet and trap.
Figure 5.4.13
A WATER CLOSET AS A CLEANOUT EQUIVALENT
A cleanout shall be provided immediately downstream from a floor drain whose strainer or grate is not removable.
  1. Fixtures and/or drain inlets subject to backflow and overflow from blocked or restricted public sewers shall be protected by a backwater valve.
  2. Such situations include those where the flood level rim of fixtures and/or drain inlets are below the overflow level of the first upstream manhole in the public sewer that will overflow due to a blockage or flow restriction in the public sewer.
  3. Backwater valves shall be installed in drain piping that receives flow only from fixtures and/or drains that are subject to backflow from public sewers.
  4. Other portions of the drainage system not subject to such backflow shall not drain through a backwater valve.
EXCEPTION: Existing buildings without backwater valves that have fixtures that are below the overflow level of the public sewer shall be permitted to install backwater valves in piping that also serves fixtures that are above the overflow level of the sewer if necessary to protect the fixtures that are below the overflow level.
See Figure 5.5.1.
Figure 5.5.1
BACKWATER VALVES
Backwater valves shall conform to ASME A112.14.1 and be installed so that their internal working parts are accessible for periodic cleaning, repair or replacement.
When backwater valves are installed in building sanitary drainage systems, a notice shall be posted at the building water service shutoff valve(s) describing where backwater valves are located.
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