ICC Subscriptions

P3005.1 Drainage fittings and connections.

Changes in direction in drainage piping shall be made by the appropriate use of sanitary tees, wyes, sweeps, bends or by a combination of these drainage fittings in accordance with Table P3005.1. Change in direction by combination fittings, heel or side inlets or increasers shall be installed in accordance with Table P3005.1 and Sections P3005.1.1 through P3005.1.4. based on the pattern of flow created by the fitting.


Horizontal to verticalc Vertical to horizontal Horizontal to horizontal
Sixteenth bend X X X
Eighth bend X X X
Sixth bend X X X
Quarter bend X Xa Xa
Short sweep X Xa,b Xa
Long sweep X X X
Sanitary tee Xc
Wye X X X
Combination wye and eighth bend X X X

For SI: 1 inch = 25.4 mm.
a. The fittings shall only be permitted for a 2-inch or smaller fixture drain.
b. Three inches and larger.
c. For a limitation on multiple connection fittings, see Section P3005.1.1.

P3005.1.1 Horizontal to vertical (multiple connection fittings).
Double fittings such as double sanitary tees and tee-wyes or approved multiple connection fittings and back-to-back fixture arrangements that connect two or more branches at the same level shall be permitted as long as directly opposing connections are the same size and the discharge into directly opposing connections is from similar fixture types or fixture groups. Double sanitary tee patterns shall not receive the discharge of back-to-back water closets and fixtures or appliances with pumping action discharge.

Back-to-back water closet connections to double sanitary tee patterns shall be permitted where the horizontal developed length between the outlet of the water closet and the connection to the double sanitary tee is 18 inches (457 mm) or greater.
P3005.1.2 Heel- or side-inlet quarter bends, drainage.
Heel-inlet quarter bends shall be an acceptable means of connection, except where the quarter bends serves a water closet. A low-heel inlet shall not be used as a wet-vented connection. Side-inlet quarter bends shall be an acceptable means of connection for both drainage, wet venting and stack venting arrangements.
P3005.1.3 Heel- or side-inlet quarter bends, venting.
Heel-inlet or side-inlet quarter bends, or any arrangement of pipe and fittings producing a similar effect, shall be acceptable as a dry vent where the inlet is placed in a vertical position. The inlet is permitted to be placed in a horizontal position only where the entire fitting is part of a dry vent arrangement.
P3005.1.4 Water closet connection between flange and pipe.
One-quarter bends 3 inches (76 mm) in diameter shall be acceptable for water closet or similar connections, provided a 4-inch by 3-inch (102 mm by 76 mm) flange is installed to receive the closet fixture horn. Alternately, a 4-inch by 3-inch (102 mm by 76 mm) elbow shall be acceptable with a 4-inch (102 mm) flange.
P3005.1.5 Dead ends.
Dead ends shall be prohibited except where necessary to extend a cleanout or as an approved part of a rough-in more than 2 feet (610 mm) in length.
P3005.1.6 Provisions for future fixtures.
Where drainage has been roughed-in for future fixtures, the drainage unit values of the future fixtures shall be considered in determining the required drain sizes. Such future installations shall be terminated with an accessible permanent plug or cap fitting.
P3005.1.7 Change in size.
The size of the drainage piping shall not be reduced in size in the direction of the flow. A 4-inch by 3-inch (102 mm by 76 mm) water closet connection shall not be considered as a reduction in size.
P3005.2 Drainage pipe cleanouts.
Drainage pipe cleanouts shall comply with Sections P3005.2.1 through P3005.2.11.

These provisions shall not apply to pressurized building drains and building sewers that convey the discharge of automatic pumping equipment to a gravity drainage system.

P3005.2.1 Materials.
Cleanouts shall be liquid and gas tight. Cleanout plugs shall be brass or plastic.
P3005.2.2 Spacing.
Cleanouts shall be installed not more than 100 feet (30 480 mm) apart in horizontal drainage lines measured from the upstream entrance of the cleanout.
P3005.2.3 Underground drainage cleanouts.
When installed in underground drains, cleanouts shall be extended vertically to or above finished grade either inside or outside the building.
P3005.2.4 Change of direction.
Cleanouts shall be installed at each fitting with a change of direction more than 45 degrees (0.79 rad) in the building sewer, building drain and horizontal waste or soil lines. Where more than one change of direction occurs in a run of piping, only one cleanout shall be required in each 40 feet (12 192 mm) of developed length of the drainage piping.
P3005.2.5 Accessibility.
Cleanouts shall be accessible. The clearance in front of cleanouts shall be not less than 18 inches (457 mm) on 3-inch (76 mm) and larger pipes, and not less than 12 inches (305 mm) on smaller pipes. Concealed cleanouts shall be provided with access of sufficient size to permit removal of the cleanout plug and rodding of the system. Cleanout plugs shall not be concealed by permanent finishing material.
P3005.2.6 Base of stacks.
A cleanout shall be provided at the base of each waste or soil stack.
P3005.2.7 Building drain and building sewer junction.
There shall be a cleanout near the junction of the building drain and building sewer. This cleanout shall be either inside or outside the building wall, provided that it is brought up to finish grade or to the lowest floor level. An approved two-way cleanout shall be permitted to serve as the required cleanout for both the building drain and the building sewer. The cleanout at the junction of the building drain and building sewer shall not be required where a cleanout on a 3-inch (76 mm) or larger diameter soil stack is located within a developed length of 10 feet (3048 mm) of the building drain and building sewer junction.
P3005.2.8 Direction of flow.
Cleanouts shall be installed so that the cleanout opens to allow cleaning in the direction of the flow of the drainage line.
P3005.2.9 Cleanout size.
Cleanouts shall be the same nominal size as the pipe they serve up to 4 inches (102 mm). For pipes larger than 4 inches (102 mm) nominal size, the size of the cleanout shall be not less than 4 inches (102 mm).

1. "P” trap connections with slip joints or ground joint connections, or stack cleanouts that are not more than one pipe diameter smaller than the drain served, shall be permitted.
2. Cast-iron cleanouts sized in accordance with the referenced standards in Table P3002.3, ASTM A 74 for hub and spigot fittings or ASTM A 888 or CISPI 301 for hubless fittings.
P3005.2.10 Cleanout equivalent.
A fixture trap or a fixture with integral trap, readily removable without disturbing concealed piping shall be acceptable as a cleanout equivalent.
P3005.2.11 Connections to cleanouts prohibited.
Clean-out openings shall not be used for the installation of new fixtures except where approved and an acceptable alternate cleanout is provided.
P3005.3 Horizontal drainage piping slope.
Horizontal drainage piping shall be installed in uniform alignment at uniform slopes not less than 1/4 unit vertical in 12 units horizontal (2-percent slope) for 21/2 inch (64 mm) diameter and less, and not less than 1/8 unit vertical in 12 units horizontal (1-percent slope) for diameters of 3 inches (76 mm) or more.

P3005.4 Drain pipe sizing.

Drain pipes shall be sized according to drainage fixture unit (d.f.u.) loads. The size of the drainage piping shall not be reduced in size in the direction of flow. The following general procedure is permitted to be used:

1. Draw an isometric layout or riser diagram denoting fixtures on the layout.
2. Assign d.f.u. values to each fixture group plus individual fixtures using Table P3004.1.
3. Starting with the top floor or most remote fixtures, work downstream toward the building drain accumulating d.f.u. values for fixture groups plus individual fixtures for each branch. Where multiple bath groups are being added, use the reduced d.f.u. values in Table P3004.1, which take into account probability factors of simultaneous use.
4. Size branches and stacks by equating the assigned d.f.u. values to pipe sizes shown in Table P3005.4.1.
5. Determine the pipe diameter and slope of the building drain and building sewer based on the accumulated d.f.u. values, using Table P3005.4.2.
P3005.4.1 Branch and stack sizing.
Branches and stacks shall be sized in accordance with Table P3005.4.1. Below grade drain pipes shall be not less than 11/2 inches (38 mm) in diameter. Drain stacks shall be not smaller than the largest horizontal branch connected.

1. A 4-inch by 3-inch (102 mm by 76 mm) closet bend or flange.
2. A 4-inch (102 mm) closet bend connected to a 3-inch (76 mm) stack tee shall not be prohibited.


11/2b 3 4
2b 6 10
21/2b 12 20
3 20 48
4 160 240

For SI: 1 inch = 25.4 mm.
a. 11/4-inch pipe size limited to a single-fixture drain or trap arm. See Table P3201.7.
b. No water closets.
P3005.4.2 Building drain and sewer size and slope.
Pipe sizes and slope shall be determined from Table P3005.4.2 on the basis of drainage load in fixture units (d.f.u.) computed from Table P3004.1.


1/8 inch 1/4 inch 1/2 inch
11/2a, b Note a Note a
2b 21 27
21/2b 24 31
3 36 42 50
4 180 216 250

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.
a. 11/2-inch pipe size limited to a building drain branch serving not more than two waste fixtures, or not more than one waste fixture if serving a pumped discharge fixture or garbage grinder discharge.
b. No water closets.
P3005.5 Connections to offsets and bases of stacks.
Horizontal branches shall connect to the bases of stacks at a point located not less than 10 times the diameter of the drainage stack downstream from the stack. Horizontal branches shall connect to horizontal stack offsets at a point located not less than 10 times the diameter of the drainage stack downstream from the upper stack.