2006 NATIONAL STANDARD PLUMBING CODE
General Regulations
2.1 RESERVED 2.2 RESERVED
2.3 CHANGES IN DIRECTION OF DRAINAGE PIPING
2.3.1 Uses for Drainage Fittings
a. Changes in direction of drainage piping shall be made with long radius drainage fittings. See Table 2.3.1.
EXCEPTION: Short radius drainage fittings shall be permitted in the drain piping for individual fixtures. See Table 2.3.1.
b. Short radius drainage fittings are those having radius or centerline dimensions that are approximately equal to or less than their nominal pipe size. The radius or centerline dimensions of long radius drainage fittings are greater than their nominal pipe size.
c. Long radius drainage fittings shall not be used to connect fixture trap arms to vertical drain and vent piping. Connections to fixture vents shall be above the top weir of the fixture trap.
2.3.2 Double Pattern Fittings
The uses for double pattern drainage fittings shall be the same as for single pattern fittings in Table 2.3.1.
EXCEPTION: Double sanitary tees and crosses shall not be used to connect blowout fixtures, back-outlet water closets, and fixtures or appliances having pumped discharge.
2.3.3 Back-to-Back Fixtures
Stack fittings, including carriers, for back-outlet fixtures installed back-to-back shall be either the wye pattern, incorporate baffles within the drainage fitting, or otherwise be designed to prevent crossflow or mixing of the discharges from the two fixtures prior to the change in direction.
2.4 FITTINGS AND CONNECTIONS IN DRAINAGE SYSTEMS 2.4.1 Prohibited Fittings
No running threads or saddles shall be used in the drainage or vent system. No drainage or vent piping shall be drilled, tapped, burned or welded.
Table 2.3.1 PERMISSIBLE DRAINAGE FITTINGS FOR CHANGES IN DIRECTION PIPE CHANGE IN DIRECTION HORIZONTAL HORIZONTAL VERTICAL TO TO TO HORIZONTAL VERTICAL HORIZONTAL long sweep sanitary tee (1) eighth bend and wye short sweep eighth bend and wye (2) combination wye & eighth bend CAST IRON wye combination wye & eighth bend long sweep HUB & combination wye & eighth bend long sweep short sweep 3\ or larger fifth bend (72-deg) short sweep quarter bend (1) SPIGOT sixth bend (60-deg) quarter bend (1) short sweep (1) CAST eighth bend (45-deg) IRON NO-HUB sixteenth bend (22 ? deg) quarter bend (1) extra long turn 90-deg elbow drainage tee (1) long turn 90-deg TY long turn 90-deg elbow short turn 90-deg TY (1) extra long turn 90-deg elbow long turn 90-deg TY (2) long turn 90-deg elbow CAST IRON long turn 45-deg elbow short turn 22 ? deg elbow 45-deg elbow and 45-deg Y short turn 90-deg elbow (1) short turn 11 ? deg elbow extra long turn 90-deg elbow 45-deg elbow & 45-deg Y branch DRAINAGE long turn 90-deg TY long turn 90-deg elbow short turn 45-deg Y branch short turn 90-deg elbow (1) (threaded) short turn 90-deg elbow (1) short turn 60-deg elbow (1) short turn 45-deg elbow (1) DWV 90-deg long radius elbow DWV tee (1) DWV long turn T-Y DWV 90-deg sanitary tee (1) 45-deg elbow and DWV 45-deg Y 90-deg elbow - long radius DWV long turn T-Y (2) DWV 90-deg long radius elbow COPPER DWV long turn T-Y DWV 45-deg Y 45-deg elbow & DWV 45-deg Y 90-deg elbow - long radius DWV 90-deg elbow (1) DWV 90-deg long radius elbow DWV 90-deg elbow (1) DWV DWV 45-deg elbow (1) 90-deg elbow - long radius DWV 90-deg elbow (1) 90-deg long turn elbow sanitary tee (1) long radius TY fixture tee (1) 45-deg elbow and 45-deg wye long sweep 1/4 bend long radius TY (2) 90-deg long turn elbow PLASTIC 60-deg elbow or 1/6 bend 45-deg elbow and 45-deg wye 90-deg elbow or 1/4 bend (1) 45-deg elbow or 1/8 bend 22 ? deg elbow or 1/16 bend 90-deg long turn elbow DWV long radius TY 90-deg elbow or 1/4 bend (1) 45-deg wye 90-deg elbow or 1/4 bend (1) long sweep tee (1) eighth bend & wye (2) sanitary tee (1) combination wye & eighth bend STAINLESS wye combination wye & eighth bend eighth bend & wye (2) long sweep STEEL combination wye & eighth bend 90-degree 1/4 bend (1) 15-degree 1/24 bend 22 ? degree 1/16 bend long sweep push-fit 30-degree 1/12 bend 90-degree 1/4 bend (1) DWV 45-degree 1/8 bend 90-degree 1/4 bend (1) MATERIAL Footnotes for Table 2.3.1
(1) Short radius fittings shall be permitted only in drain piping for individual fixtures. (2) Long radius fittings shall not be used to connect fixture trap arms to vertical drain and vent piping.
2.4.2 Heel or Side-Inlet Bends
A heel or side-inlet quarter bend shall not be used as a dry vent when the inlet is placed in a horizontal position or any similar arrangement of pipe or fittings producing a similar effect.
EXCEPTION: When the entire fitting is part of a dry vent arrangement system the heel or side-inlet bend shall be acceptable.
2.4.3 Obstruction to Flow
a. No fitting, connection, device, or method of installation that obstructs or retards the flow of water, wastes, sewage, or air in the drainage or venting systems in an amount greater than the normal frictional resistance to flow, shall be used unless it is indicated as acceptable in this Code.
b. 4x3 closet bends and 4x3 closet flanges shall not be considered as obstructions to flow.
2.4.4 Prohibited Joints
Cement mortar joints are prohibited.
EXCEPTION: When used for repairs and/or when used for connections to existing lines constructed with such joints.
2.5 HEALTH AND SAFETY
Where a health or safety hazard is found to exist on a premise, the owner or his agent shall be required to make such corrections as may be necessary to abate such nuisance, and bring the plumbing installation within the provisions of this Code.
2.6 TRENCHING, BEDDING, TUNNELING AND BACKFILLING
2.6.1 Trenching and Bedding
a. Trenching and excavation for the installation of underground piping shall be performed in compliance with occupational safety and health requirements. Trenches shall be of sufficient width to permit proper installation of the pipe. Where shoring is required, additional allowance shall be made in the width of the trench to provide adequate clearance.
b. A firm, stable, uniform bedding shall be provided under the pipe for continuous support. Bell holes shall be provided for joints in bell and spigot pipe and for other joints requiring such clearance. Blocking shall not be used to support the pipe.
c. The trench bottom may provide the required bedding when adequate soil conditions exist and when excavated to the proper depth and grade. Where trenches are excavated to depths below the bottom of the pipe, bedding shall be added beneath the pipe as required. Such bedding shall be of clean sand, gravel, or similar select material that is compacted sufficiently to provide the support required under 2.6.1.b.
d. Where rock is encountered in trenching, it shall be removed to a depth of not less than 6 inches below the bottom of the pipe and bedding shall be added as required under 2.6.1.c. The pipe shall not rest on rock at any point, including joints.
2.6.2 Side-fill
The haunch areas adjacent to the pipe between the bottom of the pipe and its horizontal centerline shall be filled with a clean coarse-grain material such as sand, gravel, or soil. Such side-fill shall be placed by hand, extending to the sides of the trench, and be compacted to provide lateral support for the pipe.
2.6.3 Initial Backfill
After installation of the side-fill, the trench shall be backfilled to a level not less than 2 feet above the top of the pipe. Backfill material shall be sand, gravel, or loose soil that is free of rocks and debris. Maximum particle size shall be 1-1/2 inches. Backfill shall be placed in not more than 6-inch layers, each tamped and compacted. Heavy compacting equipment shall not be used for the initial backfill.
2.6.4 Final Backfill
The trench shall be backfilled from the top of the compacted initial backfill to finish grade using suitable material. Heavy compacting equipment may be used for the final backfill.
2.6.5 Tunneling
When pipe is installed in a dug or bored earth tunnel, the space around the pipe between the pipe and the wall of the tunnel shall be completely filled with packed concrete or grout. When pipe is installed in a jacked-inplace conduit or sleeve, the space around the pipe between the pipe and the inside of the conduit or sleeve shall be sealed in an approved manner in accordance with Section 2.12.d.
2.6.6 Underground Plastic Pipe
a. Underground plastic pipe shall be installed in accordance with the requirements of Section 2.6.
EXCEPTIONS:
(1) The maximum particle size in the side-fill and initial backfill shall be not more than 1/2-inch for pipe 6\
(2) For water service piping, refer to ASTM D2774, Standard Practice for Underground Installation of Thermoplastic Pressure Piping.
(3) For gravity-flow drainage pipe, refer to ASTM D2321, Underground Installation of Thermoplastic Pipe for Sewers and Other Gravity-flow Applications.
b. An insulated copper tracer wire or other approved conductor shall be installed adjacent to underground non-metallic water service piping and non-metallic force mains, to facilitate finding. One end shall be brought above ground inside or outside the building wall. The tracer wire for the water service shall originate at the curb valve required in Section 10.12.1. The tracer wire for the force main shall originate at the final point of disposal. The
tracer wire shall not be less than 18 AWG insulated. The insulation shall not be yellow in color.
2.6.7 Underground Copper Piping
Underground copper piping shall be installed in accordance with the requirements of Section 2.6.
EXCEPTION: The maximum particle size in the side-fill and initial backfill shall be not more than 1/2-inch for pipe 6\
2.6.8 Safety Precautions
Rules and regulations pertaining to safety and protection of workers, other persons in the vicinity, and neighboring property shall be adhered to where trenching or similar operations are being conducted.
2.6.9 Supervision
Where excavation, bedding or backfilling are performed by persons other than the installer of the underground piping, the pipe installer shall supervise the bedding, side-fill, and initial backfill, and shall be responsible for its conformance to this Code.
2.6.10 Trenchless Pipe Replacement Systems
Trenchless replacement of water and sewer piping shall be performed using equipment and procedures recommended by the equipment manufacturer. Where underground piping beneath paved surfaces or concrete floor slabs is replaced by this method, the manufacturer’s recommendations for the specific conditions shall be used. Approved mechanical couplings shall be used to make the connections between new and existing piping.
2.7 SAFETY
Any part of a building or premise that is changed, altered, or required to be replaced as a result of the installation, alteration, renovation, or replacement of a plumbing system, or any part thereof, shall be left in a safe, non-hazardous condition.
2.8 INSTALLATION PRACTICES
Plumbing systems shall be installed in a manner conforming to this Code and industry installation standards.
2.9 PROTECTION OF PIPES
2.9.1 Breakage
Pipes passing under or through foundation walls shall be protected from breakage.
2.9.2 Corrosion
Pipe subject to corrosion by passing through or under corrosive fill, such as, but not limited to, cinders, concrete, or other corrosive material, shall be protected against external