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2.3 Changes in Direction of Drainage Piping
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Changes in direction of drainage piping shall be made with long radius drainage fittings except where short radius fittings are required or permitted.
- Short radius fittings are required to connect individual fixture trap arms to vertical drain and vent piping.
- Short radius fittings may be used in the drain piping for an individual fixture.
- Short radius fittings shall not be used in drain piping serving two or more fixtures.
- Short radius fittings shall not be used at the base of drain stacks.
- Short radius fittings may be used in vent piping.
- 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.
- 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 weir of the fixture trap.
EXCEPTION: Double wyes with 1/8 bends or 45-degree elbows that drain two lavatories into a common drain with a common vent shall be permitted.
See Figures 2.3.1-A, 2.3.1-B, 2.3.1-C, 2.3.1-D, 2.3.2, and 12.8.1-A
Figure 2.3.1 - A
DRAINAGE FITTINGS FOR HORIZONTAL-TO-VERTICAL CHANGES IN DIRECTION
DRAINAGE FITTINGS FOR HORIZONTAL-TO-VERTICAL CHANGES IN DIRECTION
Figure 2.3.1 - B
DRAINAGE FITTINGS FOR HORIZONTAL-TO-HORIZONTAL CHANGES IN DIRECTION
DRAINAGE FITTINGS FOR HORIZONTAL-TO-HORIZONTAL CHANGES IN DIRECTION
Figure 2.3.1 - C
DRAINAGE FITTINGS FOR VERTICAL-TO-HORIZONTAL CHANGES IN DIRECTION
DRAINAGE FITTINGS FOR VERTICAL-TO-HORIZONTAL CHANGES IN DIRECTION
Figure 2.3.1 - D
USE OF SHORT AND LONG RADIUS DRAINAGE FITTINGS
USE OF SHORT AND LONG RADIUS DRAINAGE FITTINGS
| Table 2.3.1 PERMISSIBLE DRAINAGE FITTINGS FOR CHANGES IN DIRECTION | |||
| PIPE MATERIAL | CHANGES IN DIRECTION | ||
| HORIZONTAL TO HORIZONTAL | HORIZONTAL TO VERTICAL | VERTICAL TO HORIZONTAL | |
| CAST IRON HUB & SPIGOT CAST IRON NO-HUB |
long sweep | sanitary tee | eighth bend & wye |
| short sweep | eighth bend & wye (2) | combination wye & eighth bend | |
| wye | combination wye & eighth bend | long sweep | |
| combination wye & eighth bend | long sweep | short sweep 3" or larger | |
| fifth bend (72-deg) | short sweep | quarter bend (1) | |
| sixth bend (60-deg) | quarter bend | short sweep (1) | |
| eighth bend (45-deg) | |||
| sixteenth bend (22-1/2 deg) | |||
| quarter bend | |||
| CAST IRON DRAINAGE (threaded) | extra long turn 90-deg elbow | drainage tee | long turn 90-deg TY |
| long turn 90-deg elbow | short turn 90-deg TY | extra long turn 90-deg elbow | |
| long turn 45-deg elbow | long turn 90-deg TY (2) | long turn 90-deg elbow | |
| short turn 22-1/2 deg elbow | 45-deg elbow or 45-deg Y branch (2) | short turn 90-deg elbow (1) | |
| short turn 11-1/4 deg elbow | extra long turn 90-deg elbow | 45-deg elbow & 45-deg Y branch (1) | |
| long turn 90-deg TY | long turn 90-deg elbow | ||
| short turn 45-deg Y branch | short turn 90-deg elbow | ||
| short turn 90-deg elbow | |||
| short turn 60-deg elbow | |||
| short turn 45-deg elbow | |||
| COPPER DWV | DWV 90-deg long radius elbow | DWV tee | DWV long turn T-Y |
| 90-deg elbow - long radius | DWV 90-deg sanitary tee | 45-deg elbow & DWV 45-deg Y | |
| DWV long turn T-Y | DWV long turn T-Y (2) | DWV 90-deg long radius elbow | |
| DWV 45-deg Y | 45-deg elbow & DWV 45-deg Y (2) | 90-deg elbow - long radius | |
| DWV 90-deg elbow | DWV 90-deg long radius elbow | DWV 90-deg elbow (1) | |
| DWV 45-deg elbow | 90-deg elbow - long radius | ||
| DWV 90-deg elbow | |||
| PLASTIC DWV | 90-deg long turn elbow | sanitary tee | long radius TY |
| long sweep 1/4 bend | fixture tee | 45-deg elbow and 45-deg wye | |
| 60-deg elbow or 1/6 bend | long radius TY (2) | 90-deg long turn elbow | |
| 45-deg elbow or 1/8 bend | 45-deg elbow & DWV 45-deg Y (2) | 90-deg elbow or 1/4 bend (1) | |
| 22-1/2 deg elbow or 1/16 bend | 90-deg long turn elbow | ||
| long radius TY | 90-deg elbow or 1/4 bend | ||
| 45-deg wye | |||
| 90-deg elbow or quarter bend | |||
| STAINLESS STEEL PUSH-FIT DWV | long sweep | tee | eighth bend & wye (2) |
| wye | sanitary tee | combination wye & eighth bend | |
| combination wye & eighth bend | eighth bend & wye (2) | long sweep | |
| 15-degree 1/24 bend | combination wye & eighth bend | 90-degree 1/4 bend (1) | |
| 22-1/2 degree 1/16 bend | long sweep | ||
| 30-degree 1/12 bend | 90-deg 1/4 bend | ||
| 45-degree 1/8 bend | |||
| 90-deg 1/4 bend | |||
NOTES FOR TABLE 2.3.1
- Short radius fittings shall not be permitted in horizontal offsets in drainage stacks and at the base of stacks.
- Long radius fittings shall not be used to connect fixture trap arms to vertical drain and vent piping.
Exception: Long radius fittings are permitted to drain two lavatories into a common drain with a common vent per Section 2.3.1.
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, back-to-back pressure-assisted water closets, and fixtures or appliances having pumped discharge. See Figure 2.3.2
Figure 2.3.2
DOUBLE PATTERN DRAINAGE FITTINGS
DOUBLE PATTERN DRAINAGE FITTINGS
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. See Figure 2.3.3
Figure 2.3.3
PREVENTING CROSSFLOW BETWEEN BACK-TO-BACK-OUTLET FIXTURES
PREVENTING CROSSFLOW BETWEEN BACK-TO-BACK-OUTLET FIXTURES
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