Fittings shall be installed to guide sewage and waste in the direction of flow. Change in direction shall be made by fittings installed in accordance with Table 706.3. Change in direction by combination fittings, side inlets or increasers shall be installed in accordance with Table 706.3 based on the pattern of flow created by the fitting. Double sanitary tee patterns shall not receive the discharge of back-to-back water closets and fixtures or appliances with pumping action discharge.
Exception: Back-to-back water closet connections to double sanitary tees shall be permitted where the horizontal developed length between the outlet of the water closet and the connection to the double sanitary tee pattern is 18 inches (457 mm) or greater.
TABLE 706.3
FITTINGS FOR CHANGE IN DIRECTION
| TYPE OF FITTING PATTERN | CHANGE IN DIRECTION | ||
| Horizontal to vertical | 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.
- The fittings shall only be permitted for a 2-inch or smaller fixture drain.
- Three inches or larger.
- For a limitation on double sanitary tees, see Section 706.3.