From the 2024 UPC Illustrated Training Manual, Chapter 9, VENTS
903.3 Changes in Direction. Changes in the direction of vent piping shall be made by the appropriate use of approved fittings, and no such pipe shall be strained or bent. Burred ends shall be reamed to the full bore of the pipe.
Approved fittings used for changes of direction of vent piping are practically the same for drainage piping. One difference is the vent 90° fitting (see Figure 903.3a), which can be used anywhere in the vent system beginning 6 inches above the overflow rim of the fixture (see Section 905.3). When 6 inches above the overflow rim of the fixture, any type of drainage fitting may be used for venting purposes.
As with drainage fittings, vent fittings must also be installed in the direction of flow. The direction of air flow in the venting system has a different orientation than drainage flows. For example, vent branch-fittings are turned in the opposite orientation than drainage fittings to enhance air flow. Not only for airflow, but also a path must be provided for condensate to flow to the fixture drain without it being trapped in the horizontal piping and blocking the flow of air. The sanitary tee is a good example of a fitting used in one position in drainage piping and reversed in vent piping (see Figure 903.3b).
(This is not to be considered the official position of IAPMO, nor is it an official interpretation of the Codes.)
IAPMO
IAPMO develops and publishes the Uniform Plumbing Code®, the most widely recognized code of practice used by the plumbing industry worldwide; Uniform Mechanical Code®; Uniform Swimming Pool, Spa and Hot Tub Code®; and Uniform Solar Energy, Hydronics and Geothermal Code™ — the only plumbing, mechanical, solar energy and swimming pool codes designated by ANSI as American National Standards — and the Water Efficiency Standard (WE-Stand)™. IAPMO works with government, contractors, labor force, and manufacturers to produce product standards, technical manuals, personnel certification/educational programs and additional resources in order to meet the ever-evolving demands of the industry in protecting public health and safety.
Last modified: January 18, 2024