Written by IAPMO 5:08 pm Uniform Codes Spotlight

UNIFORM CODES SPOTLIGHT

June 5, 2025

From the 2024 UPC Illustrated Training Manual, Chapter 3, GENERAL REGULATIONS

310.4 Use of Vent and Waste Pipes. Except as hereinafter provided in Section 908.0 through Section 911.0, no vent pipe shall be used as a soil or waste pipe, nor shall a soil or waste pipe be used as a vent. Also, single-stack drainage and venting systems with unvented branch lines are prohibited.

FIGURE 310.4A
INCORRECT USE OF VENT

FIGURE 310.4B
AN ALTERNATE ENGINEERED SINGLE-STACK DRAINAGE SYSTEM (FROM ILLUSTRATED PLUMBING CODES DESIGN HANDBOOK, ASPE)

From the 2024 UMC Illustrated Training Manual, Chapter 5, EXHAUST SYSTEMS

505.9 Minimum Velocities and Circulation. The velocity and circulation of air in work areas shall be such that contaminant’s are captured by an airstream at the area where the emissions are generated and conveyed into a product-conveying duct system. Mixtures within work areas where contaminants are generated shall be diluted to be accordance with Section 505.3 with air that does not contain other contaminants. The velocity of air within the duct shall be not less than set forth in Table 505.9.

Systems conveying particulate matter shall be designed by employing the constant velocity method. Systems conveying explosive or radioactive materials shall be prebalanced through duct sizing. Other systems shall be permitted to be designed with balancing devices such as dampers. Dampers provided to balance airflow shall be provided with securely fixed minimum-position blocking devices to prevent restricting flow below the required volume or velocity.

FIGURE 505.9
OPENING USED TO MAINTAIN A CONSTANT VELOCITY

(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: June 5, 2025

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