February 22, 2024
From the 2024 UPC Illustrated Training Manual, Chapter 6, WATER SUPPLY AND DISTRIBUTION
603.5.1 Atmospheric Vacuum Breaker. Water closet and urinal flushometer valves shall be protected against backflow by an approved backflow prevention assembly, device, or method. Where the valves are equipped with an atmospheric vacuum breaker, the vacuum breaker shall be installed on the discharge side of the flushometer valve with the critical level not less than 6 inches (152 mm), or the distance according to its listing, above the overflow rim of a water closet bowl or the highest part of a urinal.
The highest part of the urinal is the top of the urinal; it is not the overflow rim of the bowl of the urinal. The measurement to the critical level is taken from the top of the urinal (see Figure 603.5.1).
From the 2024 UMC Illustrated Training Manual, Chapter 3, GENERAL REGULATIONS
310.5 Point of Discharge. Air-conditioning condensate waste pipes shall connect indirectly to the drainage system through an air gap or air break to trapped and vented receptors, dry wells, mop sinks, leach pits, or the tailpiece of plumbing fixtures. An individual condensate drain shall be trapped in accordance with the appliance manufacturer’s instructions or in accordance with Section 310.4.
Since many air moving appliances have different negative pressure drops across the cooling coil it is important to use the manufacture’s recommendation on trap sizing. A properly functioning and designed condensate trap provides for discharge of water from the cooling coil drain pan, while the water seal (the water level maintained in the trap) prevents the flow of ambient air into or out of the air handler. Several problems result from improperly trapped systems, some of which can severely impact indoor air quality. Where a trap is improperly installed or designed, an incoming air stream may be introduced through the drain and the air flowing through the coil can possibly spray condensate into the fan intake, which can propel the moisture into other parts of the system; which can then be carried through the ducts and into the conditioned space possibly causing bacterial growth and transmission. Furthermore, improperly trapped systems can include the trap outlet is too short or the trap outlet is too tall, or other potential incorrect sizing. The manufacturer of the appliance typically provides trapping requirements that should be followed when sizing the condensate drainage trap.
(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: February 22, 2024