July 27, 2023
From the 2021 UPC Illustrated Training Manual, Chapter 7, SANITARY DRAINAGE
710.3 Sewage Ejector and Pumps. A sewage ejector or sewage pump receiving the discharge of water closets or urinals:
(1) Shall have a discharge capacity of not less than 20 gpm (1.26 L/s).
(2) In single dwelling units, the ejector or pump shall be capable of passing an 11⁄2 inch (38 mm) diameter solid ball, and the discharge piping of each ejector or pump shall have a backwater valve and gate valve, and be not less than 2 inches (50 mm) in diameter.
(3) In other than single-dwelling units, the ejector or pump shall be capable of passing a 2 inch (51 mm) diameter solid ball, and the discharge piping of each ejector or pump shall have a backwater valve and gate valve, and be not less than 3 inches (80 mm) in diameter.
To design this pumped waste system and correctly size the sump pump depends on the flow rate of the fixtures flowing into the sump. This is usually accomplished by the plumbing design professional. The discharge capacity of the pump is determined by the pump’s performance curve showing the relation between pumped gallons per minute and the total dynamic head in feet (see Figure 710.3a).
The greater the head is in height, the less the performance is in pumped gallons per minute. Therefore, the minimum discharge capacity of 20 gpm depends on the head height. For example, if the performance curve shows a discharge capacity of 20 gpm at 15 feet of head, then any height exceeding 15 feet does not meet the minimum discharge capacity of the pump. There is also a difference in design requirements between single-dwelling units (private) with one pump and a minimum discharge pipe size of two inches in diameter, and other occupancies (public) with two pumps and a minimum discharge pipe size of three inches in diameter (see Figure 710.3b).
The 2021 Uniform Plumbing Code Illustrated Training Manual is available for purchase here.
(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: July 27, 2023