Plumbing code essentials: Installation
The 2018 Code Essentials series are available as valuable companions to the 2018 International Building, Residential, Fire, Energy Conservation, Existing Building and Plumbing Codes. Aimed at all user levels — including first-time users, veteran code users and other professionals such as architects, designers and contractors — these guides use a straight-forward, focused approach to explore code requirements with non-code language, allowing readers to gain confidence in their understanding of the material and build a solid foundation for learning and applying the code’s requirements.
2018 Plumbing Code Essentials
It is important to maintain a uniform slope to the drain pipe. It is most common for horizontal drains of all sizes in a structure to be sloped at ¼ inch per foot. However, at times it may be necessary to reduce the slope, especially with larger structures where horizontal piping may extend for some distance and where the depth of the piping may be an issue. 3-inch and larger diameter piping may be run at a slope less than ¼ inch per foot. The exception is that horizontal drains discharging to a grease interceptor shall not be installed with less than ¼ inch per foot slope.
Horizontal branches must connect downstream of the base of a stack a minimum of 10 pipe diameters. Basically, multiplying the diameter of the stack by 10 provides the minimum horizontal distance in inches downstream of the stack where a horizontal drain branch may connect, 30 inches for a 3-inch stack, 40 inches for a 4-inch stack, etc. A drain stack is the vertical line of soil or waste piping that extends through not less than one story with or without offsets. The same required distance applies to horizontal connections in a stack offset.
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