What is required for most changes in direction of a sewer drainage pipe?

For most changes in direction of a sewer drainage pipe, a cleanout is required. A cleanout is a fitting that allows access to the drainage system for maintenance and cleaning purposes. When sewer lines change direction significantly—such as at a 90-degree angle—debris and blockages can accumulate in these bends. The cleanout facilitates easy access for plumbers or maintenance personnel to remove clogs and maintain the system.

While other components like inspection chambers or vent pipes play important roles in the drainage system—such as providing a point for inspection or allowing sewer gases to escape—these do not specifically cater to the need for accessing a blockage or allowing for cleaning at directional changes. Access points may help in maintenance but don't serve the specific function of addressing clogs in bends the way a cleanout does. Thus, the necessity of a cleanout in these scenarios is particularly important for ensuring efficient upkeep of the sewer drainage system.