Illinois Plumbing Code Practice Exam 2025 – All-in-One Guide for Exam Success!

The correct choice pertains to the flow control device. In the context of the Illinois Plumbing Code, flow control devices are designed to manage and regulate the flow of water within drainage systems without fundamentally obstructing the flow path. This distinction is important in existing buildings, as it helps maintain the necessary drainage capacity while preventing backflow and other flow-related issues.

Flow control devices can be installed in a manner that complies with plumbing codes and regulations, ensuring that they do not obstruct or hinder the drainage system's primary function. This allows for effective management of water flow, which is essential for preventing overflows and ensuring proper drainage.

Other types of valves, such as check valves or relief valves, may have specific applications but can sometimes impede the natural flow of drainage, depending on their design and installation. Similarly, pressure reducing valves serve a different purpose and may not be appropriate for use in fixture drains in the same way that flow control devices are.