What unit is used to quantify the load that plumbing fixtures exert on the system?

The term "Fixture Unit" is specifically designed to quantify the load that plumbing fixtures exert on a drainage system. This unit of measure takes into account various factors, including the type of fixture and its potential usage, to assess the impact of multiple fixtures on the plumbing system. By using fixture units, engineers can calculate the necessary pipe size and layout needed to efficiently handle wastewater and prevent issues like clogs or system overloads.

The other options refer to different concepts within plumbing and mechanical systems. Drainage slope relates to the angle of pipes that allows for proper drainage flow. Water hammer denotes a pressure surge resulting from a sudden change in water flow, which can create noise and potential damage to pipes. A sump pump is a device used to remove accumulated water from a sump basin, typically found in basements to prevent flooding. Understanding fixture units is critical for proper system design and ensuring functionality, which is why this is the correct choice.