What is the total fixture unit (FU) for a plumbing system composed of a flush tank water closet (4), a lavatory (1), a shower head (2), and a faucet (2)?

To determine the total fixture units for the plumbing system, you need to add up the fixture units assigned to each component based on their usage during peak demand.

In the scenario provided, the assigned fixture units are as follows:

• A flush tank water closet typically has 4 fixture units.

• A lavatory is generally assigned 1 fixture unit.

• A shower head is usually assigned 2 fixture units.

• A faucet can be assigned 2 fixture units as well.

Adding these values together gives:

• Water closet: 4 FU

• Lavatory: 1 FU

• Shower head: 2 FU

• Faucet: 2 FU

When you add these up:

4 + 1 + 2 + 2 = 9 fixture units.

Thus, the total fixture unit count for the plumbing system is 9, which supports the choice given. This calculation demonstrates how each component contributes to the overall demand for water at peak times, allowing for proper sizing and design of plumbing systems.