1. What is a Plumbing Fixture Unit Calculator?

Definition: This calculator computes the total fixture units for a plumbing system by summing the fixture units of all connected fixtures.

Purpose: It helps plumbers, engineers, and contractors determine the total demand on a plumbing system for proper pipe sizing and system design.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( FU_{total} \) — Total fixture units
• \( FU_{item} \) — Fixture units for each plumbing fixture

Explanation: Each fixture type has an assigned fixture unit value based on its water demand and frequency of use. The calculator sums all fixture units in the system.

3. Importance of Fixture Unit Calculation

Details: Proper fixture unit calculation ensures adequate water supply, proper drain sizing, and compliance with plumbing codes.

4. Using the Calculator

Tips: Select fixture types from the dropdown, enter quantities, and add more rows as needed. For non-standard fixtures, select "Custom" and enter the fixture unit value.

5. Frequently Asked Questions (FAQ)

Q1: What is a fixture unit?
A: A fixture unit is a measure of the load-producing effect of a plumbing fixture on the system, considering both water flow rate and frequency of use.

Q2: Why are fixture units important?
A: They help determine pipe sizes, water supply requirements, and drainage capacity needed for a plumbing system.

Q3: Where can I find standard fixture unit values?
A: Standard values are published in plumbing codes like IPC or UPC, or available from fixture manufacturers.

Q4: How do I calculate for a large building?
A: Calculate each branch separately, then sum the totals while considering diversity factors for simultaneous use.

Q5: What's the difference between water supply and drainage fixture units?
A: Some fixtures may have different values for supply and drainage. This calculator uses combined values for simplicity.