The UPC's water-supply sizing method (Table 610.4, "Fixture Unit Table for Determining Water Pipe and Meter Sizes") determines minimum distribution pipe, meter, and building-supply sizes. Which three variables does that table index on?
Not quite. The answer is A: Available pressure range, meter/building-supply size, and developed length
Table 610.4 is a three-dimensional lookup: it varies by the pressure range available at the service (30-45 psi, 46-60 psi, or over 60 psi), the meter and building-supply size, and the developed length of the run — not a flat WSFU-to-diameter list. A study aid that tracks only WSFU and length while ignoring available pressure and meter size cannot reproduce this table.
Reference: UPC 2021 Table 610.4; §610.8 (Fixture Unit Table for Determining Water Pipe and Meter Sizes)
Checked against the official text
The exam supplies this table at the desk, so the edition it prints is the one that counts on test day.
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