The Chicago Plumbing Code

Table § 18-29-709.2

Drainage Fixture Units for Fixture Drains or Traps

Fixture Drain or Trap Size (inches)

Drainage Fixture Unit Value

1 1/4

1

1 1/2

2

2

3

2 1/2

4

3

5

4

6

For SI: 1 inch = 25.4 mm.