Rhode Island Code of Regulations
Title 510 - Building Code Commission
Chapter 00 - N/A
Subchapter 00 - N/A
Part 3 - RISBC-3 Rhode Island Plumbing Code
Section 510-RICR-00-00-3.8 - Vents (IPC Section 900)

Roof extension insert the following:

Twelve inches (12"?) (304.8 mm)

Delete IPC section 903.2 and substitute the following:

Frost Closure: Each vent extension through a roof shall have a minimum size of three inches (3"?) in Providence County and two inches (2"?) in all others. Where this results in an increase in size of the vent extension, the change in diameter shall be made inside the building a minimum of six inches (6") below the roof with an approved fitting.