Under 2024 IRC P3005.3, what is the minimum uniform slope for a horizontal drainage pipe with a diameter of 3 inches?
- 1/8 inch per foot
- B1/4 inch per foot
- C3/8 inch per foot
- D1/2 inch per foot
Where to look it up
https://codes.iccsafe.org/content/IRC2024P2/chapter-30-sanitary-drainage
Why A is correct
P3005.3 places 3-inch and larger horizontal drainage piping in the group requiring at least ⅛ inch of fall per foot. Select the diameter group before calculating fall; crawl-space ground slope is not the criterion. Source: 2024 IRC P3005.3, https://codes.iccsafe.org/content/IRC2024P2/chapter-30-sanitary-drainage