Let's see if we could answer any and all potential 'minimums' relating to floor drains. This if for Allegheny County, PA. Local codes for townships and boroughs that are more strict will take the place of related county codes.
1. Minimum 4" when below ground install.
2. " " 3" when above ground install.
3. " " requirement by ACHD article XV is: one, in the recessed portion of a hospital sterilization room.
4. " " required for residential homes is: zero, no florr drains required by Health Dept. code.
5. " " required for residential and commercial properties by the water purveyors if a meter is installed indoors.
6. " " required for hot water tanks is: zero.
Any others?
Yeah i meant the size. reason is, to my understanding floor drains are 3"-4", but i have seen alot of plumbers install 2" p-traps for floor drains here in south texas. i looked it up in the plumbing code book and its says minimum size for a floor drain is 2". It just looks wiered using a 2" p-trap for a floor drain, but apparently its ok.