Following the IPC, Lav = 1 DFU, and using Table 710.1(1): 1-1/2 drain @ 1/4in takes max 3 DFU, whereas 2in @ 1/4 slope takes 21 DFU max. I know greatly oversized pipes are more likely to clog.. but 2 isn't greatly oversized from 1-1/2. So which is statistically less likely to clog?
The table reads 1-1/2 is plenty for a lav.. but does this translate practically to the real world? Wouldn't a 1-1/2 lav drain be more likely to clog than a 2in? Or would the scouring action in a 1-1/2 keep it cleaner than the 2?
Drain clog statistics would be interesting to look at..