I am not completely new to the IPC and the selection of water supply sizing. But today figures have given me some confusion in the IPC charts. 2009 IPC table E201.1. Let me give some examples. 50-60 psi chart, max developed length = 250'. figure meter and service pipe column. 14.5 fixture units = 3/4" pipe, 16.5 f.u. = 1" pipe, now 32 f.u. = 3/4" pipe. What?? More fixture units = smaller pipe size. This is the confusion. Now look at the 250' MDL. 87, 139 and 146 f.u. = 1-1/2" pipe in the distribution pipe column, then it goes back to 87 f.u. with 2" pipe. What is the deal? Why the jump around and change in f.u. and pipe size? Why is the 87 f.u. row list twice with different pipe sizes? I can further show the confusion with the 40', 60', 80' MDL with 32 f.u. and the various sizes under both columns to the left. Can any one help clear this up. My brain is making funny noises.