In need of plumbers help

Can someone help me. I am trying to open a wellness club; the only things that are going to be serve are shakes. My brother did the pluming himself and got a plumbing license. When he was done, the pluming inspector checked and request something's to be change, so my bother did the changes. The inspector when a second time and also gave my brother a hard time. He requested more changes, so my brother did what he request. The inspector went a third time and did the something to my brother. After my brother did all the changes the inspector requested, the fourth time the inspector, told my bother he was using the wrong sizes of pipes and all the pipes had to be change. Why didn't the inspector told my brother he was using the wrong kind of pipes since the first day he inspected? My brother is using 1 1/2in pipes and the inspector is requesting 2in pipes. The only things we are washing in the club are our hands and the blenders. Can someone tell me if the inspector is being fair or his just playing with us?

Without knowing exactly what pipes you are talking about and what they serve, I haveno clue but I seriously doubt the inspector is screwing with you.

Most underground pipes have to be at least 2". Inspectors will do that. They will look at a couple of things and reject them, then look further the next time and find other items, and then repeat it. It usually happens to DIYers because professionals either do not have any problems, or only a few. HOWEVER, when he got his permit, he should have had a drawing showing what he was going to do and the pipe sizes.

Many inspectors feel their job is not to teach, but to approve or disapprove.
Commercial kitchens are much more restrictive then a residential bathroom.
Even a kitchen sink in a home requires 2" pipe.

A commercial "Plumbing" license, that's right, there is a "B" in the work plumbing; requires one more year than a residential license, and a seperate test. Since the plumbing affects more end users, it's even more important that it's done right.

How about posting a picture of what you brother is attempting?