Hi Tom, Rubber fittings are not permitted(Table P3002.3). The fitting also reduces the diameter as the diameter was increased at hub. Also don't forget that NYS does not license plumbers. Any license the guy claims to have is a municipal contractor license. Tell your client to request an opinion from the municipal code inspector. He or she is the AHJ not the guy that did it wrong for 30 years. I can't wait till Chad chimes in! Tom Corrigan