Plan Review Section wrote:
That being
said, there are several states where the plumbing unions is strong
enough to have them banned (cuts into a plumbers profits don't ya
know.)

I have seen them fail. I am sure that their failure rate is higher than
conventional stack venting. As someone suggested the mineral content of the
water supply in some areas could cause a higher failure rate and those are
the areas more likely to have banned them. Like most regulations, the
reason for the regulation may not be obvious and people tend to ignore them
when they don't see the reason. That is really dumb thing to do and to
assume that there is not a good reason for a regulation.

--
Joseph Meehan

Dia duit