Every urinal, sink or slop sink, basin, wash trap,
bath and every tub or set of tubs and indirect waste receptor shall
be separately trapped and vented. Urinal platforms, if connected to
drain pipes, shall also be properly trapped and a supply of water
so arranged as to maintain the seal of such traps. In no case shall
the waste from the bath, tub or other fixture be connected with a
water closet bend. Brass ferrule connected to lead may have outlets
and all horizontal lines under bathroom floors shall be of such lead
or copper or brass or ductile iron pipe.