77 Ill. Adm. Code 890.1780
Flush Valves
Section 890
Section 890.1780 Flush
Valves
a) All flush valves for water closets or urinals shall conform
with Sections 890.650(e) and 890.660(b) of this Part.
b) All flush valves shall feature rubber diaphragm operation,
non-hold-open push buttons (and handles), union check stops and vacuum breakers
as approved in this Part. (See Sections 890.1130(c) and 890.1140(a) and (b).)
c) Flush valves shall be concealed wherever possible.