77 Ill. Adm. Code 890.790
Laundry Trays/Sinks and Drains
Section 890
Section 890.790 Laundry
Trays/Sinks and Drains
a) Waste openings. Each compartment of a laundry tray shall be
provided with a waste opening at least 1½ inches in diameter and with a stopper
or strainer.
b) Commercial Laundry Drains. Commercial laundry machines shall
discharge individually into a trapped and vented outlet or may discharge into a
trapped and vented trench drain. (Also see Section 890.530(b), which requires
all commercial laundries to have a lint separator/interceptor.)
c) All laundry/washer boxes shall have a minimum of a 2 inch
drain that is properly trapped and vented. (See Section 890.410(b).)