(1) An individual shall be disqualified for benefits for any week with respect to which the commissioner finds that his or her total unemployment is due to a stoppage of work which exists because of a labor dispute at the factory, establishment, or other premises where he or she is or was last employed. This section shall not apply if it is shown to the satisfaction of the commissioner that:
(a) The individual is not participating in, financing, or directly interested in the labor dispute which caused the stoppage of work; and
(b) He or she does not belong to a grade or class of workers that includes members who, immediately before the commencement of the stoppage, were employed at the premises where the stoppage occurs and who are participating, financing, or directly interested in the dispute.
(2) If in any case, separate branches of work, which are commonly conducted as separate businesses in separate premises, are conducted in separate departments of the same premises, each such department shall, for purposes of this section, be deemed to be a separate factory, establishment, or other premises.