Until further guidance is issued with respect to such employees, you’re required to use what’s called a “reasonable” method for crediting their hours of service. Here’s the method deemed reasonable by the Treasury Department and the IRS for quantifying these hours.
Credit an adjunct faculty member of an institution of higher education with:
2.25 hours of service (representing a combination of teaching or classroom time and time performing related tasks such as class preparation and grading of examinations or papers) per week, for each hour of teaching or classroom time and, separately;
an hour of service per week for each additional hour outside of the classroom that the faculty member spends performing duties which he or she is required to perform (such as required office hours or required attendance at faculty meetings).