"class hours" is correct and usable in written English.
You can use it to refer to the times that classes take place, e.g. "This week, I have three class hours on Tuesday and two on Wednesday."
Complain about the (modest) number of class hours requiring attendance.
The sound films are sometimes shown in class hours.
Using the iPad given to every student, the workshop happened outside class hours.
The study lasted 16 weeks for a total of 63 class hours.
Some details, like how many class hours are required per week, are still being decided.
Russian, Hebrew and Icelandic are more difficult (1100 class hours, "Category 2").
Your class hours drop by more half when you go to college.
In the intervention, students instructed by professional dancers collaboratively developed a dance-choreography during regular class hours in student groups.
The simulation exercises will require additional time outside of the normal weekly class hours.
"The class hours here seem shorter than on campus at Cornell.
Students are expected to be present during regular class hours for instruction and criticism.
