Some CS courses with programming assignments have a reputation of taking up very large amounts of time, even if they do not have scheduled lab sessions.
If a student at the school normally takes 4 courses per term, then 1 course would be equivalent to 4 credits in the more usual system. This is supposed to mean 12 total hours of work per week. If the normal course load is 3 courses per term, then 1 course would be equivalent to 5 credits in the more usual system, corresponding to 15 total hours of work per week.
Of course, as noted in your other thread, lab courses often exceed the nominal number of hours per week.