Since I became a chemical engineer some 50 years ago, our profession has changed.
Back when I matriculated, the normal requirement for graduation was 144 credits. Not 120 like the rest of the educational curricula, but 144. And, since we were a technical curriculum, one must recognize that a bunch of courses also required laboratories. So, when one said 144 credits were required, it did not mean that one needed to 18 hours of classes a term, but closer to 21 or 23, since a lab course only was awarded 1 credit for each 3 or 4 hours of lab work