I don't know how it works in PA, but in VA, we have a state appreniceship council. They certify all trades related activities. I would expect that your program would relate as well.
If your students are working 1/2 days (some do in VA) then that time would also go towards their apprenticeship, 2,000 hours OJT is necessary per year in VA as well as so much class time.
You may want to pursue that method first, I am not aware of any national cert program. But Hey, if ya find out about one, clue us in.