ive been in commercial/multi-family dwellings for 3 years but because of my ability to pick up fast ive been promoted to job supervisor( i have 8 years in residential total 11 years in the field). any way my new jobsite has 27 E/A risers in 2 hr rated shafts but no fd/sd. the engineer said i have to sub-duct them... from what i understand its when you tie into the riser on a 45 is that it? i would just use to 45s i just wanted to make sure before i measure up for production.. thanks guys