This lab was among those tested for air tightness.
Small leaks were detected at plumbing penetrations due to voids in the caulk seal.
Unsealed voids also left large leaks in lab rooms that made the difference in the pass/fail of the room. In this case one of the major players was the unsealed joint between the ceiling drywall and the window head.
Caulked Electrical Boxes
Although they may seem like small leaks. Caulk sealing all electrical boxes to the drywall, openings in the boxes themselves, and the conduit after the wiring has been run, is all crucial in the reduction of the overall leakage of a lab room.
Unsealed Flue Penetration
Unsealed duct penetrations also resulted in large leaks.