Sprayed-applied acoustical insulation/K-13 is typically an exposed ceiling finish, as shown in the photo below. The material provides an NRC rating that reduces noise levels, and sound transfer between walls and floors, and can act as an excellent insulator.
The photo was used in a classroom where the ceilings were going to be left exposed, the white K-13 was used as a noise reduction agent while also leaving a nice cloud-like finished ceiling.
The black K-13 in the following photo was used for noise reduction, but also provides an aesthetic look to an exposed ceiling. The photo displays a comparison between a finished acoustical spray ceiling vs. exposed deck.