In our classrooms and other core learning spaces, we are leaving a concrete, pan joist system exposed. We plan to apply acoustic spray to the underside of the slab between the joists, leaving the joists exposed. This coverage will account for approximately 75% of the overall ceiling area. Our lights are thin, linear, suspended fixtures that do not interfere with the amount of acoustic spray applied to the ceiling. We will suspend VRF cassettes from the ceiling therefore our mechanical system will not interfere with the amount of acoustical treatment on the ceiling.

We are looking for the most cost effective solution to meet the performance requirements.

So here's the question:
- Can we ignore the exposed joists in a similar manner to the allowance in Option 1 that excludes lights, diffusers, and grilles? Or,
Can we apply a higher value NRC material to the underside of the slab between the joists to achieve the same acoustic quality in the space in lieu of providing a wall and ceiling material combination equal to 100% of ceiling areas (as indicated in Option 2)?

I've searched through this thread and haven't found a similar question.