AskCodeMan

I have a municipal maintenance garage with a mixed occupancy classification of S1 and B. It is going to be sprinklered and unseparated. They are proposing an unfinished ceiling with exposed batt insulation. My question is can they leave this batt insulation exposed? THanks.

Faced or unfaced batts?

Faced batts typically all have warnings not to leave the facing exposed, that the facing must be in contact with gypsum board or other approved material.

Unfaced batts may have limited or reduced R-value with nothing to restrict the movement of air through the batt insulation, check with the manufacturer's installation instructions. Most codes also require the insulation to be in contact with the ceiling (or floor) unless designed not to be required to be (such as spray foam insulation). Unfaced batts also require a method of keeping the insulation up in place, and that method may need to be addressed (by you and the Fire Marshall).

Also check with the Fire Marshall as to their acceptance with regard to fire and the fiberglass insulation not being covered.