(pronounced SEE-ling uh-TEHN-yoo-ay-shun klas)

Also known by its acronym CAC, ceiling attenuation class rates a ceiling’s efficiency as an obstruction to airborne sound transmission between adjacent closed spaces (such as offices) when the dividing partition does not extend up to the structural ceiling. A ceiling system with CAC > 35 is high performance, while one with a CAC < 25 is considered low performance.