When measuring sound pressure levels in a classroom to determine compliance with the HVAC background...

To meet the Indoor Environmental Quality (IEQ) Prerequisite: Minimum Acoustic Performance for classrooms, sound pressure level measurements should be taken under conditions that reflect typical classroom use without occupants, ensuring accuracy in assessing HVAC background noise levels. Furnished, no occupants, HVAC operating at typical level (C) is the correct testing setup, as it accounts for sound absorption by furniture but excludes ambient noise from people. This setup provides a more accurate measure of the background noise levels produced by HVAC systems, ensuring compliance with acoustic performance requirements for optimal learning environments.