IF fundamental principles of sound and vibration control are applied in the design@ installation@ and use of HVAC and refrigeration systems@ suitable levels of noise and vibration can be achieved with a high probability of user acceptance. This chapter introduces these fundamental principles@ including characteristics of sound@ basic definitions and terminology@ human response to sound@ acoustic design goals@ and vibration isolation fundamentals. Chapter 47 of the 2003 ASHRAE Handbook - HVAC Applications and the references at the end of this chapter contain technical discussions@ tables@ and design examples helpful to HVAC designers.