This document provides an introduction and overview of acoustics and noise control for mechanical systems. It defines basic acoustical terms like amplitude, frequency, and quality of sound. It discusses indoor noise criteria curves and recommendations for limiting noise from air handling systems, roof-top units, terminal boxes, chillers, and pumps through strategies like isolation, attenuation, duct lining, and space planning.

7. Audible Frequency Range

10. NC Curves

11. NC Curves NC 47

12. RC Curves

13. RC Curves RC 35 RVa

14. RC Mark II

15. RC Mark II

16. RC Mark II

17. ASHRAE Recommendations 1991 Applications 1999 Applications

19. A-Weighting

21. Sound Power vs. Sound Pressure Total Radiated Heat/Time (BTU/hr) ~ Sound Power Heat converts to temperature based Sound power converts to pressure based on distance and heat conductance based on distance and sound of room surfaces. absorption of room surfaces. Room Temperature ~ Sound Pressure Level This is why we specify noise levels in terms of Sound Power.

23. Air Handling Unit Sound Paths

25. AHU Design Guidelines

26. Roof-top Air Handling Unit

28. Roof-top Unit Mitigation Concepts

31. Terminal Box Selection

33. Terminal Box Noise Example Room 109 Room 107 Room 105 Supply & Exhaust Supply Only Exhaust Only Supply - 2.2" w.g. NC 54 NC 44 NC 55 Exhaust - 3.0" w.g. Supply - 2.2" w.g. NC 42 NC 42 NC 49 Exhaust - 1.5" w.g. Supply - 1.25" w.g. NC 37 NC 37 NC 37 Exhaust - 1.1" w.g.

35. Chiller Vibration Isolation

36. Pump Vibration Isolation