Basic Documentation
Table Of Contents
- About this Application Guide
- Chapter 1–Introduction
- Chapter 2–Physics of Sound
- Chapter 3–HVAC Sound Sources
- Chapter 4–HVAC Sound Attenuation
- Introduction to HVAC Sound Attenuation
- Plenums
- Duct Attenuation
- Duct Takeoffs and Divisions
- Duct Silencers
- End Reflection
- Environment Adjustment Factor
- Space Effect
- Radiated Sound Attenuation
- Chapter 5–HVAC System Sound Analysis
- Chapter 6–Minimizing HVAC Sound
- Appendix
- Glossary
- Index
Appendix
RC Curves vs. Sound Pressure Level Decibels Tabular Listing
RC 31.5 63 125 250 500 1,000 2,000 4,000
CURVE Hz Hz Hz Hz Hz Hz Hz Hz
25
– 45 40 35 30 25 20 15
30
55 50 45 40 35 30 25 20
35
60 55 50 45 40 35 30 25
40
65 60 55 50 45 40 35 30
45
70 65 60 55 50 45 40 35
50
75 70 65 60 55 50 45 40
NC Curve
Noise Criterion (NC) Curve
106 Siemens Building Technologies, Inc.