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
Glossary
114 Siemens Building Technologies, Inc.
sound pressure level
The pressure (dB) on a unit area caused by a sound source some distance away. Sound
pressure is therefore only the effect of a portion of the total sound power output of a sound
source, much like the force of the air on a given area of tissue paper is only a small portion of
the total output power of a fan. Although both sound power and sound pressure are
expressed in dB, they are not referring to the same effect since decibels have no dimension
and only represent ratios within the parameter in that they are applied.
room effect
The reduction in the effect of the sound power level emitted to a room. Room effect has the
potential for lowering sound pressure level measured at a given point as the total size of the
room increases, and with the room’s ability to absorb sound due to furnishings, wall
coverings, sound treatment, etc.