Trane TRG-TRC007-EN manual Glossary

Page 78

Glossary

absorbed sound Sound energy that strikes a material and is converted from sound energy to heat energy within the material.

absorption coefficient The ratio of the sound energy absorbed by the material to the total sound energy incident upon the surface of that material.

AMCA Air Movement and Control Association International (www.amca.org)

ARI Air-Conditioning & Refrigeration Institute (www.ari.org)

ASHRAE American Society of Heating, Refrigerating and Air Conditioning Engineers (www.ashrae.org)

attenuation The reduction in the sound level as it travels along the path from a source to the receiver.

A-weightingA single number used to describe sound. It uses weighting factors, by octave band, to approximate human response to sound in the range where no hearing protection is needed. It is most appropriately used for low- volume (or quiet) sound levels and is expressed as dBA.

broadband sound Sound energy that occurs at many frequencies, usually covering the entire audible range.

center frequency Single frequency used to identify an octave band. It is calculated by taking the square root of the product of the lowest and highest frequencies in the octave band.

decibel (dB) A dimensionless ratio of two quantities that is used to describe both sound power and sound pressure. It is defined as ten times the logarithm to the base ten (log10) of the measured quantity divided by the reference quantity.

dynamic insertion loss The sound insertion loss of a duct silencer with air flowing through it.

free field A homogeneous, isotropic medium, free from boundaries. An example of a free field over a reflecting plane would be a large open area void of obstructions, like a parking lot or meadow.

free-field method A common method for testing HVAC equipment that is too large to be tested in a reverberant room, such as water chillers and cooling towers. The equipment is placed on a hard surface on a large parking lot outdoors to approximate the sound conditions in a free field above a reflecting plane. The sound pressure waves travel evenly in a hemispherical pattern away from the equipment. Sound-power levels are determined by measuring sound- pressure levels on an imaginary hemispherical surface surrounding the equipment.

frequency The number of cycles, or oscillations, per second of a wave in periodic motion. Expressed in hertz.

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Contents Air Conditioning Clinic Fundamentals of Hvac Acoustics Business Reply Mail Comment Card One of the Fundamental SeriesFundamentals of Hvac Acoustics Preface Fundamentals of Hvac AcousticsContents TRG-TRC007-EN Fundamentals of Sound Fundamentals of SoundWhat is Sound? What is Sound?Sound Wave and Frequency Wavelength Broadband Sound Broadband Sound and TonesOctave Bands Octave BandsLogarithmic sums One-Third Octave Bands Sound Power and Sound Pressure Sound Power and Sound PressureAn Analogy DB = 10 log DecibelLogarithmic Scale 10 ´ logEquation for Sound Power Equation for Sound PressureLogarithmic Addition of Decibels 50 dB + 44 dB = 51 dBSound Perception Rating Methods Human EarHuman Ear Response Loudness Contours Response to Tones Single-Number Rating MethodsSingle-Number Rating Methods C Weighting Sound Perception and Rating MethodsWeighting Example Weighting Noise Criteria NC Curves NC-39 Room Criteria RC Curves MPa DB ref Pressure Sound Perception and Rating Methods RC-31 R Phon and Sone Octave-Band Rating Method Octave-Band Rating MethodAcoustical Analysis Acoustical AnalysisSetting a Design Goal Setting a Design GoalAcoustical Analysis Acoustical Analysis Source-Path-Receiver AnalysisSource-Path-Receiver Model Typical Sound Paths AirborneExamples of a Single Sound Path Example of Multiple Sound PathsIdentifying Sound Sources and Paths Modeling Sound Paths Sound-Path ModelingSupply Algorithms for Sound-Path Modeling Computerized Analysis Tools Attenuation and Regeneration Terms Used in Sound-Path ModelingSound Transmission Insertion loss IL Noise reduction NR Transmission loss TL Absorption Reflected Sound Receiver Sound Correction Equipment Sound Rating Equipment Sound RatingFree Field Fields of Measurement= L p1 20 log Distance Correction in a Free FieldLot Near Field Reverberant Field Semireverberant Field Rating Hvac Equipment Hvac Equipment Sound RatingReverberant-Room Method Free-Field Method Industry Standards Ducted Air-Handling Equipment Air Handler Test Configurations Former Methods of Sound Testing ARI Standard Sound Power by Octave Band Review Review-Period OneReview-Period Two Noise criteria NC Room criteria RCReview-Period Three Review-Period Four Review Quiz Questions for PeriodOctave-band frequency, Hz Answers Glossary Glossary Room effect See receiver room correction Glossary Trane
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