Trane TRG-TRC007-EN manual Octave-band frequency, Hz

Page 76

Quiz

notes

sound pressure, dB ref 20 mPa

80

70

60

50

40

30

20

10

							NC-65
							NC-60
							NC-55
							NC-50
							NC-45
							NC-40
							NC-35
							NC-30
							NC-25
							NC-20
							NC-15
63	125	250	500	1,000	2,000	4,000	8,000
	octave-band frequency, Hz						Figure 74

Questions for Period 3

7True or False: Sound can only travel from a source to the receiver along one path.

8True or False: One piece of HVAC equipment may contain several sound sources.

9What term is used to describe the reduction in sound that enters a room as it travels to the receiver? It is influenced by distance and the absorptive and reflective characteristics of the surfaces and furnishings in the room.

Questions for Period 4

10A _______ (free or reverberant) sound field is characterized by a uniform, or diffuse, sound field where the sound pressure is equal at all points in the field.

11What recent ARI standard, which rates the sound due to ducted air moving and conditioning equipment, requires testing of the entire air handler, not just the fan?

TRG-TRC007-EN

69

Image 76

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 dBHuman Ear Sound Perception Rating MethodsHuman Ear Response Loudness Contours Single-Number Rating Methods Response to TonesSingle-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