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Trane TRG-TRC007-EN manual Examples of a Single Sound Path, Example of Multiple Sound Paths

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Examples of a Single Sound Path

period three

Acoustical Analysis

notes

Examples of a Single Sound Path

fan-coil

air-cooled chiller

Figure 39

Sound can travel between a single source and the receiver along one or multiple paths. In the case of an air-cooled chiller sitting on the roof of a building, and a receiver located across a parking lot at the edge of the property, sound travels along only one path.

Another example is a fan-coil unit installed under a window in an office. Sound travels primarily along one path, from the fan-coil to the receiver in the same room.

Example of Multiple Sound Paths

source

return	3	2	1	supply
airborne		2		airborne
		supply
	4	breakout

wall transmission

Figure 40

In other cases there may be several paths for sound to travel from a source to the receiver. This particular example shows the paths associated with an air handler that is installed in a mechanical equipment room adjacent to an occupied space. Only one sound source is included in this analysis, the fan located in the air handler. The receiver is the person working in the office.

The sound travels from the source to the receiver along four separate paths:

TRG-TRC007-EN

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Trane TRG-TRC007-EN Examples of a Single Sound Path, Example of Multiple Sound Paths, Acoustical Analysis, period three

Contents

One of the Fundamental Series Air Conditioning ClinicFundamentals of HVAC Acoustics TRG-TRC007-ENTRANE Attn Applications Engineering BUSINESS REPLY MAILBUSINESS REPLY MAIL 3600 Pammel Creek Road La Crosse WIFundamentals of HVAC Comment CardResponse Card AcousticsOne of the Fundamental Series A publication of Trane, an American Standard CompanyFundamentals of HVAC Acoustics Preface Fundamentals of HVAC AcousticsA Trane Air Conditioning Clinic period three Contentsperiod two Sound Perception and Rating Methods period fiveTRG-TRC007-EN Fundamentals of Sound period oneFundamentals of Sound period oneWhat is Sound? What is Sound?period one Fundamentals of SoundSound Wave and Frequency Fundamentals of Soundperiod one Wavelength Fundamentals of Soundperiod one Fundamentals of Sound Broadband SoundBroadband Sound and Tones period oneperiod one Octave BandsFundamentals of Sound Octave BandsOctave Bands Fundamentals of Soundperiod one Octave bands compress the range of frequencies between the upper and lower ends of the band into a single value. Sound measured in an octave band is the logarithmic sum of the sound level at each of the frequencies within the bandOne-ThirdOctave Bands Fundamentals of Soundperiod one Fundamentals of Sound Sound Power and Sound PressureSound Power and Sound Pressure period oneperiod one An AnalogyFundamentals of Sound K Correlates to bulb wattageFundamentals of Sound dB = 10 log10Decibel period oneperiod one Logarithmic ScaleFundamentals of Sound ratio= 20 log10 Equation for Sound Power= 10 log10 Equation for Sound PressureFundamentals of Sound Logarithmic Addition of Decibels50 dB + 44 dB = 51 dB period oneSound Perception and Rating Methods period twoSound Perception and Rating Methods period twoperiod two Loudness ContoursSound Perception and Rating Methods Sound Perception and Rating Methods Response to TonesSingle-NumberRating Methods period twoA-B-CWeighting Sound Perception and Rating Methodsperiod two A-WeightingExample Sound Perception and Rating Methodsperiod two A-Weighting Sound Perception and Rating Methodsperiod two Noise Criteria NC Curves Sound Perception and Rating Methodsperiod two Noise Criteria NC Curves Sound Perception and Rating Methodsperiod two NC-39Room Criteria RC Curves Sound Perception and Rating Methodsperiod two Room Criteria RC Curves Sound Perception and Rating Methodsperiod two dB refSound Perception and Rating Methods period twonPerceptible vibration RV The sound level in the octave bands between 16 Hz and 63 Hz falls in the shaded regions A and B. These regions indicate sound-pressurelevels at which walls and ceilings can vibrate perceptibly-rattlingcabinet doors, pictures, ceiling fixtures, and other furnishings in contact with them Room Criteria RC Curves Sound Perception and Rating Methodsperiod two RC-31RPhon and Sone Sound Perception and Rating Methodsperiod two period two Octave-BandRating MethodSound Perception and Rating Methods Octave-BandRating MethodAcoustical Analysis period threeAcoustical Analysis period threeSetting a Design Goal Setting a Design Goalperiod three Acoustical AnalysisAcoustical Analysis Setting a Design GoalWhen defining the acoustical design goal for an outdoor environment, to meet a local noise ordinance for example, the A-weightedscale is typically used. This generally takes the form of a maximum A-weighted sound-pressurelevel at the lot line of the property period threeperiod three Acoustical AnalysisAcoustical Analysis Source-Path-ReceiverAnalysisSource-Path-ReceiverModel Acoustical Analysisperiod three period three Typical Sound PathsAcoustical Analysis IAirborneAcoustical Analysis Examples of a Single Sound PathExample of Multiple Sound Paths period threeperiod three Identifying Sound Sources and PathsAcoustical Analysis packaged rooftop air conditionerperiod three Modeling Sound PathsAcoustical Analysis Sound-PathModelingExample of Multiple Sound Paths Acoustical Analysisperiod three supplyAlgorithms for Sound-PathModeling Acoustical Analysisperiod three Computerized Analysis Tools Acoustical Analysisperiod three period three Attenuation and RegenerationAcoustical Analysis Terms Used in Sound-PathModelingSound Transmission Acoustical Analysisperiod three Sound Transmission Acoustical Analysisperiod three IInsertion loss IL INoise reduction NRAbsorption Acoustical Analysisperiod three Reflected Sound Acoustical Analysisperiod three Receiver Sound Correction Acoustical Analysisperiod three Equipment Sound Rating period fourEquipment Sound Rating period fourEquipment Sound Rating period fourFree Field Fields of MeasurementDistance Correction in a Free Field = Lp120 log10 Equipment Sound RatingDistance Correction in a Free Field Equipment Sound Ratingperiod four Lp2 = 95 dB - 20 log10 120 ft / 30 ft = 83 dBNear Field Equipment Sound Ratingperiod four period four Reverberant FieldEquipment Sound Rating source reflective wallsSemireverberant Field Equipment Sound Ratingperiod four period four Rating HVAC EquipmentEquipment Sound Rating HVAC Equipment Sound RatingReverberant-RoomMethod Equipment Sound Ratingperiod four Free-FieldMethod Equipment Sound Ratingperiod four Industry Standards Equipment Sound Ratingperiod four period four Ducted Air-HandlingEquipmentEquipment Sound Rating supply-airoutletAir Handler Test Configurations Equipment Sound Ratingperiod four period four Former Methods of Sound TestingEquipment Sound Rating I ASHRAE generic fan algorithmperiod four ARI StandardEquipment Sound Rating IUses reverberant- room methodperiod four Sound Power by Octave BandEquipment Sound Rating 1 2 3Review period fiveReview period fiveReview period fiveReview-PeriodTwo TRG-TRC007-ENReview-PeriodThree Reviewperiod five Review-PeriodFour Reviewperiod five Review period fivenTrane Acoustics Program TAP Quiz Questions for PeriodQuestions for Period Questions for Period QuizQuestions for Period 7True or False Sound can only travel from a source to the receiver along one pathAnswers Glossary Glossary hertz Hz The unit of measure for frequency. One hertz is equal to one cycle per secondGlossary reverberant field A uniform, or diffuse, sound field that is the opposite of a free field. In a perfectly reverberant field, the sound-pressurelevel is equal at all pointsGlossary the receiver, and everything it encounters as it travels along the way, constitutes the pathFile Number Literature Order NumberTRG-TRC007-EN E/AV-FND-TRG-TRC007-1101-EN