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Trane TRG-TRC007-EN Sound Power by Octave Band, Equipment Sound Rating, period four, 1 2 3, 103

Models: TRG-TRC007-EN

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Sound Power by Octave Band

period four

Equipment Sound Rating

notes

Sound Power by Octave Band

octave

band

1

2

3

4

5

6

7

8

center

frequency (Hz)

63

125

250

500

1,000

2,000

4,000

8,000

equipment

sound power

(dB ref 10-12W)

103

104

100

101

98

93

88

85

Figure 67

Depending on the type of equipment, sound ratings for HVAC equipment are typically given as sound-power levels by octave band or as a single dBA rating.

Outdoor equipment, such as an air-cooled chiller or condensing unit, may be rated in terms of A-weighted sound-pressure level (dBA) at a specific distance from the equipment. This generally assumes a free-field environment and may be useful for comparing equipment from various manufacturers. Nevertheless, the sound-pressure level by octave band should still be available from the manufacturer for use in an acoustical analysis.

As mentioned, air-handling equipment is typically rated in terms of sound- power level per octave band. Typically, this data is given for the octave bands from 63 Hz through 8,000 Hz. The availability of accurate, tested sound data for HVAC equipment is vitally important to any acoustical analysis.

62	TRG-TRC007-EN

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Trane TRG-TRC007-EN manual Sound Power by Octave Band, Equipment Sound Rating, period four, 1 2 3, 103

Contents

Fundamentals of HVAC Acoustics Air Conditioning ClinicOne of the Fundamental Series TRG-TRC007-ENBUSINESS REPLY MAIL BUSINESS REPLY MAILTRANE Attn Applications Engineering 3600 Pammel Creek Road La Crosse WIResponse Card Comment CardFundamentals of HVAC 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 two Sound Perception and Rating Methods Contentsperiod three period fiveTRG-TRC007-EN Fundamentals of Sound period oneFundamentals of Sound period oneperiod one What is Sound?What is Sound? Fundamentals of SoundSound Wave and Frequency Fundamentals of Soundperiod one Wavelength Fundamentals of Soundperiod one Broadband Sound and Tones Broadband SoundFundamentals of Sound period oneFundamentals of Sound Octave Bandsperiod one Octave Bandsperiod one Fundamentals of SoundOctave Bands 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 Sound Power and Sound Pressure Sound Power and Sound PressureFundamentals of Sound period oneFundamentals of Sound An Analogyperiod one K Correlates to bulb wattageDecibel dB = 10 log10Fundamentals of Sound period oneFundamentals of Sound Logarithmic Scaleperiod one ratio= 10 log10 Equation for Sound Power= 20 log10 Equation for Sound Pressure50 dB + 44 dB = 51 dB Logarithmic Addition of DecibelsFundamentals of Sound period oneSound Perception and Rating Methods period twoSound Perception and Rating Methods period twoperiod two Loudness ContoursSound Perception and Rating Methods Single-NumberRating Methods Response to TonesSound Perception and Rating 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 period two Sound Perception and Rating MethodsNoise Criteria NC Curves NC-39Room Criteria RC Curves Sound Perception and Rating Methodsperiod two period two Sound Perception and Rating MethodsRoom Criteria RC Curves 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 period two Sound Perception and Rating MethodsRoom Criteria RC Curves RC-31RPhon and Sone Sound Perception and Rating Methodsperiod two Sound Perception and Rating Methods Octave-BandRating Methodperiod two Octave-BandRating MethodAcoustical Analysis period threeAcoustical Analysis period threeperiod three Setting a Design GoalSetting a Design Goal Acoustical AnalysisWhen 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 Setting a Design GoalAcoustical Analysis period threeAcoustical Analysis Acoustical Analysisperiod three Source-Path-ReceiverAnalysisSource-Path-ReceiverModel Acoustical Analysisperiod three Acoustical Analysis Typical Sound Pathsperiod three IAirborneExample of Multiple Sound Paths Examples of a Single Sound PathAcoustical Analysis period threeAcoustical Analysis Identifying Sound Sources and Pathsperiod three packaged rooftop air conditionerAcoustical Analysis Modeling Sound Pathsperiod three Sound-PathModelingperiod three Acoustical AnalysisExample of Multiple Sound Paths supplyAlgorithms for Sound-PathModeling Acoustical Analysisperiod three Computerized Analysis Tools Acoustical Analysisperiod three Acoustical Analysis Attenuation and Regenerationperiod three Terms Used in Sound-PathModelingSound Transmission Acoustical Analysisperiod three period three Acoustical AnalysisSound Transmission 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 fourFree Field period fourEquipment Sound Rating Fields of Measurement20 log10 = Lp1Distance Correction in a Free Field Equipment Sound Ratingperiod four Equipment Sound RatingDistance Correction in a Free Field Lp2 = 95 dB - 20 log10 120 ft / 30 ft = 83 dBNear Field Equipment Sound Ratingperiod four Equipment Sound Rating Reverberant Fieldperiod four source reflective wallsSemireverberant Field Equipment Sound Ratingperiod four Equipment Sound Rating Rating HVAC Equipmentperiod four HVAC Equipment Sound RatingReverberant-RoomMethod Equipment Sound Ratingperiod four Free-FieldMethod Equipment Sound Ratingperiod four Industry Standards Equipment Sound Ratingperiod four Equipment Sound Rating Ducted Air-HandlingEquipmentperiod four supply-airoutletAir Handler Test Configurations Equipment Sound Ratingperiod four Equipment Sound Rating Former Methods of Sound Testingperiod four I ASHRAE generic fan algorithmEquipment Sound Rating ARI Standardperiod four IUses reverberant- room methodEquipment Sound Rating Sound Power by Octave Bandperiod four 1 2 3Review period fiveReview period fiveReview-PeriodTwo period fiveReview 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 hertz Hz The unit of measure for frequency. One hertz is equal to one cycle per second Glossaryreverberant 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 points Glossarythe receiver, and everything it encounters as it travels along the way, constitutes the path GlossaryTRG-TRC007-EN Literature Order NumberFile Number E/AV-FND-TRG-TRC007-1101-EN