Manuals / Trane / Household Appliance / Air Conditioner

Trane TRG-TRC007-EN manual Rating HVAC Equipment, Equipment Sound Rating, period four

Models: TRG-TRC007-EN

1 82

Download 82 pages 1.27 Kb

Page 61

Image 61

period four

Equipment Sound Rating

notes

Rating HVAC Equipment

Figure 59

HVAC Equipment Sound Rating

As mentioned earlier, because sound pressure is influenced by the surroundings, often the best way for an equipment manufacturer to provide sound data is to provide sound-power levels.

Sound-power levels for many types of HVAC equipment are determined in an acoustics laboratory, usually by the manufacturer. Sound-power levels are determined by measuring sound-pressure levels in a test facility with known acoustical characteristics, and adding back any environmental effects attributed to the surroundings. Formal written standards qualify such test facilities and methods, in order to promote uniformity of data between different manufacturers across the industry. This allows for objective comparisons of similar equipment.

The two most common methods of determining the sound power of HVAC equipment are the reverberant-room and free-field methods.

54	TRG-TRC007-EN

Page 61

Image 61

Trane TRG-TRC007-EN manual Rating HVAC Equipment, period four, HVAC Equipment Sound Rating

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 AcousticsTrane, an American Standard Company One of the Fundamental Series A publication ofFundamentals of HVAC Acoustics Fundamentals of HVAC Acoustics PrefaceA 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 SoundFundamentals of Sound Sound Wave and Frequencyperiod one Fundamentals of Sound Wavelengthperiod 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 bandFundamentals of Sound One-ThirdOctave Bandsperiod 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 twoLoudness Contours period twoSound Perception and Rating Methods Single-NumberRating Methods Response to TonesSound Perception and Rating Methods period twoSound Perception and Rating Methods A-B-CWeightingperiod two Sound Perception and Rating Methods A-WeightingExampleperiod two Sound Perception and Rating Methods A-Weightingperiod two Sound Perception and Rating Methods Noise Criteria NC Curvesperiod two period two Sound Perception and Rating MethodsNoise Criteria NC Curves NC-39Sound Perception and Rating Methods Room Criteria RC Curvesperiod two period two Sound Perception and Rating MethodsRoom Criteria RC Curves dB refperiod two Sound Perception and Rating MethodsnPerceptible 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-31RSound Perception and Rating Methods Phon and Soneperiod 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-ReceiverAnalysisAcoustical Analysis Source-Path-ReceiverModelperiod 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 supplyAcoustical Analysis Algorithms for Sound-PathModelingperiod three Acoustical Analysis Computerized Analysis Toolsperiod three Acoustical Analysis Attenuation and Regenerationperiod three Terms Used in Sound-PathModelingAcoustical Analysis Sound Transmissionperiod three period three Acoustical AnalysisSound Transmission IInsertion loss IL INoise reduction NRAcoustical Analysis Absorptionperiod three Acoustical Analysis Reflected Soundperiod three Acoustical Analysis Receiver Sound Correctionperiod 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 dBEquipment Sound Rating Near Fieldperiod four Equipment Sound Rating Reverberant Fieldperiod four source reflective wallsEquipment Sound Rating Semireverberant Fieldperiod four Equipment Sound Rating Rating HVAC Equipmentperiod four HVAC Equipment Sound RatingEquipment Sound Rating Reverberant-RoomMethodperiod four Equipment Sound Rating Free-FieldMethodperiod four Equipment Sound Rating Industry Standardsperiod four Equipment Sound Rating Ducted Air-HandlingEquipmentperiod four supply-airoutletEquipment Sound Rating Air Handler Test Configurationsperiod 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 Review-PeriodThreeperiod five Review Review-PeriodFourperiod five period five ReviewnTrane Acoustics Program TAP Questions for Period QuizQuestions 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