ASTM E1222-1990(2002) Standard Test Method for Laboratory Measurement of the Insertion Loss of Pipe Lagging Systems《管子护套装置安放损耗的实验室测量用试验方法》.pdf

1、Designation: E 1222 90 (Reapproved 2002)Standard Test Method forLaboratory Measurement of the Insertion Loss of PipeLagging Systems1This standard is issued under the fixed designation E 1222; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r

2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the measurement of the inser-tion loss of pipe lagging systems under lab

3、oratory conditions.1.2 A procedure for accrediting a laboratory for purposes ofthis test method is given in Annex A1.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priat

4、e safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:C 423 Test Method for Sound Absorption and Sound Ab-sorption Coefficients by the Reverberation Room Method2C 634 Terminology Relating to Environmental Acous

5、tics2E 90 Test Method for Laboratory Measurement of AirborneSound Transmission Loss of Building Partitions and Ele-ments22.2 ANSI Standards:S1.4 Specification for Sound Level Meters3S1.6 Preferred Frequencies and Band Numbers for Acous-tical Measurements3S1.11 Specification for Octave Band and Fract

6、ional-Octave-Band Analog and Digital Filters33. Terminology3.1 DefinitionsThe acoustical terms used in this testmethod are consistent with Terminology C 634.3.2 Definitions of Terms Specific to This Standard:3.2.1 pipe lagging systeman arrangement of noise insu-lating materials used to cover a pipe

7、to reduce noise radiatingfrom it.4. Summary of Test Method4.1 Noise is produced inside a steel pipe located within areverberation room using band-limited white noise as a testsignal. The noise must be produced by a loudspeaker oracoustic driver located at one end of the pipe. Average soundpressure l

8、evels are measured within the reverberation room fortwo conditions, one with sound radiating from the bare pipeand the other with the same pipe covered with a laggingsystem. The insertion loss of the lagging system is thedifference in the sound pressure levels measured with soundradiating from the b

9、are and lagged pipe, with an adjustment forchanges in room absorption due to the presence of the laggingsystem. The results may be obtained in a series of 100-Hz widebands or in one-third octave bands from 500 to 5000 Hz. Using100-Hz wide bands will improve the signal-to-noise ratio in thereverberan

10、t room. This is frequently necessary when measur-ing specimens having high insertion loss.5. Significance and Use5.1 The insertion loss of a pipe lagging system dependsupon the lagging system materials, the method used to applythe materials, the pipe wall thickness, the size and shape of thebare and

11、 lagged pipe, and the mechanisms causing noiseradiation from the pipe. Insertion losses measured using thistest method should be used with some caution. In the labora-tory, measurements must be made under reproducible condi-tions, but in practical usage in the field, the conditions thatdetermine the

12、 effective insertion loss are difficult to predict andthey may lead to slightly different results. Insertion lossesmeasured with this test method can be used successfully foracoustical design purposes. Insertion losses measured with thistest method are most useful for pipes and lagging systemswhich

13、are similar to those used in the laboratory configuration.5.2 This test method may be used to rank-order pipe laggingsystems according to insertion loss or to estimate the fieldinsertion loss of pipe lagging systems installed in the field.5.3 This test method assumes that pipe wall stresses result-i

14、ng from different methods of supporting the test pipe in thelaboratory do not have a significant effect upon the measuredinsertion loss.1This test method is under the jurisdiction of ASTM Committee E33 onEnvironmental Acoustics and is the direct responsibility of Subcommittee E33.08 onMechanical and

15、 Electrical System Noise.Current edition approved June 29, 1990. Published August 1990.2Annual Book of ASTM Standards, Vol 04.06.3Available from American National Standards Institute, 25 W. 43rd St., 4thFloor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West

16、 Conshohocken, PA 19428-2959, United States.5.4 Pipe lagging systems typically have small insertion loss,and sometimes negative insertion loss, at frequencies below500 Hz. The results obtained at frequencies below 500 Hz maybe somewhat erratic. Sound sources used with this test methodnormally have a

17、 low frequency limit in the range from 300 to500 Hz. For these reasons, the lowest band of frequencies forwhich results are required is centered at 500 Hz.6. Interferences6.1 Flanking transmission may limit the maximum insertionlosses which can be reliably measured using this test method.The test pi

18、pe and reverberation room shall be constructed andarranged so as to minimize the possibility of transmission bypaths other than through the test specimen. Flanking transmis-sion should be at least 10 dB lower than the power transmittedthrough the test specimen into the reverberation room. Appen-dix

19、X1 presents one procedure for assessing flanking transmis-sion.6.2 The background noise in each test band must be at least10 dB below measured sound pressure levels for that band.7. Apparatus7.1 Reverberation RoomThe sound field in the reverbera-tion room shall approximate a diffuse field when the t

20、estspecimen is in place. The requirements for the reverberationroom are in Test Method C 423. The volume of the test roomshall be 2000 ft3or greater.7.1.1 The average sound absorption coefficients of theroom, excluding sound absorption by air and the test specimen,measured in accordance with Test Me

21、thod C 423, shall be lessthan 0.06 over the test frequency range when the test specimenis in place.7.1.2 Diffusing devices such as rotating and stationarydiffusing surfaces are useful for creating an adequate diffusesound field.7.2 Pipe:7.2.1 ConstructionThe standard test pipe shall be at least13 ft

22、 long and mounted horizontally within the reverberationroom. It shall be a nominal 12-in. diameter carbon steel pipewith a nominal wall thickness of14 in.7.2.2 Other pipes may be used but they shall have a wallthickness of at least14 in., a nominal diameter of at least 6 in.,and shall be at least 13

23、 diameters long.7.2.3 InstallationPotential flanking transmission can beminimized if both ends of the pipe are outside of the rever-beration room. For this reason, this is the preferred method ofinstalling the pipe. Alternately, the loudspeaker end of the pipemay be located outside of the reverberat

24、ion room. In this case,the other end of the pipe within the reverberation room must becarefully constructed and mounted to avoid flanking transmis-sion. Any method of terminating the pipe may be usedprovided that adequately low levels of flanking transmissionare achieved. It is usually necessary to

25、cap the end of the pipewithin the reverberation room with heavy structure and tovibration-isolate the pipe end from the reverberation room flooror ceiling. The cap may be a blind flange, at least twice as thickas the pipe wall, welded to the end of the pipe.7.2.4 No solid connections may exist betwe

26、en the surfacesof the reverberation room and the pipe or test specimen. Aflexible, nonhardening, knife grade mastic, such as availablefor sealing high-pressure ducts, should be used to seal the gapswhere the pipe passes through walls.7.3 Loudspeaker:7.3.1 TypeThe loudspeaker may be a horn-driver com

27、bi-nation or a direct radiator (cone type) loudspeaker. Normally,only acoustic drivers with horns will have sufficient output forthe tests when high insertion losses are being measured.7.3.2 InstallationThe loudspeaker shall be placed on theopen end of the pipe outside the reverberation room. The ho

28、rnof the loudspeaker must be structurally isolated from anycontact with the pipe wall.7.4 Reference Sound Source:7.4.1 A reference sound source is needed to permit adjust-ments for the change in sound absorption within the reverbera-tion room due to the lagging system.7.4.2 The sound from the refere

29、nce source shall be broad-band noise without significant single-frequency components.The maximum sound power level of any single frequencycomponent within a band should be at least 5 dB below thesound power level for that band.7.4.3 The source level in any band shall have a maximumshort-term time-va

30、riation of no greater than 2 dB measuredwith the slow dynamic characteristic of a sound level meter orthe equivalent.7.4.4 The source shall be physically small, with a maximumdimension of less than 2 ft.7.4.5 The reference source may be a loudspeaker; if so, itshould be driven with bands of white no

31、ise and its sound poweroutput should be within the limits prescribed in 7.4.3.7.4.6 A preferred reference sound source is a modifiedcentrifugal fan, directly connected to a motor with stable speedcharacteristics. The sound power level of this source as afunction of frequency is adequately constant f

32、or this testmethod.47.4.7 The source should have a resilient mounting which issuitably designed to prevent transmission of vibrations to thestructure on which it is mounted.8. Test Specimen8.1 The test specimen shall be a pipe lagging systeminstalled on the bare pipe following normal mounting proce-

33、dure. The system should be lapped and seamed following aprocedure similar to the one used in the field.8.2 If the pipe lagging system is usually installed with aseam, the test specimen shall have at least one seam around thecircumference and one longitudinal seam.8.3 The test specimen should be seal

34、ed where it butts to thewalls of the reverberation room or the capped end of the pipe.The flexible mastic used to seal gaps around the pipe is alsorecommended for this purpose. The mastic should not hardenwith age so as to cause flanking.4Sound sources that have been found suitable for this purpose

35、are available fromBrel and Kjer Instruments, Inc., 185 Forest St., Marlborough, MA 01752 (Model4204); ILG Industries, 2850 North Pulaski Road, Chicago, IL 60641; ElectricFrance (E.D.F.), Department Acoustique et Vibrations, 17, Av. de la Liberation, 92Clamart, France (Model NOVACEM); and, Acculab, 3

36、201 Ridgewood Drive,Columbus, OH 43220.E 122229. Test Signal9.1 The loudspeaker shall be driven with bands of whitenoise. To avoid nonlinearities, the total sound pressure levelshall not exceed 160 dB inside the pipe.9.2 The sound pressure level in the test band on the interiorof the pipe shall have

37、 a maximum short-term time-variation inany band no greater than 2 dB measured with the “slow”dynamic characteristic of a sound level meter or the equivalent.If necessary, longer time averages may be used.9.3 Test Frequency Bands:9.3.1 Constant Bandwidth MethodThe test signal shall becontiguous 100 H

38、z (610 Hz), wide bands of white noise witharithmetic center frequencies over the nominal range from 500to 5,000 Hz. Optionally, bands centered at 300 and 400 Hz mayalso be used.9.3.2 One-third Octave-band MethodThe test signal shallbe contiguous one-third octave bands of white noise at thepreferred

39、one-third octave band center frequencies from 500 to5000 Hz. Optionally, one-third octave bands from 315 to 5000Hz may be used.10. Measuring Instruments10.1 The minimum instrumentation required for this testmethod is as follows:10.1.1 A monitoring microphone located inside the testpipe,10.1.2 One or

40、 more room measurement microphones lo-cated in the reverberation room,10.1.3 Microphone amplifiers that satisfy the requirementsof ANSI S1.4 for Type 1 or better sound level meters with theexception that A and B-weighting networks are not required,and10.1.4 A level meter, graphic level recorder, or

41、other devicefrom which the sound pressure level can be read or recorded.The averaging time of the instruments shall be sufficient topermit the determination of the average sound pressure levelwith adequate precision.10.2 Measuring filters are required and depend upon themethod selected:10.2.1 Consta

42、nt Bandwidth MethodNominal 100-Hzwide constant bandwidth filters with arithmetic center frequen-cies consistent with the test signal frequency range.10.2.2 One-third Octave-Band MethodA one-third octavefilter set satisfying the requirements of ANSI S1.11 for Order3 or higher, Type 1 or better. The n

43、ominal center frequencies ofthe filters shall be the same as the test signal center frequency.10.3 A narrow band analyzer is optional. It may be usefulfor monitoring spectral uniformity of the sound within the pipe.11. Procedure11.1 Install the lagging specimen on the pipe.11.2 Select microphone pos

44、itions within the reverberationroom. The locations shall be at least one-half wavelength awayfrom any solid surface at the lowest test frequency.11.3 Using the reference sound source, measure the averagesound pressure levels in each test band within the reverberationroom. Turn off the reference soun

45、d source.11.4 Drive the loudspeaker at the end of the pipe with thetest signal and measure the average sound pressure levels ineach test band within the reverberation room. Measure thesound pressure levels generated by the test signal at themonitoring microphone inside the pipe.11.5 Remove the test

46、specimen from the pipe while main-taining the entire equipment set-up including all source andmeasuring instrument settings as far as practical. A precisionstep attenuator may be used to temporarily lower the test signaldriving the loudspeaker while removing the test specimen. It isof the utmost imp

47、ortance to make no changes in the loud-speaker position.11.6 Return the test signal to the previous setting.11.7 Compare the sound pressure levels generated by thetest signal at the monitoring microphone with the spectrummeasured in 11.4. If the test signal, with sufficient timeaveraging, differs by

48、 more than 2 dB in any test band from thatmeasured in 11.4 with the test specimen in place, begin theprocedure again.11.8 Measure the average sound pressure levels in each testband within the reverberation room. Turn the test signal off.11.9 Repeat step 11.3 for the bare pipe.11.10 If another specim

49、en is to be tested, repeat all stepsoutlined in 11.1-11.9.12. Calculation12.1 In each test frequency band, calculate the insertion lossof the test specimen as follows:IL 5 Lb 2 Ll 2 Lbr 2 Llr# (1)where:IL = insertion loss, dB,Lb,Ll = average sound pressure level measured withsound radiating from the bare pipe and laggedpipe respectively, dB, andLbr,Llr = average sound pressure level measured with thereference sound source with the bare and laggedpipe, respectively, dB.13. Report13.1 Report the following information:13.1.1 A statement, if true in every respect, that the test