1、Designation: C 924M 02METRICStandard Practice forTesting Concrete Pipe Sewer Lines by Low-Pressure AirTest Method1MetricThis standard is issued under the fixed designation C 924M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 practice covers procedures for testing concrete pipesewer lines, when using the low-pressure air test m
3、ethod todemonstrate the integrity of the installed material and theconstruction procedures. This practice is used for testing 100 to600-mm circular concrete pipe sewer lines utilizing gasketedjoints.1.2 This practice is also be used as a preliminary test toenable the installer to demonstrate the con
4、dition of the lineprior to backfill.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-priate safety and health practices and determine the applica-bility of regulatory limi
5、tations prior to use (see Section 6,Safety Precautions).1.4 This practice is the metric companion to Practice C 924.NOTE 1The user of this practice is advised that air test criteriapresented in this practice are similar to those in general use. The test andcriteria have been used widely and successf
6、ully in testing smaller diameterpipe, but additional data are required to confirm the safety and applica-bility or develop criteria for pipe larger than 600 mm in diameter. Largerpipe will be accepted more conveniently by visual inspection andindividual joint testing.NOTE 2The user of this practice
7、is advised that no correlation hasbeen found between air loss and water leakage.2. Referenced Documents2.1 ASTM Standards:C 822 Terminology Relating to Concrete Pipe and RelatedProducts2C 969 Practice for Infiltration and Exfiltration AcceptanceTesting of Installed Precast Concrete Pipe Sewer Lines2
8、3. Terminology3.1 DefinitionsFor definitions of terms relating to con-crete pipe, see Terminology C 822.4. Summary of Practice4.1 The sewer line to be tested is plugged. Air is introducedat low pressures into the plugged line. The amount of air lossis used to determine the acceptability of the sewer
9、 line.5. Significance and Use5.1 This is not a routine test. The values recorded areapplicable only to the sewer being tested and at the time oftesting.6. Safety Precautions6.1 The air test will be dangerous if a line is not preparedproperly and proper procedures are not followed.6.2 It is extremely
10、 important that plugs be installed andbraced in such a way as to prevent blowouts. It is alsoimperative that the pressure in the pipe be relieved completelybefore any plug is loosened for removal.NOTE 3As an example, 27-kPa air pressure acting on one side of a375-mm plug results in a total force of
11、approximately 3100 N on the plug.Such a force is capable of causing the expulsion of an improperly installedplug.6.3 Pressurizing equipment shall include a 42-kPa pressurerelief device to reduce hazards and avoid over-pressurizationwith damage to the line.6.4 No one shall be allowed in or near the m
12、anholes duringpressurization, testing, or depressurization.7. Capacity of Air Compressor7.1 To provide satisfactory test results, the air compressorshall be capable of pressurizing the sewer test section in therequired test time, or less, as determined by 9.1. The compres-sor capacity required to ac
13、complish the pressurization is equalto the rate necessary to fill the sewer to the desired pressureplus the allowable air loss rate:1This practice is under the jurisdiction of ASTM Committee C13 on ConcretePipe and is the direct responsibility of Subcommittee C13.09 on Methods of Test.Current editio
14、n approved Aug. 10, 2002. Published October 2002. Originallypublished as C 924M 84. Last previous edition C 924M 89(1998).2Annual Book of ASTM Standards, Vol 04.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C 50.17D2LT1 Q (1)whe
15、re:C = compressor capacity, m3/s,T = required test time, or less, s,D = pipe internal diameter, m,L = length of test section, m, andQ = allowable air loss, rate, m3/s.8. Preparation of the Sewer Line8.1 Where practical, clean the sewer line prior to testing towet the pipe surface and eliminate debri
16、s.NOTE 4The user of this practice is advised that a wetted interior pipesurface is desirable and will produce more consistent test results. Air maypass through the walls of dry pipe. This can be overcome by wetting thepipe. If the problem persists, segmental testing of the line will establish ifther
17、e is a significant leak.8.2 Plug all pipe outlets including laterals, which shall begiven special attention. Review safety precautions in Section 6.9. Procedure9.1 Determine the test time for the sewer line to be tested byusing Table 1. Table 1 has been established using the criteriaspecified in Tab
18、le 2, and the formulas contained in AppendixX1. The test time is the time required for the pressure to dropfrom 24 kPa to 17 kPa.NOTE 5All test pressures are measured as gage pressure, which isdefined as any pressure greater than atmospheric pressure. Since waterproduces a pressure of 3.0 kPa for ev
19、ery foot of depth, air test pressuresmust be increased to offset the depth of ground water over the sewer line.If the ground water level is 0.6 m or more above the top of the pipe at theupstream end or if the air pressure required for the test is greater than34-kPa gage, the air test method shall no
20、t be used. In that event, theinfiltration test, (see Practice C 969), shall be used.9.2 Add air until the internal air pressure of the sewer line israised to approximately 27 kPa. Allow the air pressure tostabilize. The pressure will normally drop until the temperatureof the air in the line stabiliz
21、es.9.3 When the pressure has stabilized and is at or above thestarting test pressure of 24 kPa, commence the test by allowingthe gage pressure to drop to 24 kPa at which point the timerecording is initiated. Record the drop in pressure for the testperiod.9.4 If the drop in pressure is 7 kPa or less
22、during the testperiod, accept the line. If the drop in pressure is more than 7kPa during the test period, inspect, evaluate, and retest the lineto determine the cause of excessive air loss.9.5 Use or failure of this air test shall not preclude accep-tance by appropriate water infiltration or exfiltr
23、ation testing,(see Practice C 969), or other means.10. Air Test Criteria10.1 An appropriate allowable air loss, Q, in cubic metresper minute has been established for each nominal pipe size.Based on field experience the Qs that have been selected willenable detection of any significant leak. Table 2
24、lists the Qestablished for each pipe size.10.2 When a main line with connected laterals is to be testedas a unit, the total volume of the main and laterals shall beconsidered, and the allowable air loss rate shall be that listedfor the main.11. Precision and Bias11.1 No justifiable statement is pres
25、ently capable of beingmade either on precision or bias of this procedure since the testresult merely states whether there is conformance to the criteriafor success specified. Due to the sealing effects of ground waterand internal flow on sewerline, the test conditions and resultsare not reproducible
26、.TABLE 1 Minimum Test Time for Various Pipe SizesNominalPipe Size, mmT (time)min/100 mNominalPipe Size, mmT (time)min/100 m100 0.9 375 6.8150 2.0 450 7.7200 3.5 525 9.7250 4.7 600 11.0300 6.0TABLE 2 Allowable Air Loss for Various Pipe SizesD, NominalPipe Size, mmQ,m3/minD, NominalPipe Size, mmQ,m3/m
27、in100 0.06 375 0.11150 0.06 450 0.14200 0.06 525 0.15250 0.07 600 0.17300 0.08C924M022APPENDIXES(Nonmandatory Information)X1. EQUATIONS USED IN PRACTICE C 924MX1.1 The required test time per 100 m of pipe for a singlediameter pipe using Table 2:TT5 5.3 3 1028! SD2LQD (X1.1)X1.2 The required test tim
28、e for a single diameter pipesystem using Table 1:TT5 L!ST100D(X1.2)X1.3 For testing a sewer system involving different diam-eter pipe, the allowable air loss rate is equal to that of the mainsewer line (using Table 2). For this system the minimum testtime per 100 m of pipe is equal to that of the ma
29、in sewer line(using Table 1). Each length of lateral pipe is converted into anequivalent length of main sewer line. Then each length is addedto the test length of main sewer. The minimum test time for thetotal system is computed as follows:Le5 (Sd2lD2D(X1.3)TT5 L 1 Le!ST100D(X1.4)X1.4 The symbols us
30、ed in the equations in this practice aredefined as follows:where:T = minimum test time per 100 m of pipe for pressure todrop from 24 to 17 kPa, min,TT= minimum test time for total system, min,D = designated inside diameter of test section of mainsewer, mm,d = designated inside diameter of lateral, m
31、m,L = length of test section or main sewer, m,Le= total volume of all laterals connected to the mainsewer expressed as an equivalent length of the mainsewer, m,l = total length of each diameter lateral, m, andQ = allowable air loss rate, m3/minX2. APPLICATION OF PRACTICE C 924MX2.1 The following exa
32、mples have been prepared todemonstrate the technique of applying this practice.X2.2 Example 1A sewer system consists of 180 m of450-mm diameter concrete pipe between manholesAand B; 10m of 300-mm diameter pipe between manholes B and C.X2.2.1 FindThe appropriate test times to demonstrate theintegrity
33、 of the installed lines.X2.2.2 Solution:X2.2.2.1 For the main sewer between manholes A and B,use Eq X1.1 and from Table 1, T = 7.7 min/100 m, for 450-mmpipe.TT5 L!ST100D(X2.1)TT5 180!S7.7100DTT5 14 minX2.2.2.2 Similarly, for the main sewer between manholes Band C:TT5 10!S6100D(X2.2)TT5 0.6 minX2.3 E
34、xample 2The 180 m of 450-mm diameter concretepipe between manholes A and B in Example 1 has connected150-mm laterals with a total length of 275 m.X2.3.1 FindThe appropriate test time to demonstrate theintegrity of the installed lines.X2.3.2 Solution:X2.3.2.1 Use Eq X1.3 to convert the total volume o
35、f150-mm laterals to an equivalent length of main sewer:Le5 (Sd2lD2D(X2.3)Le5S15023 2754502 DLe5 30.6 mX2.3.2.2 For the connected system, use Eq X1.4 and fromTable 1, T = 7.7 min/100 m, for 450-mm pipe:TT5 L 1 Le!ST100D(X2.4)TT5 180 1 30.6!S7.7100DTT5 16 minX2.4 If a line fails the air test, the foll
36、owing courses ofaction shall be considered: Segmentally test the line andcompare the time-air loss values in each segment. If the valuesin each segment are comparable, the air-loss problem shall bedistributed throughout the line, and further analysis shall beC924M023made. If the values in each segme
37、nt are significantly different,each segment shall be evaluated and further analysis be madeto determine the location of any significant air losses.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users o
38、f this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every fiv
39、e years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical c
40、ommittee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C924M024
