1、Designation: C 924 02Standard Practice forTesting Concrete Pipe Sewer Lines by Low-Pressure AirTest Method1This standard is issued under the fixed designation C 924; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This practice covers procedures for testi
3、ng concrete pipesewer lines, when using the low-pressure air test method todemonstrate the integrity of the installed material and theconstruction procedures. This practice is used for testing 4 to24-in. circular concrete pipe sewer lines utilizing gasketedjoints.1.2 This practice is also used as a
4、preliminary test to enablethe installer to demonstrate the condition of the line prior tobackfill.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
5、 practices and determine the applica-bility of regulatory limitations prior to use (see Section 6,Safety Precautions).1.4 A complete metric companion to Practice C 924 hasbeen developedC 924 M; therefore, no metric equivalentsare presented in this practice.NOTE 1The user of this practice is advised
6、that air test criteriapresented in this practice are similar to those in general use. The test andcriteria have been used widely and successfully in testing smaller diameterpipe, but additional data are required to confirm the safety and applica-bility or develop criteria for pipe larger than 24 in.
7、 in diameter. Larger pipewill be accepted more conveniently by visual inspection and individualjoint testing.NOTE 2The user of this practice is advised that no correlation hasbeen found between air loss and water leakage.2. Referenced Documents2.1 ASTM Standards:C 822 Terminology Relating to Concret
8、e Pipe and RelatedProducts2C 969 Practice for Infiltration and Exfiltration AcceptanceTesting of Installed Precast Concrete Pipe Sewer Lines23. 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 i
9、s plugged. Air is introducedat low pressures into the plugged line. The amount of air lossis used to determine the acceptability of the sewer 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. Safe
10、ty 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 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 completelybef
11、ore any plug is loosened for removal.NOTE 3As an example, 4-psi air pressure acting on one side of a15-in. plug results in a total force of approximately 700 lbf on the plug.Such a force is capable of causing the expulsion of an improperly installedplug.6.3 Pressurizing equipment shall include a 6-p
12、si pressurerelief device to reduce hazards and avoid over-pressurizationwith possible damage to the line.6.4 No one shall be allowed in or near the manholes duringpressurization, testing, or depressurization.7. Capacity of Air Compressor7.1 To provide satisfactory test results, the air compressorsha
13、ll 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 accomplish the pressurization is equalto the rate necessary to fill the sewer to the desired pressureplus the allowable air loss rate:1This practice is u
14、nder the jurisdiction of ASTM Committee C13 on ConcretePipe and is the direct responsibility of Subcommittee C13.09 on Methods of Test.Current edition approved Aug. 10, 2002. Published October 2002. Originallypublished as C 924 84. Last previous edition C 924 89(1997).2Annual Book of ASTM Standards,
15、 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)where:C = compressor capacity, cfm,T = required test time, or less, min,D = pipe internal diameter, ft,L = length of test section, ft, andQ = allowable air
16、loss, rate, cfm.8. Preparation of the Sewer Line8.1 Where practical, clean the sewer line prior to testing towet the pipe surface and eliminate debris.NOTE 4The user of this practice is advised that a wetted interior pipesurface is desirable and will produce more consistent test results. Air maypass
17、 through the walls of dry pipe. This can be overcome by wetting thepipe. If the problem persists, segmental testing of the line will establish ifthere is a significant leak.8.2 Plug all pipe outlets including laterals, which shall begiven special attention. Review safety precautions in Section 6.9.
18、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 Table 2, and the formulas contained in theAppendix. The test time is the time required for the pressure todrop from 3.5 psi to 2.5 psi.NOTE 5All test pres
19、sures are measured as gage pressure, which isdefined as any pressure greater than atmospheric pressure. Since waterproduces a pressure of 0.43 psi for every 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 2 ft or
20、 more above the top of the pipe at theupstream end or if the air pressure required for the test is greater than 5-psigage, the air test method shall not be used. In that event, the infiltrationtest, (see Practice C 969), shall be used.9.2 Add air until the internal air pressure of the sewer line isr
21、aised to approximately 4 psi. Allow the air pressure tostabilize. The pressure will normally drop until the temperatureof the air in the line stabilizes.9.3 When the pressure has stabilized and is at or above thestarting test pressure of 3.5 psi, commence the test by allowingthe gage pressure to dro
22、p to 3.5 psi at which point the timerecording is initiated. Record the drop in pressure for the testperiod.9.4 If the drop in pressure is 1 psi or less during the testperiod, accept the line. If the drop in pressure is more than 1 psiduring the test period, inspect, evaluate, and retest the line tod
23、etermine 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 exfiltration testing,(see Practice C 969), or other means.10. Air Test Criteria10.1 An appropriate allowable air loss, Q, in cubic feet perminute has been
24、established for each nominal pipe size. Basedon field experience the Qs that have been selected will enabledetection of any significant leak. Table 2 lists the Q establishedfor 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 lat
25、erals shall beconsidered, and the allowable air loss rate shall be that listedfor the main.11. Precision and Bias11.1 No justifiable statement is presently capable of beingmade either on precision or bias of this procedure since the testresult merely states whether there is conformance to the criter
26、iafor success specified. Due to the sealing effects of ground waterand internal flow on sewer line, the test conditions and resultsare not reproducible.TABLE 1 Minimum Test Time for Varous Pipe SizesNominalPipe Size, in.T (time),min/100 ftNominalPipe Size, in.T (time),min/100 ft4 0.3 15 2.16 0.7 18
27、2.48 1.2 21 3.010 1.5 24 3.612 1.8TABLE 2 Allowable Air Loss for Various Pipe SizesD, NominalPipe Size, in.Q ft3/min D, NominalPipe Size, in.,Q ft3/min421546218582215.10 2.5 24 612 3C924022APPENDIXES(Nonmandatory Information)X1. EQUATIONS USED IN PRACTICE C 924X1.1 The required test time per 100 ft
28、of pipe for a singlediameter pipe using Table 2:TT50.00037! SD2LQD (X1.1)X1.2 The required test time for a single diameter pipesystem using Table 1:TT5L!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
29、(using Table 2). For this system the minimum testtime per 100 ft of pipe is equal to that of the main 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
30、thetotal system is computed as follows:Le5 (Sd2lD2D(X1.3)TT5L 1 Le!ST100D(X1.4)X1.4 The symbols used in the equations in this practice aredefined as follows;where:T = minimum test time per 100 ft of pipe for pressure todrop from 3.5 to 2.5 psi, min,TT= minimum test time for total system, min,D = des
31、ignated inside diameter of test section of mainsewer, in.,d = designated inside diameter of lateral, in.,L = length of test section or main sewer, ft,Le= total volume of all laterals connected to the mainsewer expressed as an equivalent length of the mainsewer, ft,1 = total length of each diameter l
32、ateral, ft, andQ = allowable air loss rate, ft3/min.X2. APPLICATION OF PRACTICE C 924X2.1 The following examples have been prepared todemonstrate the technique of applying this practice.X2.2 Example 1A sewer system consists of 600 ft of18-in. diameter concrete pipe between manholes A and B; 35 ftof
33、12-in. diameter pipe between manholes B and C.X2.2.1 FindThe appropriate test times to demonstrate the integrity of theinstalled lines.X2.2.2 Solution:X2.2.2.1 For the main sewer between manholes A and B,use X1.2 and from Table 1, T = 2.4 min/100 ft, for 18-in. pipe.TT5L!ST100D(X2.1)TT5 600!S2.4100D
34、(X2.2)TT5 14 min (X2.3)X2.2.2.2 Similarly, for the main sewer between manholesB and C:TT5 35!S1.8100D(X2.4)TT5 0.6 min (X2.5).X2.3 Example 2The 600 ft. of 18-in. diameter concretepipe between manholes A and B in Example 1 has connected6-in. laterals with a total length of 900 ft.X2.3.1 FindThe appro
35、priate test time to demonstrate theintegrity of the installed lines.X2.3.2 Solution:X2.3.2.1 Use X1.3 to convert the total volume of 6-in.laterals to an equivalent length of main sewer:Le5(Sd2lD2D(X2.6)Le5S623 900182 D(X2.7)Le5 100 ft (X2.8)X2.3.2.2 For the connected system, use Table 1 and fromTabl
36、e 1, T = 2.4 min/100 ft, for 18-in pipe:TT5L 1 Le!ST100D(X2.9)TT5600 1 100!S2.4100D(X2.10)TT5 17 min. (X2.11)X2.4 If a line fails the air test, the following courses ofaction shall be considered:(1) Segmentally test the line and compare the time-air lossvalues in each segment.(2) If the values in ea
37、ch segment are comparable, the air-lossproblem shall be distributed throughout the line, and furtheranalysis shall be made.C924023(3) If the values in each segment are significantly different,each segment shall be evaluated and further analysis be madeto determine the location of any significant air
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41、 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).C924024
