1、Designation: D 5820 95 (Reapproved 2006)Standard Practice forPressurized Air Channel Evaluation of Dual SeamedGeomembranes1This standard is issued under the fixed designation D 5820; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、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 The practice covers a nondestructive evaluation of thecontinuity of parallel geomembrane seams separated
3、by anunwelded air channel. The unwelded air channel between thetwo distinct seamed regions is sealed regions is sealed andinflated with air to a predetermined pressure. Long lengths ofseam can be evaluated by this practice more quickly than byother common nondestructive tests.1.2 This practice shoul
4、d not be used as a substitute fordestructive testing. Used in conjunction with destructive test-ing, this method can provide additional information regardingthe seams undergoing testing.1.3 This practice supercedes Practice D 4437 for geomem-brane seams that include an air channel. Practice D 4437 m
5、aycontinue to be used for other types of seams. The user isreferred to the referenced standards, or to EPA/530/SW-91/051for additional information regarding geomembrane seamingtechniques and construction quality assurance.1.4 This standard does not purport to address all of thesafety concerns, if an
6、y, 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 limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 4437 Practice for Determining the Integrity of F
7、ieldSeams Used in Joining Flexible Polymeric SheetGeomembranesD 4439 Terminology for GeosyntheticsD 4491 Test Methods for Water Permeability of Geotextilesby Permittivity2.2 Other Standard:EPA/530/SW-91/051 Technical Guidance Document: In-spection Techniques for the Fabrication of GeomembraneField S
8、eams33. Terminology3.1 Definitions:3.1.1 dual seam, na geomembrane seam with two parallelwelded zones separated by an unwelded air space.3.1.2 DiscussionThe dual seam itself can be made by anumber of methods, the most common being the hot wedgetechnique. Other possible methods include hot air and ul
9、tra-sonic bonding techniques.3.1.3 geomembrane, nan essentially impermeable geo-synthetic composed of one or more synthetic sheets.3.1.4 DiscussionIn geotechnical engineering, imperme-able essentially means that no measurable liquid flows througha geosynthetic when tested in accordance with Test Met
10、hodsD 4491.3.1.5 seam, na permanent joining of two or more mate-rials.3.2 For definitions of other terms, see Terminology D 4439.4. Summary of Practice4.1 This practice utilizes a dual seam where an air channelexists between the two welded zones. Both ends of the airchannel are sealed and then a pre
11、ssure gauge is attached to theair space.Air pressure is applied and the gauge is monitored forexcessive gauge air pressure drop.4.2 Air pressures used in this practice are related to thethickness, stiffness and material type of the geomembrane.4.3 The minimum monitoring time is recommended to be2 mi
12、n following stabilization of the pressure.4.4 Maximum allowable loss of air pressure varies depend-ing upon thickness, stiffness and type of material of thegeomembrane.5. Significance and Use5.1 The increased use of geomembranes as barrier materialsto restrict liquid or gas movement, and the common
13、use of dual1This practice is under the jurisdiction of ASTM Committee D35 on Geosyn-thetics and is the direct responsibility of Subcommittee D35.10 on Geomembranes.Current edition approved June 1, 2006. Published June 2006. Originallyapproved in 1995. Last previous edition approved in 2001 as D 5820
14、 95 (2001)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the Superintendent of Documents,
15、 U. S. Government PrintingOffice, Washington, DC 20402.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.track seams in joining these sheets, has created a need for astandard nondestructive test by which the quality of the seamscan be
16、assessed for continuity and water tightness. The test isnot intended to provide any indication of the physical strengthof the seam.5.2 This practice recommends an air pressure test within thechannel created between dual seamed tracks whereby thepresence of unbonded sections or channels, voids, nonho
17、moge-nities, discontinuities, foreign objects, and the like, in theseamed region can be identified.5.3 This technique is intended for use on seams betweengeomembrane sheets formulated from the appropriate poly-mers and compounding ingredients to form a plastic orelastomer sheet material that meets a
18、ll specified requirementsfor the end use of the product.6. Equipment6.1 Sealing Equipment, appropriate to seal the two ends ofthe air channel.6.2 A device is necessary to insert air into the open channeland to allow monitoring its pressure.NOTE 1A sharp, hollow needle attached to a properly function
19、ingpressure gauge has been used successfully. Other devices may provideequivalent functions.6.3 Air Pump, either manual or motor driven, capable ofgenerating up to 350 kPa (50 lb/in.2) pressure is necessary. Itmust be placed on an adequate cushion to preclude damage tothe geomembrane. A flexible hos
20、e is used to connect the pumpto the air pressure device. This hose should have a quickconnect on its end for disengagement after pressure is suppliedto its desired value, that is, the pump is not to be attached whilethe air pressure is being monitored.6.4 Knife, capable of cutting or trimming the li
21、ner material.NOTE 2A hook bladed knife is recommended. Straight bladed knivesmay damage the geomembrane by cutting through the material beingtrimmed and into the underlying geomembrane.6.5 Pressure Gauge, capable of indicating the air pressure in7 kPa (1 lb/in.2) within the test range.NOTE 3The gaug
22、e should be calibrated as specified by the manufac-turer, or at a frequency of at least once per year.7. Procedure7.1 After the dual track seam is fabricated and the length ofseam that is to be evaluated is determined, seal off the two endsof the continuous air channel.7.2 Connect the pressure gauge
23、 directly to the air channel.7.3 Connect an air pump to the pressure gauge with aflexible hose via a quick connect and pressurize the air channelto the pressure appropriate for the geomembrane type.7.4 Remove the flexible hose that connects the air channelto the pressure gauge. Following pressure st
24、abilization, observethe air pressure gauge for the desired test time. The test timeshould be a minimum of 2 min. Mark the time and pressure ofthe beginning and end of the test on the geomembrane with avisible marker. The maximum allowable pressure drop may becompared to the maximum allowable value.7
25、.5 If the pressure does not drop below the maximumallowable value after the specified test period, open the airchannel at the end away from the pressure gauge. Air shouldrush out and the pressure gauge should register an immediatedrop in pressure, indicating that the entire length of the seamhas bee
26、n tested. If this does not happen, either the air channelis blocked or the equipment is faulty, and the test is not valid.Attempt to locate the problem and retest the seam in accor-dance with the project specifications.7.6 If the pressure drop is greater than the maximumallowable value after the tes
27、t period, check the end seals of theair channel. Reseal these areas if a leak is noticed and thenrepeat the entire test.NOTE 4Leaks around the end seals and air pressure device canusually be located by putting moisture around the suspected area andlooking for bubbles.7.7 If significant changes in ge
28、omembrane temperatureoccur during pressure testing (for example, cloud cover orother shading), a variation in channel pressure may be recordeddue to expansion or contraction of the air channel. If anincrease or decrease in temperature is suspected of havingcaused a pressure variation, repeat the tes
29、t after the geomem-brane temperature has stabilized.7.8 Any dual seam that cannot be successfully tested usingthis practice should be marked and tested using anothernondestructive testing practice when possible.8. Report8.1 The report of a pressurized dual seam test is usuallygiven in the form of a
30、completed chart. It should include thefollowing information as a minimum:8.1.1 Data of test,8.1.2 Time of test,8.1.3 Temperature at time of test,8.1.4 Location of test with respect to panel layout plan,8.1.5 Stabilized air channel pressure,8.1.6 Duration of test time,8.1.7 Gauge pressure drop during
31、 test,8.1.8 Outcome of test (pass/fail/retest), and8.1.9 If failremedial action is described in detail.8.2 A form as shown in Fig. 1 includes the above informa-tion and may be used for such reporting.9. Precision and Bias9.1 The precision of this test has not been established.9.2 The threshold value
32、 for accepting seam quality is thatvalue agreed upon by all parties overseeing the installation ofthe project and is thus the source of bias in this procedure.D 5820 95 (2006)2ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item menti
33、onedin this standard. Users of 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 a
34、nd must be reviewed every five 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
35、of theresponsible technical committee, 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 Bo
36、x 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).FIG. 1 Report Form for Pressurized Air Channel Test for Dual Seamed GeomembranesD 5820 95 (2006)3
