1、Designation: E2396 11Standard Test Method forSaturated Water Permeability of Granular Drainage MediaFalling-Head Method for Vegetative (Green) Roof Systems1This standard is issued under the fixed designation E2396; the number immediately following the designation indicates the year oforiginal adopti
2、on or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a procedure for determining thewater permeability
3、of coarse granular materials used in thedrainage layers of vegetative (green) roof systems.1.2 This test method addresses water permeability under thelow-head conditions that typify horizontal flow in vegetative(green) roof applications.1.3 This test method is suitable for coarse-grained materialswi
4、th 100 % of the material retained on the U.S. #8 (2.25 mm)sieve. It is not suitable for finer-grained materials.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand a
5、re not considered standard.1.5 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 to determine theapplicability of regulatory limitations
6、prior to use.2. Referenced Documents2.1 ASTM Standards:2C29/C29M Test Method for Bulk Density (“Unit Weight”)and Voids in AggregateC130 Specification for Lightweight Aggregates for Con-crete3E631 Terminology of Building ConstructionsE2114 Terminology for Sustainability Relative to the Per-formance o
7、f Buildings3. Terminology3.1 Definitions:3.1.1 For terms related to building construction, refer toTerminology E631.3.1.2 For terms related to sustainability relative to theperformance of buildings, refer to Terminology E2114.3.2 Definitions of Terms Specific to This Standard:3.2.1 water permeabilit
8、ythe coefficient which when mul-tiplied by the hydraulic gradient will yield the apparentvelocity with which water (at 68F) will move through across-section of media.3.2.2 wet densitythe density of coarse granular drainagecourse materials determined after immersion for 24 hours.4. Summary of Test Me
9、thod4.1 This procedure involves measuring the water permeabil-ity of coarse granular materials under the low-head conditionsthat characterize the environment in vegetative (green) roofsystems. A falling-head technique is used. Incidental to theprocedure is the measurement of the wet density of theme
10、dium.5. Significance and Use5.1 This test method addresses performance characteristicsfor vegetative (green) roof systems with respect to the waterpermeability of the drainage media.5.1.1 Water permeability of coarse materials is highly influ-enced by the head conditions under which it is measured.
11、Invegetative (green) roofs, coarse materials are frequently usedto create drainage zones for percolated rainfall.5.1.2 This test method is intended to provide water perme-ability data that is relevant to this design condition that ischaracterized by horizontal flow under low-head. This will alsoallo
12、w the performance of granular drainage layers in vegetative(green) roof systems to be compared directly to alternativecomponents, such as geocomposite drain layers.1This test method is under the jurisdiction of ASTM Committee E60 onSustainability and is the direct responsibility of Subcommittee E60.
13、01 on Buildingsand Construction.Current edition approved Feb. 15, 2011. Published April 2011. Originallyapproved in 2005. Last previous edition approved in 2005 as E2396 05. DOI:10.1520/E2396-11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
14、serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn. The last approved version of this historical standard is referencedon www.astm.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West
15、 Conshohocken, PA 19428-2959, United States.5.2 Determining the performance characteristics of vegeta-tive (green) roof systems provides information to facilitate theassessment of related engineering aspects of the facility. Suchaspects may include structural design requirements, mechani-cal enginee
16、ring and thermal design requirements, and fire andlife safety requirements.5.3 Determining the performance characteristics of vegeta-tive (green) roof systems provides information to facilitateassessment of the performance of one vegetative (green) roofsystem relative to another.6. Apparatus6.1 The
17、apparatus consists of nested cylinders constructedfrom stainless steel or plastic:6.1.1 Inner cylinderinner diameter of 3.75 in. (9.53 cm),32 in. (81.3 cm) long as shown in Fig. 1. Perforated at thebottom (50 % open area), with marks at 6 and 8 in. (15.2 and20.3 cm) below the top of the cylinder,6.1
18、.2 Outer cylinderinner diameter of 5.75 in. (14.6 cm)as shown in Fig. 1. This cylinder must be watertight,6.1.3 U.S. #8 (2.25 mm) sieve disc, 3.55-in. (9.02-cm)diameter, and6.1.4 Scale with accuracy of 0.005 oz (0.14 g).6.2 The apparatus is mounted so that the 8-in. (15.2-cm)mark of the inner cylind
19、er is level with the top of the outercylinder.7. Conditioning7.1 Before conducting the tests, fill the apparatus with waterand determine the elapsed time in seconds that it takes for thewater level to fall 6 in. (15.2 cm) to the first mark. This valuewill be used to establish the upper limit on the
20、measurement ofwater permeability using the apparatus.8. Procedure8.1 Place the sieve disc into the inner cylinder. Fill with thegranular material. Take care to prevent segregation of finerparticles within the column. Shake or vibrate the materialvigorously to compact it into the cylinder. Fill to th
21、e 8-in.(20.3-cm) mark. If the specific gravity of the particles is lessthan 1.0, place a sieve disc on top of the sample and weighdown with glass marbles.8.2 Begin introducing water into the inner cylinder. Thewater will fill the inner and outer cylinders and begin tooverflow. Continue to introduce
22、water for 30 min. As neces-sary, add more media to maintain the level of the media at the8-in. (20.3-cm) mark. The temperature of the water should be68 6 5F (20 6 2.75C). Check the temperature by placing athermometer in the annular space between the two cylinders.8.3 Stop introducing water to the in
23、ner cylinder and note theelapsed time, in seconds, for the water level to descend to the6-in. (15.2-cm) mark on the inner cylinder. Repeat three timesand average the results.8.4 Allow the material to stand overnight in the cylinder.8.5 Weigh a graduated beaker.8.6 After 24 hours, drain the cylinder.
24、8.7 After 15 min have elapsed, measure a portion of thegranular medium into the graduated beaker. Weigh the beakerwith its contents and subtract the weight of the beaker. Usingthe measured volume of the granular medium in the beaker,compute the wet density of the medium in units of lb/ft3(kg/m3).FIG
25、. 1 Equipment Fabrication DetailE2396 1128.8 Conduct all tests in duplicate. If the results of two testsdiffer by more than 5 %, then repeat.9. Calculation of Results9.1 Compute the upper limit of the apparatus for determin-ing water permeability as follows:Kl5 0.5 * 1996/t (1)Kl= method limit for m
26、easuring water permeability in./min, andt = elapsed time measured when the apparatus containsonly water s.9.2 Compute the water permeability, as follows:Kf5 1996/T in.2lb! (2)Kf5 84.50/T! SI!Kf = water permeability, in/min (cm/s)T = Elapsed time, sIf Kf Kl, then report Kf$Kl10. Report10.1 The report
27、 shall contain the following information:10.1.1 Sample designation,10.1.2 Grain-size distribution of the medium (SpecificationC130),10.1.3 Dry density of the medium (Test Method C29/C29M),10.1.4 Wet density of the medium,10.1.5 Water permeability,10.1.6 Upper limit of the method for measuring waterp
28、ermeability, and10.1.7 Temperature of water in the outer cylinder.11. Precision and Bias11.1 PrecisionThe precision of the procedure for measur-ing water permeability is being determined. Parties interestedin participating in interlaboratory test programs should contactCommittee E60.11.2 BiasThe bia
29、s for these measurements is undeter-mined because there are no reference values available for thematerials used.12. Keywords12.1 granular, coarse aggregate; low-head; vegetative(green) roof; water permeabilityASTM International takes no position respecting the validity of any patent rights asserted
30、in connection with any item mentionedin 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
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32、reful consideration at a meeting 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 Internatio
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