1、Designation: E 2396 05Standard Test Method forSaturated Water Permeability of Granular Drainage MediaFalling-Head Method for Green Roof Systems1This standard is issued under the fixed designation E 2396; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, 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 a procedure for determining thewater permeability of coarse
3、granular materials used in thedrainage layers of green roof systems.1.2 This test method addresses water permeability under thelow-head conditions that typify horizontal flow in green roofapplications.1.3 This test method is suitable for coarse-grained materialswith 100 % of the material retained on
4、 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 are not considered standard.1.5 This
5、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 prior to use.2. Referenced Documents
6、2.1 ASTM Standards:2C 29/C29M Test Method for Bulk Density (Unit Weight)and Voids in AggregateE 631 Terminology of Building ConstructionE2114 Terminology for Sustainability Relative to the Per-formance of Buildings3. Terminology3.1 Definitions:3.1.1 For terms related to building construction, refer
7、toTerminology E 631.3.1.2 For terms related to sustainability relative to theperformance of buildings, refer to Terminology E 2114.3.2 Definitions of Terms Specific to This Standard:3.2.1 water permeabilitythe coefficient which when mul-tiplied by the hydraulic gradient will yield the apparentveloci
8、ty 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 Method4.1 This procedure involves measuring the water permeabil-ity of coarse granular materials
9、under the low-head conditionsthat characterize the environment in green roof systems. Afalling-head technique is used. Incidental to the procedure isthe measurement of the wet density of the medium.5. Significance and Use5.1 This test method addresses performance characteristicsfor green roof system
10、s with respect to the water permeability ofthe drainage media.5.1.1 Water permeability of coarse materials is highly influ-enced by the head conditions under which it is measured. Ingreen roofs, coarse materials are frequently used to createdrainage zones for percolated rainfall.5.1.2 This test meth
11、od 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 alsoallow the performance of granular drainage layers in green roofsystems to be compared directly to alternative components,such as geocompo
12、site drain layers.5.2 Determining the performance characteristics of greenroof systems provides information to facilitate the assessmentof related engineering aspects of the facility. Such aspects mayinclude structural design requirements, mechanical engineeringand thermal design requirements, and f
13、ire and life safetyrequirements.5.3 Determining the performance characteristics of greenroof systems provides information to facilitate assessment ofthe performance of one green roof system relative to another.6. Apparatus6.1 The apparatus consists of nested cylinders constructedfrom stainless steel
14、 or plastic:1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.71on Sustainability.Current edition approved August 15, 2005. Published August 2005.2For referenced ASTM standards, visit the ASTM website, ww
15、w.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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.1.
16、1 Inner cylinderinner diameter of 3.75 in. (9.53 cm),32 in. (81.3 cm) long. Perforated at the bottom (50% openarea), with marks at 6 and 8 in. (15.2 and 20.3 cm) below thetop of the cylinder,6.1.2 Outer cylinderinner diameter of 5.75 in. (14.6 cm).This cylinder must be watertight,6.1.3 U.S. #8 (2.25
17、 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 cylinder is level with the top of the outercylinder.7. Conditioning7.1 Before conducting the tests, fill the apparatus with wateran
18、d determine the elapsed time in seconds that it takes for thewater level to fall 2 in. (5.08 cm), between the 6- and 8-in.(15.2- and 20.3-cm) marks. This value will be used to establishthe upper limit on the measurement of water permeability usingthe apparatus8. Procedure8.1 Place the sieve disc int
19、o 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 the 8-in.(20.3-cm) mark. If the specific gravity of the particles is lessthan 1.0, place a siev
20、e 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 water for 30 min. As neces-sary, add more media to maintain the level of the media at the8-in
21、. (20.3-cm) mark. The temperature of the water should be68F 6 5F (20 6 2.75C). Check the temperature by placinga thermometer in the annular space between the two cylinders.8.3 Stop introducing water to the inner cylinder and note theelapsed time, in seconds, for the water level to descend to the6-in
22、. (15.2-cm) mark on the inner cylinder. Repeat 3 times andaverage 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.8.7 After 15 min have elapsed, measure a portion of thegranular medium into the graduated beaker
23、. 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).8.8 Conduct all tests in duplicate. If the results of two testsdiffer by more than 5 %, then repeat
24、.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 measuring water permeability in./mint = Elapsed time measured when the apparatus containsonly water s9.2 Compute the water permeability, as f
25、ollows: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 shall contain the following information:10.1.1 Sample designation,10.1.2 Grain-size distribution of the medium (SpecificationC 130),10.1.3 Dry
26、density of the medium (Test Method C 29/C 29M),10.1.4 Wet density of the medium,10.1.5 Water permeability,10.1.6 Upper limit of the method for measuring waterpermeability, and10.1.7 Temperature of water in the outer cylinder.11. Precision and Bias11.1 PrecisionThe precision of the procedure for meas
27、ur-ing water permeability is being determined. Parties interestedin participating in interlaboratory test programs should contactsubcommittee E06.71.11.2 BiasThe bias for these measurements is undeter-mined because there are no reference values available for thematerials used.12. Keywords12.1 granul
28、ar, coarse aggregate; green roof; low-head; waterpermeabilityE2396052ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of an
29、y 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 five years andif not revised, either reapproved or withdrawn. Your comments are i
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31、ed 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).E2396053
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