1、Designation: E 2398 05Standard Test Method forWater Capture and Media Retention of Geocomposite DrainLayers for Green Roof Systems1This standard is issued under the fixed designation E 2398; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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 the determination of the waterand media retention of synthetic drains lay
3、ers used in greenroof systems.1.2 This standard is applicable to geocomposite drain layersthat retain water and media in cup-like receptacles on theirupper surface. Examples include shaped plastic membranesand closed-cell plastic foam boards1.3 This standard does not apply to products manufacturedfr
4、om water-absorptive 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 standard does not purport to address all of th
5、esafety 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 Documents2.1 ASTM Standards:2E 631 Terminology of Build
6、ing ConstructionE2114 Terminology for Sustainability Relative to the Per-formance of BuildingsE 2397 Practice for Determination of Dead Loads and LiveLoads Associated with Green Roof Systems3. Terminology3.1 Definitions:3.1.1 For terms related to building construction, refer toE 631.3.1.2 For terms
7、related to sustainability relative to theperformance of buildings, refer to E2114.3.2 Definitions of Terms Specific to This Standard:3.2.1 captured water, nthe quantity of water that isretained in the drainage layer of a green roof system after newwater additions have ceased and that cannot escape t
8、he roofexcept through evaporation or plant transpiration.3.2.2 coupon, na portion of a material or laboratorysample from which multiple specimens can be taken fortesting.3.2.3 geocomposite drain layer, na synthetic sheet, mat,or panel that is specifically designed to convey water horizon-tally towar
9、d the roof deck drains, gutters, or scuppers.3.2.3.1 DiscussionGeocomposite drainage layers includeabsorptive drainage mats whose principle function is drainage,but which will also contribute to water retention (see retainedwater). Some geocomposite drainage layers may incorporatereceptacles on thei
10、r upper surfaces that will capture water (seecaptured water).3.2.4 retained water, nthe quantity of water that will beretained for a prolonged period against gravity drainage in agreen roof system, or in one of its components, after newadditions by rainfall or artificial irrigation have ceased.3.2.4
11、.1 DiscussionMost of this water will not becomerunoff but will be used to the plant-mediated processes ofevapo-transpiration.3.2.5 unit media retention volume, nthe volume, ft3/ft2, (cm3/cm2) that is required to fill a geocomposite drain layerto the upper most asperities of the geocomposite drain la
12、yer.3.2.6 unit water capture volume, nthe maximum volumeof water (ft3/ft2) (cm3/cm2) that a geocomposite drain layer canhold at a specified inclination.3.2.6.1 DiscussionFor green roofs systems where thegeocomposite drain layer will be filled with granular drainagemedium, the actual volume is assume
13、d to be 25 % of themeasured volume. This assumption will allow a direct com-parison between geocomposite sheet drains without, regard to1This test method is under the jurisdiction of ASTM Committee E06 onPerformance of Buildings and is the direct responsibility of Subcommittee E06.71on Sustainabilit
14、y.Current edition approved August 15, 2005. Published August 2005.2For 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 web
15、site.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the granular drainage media used. In computing the actualwater capture of a geocomposite sheet drain employed in aspecific green roof assembly, the porosity of the granulardrainage
16、 medium used must be considered (Practice E 2397)4. Summary of Test Method4.1 This procedure provides a method for measuring thevolume of granular media or water, or both, that geocompositedrain layers can hold. The test involves filling the geocompos-ite drain layers with sand and water to establis
17、h the respectivevolumes. Since water capture will be influenced by theinclination of the geocomposite drain layer, the tests areconducted at several inclinations.5. Significance and Use5.1 Determining these performance characteristics of greenroof systems provides information to facilitate the asses
18、smentof related engineering aspects of the facility. Such aspects mayinclude structural design requirements, mechanical engineeringand thermal design requirements, and fire and life safetyrequirements.5.1.1 Accurate information about the water and mediaholding capacity of geocomposite drain layers i
19、s essential topredict dead load for green roof systems.5.2 Determining these performance characteristics of greenroof systems provides information to facilitate assessment ofthe performance of one green roof system relative to oneanother.5.2.1 Water capture is also useful in assessing irrigationrequ
20、irements for green roof designs.5.2.2 Information about the unit media retention volume isrequired to predict the quantity of material that will be requiredto construct a green roof with a specified total thickness.6. Apparatus6.1 Apparatuscontains the following:6.1.1 Scale, accurate to 0.005 oz (0.
21、14 g),6.1.2 Scoop,6.1.3 Water dropper,6.1.4 4-in. (10-cm) wide strip of aluminum or copper sheetmetal,6.1.5 Latex caulk, and6.1.6 Ruler.7. Conditioning7.1 Cut out a rectangular coupon of the geocomposite drainlayer to be tested.7.2 The coupon should contain only complete, intact recep-tacles. The co
22、upon should contain a minimum of four recep-tacles and be at least 6 in. (15 cm) square.8. Procedure8.1 Weigh the coupon in a dry condition, and record.8.2 With the coupon on a level surface, fill the receptacleswith water using a dropper. Excise caution not to moisten otherparts of the coupon.8.3 T
23、ransfer the coupon to the scale and record the weight ofthe coupon with the filled receptacles.8.4 Using a ruler, measure the distance between the centersof adjacent receptacles along the width and length of thecoupon.NOTE 1This measurement methods assumes that the receptacles arearranged in a recta
24、ngular pattern8.5 Repeat the test after filling the coupon on inclinedsurfaces. The test should be completed for the followinginclinations:8.5.1 2 degrees (3.5 %),8.5.2 5 degrees (8.7 %),8.5.3 10 degrees (17.6 %), and8.5.4 20 degrees (36.4 %).8.6 Form a fence around the margin of the coupon using th
25、emetal strip material. As necessary, seal the edge of the fenceusing latex caulk. Allow the caulk to cure. Using the ruler,measure the inside dimensions of the fence.8.7 Weigh the system and record.8.8 Fill the geocomposite drain layer with coarse sand untilthe uppermost asperities are covered. Weig
26、h and record.8.9 Determined the unit weight, lb/ft3(kg/m3), of the coarsesand.9. Calculation of Results9.1 Compute the unit media retention volume as follows:Rm 5 144 * Ws/ xg * y! in.2lb! (1)Rm 5 13106* Ws/ xg * y! SI!Where:Rm = Unit media retention volume, ft3/ft2(cm3/cm2)Ws = Weight of system fil
27、led with sand minus weight ofsystem without sand, lb (kg)x = Width fence, in. (cm)y = Length fence, in. (cm)g = Unit weight of sand, lb/ft3(kg/m3)9.2 Compute the unit water capture volume as follows:Rw 5 2.31 * Ww !/N * X * Y! in.2lb! (2)Rw 5 102* Ww !/N * X * Y! SI!Rf 5 0.25 * Rw;Where:Rw = Unit wa
28、ter capture volume, ft3/ft2(cm3/cm2)Rf = Unit water capture volume, when in-filled withmedia, ft3/ft2(cm3/cm2)Ww = Weight of coupon filled with water minus weight ofcoupon dry, lb (kg)N = Number of receptacles on the couponX = Receptacle spacing along the width of the coupon,in. (cm)Y = Receptacle s
29、pacing along the length of the coupon,in. (cm)9.3 Conduct all tests in duplicate. If the results of two testsdiffer by more than 5 %, then repeat.10. ReportReport the following information:10.1 Product designation,10.2 Size of the coupon tested,E239805210.3 Number of receptacles included on the coup
30、on,10.4 Unit media retention volume, and10.5 Unit water Capture volume, both Rw and Rf for the fiveinclinations.11. Precision and Bias11.1 PrecisionThe precision of the procedure for thesetest methods for measuring the media retention and watercapture capacity of geocomposite drain layers is being d
31、eter-mined. Parties interested in participating in interlaboratory testprograms should contact subcommittee E06.71.11.2 BiasThe bias for these measurements is undeter-mined because there no reference values available for thematerials used.12. Keywords12.1 geocomposite drain layers; green roof; media
32、 reten-tion; water captureASTM 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 any such patent rights, and the riskof infrin
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35、 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).E2398053
