1、Designation: E2398 11Standard Test Method forWater Capture and Media Retention of Geocomposite DrainLayers for Vegetative (Green) Roof Systems1This standard is issued under the fixed designation E2398; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、 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 the determination of the waterand media retention of synthetic
3、drains layers used in vegeta-tive (green) roof systems.1.2 This test method is applicable to geocomposite drainlayers that retain water and media in cup-like receptacles ontheir upper surface. Examples include shaped plastic mem-branes and closed-cell plastic foam boards1.3 This test method does not
4、 apply to products manufac-tured from 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 do
5、es 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 Documents2.1 ASTM St
6、andards:2E631 Terminology of Building ConstructionsE2114 Terminology for Sustainability Relative to the Per-formance of BuildingsE2397 Practice for Determination of Dead Loads and LiveLoads associated with Green Roof Systems3. Terminology3.1 Definitions:3.1.1 For terms related to building constructi
7、on, 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 captured water, nthe quantity of water that isretained in the drainage layer of a vegetative (green) roo
8、fsystem after new water additions have ceased and that cannotescape the roof except through evaporation or plant transpira-tion.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
9、panel that is specifically designed to convey water horizon-tally toward 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
10、). Some geocomposite drainage layers may incorporatereceptacles on their 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 avegetative (green) roof system, or in one of its c
11、omponents,after new additions by rainfall or artificial irrigation haveceased.3.2.4.1 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
12、 geocomposite drain layer tothe upper most asperities of the geocomposite drain layer.1This test method is under the jurisdiction of ASTM Committee E60 onSustainability and is the direct responsibility of Subcommittee E60.01 on Buildingsand Construction.Current edition approved Feb. 15, 2011. Publis
13、hed March 2011. Originallyapproved in 2005. Last previous edition approved in 2005 as E2398 05. DOI:10.1520/E2398-11.2For 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
14、 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.3.2.6 unit water capture volume, nthe maximum volumeof water, ft3/ft2(cm3/cm2), that a geocomposite drain layer canhold at a spec
15、ified inclination.3.2.6.1 DiscussionFor vegetative (green) roofs systemswhere the geocomposite drain layer will be filled with granulardrainage medium, the actual volume is assumed to be 25 % ofthe measured volume. This assumption will allow a directcomparison between geocomposite sheet drains witho
16、ut, re-gard to the granular drainage media used. In computing theactual water capture of a geocomposite sheet drain employed ina specific vegetative (green) roof assembly, the porosity of thegranular drainage medium used must be considered (PracticeE2397)4. Summary of Test Method4.1 This procedure p
17、rovides 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 establish the respectivevolumes. Since water capture will be influenced by theinclination of the geoco
18、mposite drain layer, the tests areconducted at several inclinations.5. Significance and Use5.1 Determining these performance characteristics of veg-etative (green) roof systems provides information to facilitatethe assessment of related engineering aspects of the facility.Such aspects may include st
19、ructural design requirements,mechanical engineering and thermal design requirements, andfire and life safety requirements.5.1.1 Accurate information about the water and mediaholding capacity of geocomposite drain layers is essential topredict dead load for vegetative (green) roof systems.5.2 Determi
20、ning these performance characteristics of veg-etative (green) roof systems provides information to facilitateassessment of the performance of one vegetative (green) roofsystem relative to one another.5.2.1 Water capture is also useful in assessing irrigationrequirements for vegetative (green) roof d
21、esigns.5.2.2 Information about the unit media retention volume isrequired to predict the quantity of material that will be requiredto construct a vegetative (green) roof with a specified totalthickness.6. Apparatus6.1 Apparatuscontains the following:6.1.1 Scale, accurate to 0.005 oz (0.14 g),6.1.2 S
22、coop,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 coupon should c
23、ontain 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 Transfer the c
24、oupon 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 rectangular patter
25、n8.5 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 themetal strip
26、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. Weigh and record.
27、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 filled with san
28、d minus weight ofsystem without sand, lb (kg),x = width fence, in. (cm),y = length fence, in. (cm), andg = 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 13103* Ww !/N * X * Y! SI!Rf 5 0.25 * Rw;where:Rw = unit wate
29、r 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),E2398 112N = number of receptacles on the coupon,X = receptacle spacing along the width of the coupon, in.(cm), and
30、Y = receptacle spacing 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. Report10.1 Report the following information:10.1.1 Product designation,10.1.2 Size of the coupon tested,10.1.3 Number of receptacles
31、included on the coupon,10.1.4 Unit media retention volume, and10.1.5 Unit water capture volume, both Rw and Rf for thefive inclinations.11. Precision and Bias11.1 PrecisionThe precision of the procedure for thesetest methods for measuring the media retention and watercapture capacity of geocomposite
32、 drain layers is being deter-mined. Parties interested in participating in interlaboratory testprograms should contact Committee E60.11.2 BiasThe bias for these measurements is undeter-mined because there no reference values available for thematerials used.12. Keywords12.1 geocomposite drain layers;
33、 media retention; vegetative(green) roof; 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
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36、ing 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E2398 113
