1、Designation: E2397 11Standard Practice forDetermination of Dead Loads and Live Loads Associatedwith Vegetative (Green) Roof Systems1This standard is issued under the fixed designation E2397; 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 () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a standardized procedure for pre-dicting the system weight of a vegetative (g
3、reen) roof system.1.2 The practice addresses the loads associated with vegeta-tive (green) roof systems. Components that are typicallyencountered in vegetative (green) roof systems include: mem-branes, non-absorptive plastic sheet components, metallic lay-ers, fabrics, geocomposite drain layers, syn
4、thetic reinforcinglayers, cover/recover boards, insulation materials, growth me-dia, granular drainage media, and plant materials.1.3 This practice also addresses the weight of the vegetative(green) roof system under two conditions: (1) weight underdrained conditions after new water additions by rai
5、nfall orirrigation have ceased (this includes the weight of retainedwater and captured water), and (2) weight when rainfall orirrigation is actively occurring and the drain layer is completelyfilled with water. The first condition is considered the dead loadof the vegetative (green) roof system. The
6、 difference in weightbetween the first and second conditions, approximated by theweight of transient water in the drain layer, is considered a liveload.1.4 This practice does not address point or line loadsassociated with architectural elements that are not essentialcomponents of a particular vegeta
7、tive (green) roof system.These architectural elements may include pavement, walls, andmasonry, and so forth.1.5 This practice does not address live loads associated withconstruction activities.1.6 This practice does not address loads associated withsnow or wind.1.7 The values stated in inch-pound un
8、its 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.1.8 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsi
9、bility 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:2E11 Specification for Woven Wire Test Sieve Cloth and TestSievesE631 Terminology of Building C
10、onstructionsE2114 Terminology for Sustainability Relative to the Per-formance of BuildingsE2396 Test Method for Saturated Water Permeability ofGranular Drainage Media Falling-Head Method forGreen Roof SystemsE2398 Test Method for Water Capture and Media Retentionof Geocomposite Drain Layers for Gree
11、n Roof SystemsE2399 Test Method for Maximum Media Density for DeadLoad Analysis of Green Roof Systems3. 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 Te
12、rminology E2114.3.2 Definitions of Terms Specific to This Standard:3.2.1 captured water, nthe quantity of water that isretained in the drain layer of a vegetative (green) roof systemafter new water additions have ceased and that cannot escapethe roof except through evaporation or plant transpiration
13、.3.2.1.1 DiscussionWater capture is a design technique forenhancing the water holding properties of a vegetative (green)roof system. Water may be captured using a number oftechniques, including reservoirs built into a geocompositedrain layer, trays, and restricting drainage in order to holdwater wit
14、hin the drain layer. In some vegetative (green) roofsystems a granular course at the bottom of the vegetative(green) roof system provides both drainage and water capturefunctions. In this case the captured water applies only to the1This Practice is under the jurisdiction of ASTM Committee E60 on Sus
15、tain-ability and is the direct responsibility of Subcommittee E60.01 on Buildings andConstruction.Current edition approved Feb. 15, 2011. Published March 2011. Originallyapproved in 2005. Last published in 2005 as E2397 05. DOI: 10.1520/E2397-11.2For referenced ASTM standards, visit the ASTM website
16、, 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
17、thickness of the granular course for which drainage is re-stricted. A method for determining the captured water associ-ated with geocomposites based on the unit water capturevolume is provided in Test Method E2398. The quantity ofcaptured water will depend on whether or not the upper surfaceof the g
18、eocomposite drain layer is in-filled with granularmedia.3.2.2 geocomposite drain layer, na synthetic sheet, mat,or panel that is specifically designed to convey water horizon-tally toward the roof deck drains, gutters, or scuppers.3.2.2.1 DiscussionGeocomposite drain layers include ab-sorptive drain
19、 mats whose principle function is drainage, butwhich will also contribute to water retention (see retainedwater). Some geocomposite drain layers may incorporatereservoirs on their upper surfaces that will capture water (seecaptured water).3.2.3 maximum media density, nthe density of a mixedmedia mat
20、erial determined after it has been subjected to aspecific amount of compaction and hydrated by immersion tosimulate prolonged exposure to both foot traffic and rainfall.3.2.3.1 DiscussionThe maximum media density appliesto media in a drained condition. The measurement of themaximum media density is
21、provided in Test Method E2399.3.2.4 maximum media water retentionthe quantity ofwater held in a media layer at the maximum media density,measured in volume percent.3.2.4.1 DiscussionA procedure for measuring the maxi-mum media water retention is provided in Test Method E2399.3.2.5 module, nmodular v
22、egetative (green) roof systemscombine many functional elements of vegetative (green) roofsystems in a pre-manufactured module.3.2.5.1 DiscussionIndependent modules are designed tobe placed adjacent to one another and linked in order to tilelarger surfaces.3.2.6 retained water, nwater which is held f
23、or a period ofhours or days but would eventually drain out given enoughtime in the absence of evaporation or plant transpiration.3.2.6.1 DiscussionRetained water is the quantity of waterthat is held for a prolonged period against gravity drainage ina vegetative (green) roof system, or in one of its
24、components,after new additions by rainfall or artificial irrigation haveceased. Neglecting the effects of capillary rise, evaporation,and plant transpiration all of this water would eventuallyproduce runoff. However, in practice most of this water will notbecome runoff but will be lost to evaporatio
25、n and the plant-mediated processes of transpiration. This procedure describesstandardized methods for estimating the quantity of waterretained in a vegetative (green) roof system.3.2.7 roof system, nsee roofing system.3.2.8 roofing system, nassembly of interacting compo-nents designed to weatherproo
26、f, and sometimes to insulate, theroof surface of a building. E6313.2.8.1 DiscussionThis term includes all componentsabove the roof deck that are not part of the overlying vegetative(green) roof system. In practice this usually means the water-proofing membrane and all materials below the waterproofi
27、ngmembrane, down to the structural deck. It may includestructural materials such as cover/recover board, insulation,protective layers, fire-suppressing materials, and waterproofingmaterials. The weight of these components (assumed dry) mustbe obtained from the manufacturer of the roofing system.3.2.
28、9 transient water, nthe quantity of water that isrequired to completely fill the drain layer of a vegetative(green) roof system, less the quantity of captured water.3.2.9.1 DiscussionTransient water fills the open space,including pore spaces. This water can only be held for a periodof minutes and dr
29、ains immediately when rainfall additions end.This moisture contributes to the live load of the vegetative(green) roof system.4. Summary of Practice4.1 This practice describes a systematic procedure for esti-mating the dead load and transient water live load of vegetative(green) roof systems using in
30、formation about the vegetative(green) roof components that are available from laboratoryanalysis.5. Significance and Use5.1 This practice addresses performance characteristics forvegetative (green) roof systems with respect to the dead loadand transient water load of the entire vegetative (green) ro
31、ofsystem.5.2 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 structural design requirements,mechanical engineering and thermal design requirement
32、s, andfire and life safety requirements.5.3 Determining these performance characteristics of veg-etative (green) roof systems provides information to facilitateassessment of the performance of one vegetative (green) roofsystem relative to another.6. Apparatus6.1 Apparatus:6.1.1 Scale, accurate to 0.
33、005 oz (0.14 g);6.1.2 Metal mesh with sieve opening size of U.S. #30(0.6 mm), or larger, suspended from a drain stand;6.1.3 Pan; and6.1.4 Water bath.6.2 Units of measure: lb/ft2(kg/m2).7. Procedure7.1 Weight of All Non-Absorptive Sheet ComponentThesematerials include plastic or rubber membranes, clo
34、sed-cellfoam layers, and the rigid or semi-rigid plastic cores ofgeocomposite drain layers. Also included is insulation pro-vided as part of protected membrane roofing (PMR) installa-tion. Absorptive drainage mats and fabrics, including fabricsintegrated with geocomposite drain layers, are excluded
35、(see7.2 and 7.3). As needed, remove fabrics bonded to geocom-posite drain layers for separate measurement according to 7.2.Weigh a 4-in. by 4-in. (10-cm by 10-cm) piece. Multiply thisweight by 9 (100) to convert to unit weight in lb/ft2(kg/m2),and record.7.2 Weight of All Fabrics4-in. by 4-in. (10-c
36、m by 10-cm)sample in the dry condition. Multiply this weight by 9 (100) toE2397 112convert to unit weight in lb/ft2(kg/m2), and record. This is thedry unit weight of the fabric. Immerse the sample in a waterbath for 15 min. Withdraw from the bath and drain for 15 minby laying the fabric flat on a su
37、spended U.S. #30 (0.6 mm) wirecloth or sieve. Weigh the sample, convert to unit weight inlb/ft2, and record. This is the unit weight of the fabric. Thedifference between the two measurements is the unit weight ofthe retained water associated with the fabric, Wr.7.3 Weight of Absorptive Drain Mats Us
38、ed as Drain LayerComponentsThese materials include open-cell foam layers,porous mats fabricated from particles of plastic or rubber, andmats manufactured from coir or other organic fibers. Weigh thepan using the scale. Weigh a 4-in. by 4-in. (10-cm by 10-cm)sample in the dry condition. Multiply this
39、 weight by 9 (100) toconvert to unit weight in lb/ft2(kg/m2), and record as the dryunit weight of the sample. Immerse the mat in the water bathfor 24 hours. Withdraw the mat from the water bath andwithout delay place the mat into the pan. Weigh the pan and itscontents. Subtract the weight of the pan
40、 and the dry weight ofthe mat. Multiply this weight by 9 (100) to convert to unitweight in lb/ft2, and record as the unit weight of the watercontained in the mat when filled to capacity. Dry the pan.Allow the mat to drain for an additional two hours by layingthe mat flat on a suspended U.S. #30 (0.6
41、 mm) wire cloth orsieve. Return the mat to the pan. Weigh the pan and itscontents. Subtract the weight of the pan. Convert to unit weightin lb/ft2, and record. This is the unit weight of the sample.Subtract the dry unit weight of the sample, and record. This isthe unit weight of the retained water,
42、Wr, in the mat. Subtractthe unit weight of the retained water from the unit weight of thewater when the mat was filled to capacity. This is the unitweight of the transient water associated with the absorptivedrain mat, Wt.7.4 Weight of Growth MediaUse Test Method E2399 todetermine the maximum media
43、density (MMD) and dry mediadensity, Ddry, both measured in lb/ft3(kg/m3), and the maxi-mum media water retention (MMWR), measured in volumepercent. Multiply the maximum media density times thethickness of the media layer in feet (metres) to convert to unitweight in lb/ft2(kg/m2), and record. This is
44、 the unit weight ofthe growth media. Multiply the dry media density times thethickness of the media layer in feet to convert to unit weight inlb/ft2, and record. This is the dry unit weight of the growthmedia. To determine the unit weight of the retained water, Wr,multiply the MMWR by the thickness
45、of the media layer in feetand by 0.624 (10) and record this unit weight in lb/ft2.7.5 Weight of Granular Drainage Media:7.5.1 Drain Layers Consisting Entirely of Granular Drain-age MediaUse Test Method E2399 to determine the MMDand dry media density, Ddry, both measured in lb/ft3(kg/m3),and the MMWR
46、 of the granular material, measured in volumepercent. Multiply the MMD times the thickness of the granulardrainage media in feet (metres). Record the unit weight of thegranular drainage media in lb/ft2(kg/m2). Multiply the drymedia density times the thickness of the media layer in feet toconvert to
47、unit weight in lb/ft2, and record. This is the dry unitweight of the granular drainage media. To determine the unitweight of the retained water, Wr, multiply the MMWR by thethickness of the layer in feet and by 0.624 (10). Record thisunit weight in lb/ft2.7.5.2 Drain Layers Incorporating Geocomposit
48、e DrainLayersIn many vegetative (green) roof systems, granulardrainage media is in-filled on the upper surface of a geocom-posite drain layer. In these instances, the effective thickness ofthe granular drainage media, ET, is the unit media retentionvolume, Rm, measured in ft3/ft2(cm3/cm2), as determ
49、inedusing Test Method E2398, plus any supplemental thickness ofgranular drainage media above the geocomposite drain layer,measured in feet (metres). Use Test Method E2399 to deter-mine the MMD and dry media density, Ddry, both measured inlb/ft3(kg/m3), and the MMWR of the granular material,measured in volume percent. Multiply the MMD times theeffective thickness of the granular drainage media in feet andby 0.624 (10). Record the unit weight of the granular drainagemedia in lb/ft2(kg/m2). Multiply the dry media density timesthe effective thickness of the gran
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