1、Designation: E2397/E2397M 15Standard Practice forDetermination of Dead Loads and Live Loads Associatedwith Vegetative (Green) Roof Systems1This standard is issued under the fixed designation E2397/E2397M; the number immediately following the designation indicates the yearof original adoption or, in
2、the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.A superscript 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
3、 vegetative (green) 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:membranes, non-absorptive plastic sheet components, metalliclayers, fabrics, geocomposite drain l
4、ayers, synthetic reinforc-ing layers, cover/recover boards, insulation materials, growthmedia, 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 additi
5、ons by rainfall 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 s
6、ystem. The 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 particu
7、lar vegetative (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 eit
8、her SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.8 This standa
9、rd 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 Documents2.1 AS
10、TM Standards:2E11 Specification for Woven Wire Test Sieve Cloth and TestSievesE631 Terminology of Building ConstructionsE2114 Terminology for Sustainability Relative to the Perfor-mance of BuildingsE2396 Test Method for Saturated Water Permeability ofGranular Drainage Media Falling-Head Method forVe
11、getative (Green) Roof SystemsE2398 Test Method for Water Capture and Media Retentionof Geocomposite Drain Layers for Vegetative (Green)Roof SystemsE2399 Test Method for Maximum Media Density for DeadLoad Analysis of Vegetative (Green) Roof Systems3. Terminology3.1 Definitions:3.1.1 For terms related
12、 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 captured water, nthe quantity of water that is re-tained in the drain layer of a
13、vegetative (green) roof systemafter new water additions have ceased and that cannot escapethe roof except through evaporation or plant transpiration.3.2.1.1 DiscussionWater capture is a design technique for1This Practice is under the jurisdiction of ASTM Committee D08 on Roofingand Waterproofing and
14、 is the direct responsibility of Subcommittee D08.24 onSustainability.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 2005. Last published in 2011 as E2397 11. DOI: 10.1520/E2397_E2397M-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orconta
15、ct ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1enhancing the water hold
16、ing 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 within the drain layer. In some vegetative (green) roofsystems a granular course at t
17、he bottom of the vegetative(green) roof system provides both drainage and water capturefunctions. In this case the captured water applies only to thethickness of the granular course for which drainage is re-stricted. A method for determining the captured water associ-ated with geocomposites based on
18、 the unit water capturevolume is provided in Test Method E2398. The quantity ofcaptured water will depend on whether or not the upper surfaceof the geocomposite drain layer is in-filled with granularmedia.3.2.2 geocomposite drain layer, na synthetic sheet, mat, orpanel that is specifically designed
19、to convey water horizontallytoward the roof deck drains, gutters, or scuppers.3.2.2.1 DiscussionGeocomposite drain layers include ab-sorptive drain mats whose principle function is drainage, butwhich will also contribute to water retention (see retainedwater). Some geocomposite drain layers may inco
20、rporatereservoirs on their upper surfaces that will capture water (seecaptured water).3.2.3 maximum media density, nthe density of a mixedmedia material determined after it has been subjected to aspecific amount of compaction and hydrated by immersion tosimulate prolonged exposure to both foot traff
21、ic and rainfall.3.2.3.1 DiscussionThe maximum media density applies tomedia in a drained condition. The measurement of the maxi-mum media density is provided in Test Method E2399.3.2.4 maximum media water retentionthe quantity of wa-ter held in a media layer at the maximum media density,measured in
22、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 vegetative (green) roof systemscombine many functional elements of vegetative (green) roofsystems in a pre-manufactured module.3.2.5.1 DiscussionIndep
23、endent 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 for a period ofhours or days but would eventually drain out given enoughtime in the absence of evaporation or plant transpiration.3.2.6.1 DiscussionRe
24、tained 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 components,after new additions by rainfall or artificial irrigation haveceased. Neglecting the effects of capillary rise, evaporation,and plant trans
25、piration all of this water would eventuallyproduce runoff. However, in practice most of this water will notbecome runoff but will be lost to evaporation and the plant-mediated processes of transpiration. This procedure describesstandardized methods for estimating the quantity of waterretained in a v
26、egetative (green) roof system.3.2.7 roof system, nsee roofing system.3.2.8 roofing system, nassembly of interacting compo-nents designed to weatherproof, and sometimes to insulate, theroof surface of a building. E6313.2.8.1 DiscussionThis term includes all componentsabove the roof deck that are not
27、part of the overlying vegetative(green) roof system. In practice this usually means the water-proofing membrane and all materials below the waterproofingmembrane, down to the structural deck. It may includestructural materials such as cover/recover board, insulation,protective layers, fire-suppressi
28、ng materials, and waterproofingmaterials. The weight of these components (assumed dry) mustbe obtained from the manufacturer of the roofing system.3.2.9 transient water, nthe quantity of water that is re-quired to completely fill the drain layer of a vegetative (green)roof system, less the quantity
29、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 drains immediately when rainfall additions end.This moisture contributes to the live load of the vegetative(green) roof system.4. Summary of Practice
30、4.1 This practice describes a systematic procedure for esti-mating the dead load and transient water live load of vegetative(green) roof systems using information about the vegetative(green) roof components that are available from laboratoryanalysis.5. Significance and Use5.1 This practice addresses
31、 performance characteristics forvegetative (green) roof systems with respect to the dead loadand transient water load of the entire vegetative (green) roofsystem.5.2 Determining these performance characteristics of veg-etative (green) roof systems provides information to facilitatethe assessment of
32、related engineering aspects of the facility.Such aspects may include structural design requirements,mechanical engineering and thermal design requirements, andfire and life safety requirements.5.3 Determining these performance characteristics of veg-etative (green) roof systems provides information
33、to facilitateassessment of the performance of one vegetative (green) roofsystem relative to another.6. Apparatus6.1 Apparatus:6.1.1 Scale, accurate to 0.005 oz 0.14 g;6.1.2 Metal mesh with sieve opening size of U.S. #300.6 mm, or larger, suspended from a drain stand;6.1.3 Pan; and6.1.4 Water bath.6.
34、2 Units of measure: lb/ft2kg m2.7. Procedure7.1 Weight of All Non-Absorptive Sheet ComponentThesematerials include plastic or rubber membranes, closed-cellfoam layers, and the rigid or semi-rigid plastic cores ofE2397/E2397M 152geocomposite drain layers. Also included is insulation pro-vided as part
35、 of protected membrane roofing (PMR) installa-tion. Absorptive drainage mats and fabrics, including fabricsintegrated with geocomposite drain layers, are excluded (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.
36、by 4-in. 10-cm by 10-cm piece. Multiply thisweight by 9 100 to convert to unit weight in lb/ft2kg/m2,and record.7.2 Weight of All Fabrics4-in. by 4-in. 10-cm by 10-cmsample in the dry condition. Multiply this weight by 9 100 toconvert to unit weight in lb/ft2kg/m2, and record. This is thedry unit we
37、ight 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 suspended U.S. #30 0.6 mm wirecloth or sieve. Weigh the sample, convert to unit weight inlb/ft2kg/m2, and record. This is the unit weight of the fabric.The diff
38、erence between the two measurements is the unitweight of the retained water associated with the fabric, Wr.7.3 Weight of Absorptive Drain Mats Used as Drain LayerComponentsThese materials include open-cell foam layers,porous mats fabricated from particles of plastic or rubber, andmats manufactured f
39、rom coir or other organic fibers. Weigh thepan using the scale. Weigh a 4-in. by 4-in. 10-cm by 10-cmsample in the dry condition. Multiply this weight by 9 100 toconvert to unit weight in lb/ft2kg/m2, and record as the dryunit weight of the sample. Immerse the mat in the water bathfor 24 hours. With
40、draw 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 and the dry weight ofthe mat. Multiply this weight by 9 100 to convert to unitweight in lb/ft2kg/m2, and record as the unit weight of thewater contained in the
41、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 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.
42、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, 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 th
43、e transient water associated with the absorptivedrain mat, Wt.7.4 Weight of Growth MediaUse Test Method E2399 todetermine the maximum media density (MMD) and dry mediadensity, Ddry, both measured in lb/ft3kg/m3, and the maxi-mum media water retention (MMWR), measured in volumepercent. Multiply the m
44、aximum media density times thethickness of the media layer in feet metres to convert to unitweight in lb/ft2kg/m2, and record. This is 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/ft2kg/m2, and record.
45、 This is the dry unit weight of thegrowth media. To determine the unit weight of the retainedwater, Wr, multiply the MMWR by the thickness of the medialayer in feet and by 0.624 10 and record this unit weight inlb/ft2kg/m2.7.5 Weight of Granular Drainage Media:7.5.1 Drain Layers Consisting Entirely
46、of Granular Drain-age MediaUse Test Method E2399 to determine the MMDand dry media density, Ddry, both measured in lb/ft3kg/m3,and the MMWR of the granular material, measured in volumepercent. Multiply the MMD times the thickness of the granulardrainage media in feet metres. Record the unit weight o
47、f thegranular drainage media in lb/ft2kg/m2. Multiply the drymedia density times the thickness of the media layer in feet toconvert to unit weight in lb/ft2kg/m2, and record. This is thedry unit weight of the granular drainage media. To determinethe unit weight of the retained water, Wr, multiply th
48、e MMWRby the thickness of the layer in feet and by 0.624 10. Recordthis unit weight in lb/ft2.7.5.2 Drain Layers Incorporating Geocomposite DrainLayersIn many vegetative (green) roof systems, granulardrainage media is in-filled on the upper surface of a geocom-posite drain layer. In these instances,
49、 the effective thickness ofthe granular drainage media, ET, is the unit media retentionvolume, Rm, measured in ft3/ft2cm3/cm2, as determinedusing 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/ft3kg/m3, and the MMWR of the granular material,measured in volume percent. Multiply the MMD times theeffective thickness of t
