1、Designation: E 2397 05Standard Practice forDetermination of Dead Loads and Live Loads associatedwith Green Roof Systems1This standard is issued under the fixed designation E 2397; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、 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 practice covers a standardized procedure for pre-dicting the system weight of a green roof system.1.2 T
3、he procedure addresses the loads associated with greenroof systems. Components that are typically encountered ingreen roof systems include: membranes, non-absorptive plasticsheet components, metallic layers, fabrics, geocomposite drainlayers, synthetic reinforcing layers, cover/recover boards, in-su
4、lation materials, growth media, granular drainage media, andplant materials.1.3 This procedure also addresses the weight of the greenroof system under two conditions: (1) weight under drainedconditions after new water additions by rainfall or irrigationhave ceased (this includes the weight of retain
5、ed water andcaptured water), and (2) weight when rainfall or irrigation isactively occurring and the drainage layer is completely filledwith water. The first condition is considered the dead load ofthe green roof system. The difference in weight between thefirst and second conditions, approximated b
6、y the weight oftransient water in the drainage layer, is considered a liveload.1.4 This procedure does not address point or line loadsassociated with architectural elements that are not essentialcomponents of a particular green roof system. These architec-tural elements may include pavement, walls,
7、and masonry, andso forth.1.5 This procedure does not address live loads associatedwith construction activities.1.6 This procedure does not address live loads associatedwith snow or wind.1.7 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathe
8、maticalconversions 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 theresponsibility of the user of this standard to establish appro-priate safety and hea
9、lth practices and to determine theapplicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C 29/C 29M Test Method for Bulk Density (Unit Weight)and Voids in AggregateE 631 Terminology of Building ConstructionE2114 Terminology for Sustainability Relative to the
10、Per-formance of BuildingsE 2396 Standard Test Method for Saturated Hydraulic Con-ductivity of Granular Drainage Media Falling-HeadMethod for Green Roof SystemsE 2398 Standard Test Method for Water and Media Reten-tion of Geocomposite Drain Layers for Green Roof Sys-temsE 2399 Standard Test Method fo
11、r Maximum Media Densityfor Dead Load Analysis of Green Roof Systems3. Terminology3.1 Definitions:3.1.1 For terms related to building construction, refer toE 631.3.1.2 For terms related to sustainability relative to theperformance of buildings, refer to E 2114.3.2 Definitions of Terms Specific to Thi
12、s 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 the roofexcept through evaporation or plant transpiration.3.2.1.1 DiscussionWater capture is a design technique forenhancin
13、g the water holding properties of a green roof system.Water may be captured using a number of techniques, includ-ing receptacles built into a geocomposite drain layer, trays, andrestricting drainage in order to hold water within the drainagelayer.In some green roof systems a granular course at the b
14、ottom1This Practice is under the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.71 onSustainability.Current edition approved August 15, 2005. Published August 2005.2For referenced ASTM standards, visit the ASTM website, www.astm.o
15、rg, 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.of the syste
16、m 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.Amethod for determining the captured water associated withgeocomposites based on the unit water capture volume isprovided in Test
17、 Method E 2398. The quantity of capturedwater will depend on whether or not the upper surface of thegeocomposite drain layer is in-filled with granular media.3.2.2 geocomposite drain layer, na synthetic sheet, mat,or panel that is specifically designed to convey water horizon-tally toward the roof d
18、eck drains, gutters, or scuppers.3.2.2.1 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 their upper surf
19、aces 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 traffic and rainfall.3.2.3.1 DiscussionThe
20、maximum media density appliesto media in a drained condition. The measurement of themaximum media density is provided in Test Method E 2396.3.2.4 maximum media water retentionthe quantity ofwater held in a media layer at the maximum media density.3.2.4.1 DiscussionA procedure for measuring the maxi-
21、mum media water retention is provided in Test Method E 2399.3.2.5 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.3.2.5.1 DiscussionRetained water is the quantity of waterthat is he
22、ld for a prolonged period against gravity drainage ina green roof system, or in one of its components, after newadditions by rainfall or artificial irrigation have ceased. Ne-glecting the effects of capillary rise, evaporation, and planttranspiration all of this water would eventually produce runoff
23、.However, in practice most of this water will not become runoffbut will be lost to evaporation and the plant-mediated processesof transpiration. This procedure describes standardized meth-ods for estimating the quantity of water retained in a green roofsystem.3.2.6 roof system, nsee roofing system.3
24、.2.7 roofing system, nassembly of interacting compo-nents designed to weatherproof, and sometimes to insulate, theroof surface of a building. (E 631)3.2.7.1 DiscussionThis term includes all componentsabove the roof deck that are not part of the overlying green roofsystem. In practice this usually me
25、ans the waterproofingmembrane and all materials below the waterproofing mem-brane, down to the structural deck. It may include structuralmaterials such as cover/recover board, insulation, protectivelayers, fire-suppressing materials, and waterproofing materials.The weight of these components (assume
26、d dry) must beobtained from the manufacturer of the roofing system.3.2.8 transient water, nthe quantity of water that isrequired to completely fill the drainage layer of a green roofsystem, less the quantity of captured water.3.2.8.1 DiscussionTransient water fills the open space,including pore spac
27、es. 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 system.4. Summary of Practice4.1 This practice describes a systematic procedure for esti-mating the dead load and transient water live load of g
28、reen roofsystems using information about the green roof componentsthat are available from laboratory analysis.5. Significance and Use5.1 This practice addresses performance characteristics forgreen roof systems with respect to the dead load and transientwater live load of the entire system.5.2 Deter
29、mining these 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 fire and life safetyrequir
30、ements.5.3 Determining these performance characteristics of greenroof systems provides information to facilitate assessment ofthe performance of one green roof system 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
31、 U.S. #30 (0.6mm), 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 plastic sheet components,excluding fabrics: Using the scale, weigh a 4-in. by 4-in.(10-cm by 10-cm) piece. Multiply this weight b
32、y 9 (100) toconvert to unit weight in lb/ft2(kg/m2) and record.7.2 Weight of all fabrics: Weigh a 4-in. by 4-in. (10-cm by10-cm) sample in the dry condition. Multiply this weight by 9(100) to convert to unit weight in lb/ft2(kg/m2), and record.This is the dry unit weight. Immerse the sample in a wat
33、er bathfor 15 min. Withdraw from the bath and drain for 15 min.Weigh the sample and record the unit weight in lb/ft2(kg/m2).This is the wet unit weight. The difference between the twomeasurements is the unit weight of the retained water associ-ated with fabric.7.3 Weight of absorptive drainage mats
34、used as drainagelayer components: Weigh the pan using the scale. Weigh a 4-in.by 4-in. (10-cm by 10-cm) sample in the dry condition. Recordthe dry unit weight of the sample in lb/ft2(kg/m2). Immerse themat in the water bath for 24 hours. Withdraw the mat from thewater bath and without delay place th
35、e mat into the pan. Weighthe pan and its contents. Subtract the weight of the pan and thedry weight of the mat. Record the unit weight of the waterE2397052contained in the mat when filled to capacity in lb/ft2(kg/m2).Dry the pan. Allow the mat to drain for an additional 2 hoursand return the mat to
36、the pan. Weigh the pan and its contents.Subtract the weight of the pan and record the unit weight inlb/ft2(kg/m2). This is the unit wet weight of the sample.Subtract the dry unit weight of the sample from its wet unitweight. This is the unit weight of the retained water in the mat,in lb/ft2(kg/m2).
37、Subtract the unit weight of the retained waterfrom the unit weight of the water when the mat was filled tocapacity. This is the unit weight of the transient water associ-ated with the absorptive drainage mat.7.4 Weight of the growth media: Use Test Method E 2396 todetermine the maximum media density
38、 (MMD) in lb/ft3(kg/m3) and the maximum media water retention (MMWR).Multiply the maximum media density times the depth of themedia layer in feet (metres). Record the unit weight inlb/ft2(kg/m2). To determine the weight of the retained watermultiply the MMWR by the depth of the media layer in feet(m
39、etres) and by 0.624 (98.10). Record the unit weight inlb/ft3(kg/m3).7.5 Weight of granular drainage media. Use Test MethodE 2396 to determine the maximum media density (MMD) inlb/ft3(kg/m3), and the maximum media water retention(MMWR) of the granular material. Multiply the maximummedia density times
40、 the depth of the drainage media in feet(metres). Record the unit weight in lb/ft2(kg/m2). In somegreen roof systems granular media is in-filled on the uppersurface of a geocomposite drain layer. In these instances, theeffective depth of the drainage medium is the unit mediaretention volume in ft3/f
41、t2(cm3/cm2), as determined using TestMethod E 2398, plus any supplemental thickness of drainagemedia above the geocomposite drain layer. To determine theweight of the retained water multiply the MMWR by theeffective depth of the media layer in feet (metres) and by 0.624(98.1). Record the unit weight
42、 in lb/ft2(kg/m2).7.6 Weight of Captured Water: For systems that incorporategeocomposite drain layers with water capture, use Test MethodE 2398 to determine the weight of captured water based on theunit water retention volume. Multiply the unit water capturevolume, stated in ft3/ft2(cm3/cm2), by 62.
43、4 (98.1). Record thisunit weight in lb/ft2(kg/m2). For systems that incorporate agranular retention layer, use Test Method C 29/C 29M todetermine the porosity, reported in percent, of the drainagemedia. Multiply the porosity times the depth of the drainagelayer in feet (metres) and by 0.624 (98.1).
44、Record this unitweight in lb/ft2(kg/m2).7.7 Weight of transient water in the drainage layer ingranular materials: Use Test Method C 29/C 29M to deter-mine the porosity, reported in percent, of the drainage media.Multiply the porosity times the depth of the drainage layer infeet (metres) and by 0.624
45、 (98.1). Record this unit weight inlb/ft2(kg/m2).7.8 Weight of transient water in a geocomposite drainlayers: For systems using absorptive drainage mats, themethod for determining the weight of transient water isdescribed in Section 7.3. For other geocomposite drain layers,use Test Method E 2398 to
46、determine the unit volume of thegeocomposite drain layer in ft3/ft2(cm3/cm2). Multiply thisunit volume by 62.4 (98.1). Subtract the unit weight ofcaptured water associated with the geocomposite drain layer.Record the resulting unit weight in lb/ft2(kg/m2).NOTE 1A method for measuring the effective o
47、pen space in ageocomposite drain layer has not been introduced at this time. In theabsence of standard method use the full thickness of the geocompositedrain layer, measured in ft and reported as ft3/ft2(cm3/cm2).7.9 Weight of Retained Water in a Green Roof System: Forpurposes of comparison between
48、systems, the weight of theretained water in a green roof system shall be determined as thesum of the following unit weights:7.9.1 Retained water in fabrics (see 7.2),7.9.2 Retained water in absorptive drainage mats (see7.3),7.9.3 Retained water in the growth media layer (see 7.4),7.9.4 Retained wate
49、r in the drainage media layer (see7.5),and7.9.5 Captured water (see 7.6).7.10 The volume of retained water, reported in inches(centimetres), associated with a green roof system is the totalweight of retained water, reported in lb/ft2(kg/m2), divided by62.4 (9,810), and multiplied by 12 (100).8. Report8.1 Use the Report Format (ANNEX) to record the unitweights determined for each green roof component.9. Keywords9.1 dead load; green roof; live load; sustainability; waterretentionE2397053ANNEX(Mandatory Information)A1. REPORT FORMAT:SYSTEM DESIGNATION:_TOTAL SYST
