1、Designation: E2400/E2400M 06 (Reapproved 2015)1Standard Guide forSelection, Installation, and Maintenance of Plants for GreenRoof Systems1This standard is issued under the fixed designation E2400/E2400M; the number immediately following the designation indicates the yearof original adoption or, in t
2、he 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.1NOTEUnits information was editorially corrected in January 2015.1. Scope1.1 This guide covers th
3、e considerations for the selection,installation, and maintenance of plants for green roof systems.1.2 This guide is applicable to both extensive and intensivegreen roof systems.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated in
4、each 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.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It i
5、s 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:2E631 Terminology of Building ConstructionsE2114 Terminology for Sustainability Re
6、lative to the Perfor-mance of Buildings3. 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 Terminology E2114.4. Summary of Guide4.1 This guide covers the s
7、election criteria for plants to beused on green roofs. Primary considerations are as follows:4.1.1 Design intent,4.1.2 Aesthetics,4.1.3 Climate; including both macroclimate andmicroclimate,4.1.4 Plant characteristics, including the rate ofestablishment, longevity, and disease and pest resistance, an
8、d4.1.5 Media composition and depth.4.2 This guide covers the installation of plants for greenroofs. Installation methods include:4.2.1 Precultivation, and4.2.2 Direct planting on roof (seeds, root cuttings, andplugs).4.3 Guidance is also provided for the maintenance of plantsfor green roofs.5. Signi
9、ficance and Use5.1 This guide addresses performance characteristics forgreen roof systems with respect to the planting. A rooftop is anextreme environment with strong and variable wind patternsand little or no protection from the suns intense heat andultraviolet radiation. Selection of plant materia
10、l can be crucialfor success of the green roof system.5.1.1 This guide provides general guidance only. It isimportant to consult with a professional horticulturist, greenroof consultant, or work with similar professionals that areknowledgeable, experienced, and acquainted with green rooftechnology an
11、d plants.5.2 Determining these performance characteristics of greenroof systems provides information to facilitate the assessmentof engineering aspects of the facility. Such aspects may includestructural design requirements, mechanical engineering andthermal design requirements, and fire and life sa
12、fety require-ments.5.3 Determining these performance characteristics of greenroof systems provides information to facilitate assessment ofthe performance of one green roof system relative to another.1This guide is under the jurisdiction of ASTM Committee D08 on Roofing andWaterproofingand is the dir
13、ect responsibility of Subcommittee D08.24 on Sustain-ability.Current edition approved Jan. 1, 2015. Published February 2015. Originallyapproved in 2006. Last previous edition approved in 2006 as E2400-06. DOI:10.1520/E2400_E2400M-06R15E01.2For referenced ASTM standards, visit the ASTM website, www.a
14、stm.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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16. Selec
15、tion6.1 In general, green roofs can be categorized into twotypes, intensive or extensive, depending on the plant materialand planned usage for the roof area.6.1.1 Intensive green roofsIntensive green roofs utilize awide variety of plant species that may include trees and shrubsand are generally limi
16、ted to flat roofs. Use of large plantsrequires deeper media layers, possibly 25 cm 10 in. or more,which results in more weight and a need for an increasedstructural load capacity of the building. Intensive green roofsusually have higher requirements for water, labor and otherresources than extensive
17、 green roofs.6.1.2 Extensive green roofsExtensive green roofs use anarrow range of species limited to herbs, grasses, mosses, anddrought tolerant succulents such as sedum, a succulent plantknown for its tolerance for extreme conditions. These types ofplants can potentially be sustained in a media la
18、yer as shallowas 2.5 cm 1.0 in. and, therefore, they can often be installed onbuildings without the cost of major structural alterations.Extensive green roofs generally require less maintenance andare generally less expensive to install than intensive greenroofs.6.2 Criteria for Selecting Species:6.
19、2.1 Design IntentThe design intent will impact plantselection. Aspects of design intent that may influence plantselection include: accessibility and use of the roof, stormwatermanagement objectives, xeriscaping objectives, and thermalinsulation objectives. Considerations for wildlife, such asestabli
20、shing connections with a wildlife corridor or providinghabitat for wildlife of local ecosystems may also impact theplant selection. Considerations for wildlife should be coordi-nated with a knowledgeable consultant and the regional Ex-tension Service to verify anticipated wildlife in that climate at
21、the rooftop elevation.6.2.1.1 The design intent and available installation andmaintenance budgets are key factors is determining mediadepths and plant selection.6.2.2 AestheticsAesthetics often drive green roof designand plant selection. Combinations of evergreens and floweringplants with a long blo
22、oming season work well together.However, flowering perennial plants may recede into theground during winter or long, hot, dry periods in the summer.If they survive roof environmental conditions, they will usuallyregenerate themselves from the root system, but periods ofdrought can leave a mass of br
23、owned-out, dead looking plantsthat could be a fire hazard. Similarly, grasses are difficult tokeep green throughout the summer. One can allow grasses togrow until June and then cut them back to approximately threeinches in height, but this practice requires extensive labor.Plants may look fantastic
24、early in the year, but most cannotwithstand summer heat and drought conditions when growingin shallow extensive roof media depths. In order to grow mostannuals, perennial flowering herbaceous plants, and grasses,either irrigation must be present or the media must be deeper.If irrigation is not avail
25、able, then succulent species such assedum, sempervivum, and delosperma are considered goodchoices because of their ability to withstand extended droughtand other adverse environmental conditions often present on arooftop. Unlike most perennials and grasses, succulents are notconsidered fire hazards
26、because of the large percentage ofwater that is stored in their leaves. The aesthetic value of theroof will continually change throughout the growing seasonand over time. Plant competition and succession will occur asin any landscape. Similarly, identical plant palettes will lookand behave different
27、ly depending on the local environmentalconditions.6.2.3 ClimateClimate has a major impact on plant selec-tion. Typically, the microclimate of the roof will be differentthan the microclimate in the same location at grade. Microcli-mates on a rooftop can dramatically affect plant health andappearance
28、and contribute to the failure of a green roof system.6.2.3.1 In particular, average high and low temperatures,extreme hot and cold temperatures, wind, and the amount anddistribution of rainfall throughout the year will determine whatspecies can survive in a specific area. Drought tolerance isimporta
29、nt because high levels of solar radiation and low mediamoisture are usually the norm, especially in shallow extensivesystems. Climatic conditions, especially the amount and dis-tribution of rainfall and temperature extremes, will eliminatethe use of certain species or will dictate the need for irrig
30、ation.6.2.3.2 Microclimate specific to the location must also beconsidered. Surrounding structures may shade a portion of theroof, thus altering the evapo-transpiration rate of the plants.Drying winds will be stronger the greater the elevation of thebuilding and a roof built with different levels ca
31、n causechanges in wind and sun patterns, leaving some areas hot anddry and other areas relatively cool and moist. Roof slope andorientation will influence the intensity of the sun, as south-facing slopes will be drier and warmer than north-facingslopes. Slope also affects water-holding capacity, as
32、slopedroofs will drain faster due to the laws of gravity. Plantsgrowing near the bottom of a slope will likely be greenerbecause of higher media moisture content relative to the top.This could be a factor in choosing plant species that will besuccessful. One must also consider the exhaust from air v
33、entsfor heating and air conditioning units as well as chemicalexhaust from industrial buildings.6.2.4 Plant CharacteristicsOther qualities usually consid-ered desirable for green roof plants include rate ofestablishment, longevity, and disease and pest resistance. Lowgrowing plants that spread rapid
34、ly to cover the media reducepotential erosion problems and inhibit weeds. Although, rapidcoverage is important, the lifespan of these plants should beconsidered, as many rapidly spreading plants may be short-lived. The ability of the plant species to be self-sustainingreduces the need for future rep
35、lanting and maintenance. Spe-cies that are long-lived, that reseed themselves, or spreadvegetatively should continue to provide full coverage as longas environmental conditions are favorable. In addition, aggres-sive plants may provide fast coverage, but one must be carefulnot to introduce invasive
36、species. For the most part, speciessuch as sedum will not become invasive in a temperate climatebecause it will not be able to compete with the local nativespecies. sedum does best on shallow, dry, media where mostother species cannot survive. Even if it does escape it is notlikely to become establi
37、shed.E2400/E2400M 06 (2015)126.2.4.1 It is nearly impossible to develop one plant list thatis suited for all areas of North America because of the vastarray of climates present. It is important to consult with aprofessional horticulturist, green roof consultant, or work withsimilar professionals tha
38、t are knowledgeable, experienced, andacquainted with green roof technology and plants.6.2.5 MediaMedium composition and depth both havemajor impacts on plant selection for green roof systems. Mostgreen roof medium is comprised of a balance of lightweight,well-drained materials as well as other compo
39、nents that havegood water and nutrient holding capacity. The ideal growingmedium has the ability to sustain plant life with little input orbreakdown over time. Expanded shale, clay, slate, lava, andpumice are porous and lightweight, but do not have muchwater holding capacity. This is particularly a
40、problem whenthese components are present at the upper surface of themedium layer, as they may not retain enough moisture to allowgood seed germination and establishment. Clay, sand, topsoil,and organic matter have good physical properties for growingplants, but are very heavy, especially at peak wat
41、er holdingcapacity.6.2.5.1 Medium depth also influences the plants that can begrown. Shallower medium depths will not only dry out faster,but they are more subject to fluctuations in temperature. Ashallow depth will likely make root systems more susceptibleto cold damage as roots are generally not a
42、s cold tolerant as thetops of plants. In colder climates, it is especially important toidentify the lowest temperature that the area experiences duringwinter. In addition, a deeper medium is necessary for woodyspecies, grasses, and many annual or perennial floweringplants. In some cases, plant growt
43、h is stunted in a shallowmedium due to restrictions in the root zone. However, a deepermedium also promotes growth of undesirable weeds.7. Installation7.1 MethodsSeveral methods exist for propagating andinstalling plant material in green roof systems. Vegetation maybe planted directly on the roof as
44、 plugs or seed, or precultivatedin the field at ground level as blankets or modular trays andthen transported onto the roof. Care must be taken to avoiddamaging the waterproofing membrane during installation.7.1.1 PrecultivationGerminating seed or rooting cuttingsis easily accomplished at ground lev
45、el where it is easier toprovide intense cultural practices and monitor results. Oncetransferred to the roof, precultivated vegetation can provideimmediate plant surface coverage.7.1.2 Direct Planting on a RoofGerminating seed orrooting cuttings directly on the roof eliminates the difficulty oftransp
46、orting and transplanting plants to the roof. However,environmental conditions are usually more extreme on a roof,which is not ideal for seed germination and plant establish-ment. Wind and direct sunlight can quickly dry out the topportion of the media and kill newly germinated seedlings. Drymedia al
47、so tends to be susceptible to wind erosion, but may beheld in place with netting to reinforce the media during plantestablishment. The use of a shade cloth may help to reduce thenegative effects of too much direct sun. An irrigation system isoften a necessity since seedlings are in danger of drying
48、outwhen rainfall is inadequate.7.1.2.1 When planting on the roof, container-grown plantsand plugs should be planted with their media surface level withthe surface of the roof media. If the media depth in thecontainer is deeper than the media layer on the roof, thenloosen the roots at the bottom of t
49、he root ball, remove excessmedia, and plant so the media levels are equal while the rootsare distributed laterally in all directions. It is best to avoidtrying to install plants with a deeper rootball than the media inwhich they are being planted. Tap rooted plants can be placedin mounded areas over structurally sound portions of the roof.7.1.2.2 PlugsPlugs already have an established root sys-tem and canopy and can continue growing after they aretransplanted. However, a large number of plants are required toachieve rapid cover because of the limited number of grow
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