1、Designation: E 2400 06Standard Guide forSelection, Installation, and Maintenance of Plants for GreenRoof Systems1This standard is issued under the fixed designation E 2400; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 guide covers the considerations for the selection,installation, and maintenance of plants for green roof syste
3、ms.1.2 This guide is applicable to both extensive and intensivegreen roof systems.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated w
4、ith 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 Documents22.1 ASTM Standards:E 631 Terminology of Building ConstructionsE2114 Terminology for
5、 Sustainability Relative to the Per-formance of Buildings3. Terminology3.1 Definitions:3.1.1 For terms related to building construction, refer toTerminology E 631.3.1.2 For terms related to sustainability relative to theperformance of buildings, refer to Terminology E2114.4. Summary of Guide4.1 This
6、 guide covers the selection 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 and microcli-mate,4.1.4 Plant characteristics, including the rate of establish-ment, longevity, and disease
7、and pest resistance, and4.1.5 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 plantsf
8、or green roofs.5. Significance 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. Sel
9、ection of plant material 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
10、green rooftechnology and 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 requirement
11、s, and fire and life safety 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.6. Selection6.1 In general, green roofs can be categorized into twotypes, inte
12、nsive 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 limited to flat roofs. Use of large plantsrequires deeper media layers, po
13、ssibly 25 cm (10 in.) or more,which results in more weight and a need for an increased1This guide is under the jurisdiction of ASTM Committee E06 on Performanceof Buildings and is the direct responsibility of Subcommittee E06.71 on Sustain-ability.Current edition approved Jan. 15, 2006. Published Fe
14、bruary 2006.2For 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 the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Dr
15、ive, PO Box C700, West Conshohocken, PA 19428-2959, United States.structural load capacity of the building. Intensive green roofsusually have higher requirements for water, labor and otherresources than extensive green roofs.6.1.2 Extensive green roofsExtensive green roofs use anarrow range of speci
16、es 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 layer as shallowas 2.5 cm (1.0 in.) and, therefore, they can often be installed onbuilding
17、s 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:6.2.1 Design IntentThe design intent will impact plantselection. Aspects of design inten
18、t that may influence plantselection include: accessibility and use of the roof, stormwatermanagement objectives, xeriscaping objectives, and thermalinsulation objectives. Considerations for wildlife, such asestablishing connections with a wildlife corridor or providinghabitat for wildlife of local e
19、cosystems 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 atthe rooftop elevation.6.2.1.1 The design intent and available installation andmaintena
20、nce 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 blooming season work well together.However, flowering perennial plants may recede into th
21、eground 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 browned-out, dead looking plantsthat could be a fire hazard. Similarly, grasses are diff
22、icult 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 early in the year, but most cannotwithstand summer heat and drought conditions when gr
23、owingin 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 available, then succulent species such assedum, sempervivum, and delosperma are considered
24、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 because of the large percentage ofwater that is stored in their leaves. The aesthetic
25、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 differently depending on the local environmentalconditions.6.2.3 ClimateClimate has a major imp
26、act 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 and contribute to the failure of a green roof system.6.2.3.1 In particular, average hi
27、gh 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 isimportant because high levels of solar radiation and low mediamoisture are usually the norm,
28、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 irrigation.6.2.3.2 Microclimate specific to the location must also beconsidered. Surroundin
29、g 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 can causechanges in wind and sun patterns, leaving some areas hot anddry and other areas
30、 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 slopedroofs will drain faster due to the laws of gravity. Plantsgrowing near the botto
31、m 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 ventsfor heating and air conditioning units as well as chemicalexhaust from industrial
32、buildings.6.2.4 Plant CharacteristicsOther qualities usually consid-ered desirable for green roof plants include rate of establish-ment, longevity, and disease and pest resistance. Low growingplants that spread rapidly to cover the media reduce potentialerosion problems and inhibit weeds. Although,
33、rapid coverageis important, the lifespan of these plants should be considered,as many rapidly spreading plants may be short-lived. Theability of the plant species to be self-sustaining reduces theneed for future replanting and maintenance. Species that arelong-lived, that reseed themselves, or sprea
34、d vegetativelyshould continue to provide full coverage as long as environ-mental conditions are favorable. In addition, aggressive plantsmay provide fast coverage, but one must be careful not tointroduce invasive species. For the most part, species such assedum will not become invasive in a temperat
35、e climate becauseit will not be able to compete with the local native species.sedum does best on shallow, dry, media where most otherspecies cannot survive. Even if it does escape it is not likely tobecome established.6.2.4.1 It is nearly impossible to develop one plant list thatis suited for all ar
36、eas 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 that are knowledgeable, experienced, andacquainted with green roof technology and plants.6.2.5 MediaMedium composi
37、tion and depth both havemajor impacts on plant selection for green roof systems. MostE2400062green roof medium is comprised of a balance of lightweight,well-drained materials as well as other components that havegood water and nutrient holding capacity. The ideal growingmedium has the ability to sus
38、tain 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 problem whenthese components are present at the upper surface of themedium layer, as they may not retai
39、n 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 water holdingcapacity.6.2.5.1 Medium depth also influences the plants that can begrown. Shallower medium d
40、epths 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 as cold tolerant as thetops of plants. In colder climates, it is especially important toidentify the low
41、est 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 growth is stunted in a shallowmedium due to restrictions in the root zone. However, a deepermedium also prom
42、otes 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 plugs or seed, or precultivatedin the field at ground level as blankets or modular trays andthen trans
43、ported 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 level where it is easier toprovide intense cultural practices and monitor results. Oncetransferred to the
44、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 oftransporting and transplanting plants to the roof. However,environmental conditions are usually more extreme
45、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 also tends to be susceptible to wind erosion, but may beheld in place with netting to reinforce the media
46、 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 outwhen rainfall is inadequate.7.1.2.1 When planting on the roof, container-grown plantsand plugs shoul
47、d 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 the root ball, remove excessmedia, and plant so the media levels are equal while the rootsare distribute
48、d 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 an
49、d 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 growingpoints. Time to achieve complete coverage depends on the size,initial spacing, and growth rate of the plugs. Also, plug plantswill take time to become anchored in the media. During thisestablishment phase, birds sometimes remove plugs as theysearch for food.7.1.2.3 CuttingsCuttings of sedum root quickly, thus pro-viding numerous growing points, but the cuttings are subject todrying out before rooting takes
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