ASTM E2400-06
(Guide)Standard Guide for Selection, Installation, and Maintenance of Plants for Green Roof Systems
Standard Guide for Selection, Installation, and Maintenance of Plants for Green Roof Systems
SIGNIFICANCE AND USE
This guide addresses performance characteristics for green roof systems with respect to the planting. A rooftop is an extreme environment with strong and variable wind patterns and little or no protection from the sun’s intense heat and ultraviolet radiation. Selection of plant material can be crucial for success of the green roof system.
5.1.1 This guide provides general guidance only. It is important to consult with a professional horticulturist, green roof consultant, or work with similar professionals that are knowledgeable, experienced, and acquainted with green roof technology and plants.
Determining these performance characteristics of green roof systems provides information to facilitate the assessment of engineering aspects of the facility. Such aspects may include structural design requirements, mechanical engineering and thermal design requirements, and fire and life safety requirements.
Determining these performance characteristics of green roof systems provides information to facilitate assessment of the performance of one green roof system relative to another.
SCOPE
1.1 This guide covers the considerations for the selection, installation, and maintenance of plants for green roof systems.
1.2 This guide is applicable to both extensive and intensive green roof systems.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.
General Information
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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: E2400 − 06
StandardGuide for
Selection, Installation, and Maintenance of Plants for Green
Roof Systems
This standard is issued under the fixed designation E2400; the number immediately following the designation indicates the year of
original adoption or, in 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. Scope 4.1.3 Climate; including both macroclimate and
microclimate,
1.1 This guide covers the considerations for the selection,
4.1.4 Plant characteristics, including the rate of
installation, and maintenance of plants for green roof systems.
establishment, longevity, and disease and pest resistance, and
1.2 This guide is applicable to both extensive and intensive
4.1.5 Media composition and depth.
green roof systems.
4.2 This guide covers the installation of plants for green
1.3 The values stated in SI units are to be regarded as the
roofs. Installation methods include:
standard. The values given in parentheses are for information
4.2.1 Precultivation, and
only.
4.2.2 Direct planting on roof (seeds, root cuttings, and
1.4 This standard does not purport to address all of the plugs).
safety concerns, if any, associated with its use. It is the
4.3 Guidance is also provided for the maintenance of plants
responsibility of the user of this standard to establish appro-
for green roofs.
priate safety and health practices and to determine the
applicability of regulatory limitations prior to use.
5. Significance and Use
5.1 This guide addresses performance characteristics for
2. Referenced Documents
green roof systems with respect to the planting.Arooftop is an
2.1 ASTM Standards:
extreme environment with strong and variable wind patterns
E631 Terminology of Building Constructions
and little or no protection from the sun’s intense heat and
E2114 Terminology for Sustainability Relative to the Perfor-
ultraviolet radiation. Selection of plant material can be crucial
mance of Buildings
for success of the green roof system.
5.1.1 This guide provides general guidance only. It is
3. Terminology
important to consult with a professional horticulturist, green
3.1 Definitions:
roof consultant, or work with similar professionals that are
3.1.1 For terms related to building construction, refer to
knowledgeable, experienced, and acquainted with green roof
Terminology E631.
technology and plants.
3.1.2 For terms related to sustainability relative to the
5.2 Determining these performance characteristics of green
performance of buildings, refer to Terminology E2114.
roof systems provides information to facilitate the assessment
of engineering aspects of the facility. Such aspects may include
4. Summary of Guide
structural design requirements, mechanical engineering and
4.1 This guide covers the selection criteria for plants to be
thermal design requirements, and fire and life safety require-
used on green roofs. Primary considerations are as follows:
ments.
4.1.1 Design intent,
5.3 Determining these performance characteristics of green
4.1.2 Aesthetics,
roof systems provides information to facilitate assessment of
the performance of one green roof system relative to another.
This guide is under the jurisdiction of ASTM Committee D08 on Roofing and
Waterproofingand is the direct responsibility of Subcommittee D08.24 on Sustain-
6. Selection
ability.
6.1 In general, green roofs can be categorized into two
Current edition approved Jan. 15, 2006. Published February 2006. DOI:
10.1520/E2400-06.
types, intensive or extensive, depending on the plant material
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and planned usage for the roof area.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6.1.1 Intensive green roofs—Intensive green roofs utilize a
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. wide variety of plant species that may include trees and shrubs
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2400 − 06
and are generally limited to flat roofs. Use of large plants in any landscape. Similarly, identical plant palettes will look
requires deeper media layers, possibly 25 cm (10 in.) or more, and behave differently depending on the local environmental
which results in more weight and a need for an increased conditions.
structural load capacity of the building. Intensive green roofs
6.2.3 Climate—Climate has a major impact on plant selec-
usually have higher requirements for water, labor and other
tion. Typically, the microclimate of the roof will be different
resources than extensive green roofs.
than the microclimate in the same location at grade. Microcli-
6.1.2 Extensive green roofs—Extensive green roofs use a mates on a rooftop can dramatically affect plant health and
narrow range of species limited to herbs, grasses, mosses, and appearance and contribute to the failure of a green roof system.
drought tolerant succulents such as sedum, a succulent plant
6.2.3.1 In particular, average high and low temperatures,
known for its tolerance for extreme conditions. These types of
extreme hot and cold temperatures, wind, and the amount and
plants can potentially be sustained in a media layer as shallow
distribution of rainfall throughout the year will determine what
as 2.5 cm (1.0 in.) and, therefore, they can often be installed on
species can survive in a specific area. Drought tolerance is
buildings without the cost of major structural alterations.
important because high levels of solar radiation and low media
Extensive green roofs generally require less maintenance and
moisture are usually the norm, especially in shallow extensive
are generally less expensive to install than intensive green
systems. Climatic conditions, especially the amount and dis-
roofs.
tribution of rainfall and temperature extremes, will eliminate
the use of certain species or will dictate the need for irrigation.
6.2 Criteria for Selecting Species:
6.2.3.2 Microclimate specific to the location must also be
6.2.1 Design Intent—The design intent will impact plant
considered. Surrounding structures may shade a portion of the
selection. Aspects of design intent that may influence plant
roof, thus altering the evapo-transpiration rate of the plants.
selection include: accessibility and use of the roof, stormwater
Drying winds will be stronger the greater the elevation of the
management objectives, xeriscaping objectives, and thermal
building and a roof built with different levels can cause
insulation objectives. Considerations for wildlife, such as
changes in wind and sun patterns, leaving some areas hot and
establishing connections with a wildlife corridor or providing
dry and other areas relatively cool and moist. Roof slope and
habitat for wildlife of local ecosystems may also impact the
orientation will influence the intensity of the sun, as south-
plant selection. Considerations for wildlife should be coordi-
facing slopes will be drier and warmer than north-facing
nated with a knowledgeable consultant and the regional Ex-
slopes. Slope also affects water-holding capacity, as sloped
tension Service to verify anticipated wildlife in that climate at
roofs will drain faster due to the laws of gravity. Plants
the rooftop elevation.
growing near the bottom of a slope will likely be greener
6.2.1.1 The design intent and available installation and
because of higher media moisture content relative to the top.
maintenance budgets are key factors is determining media
This could be a factor in choosing plant species that will be
depths and plant selection.
successful. One must also consider the exhaust from air vents
6.2.2 Aesthetics—Aesthetics often drive green roof design
for heating and air conditioning units as well as chemical
and plant selection. Combinations of evergreens and flowering
exhaust from industrial buildings.
plants with a long blooming season work well together.
6.2.4 Plant Characteristics—Other qualities usually consid-
However, flowering perennial plants may recede into the
ered desirable for green roof plants include rate of
ground during winter or long, hot, dry periods in the summer.
establishment, longevity, and disease and pest resistance. Low
Iftheysurviveroofenvironmentalconditions,theywillusually
growing plants that spread rapidly to cover the media reduce
regenerate themselves from the root system, but periods of
potential erosion problems and inhibit weeds. Although, rapid
drought can leave a mass of browned-out, dead looking plants
coverage is important, the lifespan of these plants should be
that could be a fire hazard. Similarly, grasses are difficult to
considered, as many rapidly spreading plants may be short-
keep green throughout the summer. One can allow grasses to
lived. The ability of the plant species to be self-sustaining
grow until June and then cut them back to approximately three
reduces the need for future replanting and maintenance. Spe-
inches in height, but this practice requires extensive labor.
cies that are long-lived, that reseed themselves, or spread
Plants may look fantastic early in the year, but most cannot
vegetatively should continue to provide full coverage as long
withstand summer heat and drought conditions when growing
as environmental conditions are favorable. In addition, aggres-
in shallow extensive roof media depths. In order to grow most
sive plants may provide fast coverage, but one must be careful
annuals, perennial flowering herbaceous plants, and grasses,
not to introduce invasive species. For the most part, species
either irrigation must be present or the media must be deeper.
such as sedum will not become invasive in a temperate climate
If irrigation is not available, then succulent species such as
because it will not be able to compete with the local native
sedum, sempervivum, and delosperma are considered good
species. sedum does best on shallow, dry, media where most
choices because of their ability to withstand extended drought
other species cannot survive. Even if it does escape it is not
and other adverse environmental conditions often present on a
likely to become established.
rooftop. Unlike most perennials and grasses, succulents are not
considered fire hazards because of th
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