ASTM E2398/E2398M-15

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Designation: E2398/E2398M − 15
StandardTest Method for
Water Capture and Media Retention of Geocomposite Drain
1
Layers for Vegetative (Green) Roof Systems
ThisstandardisissuedunderthefixeddesignationE2398/E2398M;thenumberimmediatelyfollowingthedesignationindicatestheyear
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 3.1.1 For terms related to building construction, refer to
Terminology E631.
1.1 This test method covers the determination of the water
3.1.2 For terms related to sustainability relative to the
and media retention of synthetic drains layers used in vegeta-
performance of buildings, refer to Terminology E2114.
tive (green) roof systems.
3.2 Definitions of Terms Specific to This Standard:
1.2 This test method is applicable to geocomposite drain
3.2.1 captured water, n—the quantity of water that is re-
layers that retain water and media in cup-like receptacles on
tained in the drainage layer of a vegetative (green) roof system
their upper surface. Examples include shaped plastic mem-
after new water additions have ceased and that cannot escape
branes and closed-cell plastic foam boards.
the roof except through evaporation or plant transpiration.
1.3 This test method does not apply to products manufac-
3.2.2 coupon, n—a portion of a material or laboratory
tured from water-absorptive materials.
sample from which multiple specimens can be taken for
1.4 The values stated in either SI units or inch-pound units testing.
are to be regarded separately as standard. The values stated in
3.2.3 geocomposite drain layer, n—asyntheticsheet,mat,or
each system may not be exact equivalents; therefore, each
panel that is specifically designed to convey water horizontally
system shall be used independently of the other. Combining
toward the roof deck drains, gutters, or scuppers.
values from the two systems may result in non-conformance
3.2.3.1 Discussion—Geocomposite drainage layers include
with the standard.
absorptive drainage mats whose principle function is drainage,
1.5 This standard does not purport to address all of the
but which will also contribute to water retention (see retained
safety concerns, if any, associated with its use. It is the
water). Some geocomposite drainage layers may incorporate
responsibility of the user of this standard to establish appro-
receptacles on their upper surfaces that will capture water (see
priate safety and health practices and to determine the
captured water).
applicability of regulatory limitations prior to use.
3.2.4 retained water, n—the quantity of water that will be
retained for a prolonged period against gravity drainage in a
2. Referenced Documents
vegetative (green) roof system, or in one of its components,
2
2.1 ASTM Standards:
after new additions by rainfall or artificial irrigation have
E631 Terminology of Building Constructions
ceased.
E2114 Terminology for Sustainability Relative to the Perfor-
3.2.4.1 Discussion—Most of this water will not become
mance of Buildings
runoff but will be used to the plant-mediated processes of
E2397 Practice for Determination of Dead Loads and Live
evapo-transpiration.
Loads Associated with Vegetative (Green) Roof Systems
3 2
3.2.5 unit media retention volume, n—the volume, ft /ft
3 2
3. Terminology
[cm /cm ], that is required to fill a geocomposite drain layer to
the upper most asperities of the geocomposite drain layer.
3.1 Definitions:
3.2.6 unit water capture volume, n—the maximum volume
3 2 3 2
1
This test method is under the jurisdiction ofASTM Committee D08 on Roofing of water, ft /ft [cm /cm ], that a geocomposite drain layer can
and Waterproofing and is the direct responsibility of Subcommittee D08.24 on
hold at a specified inclination.
Sustainability.
3.2.6.1 Discussion—For vegetative (green) roofs systems
CurrenteditionapprovedJune1,2015.PublishedJuly2015.Originallyapproved
where the geocomposite drain layer will be filled with granular
in 2005. Last previous edition approved in 2011 as E2398 – 11. DOI: 10.1520/
E2398_E2398M-15.
drainage medium, the actual volume is assumed to be 25 % of
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the measured volume. This assumption will allow a direct
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
comparison between geocomposite sheet drains without, re-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. gard to the granular drainage media used. In computing the
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