ASTM D7408-12(2020)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:D7408 −12 (Reapproved 2020)
Standard Specification for
Non-Reinforced PVC (Polyvinyl Chloride) Geomembrane
Seams
This standard is issued under the fixed designation D7408; 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 D882 Test Method for Tensile Properties of Thin Plastic
Sheeting
1.1 This specification covers the minimum values for seams
D4439 Terminology for Geosynthetics
fabricated into unreinforced PVC geomembranes in factory
D7176 Specification for Non-Reinforced Polyvinyl Chloride
and field applications.
(PVC) Geomembranes Used in Buried Applications
1.2 This specification covers PVC geomembranes in thick-
3. Terminology
ness of 0.25 through 1.52 mm (0.010 through 0.060 in.).
3.1 Definitions:
1.3 In addition to structural characteristics, the specifier
3.1.1 adhesive or bodied solvent, n—these seams are typi-
shall evaluate other characteristics beyond the scope of this
cally produced by applying an adhesive to both sides of the
specification that affect the final choice of construction. These
sheet to be bonded and then pressure is applied to the top sheet
include, but are not limited to, functional, legal, insurance, and
with the bottom sheet supported by a flat, firm surface.
economic considerations.
3.1.2 chemical fusion seams, n—use of a chemical agent to
1.4 This specification is not intended to exclude products or
dissolve the surface of the geomembrane for bonding.
systems not covered by the referenced documents.
3.1.3 hot air or knife, n—this technique melts the two
1.5 The values stated in inch-pound units are to be regarded
geomembrane surfaces to be seamed by running a hot metal
as standard. The values given in parentheses are mathematical
wedge or hot air between them. Pressure is applied to the top
conversions to SI units that are provided for information only
or bottom geomembrane, or both, to form a continuous bond.
and are not considered standard.
These seams are usually produced with a combination of a
1.6 This standard does not purport to address all of the
hand-held heat gun or hand-held hot wedge along with a hand
safety concerns, if any, associated with its use. It is the
roller.
responsibility of the user of this standard to establish appro-
3.1.4 thermal fusion, n—alsoknownashotairorhotwedge,
priate safety, health, and environmental practices and deter-
this technique introduces high-temperature air or gas or a hot
mine the applicability of regulatory limitations prior to use.
wedge between two geomembrane surfaces to facilitate melt-
1.7 This international standard was developed in accor-
ing. Pressure is applied to the top and/or bottom sheets of the
dance with internationally recognized principles on standard-
geomembrane, forcing together the two surfaces to form a
ization established in the Decision on Principles for the
continuous bond.
Development of International Standards, Guides and Recom-
3.1.4.1 Discussion—Some seams of this kind are made with
mendations issued by the World Trade Organization Technical
dual bond tracks separated by a non-bonded gap. These seams
Barriers to Trade (TBT) Committee.
are referred to as dual-track seams or double-track seams.
2. Referenced Documents
3.2 For definitions of other terms, see Terminology D4439.
2.1 ASTM Standards:
4. Classification
D638 Test Method for Tensile Properties of Plastics
4.1 Types of seams covered in this specification:
This specification is under the jurisdiction of ASTM Committee D35 on
4.1.1 Chemical fusion,
Geosynthetics and is the direct responsibility of Subcommittee D35.06 on Geosyn-
4.1.2 Adhesive or bodied solvent,
thetic Specifications.
4.1.3 Dielectric, and
Current edition approved Feb. 15, 2020. Published February 2020. Originally
approved in 2008. Last previous edition approved in 2012 as D7408 – 12. DOI: 4.1.4 Thermal fusion.
10.1520/D7408-12R20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 5. Significance and Use
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1 Significance—The increased use of geomembranes as
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. barrier materials to restrict fluid migration from one location to
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D7408−12 (2020)
NOTE 1—Larger samples sizes may be required on site-specific or
another in various applications, and the various types of
project-specific or requirements for the purpose of archiving or third party
seaming methods used in joining geomembrane sheets, has
testing.
created a need to standardize minimum seam strength require-
ments. 7.2 Once the sample is received at the testing facility, the
sample shall be acclimated at a standard laboratory
5.2 Use—Standard seam specification provides information
environment, Humidity between 50 and 70 % and a tempera-
as to the status of the seam. Data obtained by this standard can
ture of 21.6 6 2 °C (70.6 6 4 °F) for a minimum of 40 h for
beusedinCQC/CQAdocuments.Thistestmethodisusefulfor
all types of seams, except thermo and dielectric type seams, for
specification testing and for comparative purposes but does not
these types of seams a minimum of4hatthe standard
necessarily measure the ultimate strength that the seam may
laboratory environment is required.
acquire.
NOTE 2—If samples are sent to the lab and testing is preformed prior to
6. Apparatus
the required lab acclimating pe
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