TM 5-814-7
tiles are used to protect synthetic membranes, it is
the liner field seams, installation should be avoided
important that they, like the synthetic membranes, be
during these periods.
tested for compatibility with hazardous waste. Only very
(f) During placement of the liner and before
limited compatibility testing data are currently available
wastes are placed, tests of the seam strength and
on geotextile fabrics; however, many such fabrics are
bonding effectiveness should be conducted, using visual
made of polypropylene or polyester materials and may
inspection, air lance, ultrasonic and vacuum techniques.
have compatibility characteristics similar to those
In addition, random samples of seams should be cut
exhibited by liners of the same materials.
from the liner and subjected to on-site and laboratory
(d) Fabricated liner panels must be constructed
testing. A replacement patch will be required. Liner
so as to minimize the number of field seams and to
placement, seaming and testing are covered in detail in a
enable placement of field seams at locations where least
number of publications, including EPA SW-870.
severe field conditions occur (e.g., at ridge areas for leak
detection and leachate collection systems; see figure 6-
6-4. Leak detection and leachate collection and
2).
Project specifications should delineate liner
removal systems
placement procedures for field panel, shop and field
seaming procedures, and protective cover requirements.
a. Introduction. The leak detection system,
Additional specifications include work responsibilities and
located between the two liners underlying the hazardous
quality assurance/certification requirements of the
waste facility, enables the owner or operator to
engineer, contractor, manufacturer, fabricator and
determine whether any liquid has entered the space
installer. As part of the project details for the base liner
between the liners. Should the presence of liquid in this
system, a panel installation plan must be prepared with
space lead to the discovery that the liner has leaked, the
the grading plan.
owner/operator will implement procedures to ensure
(e) Aside from puncture and tearing of the liner,
protection of ground water. Leachate collection and
the most common cause of liner failure is inadequate
removal systems are required immediately above the
seaming. The joining of liner panels should therefore be
liners in new hazardous waste landfills and waste piles.
conducted under controlled conditions, in strict
Such systems must be capable of maintaining a leachate
accordance with the manufacturer's recommendations
depth of 1 foot or less above the liner and of withstanding
and with installer's trained personnel. The installer
clogging, chemical attack, and forces exerted by wastes,
should pay strict attention to the overlap specified by the
equipment or soil cover.
General procedures for
manufacturer, which may range from a minimum of 2
designing leachate collection and removal systems are
upwards to 12 inches. In addition, field seams shall
provided in SW-870, paragraph 5-6 and appendix V.
always be lapped over the downslope liner to prevent
b. Components of the leak detection system.
piping if a seam fails. Each type of membrane liner also
The leak detection system can be a drain system or
requires specific seaming provisions to achieve an
instrumentation that will permit detection of any liquid
effective bond, as summarized in table 6-3. Since
that migrates into the space between the liners.
adverse weather conditions (e.g., extreme heat or cold,
Although
precipitation, and winds) can affect adequate bonding of
Table 6-3. Seaming Provisions for Synthetic Liners'
Type of
Place
Bodied
Solvent
Contact
Vulcanizing
Heat
compound a
used
Solvents solvents
cements
cements
adhesives
Tapes
sealed
Dielectric
Butyl rubber
XL
Factory
...
...
...
X
X
...
...
...
Field
...
...
...
X
X
X
...
...
Chlorinated Polyethylene
TP
Factory
X
X
X
X
...
...
X
X
Field
X
X
X
X
...
X
X
...
Chlorosulfonated polyethylene
TP
Factory
X
X
X
X
...
X
X
X
Field
X
X
X
X
...
...
X
...
Elasticized polyolefin
TP
Factory
...
...
...
X
...
...
X
...
Field
..
...
...
X
...
...
X
Ethylene propylene rubber
XL
Factory
...
...
...
X
X
...
...
...
Field
...
...
...
X
X
X
...
...
Low-density polyethylene
TP
Factory
...
X
...
...
X
...
Field
...
...
...
X
...
X
X
...
Neoprene (polychloroprene)
XL
Factory
...
...
X
...
..
...
...
Field
...
...
...
X
...
...
...
...
Poly(vinyl chloride)
TP
Factory
X
X
X
X
...
...
X
X
Field
X
X
X
X
...
X
X
...
a XL = Crosslinked or vulcanized; TP = Thermoplastic
Adapted from Liner Materials Exposed to Municipal Solid Waste Leachate (Draft), EPA Contract No. 68-03-2134, February 1982
6-11
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