State of Technology Report for Force Main Rehabilitation, Final ...

3.3.3 Joint Repair
3.3.3.1 Internal Joint Repair. The basic principal of most internal joint repair systems is a rubber
sleeve that bridges over the leaking joint, which is then compressed and sealed against the adjacent pipe
wall by expanding two stainless steel compression rings. For wastewater or water applications, the sleeve
is made of ethylene propylene diene M-class (EPDM) rubber.
These sleeves can also be used to seal a radial crack in a pipe wall or transition between two different pipe
materials. The AMEX 10 ® seal incorporates a medium density polyethylene (MDPE) backing band
behind the rubber seal to accommodate external hydrostatic pressure (Figure 3-5). The AMEX 10 Vario
can also be used to seal a longitudinal crack with its ability to span an extended longitudinal length by
stacking the sleeves. The sleeves have enough flexibility to allow some additional joint rotation without
leakage after installation. Naturally, for a good leak tight seal, the inner surface must be free of any
corrosion by-product and smooth. They have also been used to seal a steel slipliner, grouted inside a
PCCP pipe, to the PCCP pipe wall. Specially designed transition sleeves are required to accommodate
the large difference in internal diameter associated with this application.
As shown in Table 3-2, there are three primary manufacturers of internal joint repair sleeves.
Figure 3-5. AMEX 10 Mono Seal
Table 3-2. Summary of Internal Joint Vendors
Supplier Product Name Diameter Range Max. Internal Pressure
Miller Pipeline Corp. Weko-Seal ®
16 to 216 inches 300 psi
AMEX, Gmbh AMEX 10
(Germany)
® Mono and 20 to 236 inches 290 psi
Vario
NPC, Inc. NPC Internal Joint Seal 18 to 122 inches 30 psi
3.3.3.2 External Joint Repair. Most of the external joint seals on the market are designed to seal a
gravity pipe joint, with minimal internal pressure. There have been mechanical devices designed in the
past that will seal a leaking PVC bell joint with a displaced gasket, or one for a lead caulked CI joint,
which encapsulates the joint in a bitumastic material. However, the market for these specialty products is
very limited. The most common repair technique is to remove the offending joint rather than trying to
patch a repair.
16