Technical data

FITTING RESTRAINT
ELECTROFUSION COUPLINGS
Important Note:
All Electrofusion Couplings (regardless of manufacturer) require the pipe
to be restrained or sufficiently supported on each side of the pipe to; a)
restrict movement during the fusion and cooling process, and b) allevi-
ate or eliminate sources of stress and/or strain until both the fusion cycle
and the cooling cycle are completed.
Central Plastics recommends the use of some form of pipe restraint and/or
support for the primary purpose of controlling and eliminating any movement
of the fitting due to fusion pressures generated during the fusion process
and/or any external forces exerted on the pipe or the fitting. The basis for
using pipe restraint and/or support when joining two pieces of PE pipe with an
electrofusion coupling is to:
· Minimize potential short-stab, mis-stab or binding situations
· Ensure proper cold-zone contact with the prepared fusion area so that
sufficient interfacial pressure is built up.
· Eliminate unwanted loss of molten material from the fusion zone
(resulting loss of interfacial pressure can be a source of voiding or a
defective and unsatisfactory joint)
A properly prepared and assembled joint that is kept stationary and free
from stresses and strains during the fusion process and recommended
cooling time should have good joint integrity.
ELECTROFUSION SADDLES
Electrofusion Saddle fittings (Tapping Tees, Branch Saddles, Corp Saddles,
etc.) Installation of an electrofusion saddle requires the use of recom-
mended restraint systems for the purpose of;
· Holding the fitting in place during the fusion process
· Eliminating fitting movement due to material expansion
· Ensuring proper cold-zone contact with the prepared fusion area so
that sufficient interfacial pressure is built up.
Page 7