Technical data

DESTRUCTIVE TESTING PROCEDURES
FOR ELECTROFUSION FITTING QUALIFICATION
The following test methods are useful as an evaluation of bonding strength and quality
between the pipe and fitting. Similar tests can be used as user qualification criteria. As
these methods are destructive, they are only useful in determining joint quality of a fusion
to verify that proper procedures were followed.
The following steps should be used only as a guide for cursory analysis of suspect fittings
or fusions, this guide should not be considered as proof of long-term performance of pipe
and fitting fusions.
General information regarding a suspect fusion or fitting failure that should be obtained
whenever possible:
1. Heating coil ohmic value
2. ID resistor ohmic value
3. Label fuse time information
4. Barcode label information
5. Fusion download (if possible)
6. Visible indications of malfunction or preparation errors
7. Field conditions/Site conditions (weather factors, generator size, etc.)
8. Fitting Lot number
9. Fitting production date
1. COUPLINGS:
After all relevant information is gathered, the fitting should be cut and subjected to joint
evaluation tests. Bend tests, peel tests, and crush tests are helpful in locating fusion weak-
nesses. It is desirable to obtain x-ray photographs of the fitting before dissection to locate
any possible contact points of the fusion coil.
To prepare a specimen for crush testing, it is necessary to cut the pipe and coupling longi-
tudinally in half as near to the centerline of the pipe and coupling as possible. It is desir-
able to leave at least 3"(75mm) to 5"(125mm) of pipe length at each end of the coupler.
Place a specimen half in a vise so that the outermost wire of the fusion zone is approxi-
mately 1 1/4" (32mm) from the vise jaws, ( Figure 1)
Close the vise jaws until the pipe walls meet, ( Figure 2) Repeat this process for each end
of both halves of the coupling.
Inspect the crushed specimens for separation of the pipe and fitting in the fusion zone.
Some minor separation (up to 15%) may be seen at the outermost region of the fusion
zone, this does not constitute failure. Ductile failure of the pipe, fitting, or PE insulation
around the wires is acceptable. There should be no separation at the fusion interface of
the pipe and fitting.
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