Underground Construction - August 2017 - 45

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Thermoplastic jetter hose, regardless of the size,
is constructed using three components. The first
is the inner liner that is colored for manufacturer
identification, and is also very smooth, resulting
in minimal friction or pressure loss. The second
component is the white nylon wrap over the inner liner
which gives the hose its strength. The third and final
component is the thermoplastic cover which gives the
hose durability when dragged over sharp edges. The
outside color of the jetter hose will also indicate the
pressure rating of the hose.
Proper use and maintenance techniques:
1. Use the right tools! The industry has a color
code on the inside liner of the hose to identify the
manufacturer. Each manufacturer has its own
specifications, and the inside and outside diameter
of the hose will change from manufacturer to
manufacturer. Using the wrong manufacturer's
hose repair fitting and swaging equipment is
extremely dangerous. When the fitting is not
swaged to the hose properly, the fitting can blow
off and the jetter hose will flail around violently,
endangering employees and damaging equipment.
2. Never crimp fittings to thermoplastic hose. The
use of crimping machines to attach the fitting to
the hose instead of a swaging machine can
endanger employees. The difference between
swaging and crimping is that swaging pushes the
fitting through a set of dies, and crimping comes
in from the side and squeezes the fitting, leaving a
flare at the back of the fitting that will get caught on
obstacles in the pipe. Properly swaged hoses can
also be repaired in the field, which is a benefit. You
can also install splicer repair fittings with the same
swage machine.
3. Make sure that the hose is installed all the way in
the repair fitting. Holding the repair fitting next to
the hose and marking the hose will help when you
install the fitting to make sure it is inserted properly.

You will need to match the inside color of the hose,
the color on the fitting and the color on swage dies
for proper installation.
4. Take care of the equipment when in use. The use
of a tiger tail hose guide (where the hose enters
the pipe) and a top manhole roller (where the hose
comes in contact with other sharp edges like the
manhole ring), will reduce the wear on the jetter
hose. A practice commonly used to get a hose or
nozzle unstuck from a line is to attach the hose to
the truck and drive away, stretching the hose and
severely damaging the hose. This is not always
visible until you start using the jetter the next time
out. Large bubbles will appear in the outer cover of
the hose, which is caused by the separation of the
layers from stretching the hose.
5. Know when a jetter hose should be taken out of
service for repair or replacement. The first telltale sign is when the outer cover is torn back far
enough that you can see the white nylon wrap.
Also, the condition of the hose just behind any
fitting needs to be intact. If it's not, the hose should
be repaired or replaced.
The use of splicers or menders is a common practice
in today's jetting industry. The same swagger can be
used to install the splicer. One thing to keep in mind is
that for every fitting you install in your reel of hose, you
will have additional pressure loss due to the inside
diameter of that fitting being smaller than the inside
diameter of the hose.

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Underground Construction - August 2017

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