the international standard is intent to rule
out the re-ending of exible hydraulic
hoses. The scheme also adheres to BS EN
ISO 4414, which mirrors this advice for
pneumatic hoses.
DON’T DO IT
Trade associations, industry experts and
health and safety bodies all agree that you
simply don’t re-end hoses, because the
risks are too great. The problem is that
hose re-ending remains prevalent across
much of the industry, with most people
citing cost as the primary rationale.
Martyn Smart, national training and
health and safety manager at hose supplier
Pirtek UK, says: “It is hard to convince
people to hand over £200 for a new hose
assembly, when they can get it re-ended
for £50. With cost being such a de ning
factor, it’s a real battle to convince them
otherwise. I have seen 2,000PSI 138Bar
water jet hoses repaired with tape and a
jubilee clip. The message just isn’t getting
through.”
Andy Dickens, operations manager at
equipment supplier Interpump Hydraulics
(UK), adds: “Companies are put under huge
commercial pressure, so much so that
re-ending is seen as the commerciallyattractive
alternative. We have seen hoses
repaired with a bundle of ga er tape.
People don’t seem to appreciate just how
much pressure these systems are under.
There is a massive amount of naivety, with
people being blissfully unaware of the
dangers of high-pressure uid systems.”
A hose made from a “pick-and-mix of
PNEUMATICS & HYDRAULICS – HOSE SAFETY
third-party components” simply cannot
guarantee the tolerances necessary to
ensure a quality hose assembly, continues
Smart: “Add to this the fact that you didn’t
know the operational history of the hose
being re-ended and you have a potential
recipe for disaster. No one will o er a
guarantee or warranty on a re-end. We
use matched components, all of which
are tested by their manufacturers to meet
tolerances, which for a swaged ferrule are
+0 mm/-0.2 mm.”
Dickens adds to this: “When you’re
re-ending, you’re mixing and matching
components. The products may appear
to be the same, but there are di erences.
Our ferrules t our hoses. If you use a thirdparty
ferrule that’s at the upper end of
the tolerance band, it may not t properly.
I’m not saying that ours are better – they
just match our hoses. Anyone who’s done
a re-end has lost those tolerances. From
where are they getting measurement
information? Whose data are they using?”
EXTREME FORCE
Smart concludes: “There is an extreme
amount of force trying to push these
components apart. We set up an assembly
with a mis-manufactured hose, which is
then put under 350Bar of pressure. In this
instance, it blew within 15 seconds and
decimated a melon we had put next to it.
We had to use a 2,000 frame per second
camera to catch the failure and resulting
impact. The hose end was measured to be
moving at 600 fps – similar to the muzzle
velocity of a ri e.”
The consensus from Smart, Dickens
and the BFPA is that hydraulic hoses need
to be addressed with the same level of
importance and attention to detail that
would be given to any precision engineered
component. In addition to the simple cost of
replacement, users must consider the cost
of failure, from both a nancial and a cost
perspective.
Smart says: “The more we educate
people, the better and safer the industry
will become. Hoses will get damaged
in their everyday use. We need users to
consider how and where they are used and
then develop a proactive inspection and
maintenance plan. This way, early failures
can be more easily predicted and even have
their causes designed out. Some protective
systems are highly e ective and are more
palatable in cost terms versus replacement.”
Dickens concludes: “None of us seem
to know who is doing this re-ending. But
it is still going on. We will replace entire
assemblies that have failed testing rather
than individual elements, even though it
costs us more. This is how committed we
are to the safety of users, as should be all of
industry.”
Autumn 2020 www.operationsengineer.org.uk 25
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Re-ending hoses risks introducing a
weak point into the system
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