Page 26 - Industrial Technology March 2020 issue

MACHINE BUILDING
Money saving fallacy of hose
Coupling which has "blown off" and disconnected from the hose costs often equating to less exacting workmanship, standard is intent to outlaw the re-ending of flexible
“ sorts of decisions and to promote best practice – that risks are too great; but the problem is that hose re-ending
A HOSE MADE FROM A ‘PICK-
AND-MIX’ OF THIRD-PARTY
COMPONENTS SIMPLY CANNOT
GUARANTEE THE TOLERANCES
NECESSARY TO ENSURE A
QUALITY HOSE ASSEMBLY
Coupling has "blown off" the hose
26
HYDRAULICS & PNEUMATICS
HOSE RE-ENDING IS A VERY RISKY BUSINESS. WHEN YOU PUT A
COST ON DOWNTIME, MAINTENANCE AND SAFETY, HOW MUCH
MONEY DO YOU REALLY SAVE? WE ASKED THE BFPA
uality is probably one of the most important requirements for systems and their components’ states:
metrics in the industrial world. When people “Hose assemblies shall be constructed from hoses that
pay for a product or service, they expect to get have not been previously used in operation as part of
Qthe best possible solution to their needs – not another hose assembly and that fulfil all performance and
just in terms of cost, but also fitness for purpose, marking requirements given in appropriate standards.” It
capabilities and, of course, safety. is worth noting at this stage that in CEN and ISO parlance,
Like so many things in life however, the expression the word ‘shall’ is taken as ‘must comply’ – it is non-
“you only get what you pay for” rings true; with lower negotiable. It is therefore quite clear that the international
increased wear, reduced operational life, or, indeed, all hydraulic hoses. The scheme also adheres to BS EN ISO
three. If you have money to burn, this is your choice, but 4414, which mirrors this advice for pneumatic hoses.
when safety is a major part of the equation, you must
consider if your short-term cost savings are really the most Prevalent practice
prudent – and ethical or even legal – course of action. Trade associations, industry experts and health and safety
It is for this very reason – to help people make these bodies all agree that you simply don’t re-end hoses, the
is still prevalent across much of the industry, with most
standards exist to cover almost all facets of the industrial
universe. The problem is, if these standards are not people citing cost as the primary rationale.
“It is hard to convince people to hand over £200 for a
enforceable under law, you must rely on people applying
them from a best-practice standpoint. new hose assembly, when they can get it re-ended for
It is in these situations that trade bodies play a vital £50,” explains Pirtek’s Martyn Smart. “With cost being
role, ensuring and supporting their members to adhere to such a defining factor, it’s a real battle to convince them
good engineering practice – not only to bolster quality and otherwise. I have seen 2,000 psi water jet hoses repaired
the reputation of the industry, but also to ensure that any with tape and a jubilee clip. Counter this with the fact that
safety concerns are readily explained, understood and we have purchased and delivered over 4,000 BFPA books
adhered to. A case in point would be the British Fluid detailing the impact of fluid injection injuries and you can
Power Distributor’s Association’s (BFPDA) Approved Hose see that the message just isn’t getting through – especially
Assemblies Scheme. Since its introduction in 1995, the when bottom lines are a defining factor in the decision.”
scheme’s ‘Q-Approved’ logo has become a recognised Andy Dickens, operations manager at Interpump
symbol of quality, integrity and safety in the fluid power Hydraulics (UK), adds: “Companies are put under huge
industry. commercial pressures, so much so that re-ending is seen
as the commercially attractive alternative.” Backing up
Assembly, storage and supply Martyn Smart, he adds: “We have seen hoses repaired
Comprising an accreditation process and resulting with a bundle of gaffer tape. People don’t seem to
customer assurances, the scheme – developed by a panel appreciate just how much pressure these systems are
of industry experts, including members of the BFPDA and under. There is a massive amount of naivety, with people
BFPA – sets an industry-wide standard for the assembly, being blissfully unaware of the dangers of high-pressure
storage and supply of hydraulic hoses. As well as fluid systems.”
delivering best-practice guidelines, it also counters and Smart comments: “A hose made from a ‘pick-and-mix’
addresses the health and safety issues associated with the of third-party components simply cannot guarantee the
risky practice of re-ending hoses. The core message tolerances necessary to ensure a quality hose assembly.
behind these guidelines is that best practice recommends, Add to this the fact that you didn’t know the operational
very plainly, that you don’t re-end hoses. history of the hose being re-ended and you have a
At the core of the scheme are the guidelines laid down potential recipe for disaster. No one will offer a guarantee
by international standards. They state that all hose or warranty on a re-end.
assembly practices must conform to the international “We use matched components, all of which are tested
recommendations within BS EN ISO 4413 and BS EN ISO by their manufacturers to meet tolerances, which for a
4414, and meet the guidelines. Both are Harmonised swaged ferrule are +0mm/–0.2 mm.”
Standards of the Machinery Directive, which is written Dickens adds to this: “When you’re re-ending, you’re
into legislation. mixing and matching components. The products may
Clause 5.4.6.5.1 a) – within ‘BS EN ISO 4413 appear to be the same, but there are differences. Our
Hydraulic Fluid Power – General rules and safety ferrules fit our hoses. If you use a third-party ferrule that’s
INDUSTRIAL TECHNOLOGY • March 2020