Hose re-ending: the fallacies behind ‘saving a bit of money’

13 May, 2020

Major risks

Trade associations, industry experts and health & safety bodies all agree that you simply don’t re-end hoses, the risks are too great; but the problem is that hose reending is still prevalent across much of the industry, with most people citing cost as the primary rationale.

“It is hard to convince people to hand over £200 for a new hose assembly, when they can get it re-ended for £50,” explains Pirtek’s Martyn Smart. “With cost being such a defining factor, it’s a real battle to convince them otherwise. I have seen 2000 psi water jet hoses repaired with tape and a jubilee clip! Counter this with the fact that we have purchased and delivered over 4000 BFPA books detailing the impact of fluid injection injuries and you can see that the message just isn’t getting through – especially when bottom lines are a defining factor in the decision.”

Andy Dickens, operations manager at Interpump Hydraulics (UK) Ltd, says: “Companies are put under huge commercial pressures, so much so that reending is seen as the commercially attractive alternative.” Backing up Martyn Smart, Dickens adds: “We have seen hoses repaired with a bundle of gaffer 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 fluid systems.”

“A hose made from a ‘pick-and-mix’ of third-party components simply cannot guarantee the tolerances necessary to ensure a quality hose assembly,” says 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 offer 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: “When you’re re-ending, you’re mixing and matching components. The products may appear to be the same, but there are differences. Our ferrules fit our hoses. If you use a third-party ferrule that is at the upper end of the tolerance band, it may not fit properly. I’m not saying that that ours are better – they just match our hoses. Anyone who has done a re-end has lost those tolerances. From where are they getting measurement information from? Whose data are they using?”

“There is an extreme amount of force trying to push these components apart,” Smart explains. “In its own right it is hard to put into words, but we have showcased it by setting up an assembly with a mis-manufactured hose, which is then put under 350 Bar of pressure. In this instance, it blew within 15 seconds and decimated a 3 kg melon we had put next to it. We had to use a 2000 frames per second camera to catch the failure and resulting impact. The hose end was measured at 600 ft. per second – similar to the muzzle velocity of a rifle.”

High cost of failure

The consensus from Smart, Dickens and the British Fluid Power Association (BFPA) is that hydraulic hoses need to be addressed with the same level of importance and attention to detail that you would give to any precision engineered component. In addition to the simple cost of replacement, users must consider the cost of failure, from both a financial and a cost perspective.