HP Hose Failure

[The Chairman]

As I said earlier "Perception is for the misguided, the foolish and the idiot."

You were wrong the first time you posted this. Sure, you want to sound superior, but the only one you're fooling is yourself.

Fit and comfort are all about the diver's perception. It's the most important aspect in chosing my diving gear. Miflex had a 1% failure rate and they did a massive recall. Good on them. They fixed their problem, and these Italian made hoses are still great. Would I dive them? I actually prefer them. Do I dive their HP hoses? Yes, I do.

All hoses will fail. I don't care how much you adore or malign a particular hose, they will still fail. Those made in Taiwan, the USA, and Italy will all fail. Hoses are a consumable commodity, so treat them as such. Spares are great thing to carry if within your weight allowance.

Are there better hoses? Sure. All of them claim to be the "best", but I don't see any empirical data to support those claims. Are there hoses made just for a profit? Obviously, all hoses are built and sold to make a profit. I dare you to find a single hose that's sold for no profit. Are you afraid of them thar skinny HP hoses? Then dont buy them. They work for me, and at some point, I expect them to fail, just like the fatties used by other divers. I like the slipperiness of MiFlex hoses. They hang up less. It all comes back to fit and comfort, which is nothing more than perception.

 

[iain/hsm]

What's a FRIT?

A FRIT is a technical term used in gas pressure and flow control and is in effect a gas flow restrictor that can either reduce the flow of a high pressure gas or control the flow of the gas in such applications as critical gas flow requirements.

This is opposed to the other cheaper option of using a single orifice restrictor usually a small laser cut hole say 30 thou in diameter that can by application be clogged or block.

A FRIT by contrast has multiple porous holes similar in design to a sintered filter in offering a lack or resistance to clogging while at the same time allowing a designed and controlled flow and is not affected by the Dp DeltaP pressure differential across the FRIT itself

The reason for the FRIT at the 1st stage outlet port is mainly to avoid the high temperature adiabatic
increase in gas temperature as the gas at sonic velocity equal to the speed of sound fires down the short length of thermoplastic hose and at hitting the end of the tube at the HP gauge inlet fitting end it creates a massive albeit short rise in gas temperature.

That and the susceptibility for polymers to burn at worse and melt to leak at best added to which any particulate contaminant (fuel) in a high oxygen atmosphere can create what is called a kindling effect with the heat created by the exothermic compression rate is mixed with the kindling (Fuel) component in a high oxygen atmosphere can result in a small oxygen rich ignition while the kindling can be the cause of a full blown fire when the polymer mass takes over as the fuel supply for the continuation of the fire. Critical in such applications as Hyperbaric chambers to avoid deaths due to fire and important to divers using high oxygen concentrations.

The publication a copy I enclose below The British Hyperbaric Association Fire Safety Guidelines for Multiple Hyperbaric Treatment Facilities October 2018

Outlines the safety aspects and considerations you may find interesting.
And as I was one of the original authors of the publication I think I can freely share.
without too much trouble.

 

[iain/hsm]

You were wrong the first time you posted this. Sure, you want to sound superior, but the only one you're fooling is yourself.

While I respect you have the right of your opinion. Defending it purely on the grounds of your perspective is frankly misguided in the extreme.

Fit and comfort are all about the diver's perception. It's the most important aspect in chosing my diving gear.

Again while I would agree to a point when say choosing your underwear your pants or a wet suit developing this into the realms of diving equipment in general is frankly misguided. How you "feel" bares no relevance whatsoever to performance capability and standards required in diving equipment components in general with the exception I guess of your wet suit fins and mask. Unless you consider as a diver your thermal protection requirements for the suit and safety glass type for the mask

Miflex had a 1% failure rate and they did a massive recall. Good on them.

Not quite a true statement my friend it was in fact the United States Consumer Product Safety Commission that required the "massive" recall and nothing to do with Miflex who at the time were more than happy to sell you junk for profit.

All hoses will fail. I don't care how much you adore or malign a particular hose, they will still fail. Those made in Taiwan, the USA, and Italy will all fail. Hoses are a consumable commodity, so treat them as such. Spares are great thing to carry if within your weight allowance.

Again not a true statement and an example of the peril of using perception as your guide in making your retail consumer purchasing decisions without the benefit of sound engineering experience and specification. Some might even call it foolish.

I like the slipperiness of MiFlex hoses. They hang up less. It all comes back to fit and comfort, which is nothing more than perception.

I will leave it at that for fear of being accused of being offence
but I trust you will come in time to appreciate that "Perception as the mechanism by which you make your informed choice on equipment purchase decisions is only suitable for the misguided, and the foolish.

How you feel doesn't wash either nor is it as you put it (quote)
"It's the most important aspect in chosing my diving gear."
To you it may well be you have that right and I respect it
Although by me saying I simply don't agree is too mild a response but I have no wish to be rude or offensive.
Save to say enjoy the "slipperiness" as you put it and I hope it feels good for you.

 

[Eric Sedletzky]

Like most things in recreational sports diving scuba equipment la la land the differences are more
in the use of made for profit components sourced from the cheapest recreational rink dink provider of toilet
and garden hose using compounds out of some backstreet chemical vendors back yard to some recreational sports DEMA standard and the inadequate standard of EN250 at the cheapest possible price for the importer distributor and retail dive store to maximise profit out of you the cash cow end user.

Rather than accept an international recognised standard for high pressure flexible hose pressure and gas of SAE 100R7 and R8 with the additional Non conductive option of core material for elevated oxygen concentrations and the advantage discussed earlier of a pricked outer cover or sheath.

Added to which end fitting that are professionally swaged by method of swaging or pallet swaged with a recognised with a certified bend radius performance and a pull test under pressure over a radius template.

The difference is in capability knowledge calibration certification together with quality assurance.

A properly manufactured frit at the regulator end also helps reduce and control the pressure shock loads and adiabatic shock pressure and heat loadings on the hose by contrast to when you fit the thing into the gauge to protect the internal ancient but cheap bourdon tube movement and the poor solder connections. Made for profit junk. Just saying.

For consideration Mind and perception is for the misguided the foolish and the idiot.

Now that's fixed it for you.

In other words, don't buy cheap Chinese crap.

 

[The Chairman]

Perception as the mechanism by which you make your informed choice on equipment purchase decisions is only suitable for the misguided, and the foolish

Big words that are not backed up by numbers. What studies are you relying on to make such assertions? It seems that you see your perceptions as "truth", and then demean all other opinions as somehow being "less".

Still, you haven't produced a single statistic to back your opinions up. How many divers have been injured or died due to their choice of hose? How many dives lost? Which hoses? You sound like a Chevy guy disparaging a Ford guy citing "engineering". Your preferences are no more valid than mine as they are based on your perceptions of quality.

On the lighter side, this reminds me of the anti-splitfin peeps telling everyone they're gonna die. What? You put your mask on your forehead too??? WHAT ARE YOU THINKING, YOU FOOL??? It's just silly. We're talking about stupid hoses, here. They will all eventually fail. They are best changed every few years before they leak. I do have a set of Miflex that are around 20 years old. They breathe great and don't leak.

PS: Goodyear makes far better hoses and belts than Gates ever could. You have no idea where a Gates hose was made as they are made on all continents, even Asia. However, Goodyear hoses are made only in North America. Yes, they make tires all over, but their belts and hoses are made here and in Canada. How do I know? I get a pension from working for Goodyear. I'm still loyal.

 

[The Chairman]

{Edited by Mod}

I'm still waiting for some figures and studies to back up your contentions.

 

[iain/hsm]

PS: Goodyear makes far better hoses and belts than Gates ever could. You have no idea where a Gates hose was made as they are made on all continents, even Asia. However, Goodyear hoses are made only in North America. Yes, they make tires all over, but their belts and hoses are made here and in Canada. How do I know? I get a pension from working for Goodyear. I'm still loyal.

Your pension aside maybe you will know the relevance of the three specifications I gave earlier for intermediate and high pressure divers hose. Albeit I have no idea your position at Goodyear.
But if you get chance look up the three below and we could discuss design performance and quality in detail further.

SAE 100R3 was supplied as divers hose to US. Divers Corp for the intermediate hose as 1/4ID for both the US Navy the Royal Navy Conshelf XIV Supreme and the recreational scuba markets all manufactured by Gates.

SAE 100R3 supplied as divers umbilical for surface supplied 110 M umbilicals for the Royal Navy in 3/8' ID and in similar lengths Again only manufactured by Gates.

SAE 100 R3 Bell umbilical for both hot water and gas
SAE 100 R8 High Pressure Filling and gas ramp hose and compressor charging hose
SAE 100 R7 High pressure submersible high pressure hose

All three international SAE standards are accepted as divers hose within the commercial recreational and military diving applications and with respect Goodyear they were never a supplier of divers hose although in drive belts and hydraulic SAE100R1 and R2 steel wire reinforced hydraulic applications hose and compressor dirive belts were well received for quality and working life expectancy so I would agree they do offer in the range of production they excel in a superior product when compared to others I could mention.

Then look up the specification for our current scuba junk hose the EN250 or DEMA 250 as it's sometimes called and compare the two specs. Then come back and tell me I have no idea and its feelings that count. We haven't even started.

 

[davehicks]

I love the clash of philosophies, but didn't expect to ignite a holy war over high pressure hose construction and value. Let's put away the spec sheets and move on to the next thing!

 

[The Chairman]

Besides the level of technical information given alone so far

No figures to back up your assertions so far. None. Nada. Squat. It's not rocket science: it's a hose. You even assumed it was made in Asia because it failed. All hoses will fail.

 

[The Chairman]

I love the clash of philosophies, but didn't expect to ignite a holy war over high pressure hose construction and value. Let's put away the spec sheets and move on to the next thing!

It's the split-fin effect. Posters claim expertise sans figures and studies. If you don't agree with them, you will surely die. Meh.