Problem with generic braided hoses

[redacted]

The repetitious anecdotal statements that rubber hoses are good for X number of years etc. are not scientific and are not documented by any literature from the manufacturer. I seriously doubt any manufacture of rubber hoses would claim a lifetime service of 30 years and that several guys on here continue to use 20 and 30 year old rubber hoses just because they have not failed yet is again anecdotal and not scientific analysis. I might, in 20 more years have Miflex hoses still hanging in there. Who knows. What I do know is that the rubber hoses DO NOT have a stated lifetime of 20 or 30 years. Unless someone can provide the document stating so, hog wash. And I have seen failed rubber hoses and LP hoses that would not flow air or which looked fine but leaked at the swages.

You guys can continue to use 30 year old hoses for technical, deep and overhead/deco diving but I think I will not, never have. I have new(er) hoses on all of the regulators I actually use including my wife's. What do I do with old hoses, well, cut them up and throw them away, use some for test equipment, one older set is on my pool regulator, I think I can make a free ascent from the deep end.

I worry a lot more over LP hoses than HP hoses.

N

How do you keep track of the age of your hoses? I just went through 3 of my rigs, all with conventional rubber hoses, and found no date markings. I did find some manufacturing standard markings which might provide an upper limit on their age.

Maybe it is a good thing these braided hoses have a manufacturing date indication.

While I don't do tech, overhead, or deco; I will continue to use my rubber hoses of unknown age until they give me reason to replace them. And even then, I will probably replace them from a drawer of hoses of unknown age as long as they perform well. I do have quite a few (way too many) older regulators for which I paid about $30 per stage including hoses and SPGs. It has been about 4 years since I picked up a pair of original Scubapro Pilots (with hoses) so I have not looked to see what these older regs are setting folks back today. But I did just look at the price of hoses. A new Miflex LP hose is running in the $40 to $50 range - ouch. Knock-offs are half that price as are conventional rubber hoses. That means a new replacement hose would cost as much as I'm used to paying for a regulator stage. If many of my hoses start to fail, I'll probably just reduce the size of my stable. My wife keeps asking why I need a dozen kits ready to dive and I guess I don't know.

I have had a number of hose failures. Most were defective hoses received on used regulators. All had small leaks. None failed to deliver gas or had leaks so bad that they would require a dive be aborted.

Need some data? I have about 1300 dives and have never had to abort a dive due to any type of regulator related failure. I do not do periodic rebuilds on any of my regulators. I only do regulator parts replacement when there is some type of indication of a problem. With a regulator hose, that would be a leak or cracking of the outer cover.

 

[Hatul]

It does appear that Andy's hose was a Miflex hose as those are Miflex markings and my title to this thread is therefore incorrect. Andy attributes the failure to repeated heating and cooling of the inner material and it may be showing itself first in the hot Philippines climate.

Another poster in this forum reports a failure in the Phantom LP hose resulting in a leak rather than blockage. All braided hoses are now suspect as the construction is similar.

I have a lot of braided hoses both Miflex and DGX generic brand and will probably go back to the Atomic rubber hose with swivel for my primary reg, which I converted to Miflex. Personally I would not buy any more braided hoses-- it's just not worth it to save a bit of weight and gain a little flexibility at the risk of sudden failure. This kind of equation is like reverse insurance, and I'd rather pay a small price of less convenience to avoid a catastrophic failure under water.

 

[Nemrod]

How do you keep track of the age of your hoses? I just went through 3 of my rigs, all with conventional rubber hoses, and found no date markings. I did find some manufacturing standard markings which might provide an upper limit on their age.

Maybe it is a good thing these braided hoses have a manufacturing date indication.

While I don't do tech, overhead, or deco; I will continue to use my rubber hoses of unknown age until they give me reason to replace them. And even then, I will probably replace them from a drawer of hoses of unknown age as long as they perform well. I do have quite a few (way too many) older regulators for which I paid about $30 per stage including hoses and SPGs. It has been about 4 years since I picked up a pair of original Scubapro Pilots (with hoses) so I have not looked to see what these older regs are setting folks back today. But I did just look at the price of hoses. A new Miflex LP hose is running in the $40 to $50 range - ouch. Knock-offs are half that price as are conventional rubber hoses. That means a new replacement hose would cost as much as I'm used to paying for a regulator stage. If many of my hoses start to fail, I'll probably just reduce the size of my stable. My wife keeps asking why I need a dozen kits ready to dive and I guess I don't.

I have had a number of hose failures. Most were defective hoses received on used regulators. All had small leaks. None failed to deliver gas or had leaks so bad that they would require a dive be aborted.

Need some data? I have about 1300 dives and have never had to abort a dive due to any type of regulator related failure. I do not do periodic rebuilds on any of my regulators. I only do regulator parts replacement when there is some type of indication of a problem. With a regulator hose, that would be a leak or cracking of the outer cover.

Again, anecdotal observations are interesting and not completely to be dismissed but not very useful either. But, to answer your question, for the regulator sets that I actually dive with (as opposed to the mnay that sit around in boxes and under my bench that have not seen water in a coons age) I keep logs including rebuild dates, hoses dates or installation of the new hoses etc. Yes, like the aviation engineer/mechanic/pilot that I am, I keep logs.

As to rubber hoses, , perhaps if you had some made in this century you would see they have dates like this because nothing has an unlimited life:

Since the hoses come on bulk reels to the crimping facility I imagine it is possible to have hoses with no date stamp, especially short hoses. But, to reiterate, I do log in the hose and I do not use twenty year old hoses in technical situations. If I cannot determine the age, I remove it from service. Hoses are cheap as has been pointed out and no reason to use something that might not be 100%. There are also stampings on the hoses crimps BTW.

I agree with one poster, sounds like an issue with the inner hose plasticizer ingredient. Could be a bad run. This is for the manufacturer to determine.

My wife just asked me, seeing me running around with armfuls of hoses if we were still arguing about hoses, yes .

N

 

[uncfnp]

Fortunately I couldn't check them all since many are packed for my upcoming dive trip but of the rubber hoses I could access none had dates. And that includes my long hose.

 

[redacted]

Well, I went through about 30 hoses, I know I bought a couple of them new this century, and the only ones I found with dates are 2 Myflex hoses.

I also got to thinking more about the idea of "data". While there is clearly some estimation involved (could be addressed with a little sensitivity analysis), I realized that my 1300 dives does provide data that can be used to estimate hose reliability. Assuming each dive had a duration of 1 hour and used 3 LP hoses, that is 3900 hours of use with no dive aborting failures. That would produce a 90% confidence interval of 1302 hours (MTBF) lower bound and 75726 hours upper bound. That is a pretty big interval but the failure rates are pretty low when some seem to be talking about discarding hoses after 500 hours. The 50% on this MTBF estimate would be about 5655 hours. So, you might just want to ask yourself if discarding hose after a few years makes any more sense than changing the belts in your car every year. With the classic "bathtub curve" often associated with reliability over time ( https://en.wikipedia.org/wiki/Bathtub_curve ) you may well be replacing perfectly good hoses with a new hose of lower reliability.

Got Data?

 

[Nemrod]

Well, I went through about 30 hoses, I know I bought a couple of them new this century, and the only ones I found with dates are 2 Myflex hoses.

I also got to thinking more about the idea of "data". While there is clearly some estimation involved (could be addressed with a little sensitivity analysis), I realized that my 1300 dives does provide data that can be used to estimate hose reliability. Assuming each dive had a duration of 1 hour and used 3 LP hoses, that is 3900 hours of use with no dive aborting failures. That would produce a 90% confidence interval of 1302 hours (MTBF) lower bound and 75726 hours upper bound. That is a pretty big interval but the failure rates are pretty low when some seem to be talking about discarding hoses after 500 hours. The 50% on this MTBF estimate would be about 5655 hours. So, you might just want to ask yourself if discarding hose after a few years makes any more sense than changing the belts in your car every year. With the classic "bathtub curve" often associated with reliability over time ( https://en.wikipedia.org/wiki/Bathtub_curve ) you may well be replacing perfectly good hoses with a new hose of lower reliability.

Got Data?

While I generally find myself far more often in agreement with you than not, in this case not. That is not a good sample, you admit you do not know the age of the hoses and there is no control group. The same numbers could be generated with braided hoses. You cannot really think that the only scuba hose failures on planet earth are braided hoses say in the last year. You have not had failures, I have. We do not know from anecdotalisms what the percentage or mean time to failure is until you have a representative sample and control group and a test plan specifying the procedures and conditions.

I often run tests and write test plans, diving with a bunch of old hoses and not experiencing failure could just be luck, that is not data, it is background noise.


James

 

[buddhasummer]

None of my rubber hoses have dates either, strange. Mine all came from DGX or with wings I've bought. I think I'm going to start fresh, buy all new rubber hoses and do as James does and log dates. Any one want a selection of Miflex and generic braided hoses? They all "look" new

I lied, one of my 7' rubber hoses has a date 2Q14 written on it. Sorry James.

 

[AdivingBel]

None of my rubber hoses have dates either, strange. Mine all came from DGX or with wings I've bought. I think I'm going to start fresh, buy all new rubber hoses and do as James does and log dates. Any one want a selection of Miflex and generic braided hoses? They all "look" new

I assume you're giving them away since they are likely to kill me. I guess I could contribute to my own demise by covering the shipping.

 

[buddhasummer]

I assume you're giving them away since they are likely to kill me. I guess I could contribute to my own demise by covering the shipping.

Yes, they would be free but you'd have to sign a waiver...

 

[redacted]

While I generally find myself far more often in agreement with you than not, in this case not. That is not a good sample, you admit you do not know the age of the hoses and there is no control group. The same numbers could be generated with braided hoses. You cannot really think that the only scuba hose failures on planet earth are braided hoses say in the last year. You have not had failures, I have. We do not know from anecdotalisms what the percentage or mean time to failure is until you have a representative sample and control group and a test plan specifying the procedures and conditions.

I often run tests and write test plans, diving with a bunch of old hoses and not experiencing failure could just be luck, that is not data, it is background noise.


James

Testing is one way of obtaining data. I spent quite a bit of my working years doing just that. I also spent a few years evaluating military systems in the absence of good test data. Unfortunately, good test data are often prohibitively expensive; yet it is wrong to claim "we don't know because we don't have any test data.

Sure, there are clear limitations to what I have done. And the starting age of the "test" items might have been an issue had there been failures. And conducting reliability testing on 3900 items for one hour each would be quite different from conduction a 1300 hour test on three item but when you think this one through, you should realize that the first approach would be most problematic and my data is somewhere in between and closer to the later approach. Once again, with no failures, I'm not sure what this ill-defined sample would lack in comparison to a controlled, representative sample other than infant mortality failures. And I am not at all sure what role you see for a control group in this case unless you want to bring in specific independent variables.

I am not questioning the reliability of braided hose. My issue was with the idea that some want to change out hoses based on age or usage time with no apparent basis (data). My issue with these braided hose is not their reliability but the failure mode they seem to present. I have no problem with the idea of identifying incipient failures in any scuba hose and replacing that hose before their is a serious failure. But it looks like this may require frequent disassembly and inspection with Miflex LP hoses. It is hard enough to get diver to inspect for cracks and bubbles. This may be asking too much.

---------- Post added August 7th, 2015 at 10:13 AM ----------

None of my rubber hoses have dates either, strange. Mine all came from DGX or with wings I've bought. I think I'm going to start fresh, buy all new rubber hoses and do as James does and log dates. Any one want a selection of Miflex and generic braided hoses? They all "look" new

Why would you log dates? What makes you think age is an important variable?