Useful life of HP and LP hoses; identifying manufacturing date; quality differences

[2airishuman]

As far as I've been able to determine, the most recent advice from DAN is:

All regulator hoses, including braided hoses, have a limited service life regardless of external appearance or reinforcement and protection provided by hose protectors or the braiding itself. The failed hoses we have seen are more than five years old.

While this appears in an article about failures of double-braided flex hoses, DAN wrote in the same article:

[...] a deteriorated internal surface would be completely invisible to a cursory external inspection. It would be premature to speculate that this deterioration is limited to braided hoses.

I'd like to broaden and continue the discussion that started in a thread on an unrelated topic.

All the hoses I have purchased in the last few years have been stamped with a date code. LP hoses have a printed quarter and year along the length of the hose, and HP hoses have a date code stamped in the crimp on the SPG end. All bear a CE mark. None of them are marked with their country of origin, supplier name, or any sort of SAE designation.

I believe this is common, but since I have purchased my hoses from a group of closely related direct-to-consumer vendors, I would invite comments on whether this is also common for hoses sold under major brands through dealers (ScubaPro, Mares, Tusa, Atomic, Aqua Lung, etc.)

I offer these questions to frame the discussion:

1. Is the DAN guidance, vague as it is, sound? Is any investigation ongoing that may provide us with more detailed guidance?
2. At what number of years since manufacture should a plain rubber SCUBA hose be removed from service, regardless of condition?
3. Is there any way to determine, by inspection, whether a plain rubber hose is made using materials similar to those in flexible hoses, justifying more frequent replacement?
4. What is a reasonable expectation for freshness of hoses purchased at retail?
5. Where is the hose stock coming from for the majority of plain rubber SCUBA hoses?
   
6. Are there any dealers selling hoses made from hose stock that is readily traceable to a higher-quality vendor where a longer useful life could be expected?

@iain/hsm @John C. Ratliff @herman @Luis H

 

[tbone1004]

1. highly unlikely that any proper studies including accelerated aging are being done or will be done. This is going to end up like the regulator service interval of 1 or 2 years which is a CYOA policy more than anything.

2. it depends on what the inner core material is and since you don't actually know what the inner core material is, it's a guessing game. It also depends on variables, has that hose lived on the boat deck of a dive boat and been exposed to extreme heat and sun, is it in a pool being exposed to chlorine, do you baby your gear and leave it out of the sun and heat all the time, etc.

3. not without cutting it open

4. you can't determine that because you don't know the stocking or turnover at the shops. They certainly won't be trashing good inventory based on age unless the manufacturer gives them a strict year as a "sell-by" date like we have in the food industry. If you buy "normal" length hoses from places like DRiS, Cave Adventurers, DGX, etc. then they probably aren't there for more than 6 months. If you go to your LDS, they may be there for 3-5 years. If they're stored in a climate controlled area, away from chemicals and pollution *particularly ozone from fridges etc*, then they probably will have no measurable degradation over that time

5. Asia, though used to be hydraulic hose suppliers when they were still made in USA. Companies like Deep Sea Supply still purchase all of their hoses from the US but most everyone else is playing the price game and purchasing from Asia since no one has ever really cared about hose quality before.

6. Oxycheq

 

[JamesBon92007]

5. Asia, though used to be hydraulic hose suppliers when they were still made in USA. Companies like Deep Sea Supply still purchase all of their hoses from the US but most everyone else is playing the price game and purchasing from Asia since no one has ever really cared about hose quality before.

Asia? Hmmm. I bought a couple of generators made in China. The engines and alternators etc held up fine but everything made out of rubber fell apart. Are regulator hoses actually made of rubber? To me most of mine look more like polysomethingorother.

 

[kelemvor]

So it sounds like DAN wants to recommend hose replacement at 5 years but they stopped short of actually saying that. I'm sure that would make things a good bit more reliable, but at a considerable cost. Unless hose prices start plummeting.

I guess it would be cheap enough to do in my 2 hose open water regulators. When it comes to my sidemount doubles config for cave diving, things get a little less appealing, and yet simultaneously more pressing :/. Good lord, there's no end to the stuff I've got to buy for diving. Luckily, I think we have some gift cards left that we won on the last invasion!

 

[tbone1004]

if I had to do 5 year replacement I'd be in for the following

3x 22" HP hose
3x 22" reg hose
2x 84" reg hose
3x drysuit LPI
8x 9" HP hose
1x 108" reg hose
7x 40" reg hose

I have 1x singles rig, 1x doubles rig, 1x double hose, 1x sidemount, 4x stage bottles, 2x deco bottles.
27 hoses, average $25 each, with tax and shipping, call it $700 every 5 years in hoses. HELL NO!

 

[2airishuman]

6. Oxycheq

Doing some checking, they appear to use . According to their website, Danicorp stamps their hoses with a "D" and a date code.

I have found this stamp on all the hoses I have purchased from DGX, Piranha, VDH, and through HOG dealers, so I don't think Oxcheq is special in this regard.

Danicorp states on their web site that: "We use only the highest quality breathing hose from name brand manufactures here in the US." They indicate that their LP hoses have a "Type C (Nitrile) Black" inner tube and their HP hoses have a "Black Odorless Nitrile Rubber (Buna-N-Vinyl)" inner tube. These are very broad descriptions but are at least indicative that the materials are not thermoplastics.

 

[2airishuman]

I have 1x singles rig, 1x doubles rig, 1x double hose, 1x sidemount, 4x stage bottles, 2x deco bottles.
27 hoses, average $25 each, with tax and shipping, call it $700 every 5 years in hoses. HELL NO!

Well, then how long do you think they remain safe? Forever? Serious question -- there are some people who do as long as the outside cover looks OK.

 

[guruboy]

If the outer sleeve looks cracked or torn, I'll replace it.

Otherwise, if it delivers air and doesn't leak, I'll keep using it.

 

[tbone1004]

@2airishuman
DGX, Piranha, VDH except for the funky HP hose, and HOG purchase their hoses from asia. They may purchase the fittings from Danicorp or may follow the same stamp procedure, but if you ask any of them directly, they're coming from Asia and using the same plastic cores as the braided hoses.

In terms of how long they remain safe? If they're rubber inners and won't crumble, then they last as long as they hold air and don't leak. In the case of your HP hose which we know is from the US and uses the nitrile inner tube, then it lasts until it starts bubbling.

 

[2airishuman]

@2airishuman
DGX, Piranha, VDH except for the funky HP hose, and HOG purchase their hoses from asia. They may purchase the fittings from Danicorp or may follow the same stamp procedure, but if you ask any of them directly, they're coming from Asia and using the same plastic cores as the braided hoses.

In terms of how long they remain safe? If they're rubber inners and won't crumble, then they last as long as they hold air and don't leak. In the case of your HP hose which we know is from the US and uses the nitrile inner tube, then it lasts until it starts bubbling.

The HP hose that "we know is from the US" is visually indistinguishable from the HP hoses from these other suppliers except for the fitting size. Same stamp on the crimp, same markings on the hose other than a four-digit number -- which could be the lot number or the number of feet or meters from the end of the spool.