HP Hose Failure

[iain/hsm]

I also do not see how you can think I made an error from bar to psi, EN250 is fairly straightforward.

I didn't. It was for the benefit for some of our American cousins on the forum posts who may have got confused between the Psi terms we were using in the original earlier posts if we were now to jump over into Bar.

 

[BRT]

Heck busted LOL....No.... But now I have to point out in reply that your statement quoted above is factually misleading and convert Bar to Psi by the look of it. But your statement is still misleading and EN centric if you dont mind me saying. But they are two vastly contrasting standards.

1. Under EN 250 the LP hose is tested to 30 Bar (435 psig) and withstands 100 Bar (1450 psig)

Now contrast that to the original American Diving Hose LP standard SAE100R3 DIVERS HOSE
and please note this is not the same as SAE100R3 Hydraulic hose as you implied.

2. Under SAE100R3 Divers Hose The minimum working pressure is 86 Bar (1250 psig) and the minimum test burst pressure is 345 Barg (5000 psig)

We Agree so far? Yes.

Therefore by our agreed calculation the American SAE100R3 Divers Hose is four times that of the EU250 standard for there junk toilet water hose that was introduced into the EU market by the vested interest parties of the various committee members in order to introduce the cheap junk from China et al and the multiple recalled toilet water hose from Italy. This is when the first misleading fudge of 4:1 is introduced to the unsuspecting scuba diving market together with pretty colours matching options.

We still agree?

While the Americans scuba divers were simply sold down the river with the plethora of junk made for profit trinkets and the original American standard dumped in favour of this inferior EU junk.
Others may disagree. Feel Free. But one of them is tested to 30 bar while the other is happily working at 86 bar. And to put it another way one withstands 1450 psi while the other 5000 psi and were only starting by talking low pressure 10 bar (150psi) intermediate hose.

I may not agree with you on lots of things but I really appreciate that you do what you do on a "not for profit" basis. I don't know what you live on.

 

[iain/hsm]

Otherwise I assume you reference a 100R3 SAE dash-size 4. This hose has a nominal inside diameter of around 6mm to 7mm which would closely put it to a standard SCUBA hose. This hose is indeed rated to 87bar and has four times the burst pressure.

The internal bore for the intermediate LP divers hose was 0.250" or 1/4" for the divers intermediate hose and 3/8" bore for the divers umbilical hose up to 110 Metes in length.

Our original standard encompassed all diving application and recreational diving and was always a part of the design brief and it included all the specific design details I listed earlier.

However I omitted pretty much all of the finer design details and to answer your specific question being an internal diameter test down the entire length was undertaken for each reel of the hose in manufacture where a magnetic steel ball bearing was slowly fired down the hose until hopefully it popped out the other end of what could be a 1200 foot length of hose, If it didn't the steel was easily detected and the ball cut out and the hose cut back both sides and the ball place back to continue the test on the remaining length.

This was to test for any elongation or deflection inside the internal hose diameter reel and to assure a non restrictive passage of a guaranteed and validated diameter down the entire length.

The same test was done on small sample hose lengths over various diameter cylindrical mandrels
while at the same time a range of pull test were undertaken to assess the elongation and deflection (narrowing) of the diameter to gauge where we were in the spectrum of the design range. To check for any deviations in performance in the various batch drums. As well as to test the mandrel to quill diameter clearances prior to the pallet swaging and to ensure an adequate pull test to destruction.

 

[BoltSnap]

Not to be mundane . . . I had one of the standard 6” AI transmitter standoff HP hoses develop a large (~1/2”) bubble and smaller bubbles after maybe 18 months of use. We’ve stopped using them—I liked having the seeming protection against the transmitter being used as a handle, but not the idea of a short HP hose I couldn’t reach exploding next to my ear and draining my gas—much less adding two possible failure points to the kit. I don’t know whether it would have progressed to catastrophic failure, but it seemed likely.

To this end, I just got myself several kevlar something very heavy duty short HP hose from SP to use with my many computer transmitters. (Fairly expensive )