Hoses for above 40% O2

[Polarorbit]

A recent discussion made me think about the components of my deco tank. I have a regulator and SPG that are approved for more than 40% O2. However, a thread on SB asked about O2 cleaning hoses. That made me think more about the hoses on deco tanks. I looked at XS Scuba and can't find any information about FO2 and their rubber hoses. I checked Miflex and found the following (for all their hoses, even the XT-Tech):

The hose is designed to use air or nitrogen/oxygen mixtures containing up to 40% oxygen. Use of gas mixtures with increased oxygen or the addition of other substances may cause corrosion, deterioration, premature aging or failure of the hose.​

Clearly deco tanks should not use Miflex hoses since FO2 is frequently 50% or greater. However, does anyone have information from rubber hose manufacturers indicating they are approved for these high FO2 levels? What about information on the use of specific hoses for trimix? The statement from Miflex seems to indicate their hoses are not approved for trimix, since helium would be an "other substance". I know there is plenty of anecdotal evidence that various hoses are okay since people are using them but do any manufacturers actual state that it's okay?

 

[boriss]

A recent discussion made me think about the components of my deco tank. I have a regulator and SPG that are approved for more than 40% O2. However, a thread on SB asked about O2 cleaning hoses. That made me think more about the hoses on deco tanks. I looked at XS Scuba and can't find any information about FO2 and their rubber hoses. I checked Miflex and found the following (for all their hoses, even the XT-Tech):

The hose is designed to use air or nitrogen/oxygen mixtures containing up to 40% oxygen. Use of gas mixtures with increased oxygen or the addition of other substances may cause corrosion, deterioration, premature aging or failure of the hose.​

Clearly deco tanks should not use Miflex hoses since FO2 is frequently 50% or greater. However, does anyone have information from rubber hose manufacturers indicating they are approved for these high FO2 levels? What about information on the use of specific hoses for trimix? The statement from Miflex seems to indicate their hoses are not approved for trimix, since helium would be an "other substance". I know there is plenty of anecdotal evidence that various hoses are okay since people are using them but do any manufacturers actual state that it's okay?

Miflex hoses are ubiquitous, the only thing I'd be concerned about is helium escaping through the hose, but as long as it's not stored under pressure that's not a problem.

People overthink the whole O2 clean thing... here's an interesting read for some context and to get the thread rolling

Oxygen Clean - Is a Myth ADVANCED DIVER MAGAZINE By Bart Bjorkman

 

[broncobowsher]

I'm in the don't overthink it camp. The low pressure side I can give zero Fs about it.
Probably spent too much time working an Oxy-acetylene torch with real life experience with O2 in fires.

 

[Beau Holden]

Probably spent too much time working an Oxy-acetylene torch with real life experience with O2 in fires.

Only time ever had high O2 in fires is at the end of a torch. I'm with you on overthinking the whole O2 clean thing. Partial pressure blended to many tanks. Use torches and Oxy-acetylene regulators in some nasty dirty shops and some nasty dirty regulators. How many O2 cylinders has we seen marked as O2 clean from a gas supplier?

 

[tbone1004]

A recent discussion made me think about the components of my deco tank. I have a regulator and SPG that are approved for more than 40% O2. However, a thread on SB asked about O2 cleaning hoses. That made me think more about the hoses on deco tanks. I looked at XS Scuba and can't find any information about FO2 and their rubber hoses. I checked Miflex and found the following (for all their hoses, even the XT-Tech):

The hose is designed to use air or nitrogen/oxygen mixtures containing up to 40% oxygen. Use of gas mixtures with increased oxygen or the addition of other substances may cause corrosion, deterioration, premature aging or failure of the hose.​

Clearly deco tanks should not use Miflex hoses since FO2 is frequently 50% or greater. However, does anyone have information from rubber hose manufacturers indicating they are approved for these high FO2 levels? What about information on the use of specific hoses for trimix? The statement from Miflex seems to indicate their hoses are not approved for trimix, since helium would be an "other substance". I know there is plenty of anecdotal evidence that various hoses are okay since people are using them but do any manufacturers actual state that it's okay?

O2 cleaning is not required for the low pressure side. SPG's don't really have any flow through them once they pressurize which is helpful in mitigating risk.

 

[Polarorbit]

Okay, I get that we probably don't need to worry about spontaneous combustion in the low-pressure side. What about the impact of high FO2 on the actual hose material? That seems to be what Miflex was concerned about in their hoses.

 

[happy-diver]

Here's my all rubber 50yrish old O2 setup

 

[PfcAJ]

Okay, I get that we probably don't need to worry about spontaneous combustion in the low-pressure side. What about the impact of high FO2 on the actual hose material? That seems to be what Miflex was concerned about in their hoses.

It seems to be a nonissue in practice. I’m sure there’s some theoretical impact, but for real life it’s fine.

 

[jadairiii]

Somewhere (and I know I remember reading it) the US Navy did their best to touch an MR 12 regulator with pure O2 and couldn't get it to do it.

99% of your "risk" is on the HP side. Like when I cooked a valve and the inside of my regulator looked like the exhaust manifold of a 1976 350 with a bad Holly double pumper on it.

 

[BoltSnap]

Here's my all rubber 50yrish old O2 setup

View attachment 752116

Aquarius first stage?