Stretched "O" ring incident

geordiediver · 8th August 2007, 15:40

A couple of weeks ago I was diving a wreck out of Dartmouth in about 30m, this was the third dive in a series on the same scrubber (the other two dives were around 25m and lasted about 40mins each, and took place on the day before the incident).

After about 30 minutes into the 3rd dive, I was feeling a little short of breath, and my breathing rate was increased from the norm. Whilst I did not believe that I was having a CO2 attack, and put it down to some hard finning, I switched over to OC using my BOV, more as a training drill rather than because I feared a major problem, and within a couple of minutes I felt better. I did a dil flush and went back on the loop, and finished the dive (I had only 2 mins of deco according to the VR3), I did not notice any further symptoms. I was only back on the loop for about 10 mins before I surfaced and got back on the boat.

Later that evening I was taking my unit apart to change the scrubber, and found the cause of the problem.

The cannister "O" ring had not been replaced for around 12 months, and i was aware that it was slightly stretched - I thought nothing of this at the time, deciding that I would pick up a new one next time I was at the dive shop.

What had happened on the dive was that the "O" ring had somehow streched even further, and had pushed itself up between the spacer ring and the cannister causing a pathway for unscrubbed gas.

I was lucky that the problem took place on a shallow dive in good viz when I had a clear head through using a "light" trimix as diluent - it could have been much worse if it had happened deeper.

The moral of the story is easy - don't delay in replacing any parts that are on the way out, your life may depend upon this.

Drmike · 8th August 2007, 16:05

Quote: (Originally Posted by geordiediver)

The moral of the story is easy - don't delay in replacing any parts that are on the way out, your life may depend upon this.

(
the other moral of the story is that seal method on inspos is a really crap (dangerous) design.

glad it didnt get you

**Gill Envy** · 8th August 2007, 17:45

geordiediver, have some green

, thanks for posting your incident. sharing this kind of information is what it's all about.... Every rebreather has it's areas that need a little extra care and the spacer- "O" ring relationship on Inspo/evo's is one of them...a good reminder for anyone using that design.

When in doubt, flush it out! And get off the loop...which is exactly what you did.

DepthCharge · 9th August 2007, 01:27

Quote: (Originally Posted by Gill Envy)

Every rebreather has it's areas that need a little extra care and the spacer- "O" ring relationship on Inspo/evo's is one of them...a good reminder for anyone using that design.

I like Dr. Mike's description better

Drmike · 9th August 2007, 01:32

Quote: (Originally Posted by Gill Envy)

Every rebreather has it's areas that need a little extra care and the spacer- "O" ring relationship on Inspo/evo's is one of them.

yeh lets all accept possibly dangerous design flaws because all units have them - hey its only a life support system

Im actually happier with the Meg sensor position design flaw that I ever was with that damn o-ring. Almost killed me and I can think of at least half a dozen others who it almost got. Sure just like the other design flaws in other units we can as users make special allowances and be extra careful so these fundamental design flaws dont get us killed - but we really shouldnt need to - its not as if Rebreather diving isnt dangerous enough. That seal design should have been changed a decade ago IMHO. Didnt they change it on the EVO?

**Gill Envy** · 9th August 2007, 02:09

Admitting you had an accident, your fault or not, is hard enough and deserves commending, not cutting down of the very design of the poster's rig. I think there is a good reason Accidents and incidents was put in the "rebreather training forum" and not under the "Rebreather Design & Operation" Forum. Accidents and Incidents seems like a good place for discussing mistakes, which it sounds like this was, while the Design and operation forum would be a better place for discussing the way design may effect the propensity toward such mistakes...both are good discussions but becuase it's all to easy to descourage such admissions, I think they are best done in different threads/forums. IMHO

Drmike · 9th August 2007, 02:25

Quote: (Originally Posted by Gill Envy)

I think there is a good reason Accidents and incidents was put in the "rebreather training forum" and not under the "Rebreather Design & Operation" Forum. Accidents and Incidents seems like a good place for discussing mistakes, which it sounds like this was, while the Design and operation forum would be a better place for discussing the likelyhood of such a mistake as it relates to design. Admitting you had an accident, your fault or not, is hard enough and deserves commending not cutting down of the very design of the unit... IMHO

oh for crying out loud.

critiquing the inspo design in no way is cutting him down and making it harder for people to admit an accident. thats a stupid association . iF ANYTHING its taking blame away from the user.

Unless like some he is having an intimate sexual relationship with his unit and thus takes any critisism of it no matter how justified as a personal afront....hmm that sounds familar.

See your diving an Evo now too

as for if this discussion should be made here or in an a different catagory..oh dear -how sad -never mind

if a mod wants to move it elsewhere then whso cares - hardly a crime me posting it here - worse things happen at sea (just ask john). personally i would have thought a thread discussing a near accident involving the o-ring seal design on the inspo is exactly the right place to have a discussion on the dangers of the o-ring seal design on the inspo

but then again Im no ostrich nor am I in love with my units nor do I casually and HABITUALY accept faulty designs in LIFE SUPPORT SYSTEMS

Personaly Id rather people pulled their heads out of the sand dropped their silly personal bias stop habitualy accepting design flaws as the norm and then, maybe, we wont have threads like this one or other near misses to read in the 1st place. Now hows that for an idea?

Its called prevention rather than cure. This design flaw has been know for a decade (since the 1st user took a hit) if we as a community had done something about it then (instead of just as usual accepting it and saying something like 'all units have their ares that need a little extra care" then this guy wouldnt have been in a potentialy life threatening situation in the 1st place.

Life support systems should be robustly designed. They should not have areas that need 'little extra care', they shouldnt have any 'gotchas' . Is the seal design safe? Yes - IF the user is extra carefull with it. But humans make mistakes. A safe design should take that into accout as much as possible and be as far as possible IDIOT Proof. Yes he made an assembly error - but the fact is the design isnt robuist enough for that not to be a problem (or exist in the 1st place) The seal design is a 'gotcha' that could and should have been removed years ago IMO.

**Gill Envy** · 9th August 2007, 04:52

I see your perspective, you have good arguments and a healthy level of detachement from your rig(s), more than most, and I think it's still fairly plain to see that such comments kill a thread like this. I'm interested in what seems to encourage vs descourage the relatively rare admission of mistakes and near misses... kid gloves seem appropriate here.

I guess I've come to covette such first hand accounts, maybe i'm being too protective, But I do get a lot more out of hearing first hand accounts than discussions about what might have gone wrong in an accident where the person did not live to tell about it and nothing was left of the evidence. examining near misses seems a lot more fruitful than speculation over fatalities... I just wish people would talk more about their near misses.

I'm really not such a sensative guy in real life, I go to extra ends to try and adjust my tone here to take extra care in keeping the information flowing.

Quote: (Originally Posted by Drmike)

oh for crying out loud.

critiquing the inspo design in no way is cutting him down and making it harder for people to admit an accident. thats a stupid association . iF ANYTHING its taking blame away from the user.

Unless like some he is having an intimate sexual relationship with his unit and thus takes any critisism of it no matter how justified as a personal afront....hmm that sounds familar.

See your diving an Evo now too

as for if this discussion should be made here or in an a different catagory..oh dear -how sad -never mind

if a mod wants to move it elsewhere then whso cares - hardly a crime me posting it here - worse things happen at sea (just ask john). personally i would have thought a thread discussing a near accident involving the o-ring seal design on the inspo is exactly the right place to have a discussion on the dangers of the o-ring seal design on the inspo

but then again Im no ostrich nor am I in love with my units nor do I casually and HABITUALY accept faulty designs in LIFE SUPPORT SYSTEMS

Personaly Id rather people pulled their heads out of the sand dropped their silly personal bias stop habitualy accepting design flaws as the norm and then, maybe, we wont have threads like this one or other near misses to read in the 1st place. Now hows that for an idea?

Its called prevention rather than cure. This design flaw has been know for a decade (since the 1st user took a hit) if we as a community had done something about it then (instead of just as usual accepting it and saying something like 'all units have their ares that need a little extra care" then this guy wouldnt have been in a potentialy life threatening situation in the 1st place.

Life support systems should be robustly designed. They should not have areas that need 'little extra care', they shouldnt have any 'gotchas' . Is the seal design safe? Yes - IF the user is extra carefull with it. But humans make mistakes. A safe design should take that into accout as much as possible and be as far as possible IDIOT Proof. Yes he made an assembly error - but the fact is the design isnt robuist enough for that not to be a problem (or exist in the 1st place) The seal design is a 'gotcha' that could and should have been removed years ago IMO.

Gilles · 9th August 2007, 05:11

Quote: (Originally Posted by Drmike)

oh for crying out loud.

critiquing the inspo design in no way is cutting him down and making it harder for people to admit an accident. thats a stupid association . iF ANYTHING its taking blame away from the user.

Unless like some he is having an intimate sexual relationship with his unit and thus takes any critisism of it no matter how justified as a personal afront....hmm that sounds familar.

See your diving an Evo now too

as for if this discussion should be made here or in an a different catagory..oh dear -how sad -never mind

if a mod wants to move it elsewhere then whso cares - hardly a crime me posting it here - worse things happen at sea (just ask john). personally i would have thought a thread discussing a near accident involving the o-ring seal design on the inspo is exactly the right place to have a discussion on the dangers of the o-ring seal design on the inspo

but then again Im no ostrich nor am I in love with my units nor do I casually and HABITUALY accept faulty designs in LIFE SUPPORT SYSTEMS

Personaly Id rather people pulled their heads out of the sand dropped their silly personal bias stop habitualy accepting design flaws as the norm and then, maybe, we wont have threads like this one or other near misses to read in the 1st place. Now hows that for an idea?

Its called prevention rather than cure. This design flaw has been know for a decade (since the 1st user took a hit) if we as a community had done something about it then (instead of just as usual accepting it and saying something like 'all units have their ares that need a little extra care" then this guy wouldnt have been in a potentialy life threatening situation in the 1st place.

Life support systems should be robustly designed. They should not have areas that need 'little extra care', they shouldnt have any 'gotchas' . Is the seal design safe? Yes - IF the user is extra carefull with it. But humans make mistakes. A safe design should take that into accout as much as possible and be as far as possible IDIOT Proof. Yes he made an assembly error - but the fact is the design isnt robuist enough for that not to be a problem (or exist in the 1st place) The seal design is a 'gotcha' that could and should have been removed years ago IMO.

That post definitely merits green

and more. I hope the integrity of cells improve (eventually at least), and ISC determines a clever way to remove cells from the critical path of Meg loop integrity.

Quote: (Originally Posted by geordiediver)

After about 30 minutes into the 3rd dive, I was feeling a little short of breath, and my breathing rate was increased from the norm. Whilst I did not believe that I was having a CO2 attack, and put it down to some hard finning, I switched over to OC using my BOV, more as a training drill rather than because I feared a major problem, and within a couple of minutes I felt better. I did a dil flush and went back on the loop, and finished the dive (I had only 2 mins of deco according to the VR3), I did not notice any further symptoms. I was only back on the loop for about 10 mins before I surfaced and got back on the boat.

Later that evening I was taking my unit apart to change the scrubber, and found the cause of the problem.

This one too

.

I'd like to add that another useful lesson for us is the generous use of BOV/bailout, and/or dil flush on the basis of a slightest inkling (imagined or not).

silent running · 9th August 2007, 06:04

Quote: (Originally Posted by Gill Envy)

I see your perspective, you have good arguments and a healthy level of detachement from your rig(s), more than most, and I think it's still fairly plain to see that such comments kill a thread like this. I'm interested in what seems to encourage vs descourage the relatively rare admission of mistakes and near misses... kid gloves seem appropriate here.

Hi Gill, like most people on Rebreather World, I very much value reading near miss acounts. And while I understand what motivated your reponse to Mike's post, I have to say that anybody so thin skinned as to take personally an obvious, generalized and legitimate criticism of a design flaw in their unit, that they decide to keep quiet...the phrase "shrinking violet" comes to mind. In fact, I'd be wiling to bet that any such shrinking violet may actually be timid because they have a reason to be, like not telling us all the embarassing details, which may be understandable, but might also make the whole experience a bit less valuable...

Most of us value firsthand accounts of oversights/complacency/dumbass mistakes enough that I think there's always more people here encouraging those posts than not.

8th August 2007, 15:40	#1 (permalink)
geordiediver New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jul 2005 Location: England Posts: 12	Stretched "O" ring incident A couple of weeks ago I was diving a wreck out of Dartmouth in about 30m, this was the third dive in a series on the same scrubber (the other two dives were around 25m and lasted about 40mins each, and took place on the day before the incident). After about 30 minutes into the 3rd dive, I was feeling a little short of breath, and my breathing rate was increased from the norm. Whilst I did not believe that I was having a CO2 attack, and put it down to some hard finning, I switched over to OC using my BOV, more as a training drill rather than because I feared a major problem, and within a couple of minutes I felt better. I did a dil flush and went back on the loop, and finished the dive (I had only 2 mins of deco according to the VR3), I did not notice any further symptoms. I was only back on the loop for about 10 mins before I surfaced and got back on the boat. Later that evening I was taking my unit apart to change the scrubber, and found the cause of the problem. The cannister "O" ring had not been replaced for around 12 months, and i was aware that it was slightly stretched - I thought nothing of this at the time, deciding that I would pick up a new one next time I was at the dive shop. What had happened on the dive was that the "O" ring had somehow streched even further, and had pushed itself up between the spacer ring and the cannister causing a pathway for unscrubbed gas. I was lucky that the problem took place on a shallow dive in good viz when I had a clear head through using a "light" trimix as diluent - it could have been much worse if it had happened deeper. The moral of the story is easy - don't delay in replacing any parts that are on the way out, your life may depend upon this.
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8th August 2007, 16:05	#2 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Stretched "O" ring incident Quote: (Originally Posted by geordiediver) The moral of the story is easy - don't delay in replacing any parts that are on the way out, your life may depend upon this. ( the other moral of the story is that seal method on inspos is a really crap (dangerous) design. glad it didnt get you __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
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8th August 2007, 17:45	#3 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,292	Re: Stretched "O" ring incident geordiediver, have some green , thanks for posting your incident. sharing this kind of information is what it's all about.... Every rebreather has it's areas that need a little extra care and the spacer- "O" ring relationship on Inspo/evo's is one of them...a good reminder for anyone using that design. When in doubt, flush it out! And get off the loop...which is exactly what you did. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 10th August 2007 at 15:30.
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9th August 2007, 01:27	#4 (permalink)
DepthCharge New Member Current Rebreather/s: Inspiration Classic Home Build Other Rebreather/s: Home Build Join Date: Mar 2005 Location: upstate NY Posts: 228	Re: Stretched "O" ring incident Quote: (Originally Posted by Gill Envy) Every rebreather has it's areas that need a little extra care and the spacer- "O" ring relationship on Inspo/evo's is one of them...a good reminder for anyone using that design. I like Dr. Mike's description better __________________ Later, John It's better to beg forgiveness than ask permission
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9th August 2007, 01:32	#5 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Stretched "O" ring incident Quote: (Originally Posted by Gill Envy) Every rebreather has it's areas that need a little extra care and the spacer- "O" ring relationship on Inspo/evo's is one of them. yeh lets all accept possibly dangerous design flaws because all units have them - hey its only a life support system Im actually happier with the Meg sensor position design flaw that I ever was with that damn o-ring. Almost killed me and I can think of at least half a dozen others who it almost got. Sure just like the other design flaws in other units we can as users make special allowances and be extra careful so these fundamental design flaws dont get us killed - but we really shouldnt need to - its not as if Rebreather diving isnt dangerous enough. That seal design should have been changed a decade ago IMHO. Didnt they change it on the EVO? __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you
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9th August 2007, 02:09	#6 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,292	Re: Stretched "O" ring incident Admitting you had an accident, your fault or not, is hard enough and deserves commending, not cutting down of the very design of the poster's rig. I think there is a good reason Accidents and incidents was put in the "rebreather training forum" and not under the "Rebreather Design & Operation" Forum. Accidents and Incidents seems like a good place for discussing mistakes, which it sounds like this was, while the Design and operation forum would be a better place for discussing the way design may effect the propensity toward such mistakes...both are good discussions but becuase it's all to easy to descourage such admissions, I think they are best done in different threads/forums. IMHO __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 9th August 2007 at 02:15.
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9th August 2007, 02:25	#7 (permalink)
Drmike Custom Title Allowed! Current Rebreather/s: MK 15.X Ouroboros Other CCR Home Build Other Rebreather/s: Inspiration Classic Other CCR Home Build Join Date: Feb 2005 Posts: 3,128	Re: Stretched "O" ring incident Quote: (Originally Posted by Gill Envy) I think there is a good reason Accidents and incidents was put in the "rebreather training forum" and not under the "Rebreather Design & Operation" Forum. Accidents and Incidents seems like a good place for discussing mistakes, which it sounds like this was, while the Design and operation forum would be a better place for discussing the likelyhood of such a mistake as it relates to design. Admitting you had an accident, your fault or not, is hard enough and deserves commending not cutting down of the very design of the unit... IMHO oh for crying out loud. critiquing the inspo design in no way is cutting him down and making it harder for people to admit an accident. thats a stupid association . iF ANYTHING its taking blame away from the user. Unless like some he is having an intimate sexual relationship with his unit and thus takes any critisism of it no matter how justified as a personal afront....hmm that sounds familar. See your diving an Evo now too as for if this discussion should be made here or in an a different catagory..oh dear -how sad -never mind if a mod wants to move it elsewhere then whso cares - hardly a crime me posting it here - worse things happen at sea (just ask john). personally i would have thought a thread discussing a near accident involving the o-ring seal design on the inspo is exactly the right place to have a discussion on the dangers of the o-ring seal design on the inspo but then again Im no ostrich nor am I in love with my units nor do I casually and HABITUALY accept faulty designs in LIFE SUPPORT SYSTEMS Personaly Id rather people pulled their heads out of the sand dropped their silly personal bias stop habitualy accepting design flaws as the norm and then, maybe, we wont have threads like this one or other near misses to read in the 1st place. Now hows that for an idea? Its called prevention rather than cure. This design flaw has been know for a decade (since the 1st user took a hit) if we as a community had done something about it then (instead of just as usual accepting it and saying something like 'all units have their ares that need a little extra care" then this guy wouldnt have been in a potentialy life threatening situation in the 1st place. Life support systems should be robustly designed. They should not have areas that need 'little extra care', they shouldnt have any 'gotchas' . Is the seal design safe? Yes - IF the user is extra carefull with it. But humans make mistakes. A safe design should take that into accout as much as possible and be as far as possible IDIOT Proof. Yes he made an assembly error - but the fact is the design isnt robuist enough for that not to be a problem (or exist in the 1st place) The seal design is a 'gotcha' that could and should have been removed years ago IMO. __________________ Get a girlfriend you sad twat - a Rebreather is an unfaithful mistress - dont blind yourself to her faults just because she goes down on you Last edited by Drmike : 9th August 2007 at 02:57.
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9th August 2007, 04:52	#8 (permalink)
Gill Envy Shearwater Copis Diver Current Rebreather/s: Other CCR Other Rebreather/s: Evolution Other CCR Join Date: Nov 2005 Location: seattle Posts: 1,292	Re: Stretched "O" ring incident I see your perspective, you have good arguments and a healthy level of detachement from your rig(s), more than most, and I think it's still fairly plain to see that such comments kill a thread like this. I'm interested in what seems to encourage vs descourage the relatively rare admission of mistakes and near misses... kid gloves seem appropriate here. I guess I've come to covette such first hand accounts, maybe i'm being too protective, But I do get a lot more out of hearing first hand accounts than discussions about what might have gone wrong in an accident where the person did not live to tell about it and nothing was left of the evidence. examining near misses seems a lot more fruitful than speculation over fatalities... I just wish people would talk more about their near misses. I'm really not such a sensative guy in real life, I go to extra ends to try and adjust my tone here to take extra care in keeping the information flowing. Quote: (Originally Posted by Drmike) oh for crying out loud. critiquing the inspo design in no way is cutting him down and making it harder for people to admit an accident. thats a stupid association . iF ANYTHING its taking blame away from the user. Unless like some he is having an intimate sexual relationship with his unit and thus takes any critisism of it no matter how justified as a personal afront....hmm that sounds familar. See your diving an Evo now too as for if this discussion should be made here or in an a different catagory..oh dear -how sad -never mind if a mod wants to move it elsewhere then whso cares - hardly a crime me posting it here - worse things happen at sea (just ask john). personally i would have thought a thread discussing a near accident involving the o-ring seal design on the inspo is exactly the right place to have a discussion on the dangers of the o-ring seal design on the inspo but then again Im no ostrich nor am I in love with my units nor do I casually and HABITUALY accept faulty designs in LIFE SUPPORT SYSTEMS Personaly Id rather people pulled their heads out of the sand dropped their silly personal bias stop habitualy accepting design flaws as the norm and then, maybe, we wont have threads like this one or other near misses to read in the 1st place. Now hows that for an idea? Its called prevention rather than cure. This design flaw has been know for a decade (since the 1st user took a hit) if we as a community had done something about it then (instead of just as usual accepting it and saying something like 'all units have their ares that need a little extra care" then this guy wouldnt have been in a potentialy life threatening situation in the 1st place. Life support systems should be robustly designed. They should not have areas that need 'little extra care', they shouldnt have any 'gotchas' . Is the seal design safe? Yes - IF the user is extra carefull with it. But humans make mistakes. A safe design should take that into accout as much as possible and be as far as possible IDIOT Proof. Yes he made an assembly error - but the fact is the design isnt robuist enough for that not to be a problem (or exist in the 1st place) The seal design is a 'gotcha' that could and should have been removed years ago IMO. __________________ Gill Envy ...Because I wasn't born with gills! ><(°>><(°>><(°>><(°>><(°>><(°>><(°>><(°> Last edited by Gill Envy : 10th August 2007 at 23:36.
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9th August 2007, 05:11	#9 (permalink)
Gilles Worship the feminine Current Rebreather/s: Megalodon Other Rebreather/s: Join Date: Sep 2005 Location: Den Haag (Netherlands) Posts: 761	Re: Stretched "O" ring incident Quote: (Originally Posted by Drmike) oh for crying out loud. critiquing the inspo design in no way is cutting him down and making it harder for people to admit an accident. thats a stupid association . iF ANYTHING its taking blame away from the user. Unless like some he is having an intimate sexual relationship with his unit and thus takes any critisism of it no matter how justified as a personal afront....hmm that sounds familar. See your diving an Evo now too as for if this discussion should be made here or in an a different catagory..oh dear -how sad -never mind if a mod wants to move it elsewhere then whso cares - hardly a crime me posting it here - worse things happen at sea (just ask john). personally i would have thought a thread discussing a near accident involving the o-ring seal design on the inspo is exactly the right place to have a discussion on the dangers of the o-ring seal design on the inspo but then again Im no ostrich nor am I in love with my units nor do I casually and HABITUALY accept faulty designs in LIFE SUPPORT SYSTEMS Personaly Id rather people pulled their heads out of the sand dropped their silly personal bias stop habitualy accepting design flaws as the norm and then, maybe, we wont have threads like this one or other near misses to read in the 1st place. Now hows that for an idea? Its called prevention rather than cure. This design flaw has been know for a decade (since the 1st user took a hit) if we as a community had done something about it then (instead of just as usual accepting it and saying something like 'all units have their ares that need a little extra care" then this guy wouldnt have been in a potentialy life threatening situation in the 1st place. Life support systems should be robustly designed. They should not have areas that need 'little extra care', they shouldnt have any 'gotchas' . Is the seal design safe? Yes - IF the user is extra carefull with it. But humans make mistakes. A safe design should take that into accout as much as possible and be as far as possible IDIOT Proof. Yes he made an assembly error - but the fact is the design isnt robuist enough for that not to be a problem (or exist in the 1st place) The seal design is a 'gotcha' that could and should have been removed years ago IMO. That post definitely merits green and more. I hope the integrity of cells improve (eventually at least), and ISC determines a clever way to remove cells from the critical path of Meg loop integrity. Quote: (Originally Posted by geordiediver) After about 30 minutes into the 3rd dive, I was feeling a little short of breath, and my breathing rate was increased from the norm. Whilst I did not believe that I was having a CO2 attack, and put it down to some hard finning, I switched over to OC using my BOV, more as a training drill rather than because I feared a major problem, and within a couple of minutes I felt better. I did a dil flush and went back on the loop, and finished the dive (I had only 2 mins of deco according to the VR3), I did not notice any further symptoms. I was only back on the loop for about 10 mins before I surfaced and got back on the boat. Later that evening I was taking my unit apart to change the scrubber, and found the cause of the problem. This one too . I'd like to add that another useful lesson for us is the generous use of BOV/bailout, and/or dil flush on the basis of a slightest inkling (imagined or not). __________________ Gilles http://www.dirrebreather.com Last edited by Gilles : 9th August 2007 at 05:38.
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9th August 2007, 06:04	#10 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,808	Re: Stretched "O" ring incident Quote: (Originally Posted by Gill Envy) I see your perspective, you have good arguments and a healthy level of detachement from your rig(s), more than most, and I think it's still fairly plain to see that such comments kill a thread like this. I'm interested in what seems to encourage vs descourage the relatively rare admission of mistakes and near misses... kid gloves seem appropriate here. Hi Gill, like most people on Rebreather World, I very much value reading near miss acounts. And while I understand what motivated your reponse to Mike's post, I have to say that anybody so thin skinned as to take personally an obvious, generalized and legitimate criticism of a design flaw in their unit, that they decide to keep quiet...the phrase "shrinking violet" comes to mind. In fact, I'd be wiling to bet that any such shrinking violet may actually be timid because they have a reason to be, like not telling us all the embarassing details, which may be understandable, but might also make the whole experience a bit less valuable... Most of us value firsthand accounts of oversights/complacency/dumbass mistakes enough that I think there's always more people here encouraging those posts than not.
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