Nitrox under pressure (300 bar) - Page 2

***wilbo*** · May 26th, 2009, 04:41 PM

Quote: (Originally Posted by Fiona)

Lots of people don't have a "team"

Very, very true.

Quote:

Adam buy what is right for you, but I don't think there would be any advantage in buying 300 bar 10's.

The standard set is D12s. If you get onto a boat and dive with other DIR divers in a DIR team in the UK - there is a very high probablility that they will have D12s.

**keri.lewis** · May 26th, 2009, 05:00 PM

Quote: (Originally Posted by Fiona)

but I don't think there would be any advantage in buying 300 bar 10's.

Most 10l 300bar Fabers are around 14.4Kg with a net buoyancy of about negative 2.8kg each without the fill, bands and manifold.. they would be over 10Kg negative as a twinset if full of nitrox..

This compares to a 12l 232bar ECS with a weight of around 13.9Kg and a buoyancy of about +0.3kg without fill, bands and manifold

So the weight will be about the same on your back out of the water or moving from car to boat (there may be a personal, integrated-weight difference). Just the potential fill issues and balancing issues.

adrian.brown · May 26th, 2009, 07:08 PM

When I started out down the twin set route a few years back and was a dumb-ass-deep-air-diver I thought 300 bar twin 10's were the right choice 6000 litres of gas and all that.

Shortly after the purchase I found out how wrong I was as you never get the 300 bar worth of gas fill with air and a fill station that pumps nitrox to that pressure is rare.

The real pain with ten's is their too short, hard to get your rig on and off even harder to trim out properly and don't aid weight wise with a balanced rig. I used them around ten times and then got shot of them.

Adam1V · May 29th, 2009, 01:42 PM

Quote:

The real pain with ten's is their too short

This isnt true for the euro style cylinders.
I bought my first set of twin 10s (232) around 2-3 months ago. I instantly fell in love with twins, but shortly realised they were too small (from a capacity point of view).
Not only that, but when I almost sucked them dry last weekend there was a big difference between empty and full weight, when I was stopped at 6m I found myself quite light, but still managed to hold it for 10 mins of deco.

The Euro Style twin 10s im currently using are longer than the normal 10s that most people are famililar with.

I've found out the following information with reference to cylinder differences:

Quote:

Euro 10 232b single cylinder 14 / 16Kg
Euro 10 300b single cylinder 17.5 / 20Kg
Euro 12 232b single cylinder 16 / 18Kg
Euro 12 300b single cylinder 20.5 / 23kg

With valve and boot

The weights above are for empty / full.
The banding and center connections add an additional 3kg on top.

Can I ask what the 'D' is before the 12? Is it just a standard Faber 12L style cylinder?

***wilbo*** · May 29th, 2009, 01:53 PM

Quote: (Originally Posted by Adam1V)

Can I ask what the 'D' is before the 12? Is it just a standard Faber 12L style cylinder?

If you are referring to my post - D12 = Double 12's/ twinset 12s / 24 litres..

badger · May 29th, 2009, 11:29 PM

Quote: (Originally Posted by Fiona)

Lots of people don't have a "team"

Adam buy what is right for you, but I don't think there would be any advantage in buying 300 bar 10's.

Yeah, duh Wilbo.....

lizardland · May 31st, 2009, 05:09 PM

Quote: (Originally Posted by adrian.brown)

When I started out down the twin set route a few years back and was a dumb-ass-deep-air-diver I thought 300 bar twin 10's were the right choice 6000 litres of gas and all that.

Shortly after the purchase I found out how wrong I was as you never get the 300 bar worth of gas fill with air and a fill station that pumps nitrox to that pressure is rare.

The real pain with ten's is their too short, hard to get your rig on and off even harder to trim out properly and don't aid weight wise with a balanced rig. I used them around ten times and then got shot of them.

Yeah, I've bought 300bar cylinders on and off over the years and always regretted it.

It's nothing to do with gas physics, shops don't like doing 300bar fills because it's more work for them for air fills and it means they need to tap into their higher pressure j's sooner for doing nitrox fills which shops without boosters hate to do. Inevitably you get 270bar fills if you're lucky. My local shop fills my 232bar cylinders to 250bar anyway (I guess they know me too well

) so the added weight and cost and hassle just for an extra 20bar seems daft.

The only 300bar cylinders worth having are 7l's but that's more to do with their size and weight than gas volume. Or 300bar 3's for sump diving... but that's not really DIR

*Fredrik Taule* · May 31st, 2009, 07:17 PM

Quote: (Originally Posted by lizardland)

Yeah, I've bought 300bar cylinders on and off over the years and always regretted it.

It's nothing to do with gas physics, shops don't like doing 300bar fills because it's more work for them for air fills and it means they need to tap into their higher pressure j's sooner for doing nitrox fills which shops without boosters hate to do. Inevitably you get 270bar fills if you're lucky. My local shop fills my 232bar cylinders to 250bar anyway (I guess they know me too well

) so the added weight and cost and hassle just for an extra 20bar seems daft.

The only 300bar cylinders worth having are 7l's but that's more to do with their size and weight than gas volume. Or 300bar 3's for sump diving... but that's not really DIR

For people who are diving 15l 232bar single tanks, a 12l 300bar cylinders is probably a better alternative (unless the additional negative bouyancy will mess it up).
At 230bar (15l) and 275-300bar (12l) they're "pretty much the same" in terms of volume. The 12l 300bar i more slim (171mm instead of 203mm diamter), longer/taller and saves you 2-3kg's of weight (which is nice for cold water drysuit diving). They're pretty much the same price.
I've never liked the short and fat 15l 232bar cylinders, so when we came across 12l 300bar cylinders I liked that idea better from day 1.

Fredrik

*Fredrik Taule* · May 31st, 2009, 07:24 PM

Quote: (Originally Posted by Adam1V)

Hi,
Im considering 300bar cylinders but unfortunatly I have very little experience with this.
I have heard whispers from various people that nitrox under pressure (above 270bar) reacts differently and therefore may not be as expected,
for example, a 32% @ 300bar might even out to 30% at 260bar.
Is it likely to change that much or is it very neglegable?

I have very little experience with this so any information would be interesting to learn.
My question is really from two points of view, how does it affect the diver (if so) and the nitrox blender.

thanks,

Our 32% nitrox bank are 80 liter 300 bar cylinders. There are lots of similarities between filling 200 and 300 bar nitrox 32, and no big difference for the blender.
Doesn't make a difference to the diver either.

If you're considering a twin set that you can use for a lot of different types of diving 2*12 232bar is really the "only" smart choice.

Fredrik

speedlime · June 1st, 2009, 04:41 PM

2*12 232bar is really the "only" smart choice. I agree with Fredric. We have 8 sets in our team and they are well used for cave and T1 type diving here.

May 26th, 2009, 04:41 PM	#11 (permalink)
*wilbo* (Online) Moderator Join Date: Nov 2005 Location: UK Posts: 1,569	Quote: (Originally Posted by Fiona) Lots of people don't have a "team" Very, very true. Quote: Adam buy what is right for you, but I don't think there would be any advantage in buying 300 bar 10's. The standard set is D12s. If you get onto a boat and dive with other DIR divers in a DIR team in the UK - there is a very high probablility that they will have D12s. __________________ Cheers! Wilbo DIR explorers: DIR Yorkshire Divers: YorkshireDivers One of the Foxturd chimps

May 26th, 2009, 05:00 PM	#12 (permalink)
keri.lewis(Offline) Wreck Ferret Join Date: Nov 2007 Location: Hampshire Posts: 1,065	Quote: (Originally Posted by Fiona) but I don't think there would be any advantage in buying 300 bar 10's. Most 10l 300bar Fabers are around 14.4Kg with a net buoyancy of about negative 2.8kg each without the fill, bands and manifold.. they would be over 10Kg negative as a twinset if full of nitrox.. This compares to a 12l 232bar ECS with a weight of around 13.9Kg and a buoyancy of about +0.3kg without fill, bands and manifold So the weight will be about the same on your back out of the water or moving from car to boat (there may be a personal, integrated-weight difference). Just the potential fill issues and balancing issues. __________________ Even a "bad" day diving beats a day in the office... Keri The more I learn.. the more ignorant I realise I am..

May 26th, 2009, 07:08 PM	#13 (permalink)
adrian.brown(Offline) U.K's first XK1 owner :) Join Date: Feb 2008 Location: Somerset. United Kingdom Posts: 614	When I started out down the twin set route a few years back and was a dumb-ass-deep-air-diver I thought 300 bar twin 10's were the right choice 6000 litres of gas and all that. Shortly after the purchase I found out how wrong I was as you never get the 300 bar worth of gas fill with air and a fill station that pumps nitrox to that pressure is rare. The real pain with ten's is their too short, hard to get your rig on and off even harder to trim out properly and don't aid weight wise with a balanced rig. I used them around ten times and then got shot of them. __________________ Im not ginger im sandy gold

May 29th, 2009, 01:53 PM	#15 (permalink)
*wilbo* (Online) Moderator Join Date: Nov 2005 Location: UK Posts: 1,569	Quote: (Originally Posted by Adam1V) Can I ask what the 'D' is before the 12? Is it just a standard Faber 12L style cylinder? If you are referring to my post - D12 = Double 12's/ twinset 12s / 24 litres.. __________________ Cheers! Wilbo DIR explorers: DIR Yorkshire Divers: YorkshireDivers One of the Foxturd chimps

May 29th, 2009, 11:29 PM	#16 (permalink)
badger(Offline) GUE Instructor Intern Join Date: Apr 2006 Location: British Isles Posts: 254	Quote: (Originally Posted by Fiona) Lots of people don't have a "team" Adam buy what is right for you, but I don't think there would be any advantage in buying 300 bar 10's. Yeah, duh Wilbo..... __________________ "I may say that this is the greatest factor -- the way in which the expedition is equipped -- the way in which every difficulty is foreseen, and precautions taken for meeting or avoiding it. Victory awaits him who has everything in order -- luck, people call it. Defeat is certain for him who has neglected to take the necessary precautions in time; this is called bad luck." --from The South Pole, by Roald Amundsen.

May 29th, 2009, 01:42 PM	#14 (permalink)
Adam1V(Offline) New Member Join Date: Apr 2009 Location: UK Posts: 38	Quote: The real pain with ten's is their too short This isnt true for the euro style cylinders. I bought my first set of twin 10s (232) around 2-3 months ago. I instantly fell in love with twins, but shortly realised they were too small (from a capacity point of view). Not only that, but when I almost sucked them dry last weekend there was a big difference between empty and full weight, when I was stopped at 6m I found myself quite light, but still managed to hold it for 10 mins of deco. The Euro Style twin 10s im currently using are longer than the normal 10s that most people are famililar with. I've found out the following information with reference to cylinder differences: Quote: Euro 10 232b single cylinder 14 / 16Kg Euro 10 300b single cylinder 17.5 / 20Kg Euro 12 232b single cylinder 16 / 18Kg Euro 12 300b single cylinder 20.5 / 23kg With valve and boot The weights above are for empty / full. The banding and center connections add an additional 3kg on top. Can I ask what the 'D' is before the 12? Is it just a standard Faber 12L style cylinder?

May 31st, 2009, 05:09 PM	#17 (permalink)
lizardland(Offline) LCS Join Date: Nov 2005 Location: Evidently Chickentown Posts: 1,117	Quote: (Originally Posted by adrian.brown) When I started out down the twin set route a few years back and was a dumb-ass-deep-air-diver I thought 300 bar twin 10's were the right choice 6000 litres of gas and all that. Shortly after the purchase I found out how wrong I was as you never get the 300 bar worth of gas fill with air and a fill station that pumps nitrox to that pressure is rare. The real pain with ten's is their too short, hard to get your rig on and off even harder to trim out properly and don't aid weight wise with a balanced rig. I used them around ten times and then got shot of them. Yeah, I've bought 300bar cylinders on and off over the years and always regretted it. It's nothing to do with gas physics, shops don't like doing 300bar fills because it's more work for them for air fills and it means they need to tap into their higher pressure j's sooner for doing nitrox fills which shops without boosters hate to do. Inevitably you get 270bar fills if you're lucky. My local shop fills my 232bar cylinders to 250bar anyway (I guess they know me too well ) so the added weight and cost and hassle just for an extra 20bar seems daft. The only 300bar cylinders worth having are 7l's but that's more to do with their size and weight than gas volume. Or 300bar 3's for sump diving... but that's not really DIR __________________ Can you imagine drifting along in the sea with your mouth open and a load of f***ing plankton going in? You'd like it, would you? www.westons-cider.co.uk The Lot isn't the only place to dive: http://www.lulu.com/content/613554

May 31st, 2009, 07:17 PM	#18 (permalink)
Fredrik Taule(Offline) GUE Instructor Join Date: Oct 2006 Location: Oslo, Norway Posts: 120	Quote: (Originally Posted by lizardland) Yeah, I've bought 300bar cylinders on and off over the years and always regretted it. It's nothing to do with gas physics, shops don't like doing 300bar fills because it's more work for them for air fills and it means they need to tap into their higher pressure j's sooner for doing nitrox fills which shops without boosters hate to do. Inevitably you get 270bar fills if you're lucky. My local shop fills my 232bar cylinders to 250bar anyway (I guess they know me too well ) so the added weight and cost and hassle just for an extra 20bar seems daft. The only 300bar cylinders worth having are 7l's but that's more to do with their size and weight than gas volume. Or 300bar 3's for sump diving... but that's not really DIR For people who are diving 15l 232bar single tanks, a 12l 300bar cylinders is probably a better alternative (unless the additional negative bouyancy will mess it up). At 230bar (15l) and 275-300bar (12l) they're "pretty much the same" in terms of volume. The 12l 300bar i more slim (171mm instead of 203mm diamter), longer/taller and saves you 2-3kg's of weight (which is nice for cold water drysuit diving). They're pretty much the same price. I've never liked the short and fat 15l 232bar cylinders, so when we came across 12l 300bar cylinders I liked that idea better from day 1. Fredrik __________________ Oceanic Tech, Fue.no - www.fue.no Last edited by Fredrik Taule; June 1st, 2009 at 11:21 PM..

May 31st, 2009, 07:24 PM	#19 (permalink)
Fredrik Taule(Offline) GUE Instructor Join Date: Oct 2006 Location: Oslo, Norway Posts: 120	Quote: (Originally Posted by Adam1V) Hi, Im considering 300bar cylinders but unfortunatly I have very little experience with this. I have heard whispers from various people that nitrox under pressure (above 270bar) reacts differently and therefore may not be as expected, for example, a 32% @ 300bar might even out to 30% at 260bar. Is it likely to change that much or is it very neglegable? I have very little experience with this so any information would be interesting to learn. My question is really from two points of view, how does it affect the diver (if so) and the nitrox blender. thanks, Our 32% nitrox bank are 80 liter 300 bar cylinders. There are lots of similarities between filling 200 and 300 bar nitrox 32, and no big difference for the blender. Doesn't make a difference to the diver either. If you're considering a twin set that you can use for a lot of different types of diving 212 232bar is really the "only" smart choice. Fredrik __________________ Oceanic Tech, Fue.no - www.fue.no Last edited by Fredrik Taule; June 1st, 2009 at 11:20 PM..*

June 1st, 2009, 04:41 PM	#20 (permalink)
speedlime(Offline) GUE Member Join Date: Nov 2006 Location: Bermuda Posts: 145	2*12 232bar is really the "only" smart choice. I agree with Fredric. We have 8 sets in our team and they are well used for cave and T1 type diving here.