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TRACI
10-18-2007, 12:27
Should you store you tank for the Winter full, partially full or empty?

ertechsg
10-18-2007, 12:30
store it how ever... if its full one less thing to do for the next time you need it . either way does not hurt the tank or air

RoadRacer1978
10-18-2007, 12:33
I try to keep mine full. Never know when the bug might hit to go diving and I like it to be ready for the adventure. I might wake up one day and decide it's time to join the polar bear club :)

TRACI
10-18-2007, 12:54
I did the Polar Bear thing in Feb at Lake Ouchita in Arkansas, with only a wetsuit, it was freezing!!!!!!!!!!!

RoadRacer1978
10-18-2007, 13:00
I'm thinking about it sometime this winter. Maybe just one dive in a wetsuit to say I've done it. Not anything crazy deep, but I can't afford a drysuit right now or a trip to some warm water place and I really don;t want to stop diving for the winter. I may have to suit up and sit in the bathtub. :) Just to keep from going through withdrawls.

No Misses
10-18-2007, 13:08
Store it any way except empty. If you walk into your LDS with an empty tank, They will insist on a VIP prior to filling the tank. I usually keep mine filled. As Roadracer said, you never know when the bug will hit you :-) It drives be crazy that one of my regular dive buddies does not get her tanks filled until the day before the dive. We live in Florida. Your tanks should be ready to go at a moments notice! It's kind of like a surfer that keeps his board strapped to the car. He is ready when the surf is right.

Happy diving.

skdvr
10-18-2007, 16:07
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.

I am sure that someone will correct me if I am wrong but this is what I have been told.

I personally say dive all year, but if you cannot then keep the tanks full. You may have more days like we are having in Mo. right now where it is the middle of Oct and it is 85* and sunny. It would be a great day to be in the water.

Phil

BSea
10-18-2007, 16:12
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.
Phil

I had never heard this before, but it makes sense.

And as someone else mentioned. Never ever store them empty.

CompuDude
10-18-2007, 16:15
skdvr is right.

Keep them full, or with about 300-500 psi in them. Either way is fine, but completely empty is bad (requires a vis), as is partially full (explosion hazard in a fire).

There's no hard and fast "expiration date" on air fills, but my personal rule of thumb is that if it's more than 6 months old, it's worth a few buck to drain and re-fill. That should get you through the winter. (I know some others who will take their tanks to a year before draining... personally, I've never hit 6 months. LOL)

Venio
10-18-2007, 17:32
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.

I am sure that someone will correct me if I am wrong but this is what I have been told.

I personally say dive all year, but if you cannot then keep the tanks full. You may have more days like we are having in Mo. right now where it is the middle of Oct and it is 85* and sunny. It would be a great day to be in the water.

Phil

Phil, no offense but pressure cannot be represented in pounds since that is a measure of force and not of pressure, which in this country is measured most commonly in psi(pounds per square inch). I'm making the remark only so so we don't confuse people that are trying to learn.

Thanks.

terrillja
10-18-2007, 17:40
I just dump to 250-500Lbs for the winter, but it looks like I will be diving over thanksgiving, so I'll have to get them refilled. I was told that it is better to to leave the tanks with lower pressure, so they don't push too much pressure out on the AL. I also have stickers on my tanks that mark them as nonflammable compressed air, just so people know if that valve opens near a flame, it isn't going to explode. (Since all my tanks are 21, not EAN)

skdvr
10-18-2007, 18:38
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.

I am sure that someone will correct me if I am wrong but this is what I have been told.

I personally say dive all year, but if you cannot then keep the tanks full. You may have more days like we are having in Mo. right now where it is the middle of Oct and it is 85* and sunny. It would be a great day to be in the water.

Phil

Phil, no offense but pressure cannot be represented in pounds since that is a measure of force and not of pressure, which in this country is measured most commonly in psi(pounds per square inch). I'm making the remark only so so we don't confuse people that are trying to learn.

Thanks.


You are correct and I appologize. I guess I just put it like that because that it how I would say it if someone asked how much air I had in my tank. I would say 3000 lbs not 3000 pounds per square inch.

I completely understand what you are saying and I should have been more clear.

Thank you for clearing it up...

Phil

DZorn00
10-19-2007, 13:24
Also keeping them full keeps the tank from collecting moisture inside and corroding.

mm2002
10-19-2007, 19:38
I'm thinking about it sometime this winter. Maybe just one dive in a wetsuit to say I've done it. Not anything crazy deep, but I can't afford a drysuit right now or a trip to some warm water place and I really don;t want to stop diving for the winter. I may have to suit up and sit in the bathtub. :) Just to keep from going through withdrawls.

Man, I'm totally with you there. I'm dreading the winter time now. I'll find a way around it though :smiley36:

Charlotte Smith
10-20-2007, 09:04
Im just NOT gonna have a winter...like someone said already, it had been 85 and sunny some days and a couple of jugs of very warm water will make it more comfortable to dive with a wetsuit this time of year . And then there is Cozumel in December and MORE warm water until spring.....
However.....I store mine full.....in my house where the climate is controlled year round and I drain and refill if it's awhile before I dive...sometimes after 3 months....but that's just me.....I want fresh air all the time.....

cheebaweebie
10-20-2007, 10:54
Good call on the jugs of warm water in the suit. Beats pissing in it. I store my tanks also either full or no less than 300 lbs. I you drain completely empty they can flash rust inside then your out a few $ getting the tanks repaired. I dive hp steel 120's but also have AL 80's. LOVE my steels

Charlotte Smith
10-20-2007, 21:13
Good call on the jugs of warm water in the suit. Beats pissing in it. I store my tanks also either full or no less than 300 lbs. I you drain completely empty they can flash rust inside then your out a few $ getting the tanks repaired. I dive hp steel 120's but also have AL 80's. LOVE my steels
We stuff a cooler full of hot water to pour down our suits.....if we could only figure out how to carry warmed blankets on the boat for the surface interval.:smiley2:

chace_nicole
10-20-2007, 22:25
I'm thinking about it sometime this winter. Maybe just one dive in a wetsuit to say I've done it. Not anything crazy deep, but I can't afford a drysuit right now or a trip to some warm water place and I really don;t want to stop diving for the winter. I may have to suit up and sit in the bathtub. :) Just to keep from going through withdrawls.

Oklahoma City Community College has scuba tuesdays $3 6pm-8pm, with 18ft divewell. It's still a pool but it keeps the withdrawls at bay. :)

MSilvia
10-21-2007, 07:24
If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk.
Why on earth would you have a 5000 psi burst disk? In any case, I think the best way to store a tank for the winter is the same way you store it during the rest of the year... ready to dive.
http://farm1.static.flickr.com/134/373265049_b50e36f664.jpg

Splitlip
10-21-2007, 08:40
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.

I am sure that someone will correct me if I am wrong but this is what I have been told.

I personally say dive all year, but if you cannot then keep the tanks full. You may have more days like we are having in Mo. right now where it is the middle of Oct and it is 85* and sunny. It would be a great day to be in the water.

Phil

Phil, no offense but pressure cannot be represented in pounds since that is a measure of force and not of pressure, which in this country is measured most commonly in psi(pounds per square inch). I'm making the remark only so so we don't confuse people that are trying to learn.

Thanks.


You are correct and I appologize. I guess I just put it like that because that it how I would say it if someone asked how much air I had in my tank. I would say 3000 lbs not 3000 pounds per square inch.

I completely understand what you are saying and I should have been more clear.

Thank you for clearing it up...

Phil

Phil:
I would nor worry about it. I think we all know what is meant when we say "x" lbs when measuring gas in a cylinder.

Splitlip
10-21-2007, 09:01
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.

I am sure that someone will correct me if I am wrong but this is what I have been told.

I personally say dive all year, but if you cannot then keep the tanks full. You may have more days like we are having in Mo. right now where it is the middle of Oct and it is 85* and sunny. It would be a great day to be in the water.

Phil

Phil, no offense but pressure cannot be represented in pounds since that is a measure of force and not of pressure, which in this country is measured most commonly in psi(pounds per square inch). I'm making the remark only so so we don't confuse people that are trying to learn.

Thanks.

Hopefully people trying to learn are doing so with a qualified instructor and not just by lurking here. :smiley36: Even if they have no understanding of physical science or have never checked a tire's pressure, we would hope that during their BOW they will understand that "3000 lb in an Al80", does not weigh a ton and a half.

rhephburn3900
10-21-2007, 09:14
store it full, You never when a dive opertunity will present itself,
but keep it above 300 psi to avoid any moisture entering the tank.
I keep all of my tanks full.
Stay Wet!

mitsuguy
10-21-2007, 10:29
If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk.
Why on earth would you have a 5000 psi burst disk? In any case, I think the best way to store a tank for the winter is the same way you store it during the rest of the year... ready to dive.


the actual disk failure should be at 4200 psi... enough difference so that if a slightly overfilled tank (3300-3400 psi) is left in a hot car, it will not be enough to blow a disk, but if subjected to real heat, it will pop the disk... the aluminum tank ~should~ be able to hold past 4200 psi which is why that value is used...

Venio
10-21-2007, 11:27
I have always heard best to store it completely full or with a couple of hundred lbs in it. Reason being is incase of a fire.

Completely full = If there is a fire the burst disc will go before the metal is comprimised and the tank explodes.

couple hundred lbs = If there is a fire the metal of the tank will fail but there will be very little pressure built up in the tank when it happens causing no real exposion.

If there is say 2000 lbs in a 3000lb tank the metal could fail before the pressure reaches the 5000 psi fail point of the burst disk. The pressure may get to 4500 lbs and if the metal fails at that point then if there is a fireman near by it could really ruin their day.

I am sure that someone will correct me if I am wrong but this is what I have been told.

I personally say dive all year, but if you cannot then keep the tanks full. You may have more days like we are having in Mo. right now where it is the middle of Oct and it is 85* and sunny. It would be a great day to be in the water.

Phil

Phil, no offense but pressure cannot be represented in pounds since that is a measure of force and not of pressure, which in this country is measured most commonly in psi(pounds per square inch). I'm making the remark only so so we don't confuse people that are trying to learn.

Thanks.

Hopefully people trying to learn are doing so with a qualified instructor and not just by lurking here. :smiley36: Even if they have no understanding of physical science or have never checked a tire's pressure, we would hope that during their BOW they will understand that "3000 lb in an Al80", does not weigh a ton and a half.

The statement is incorrect and I just point out the mistake! I've actually heard "qualified instructor" also making an incorrect statement when talking about pressure in class. So, forgive me for correcting such an obvious mistake. In any case physics is an exact science when it comes to units and terminology.

Hollywood703
10-22-2007, 11:32
never ever store the tank empty......unpressurized tanks are more likely to inhibt rust as water isnt fighting against pressure to get in....even if you have 100psi, its better than leaving it empty. Only time it should be empty is when they hydro or VIP the tank.

MSilvia
10-22-2007, 11:46
the actual disk failure should be at 4200 psi... enough difference so that if a slightly overfilled tank (3300-3400 psi) is left in a hot car, it will not be enough to blow a disk, but if subjected to real heat, it will pop the disk... the aluminum tank ~should~ be able to hold past 4200 psi which is why that value is used...
Right... using a 5000 psi burst disk in an AL80 seems rather excessive. I'd want a disk to go way before 5000 psi.

TxHockeyGuy
10-22-2007, 12:24
I've been told several times you always store full or completely empty because of the risk of explosion in a fire. I personally don't think it is a good idea to store with only a 100 or so psi in the tank as that 100 psi will easily be 300 psi or more in the event of a fire and 300 psi is still quite a bit of force.

CompuDude
10-22-2007, 14:07
I've been told several times you always store full or completely empty because of the risk of explosion in a fire. I personally don't think it is a good idea to store with only a 100 or so psi in the tank as that 100 psi will easily be 300 psi or more in the event of a fire and 300 psi is still quite a bit of force.

300 PSI is 1/10th the rated capacity of a 3000psi-rated tank. How is this a lot of force?

Never empty a tank completely, unless you like wasting money on visual inspections and like to risk rust and other moisture-related problems with the tanks you own.

300-500 psi is the correct amount to store them with, if you don't want to store them full.

MSilvia
10-22-2007, 15:02
I've been told several times you always store full or completely empty because of the risk of explosion in a fire.
I've been told several times not to watch tv with the lights out because of the risk it'll cause blindness. That doesn't mean the risk is significant, so much as it means some people are more likely to believe a rumor started by a lightbulb salesman than they are to question the accuracy of what they're told.

I would think that in a fire, your neck o-ring and burst disk would fail and vent the tank long before the tank itself was structurally compromised enough to make tank failure a significant risk to a fire fighter... which is the only reason a tank failure in a fire would matter at all. It's not like you're going to be able to use it afterward either way.

I'd recommend storing the tank under the assumption that it isn't going to be destroyed before you use it next, avoid smoking in bed, and don't plug too many frayed electrical cords into the same outlet.

TxHockeyGuy
10-22-2007, 18:28
I've been told several times you always store full or completely empty because of the risk of explosion in a fire. I personally don't think it is a good idea to store with only a 100 or so psi in the tank as that 100 psi will easily be 300 psi or more in the event of a fire and 300 psi is still quite a bit of force.

300 PSI is 1/10th the rated capacity of a 3000psi-rated tank. How is this a lot of force?

Never empty a tank completely, unless you like wasting money on visual inspections and like to risk rust and other moisture-related problems with the tanks you own.

300-500 psi is the correct amount to store them with, if you don't want to store them full.

300 PSI can still do a lot of damage, being at 1/10th the rated capacity has nothing to do with it. If you had a tank that could handle 30,000 psi (they do exist but not for scuba) I don't think anyone would argue that 3,000 psi (1/10th the rated capacity) could be dangerous if released suddenly. I honestly have no idea what in the tank would fail first in the event of a fire but it's possible that if the tank did fail it could send nearby things off at a very high rate of speed, even with just 300 psi in the tank.

The post from MSilvia does have some good points. The closest I've seen to anything like a scuba cylinder in a fire is a a fire extinguisher. In that case it's burst disk went before any neck o-ring, but it was full. I'd be interested to hear if anyone knows of any tests ever performed on partially full tanks in a fire. The only tests I know of is with a full tank and since that result is known, I'll stick with that. To each their own.