The great Spare Air / SpareAir topic

[WreckWriter]

I had one basically explode in my hands once. It was a long time ago, when they were rated at about 1800 psi. I was filling it and didn't check my bank valves, put 3000 in it. The "burst disc" blew which in turn blew off the whole top of it. Parts, pieces, and springs everywhere. Scared me 3/4 to death and if I had it pointed in the opposite direction would have certainly hurt me. I never touched another one since.

Tom

 

[MikeFerrara]

Here is my idea for a good use of a spair air. After reviewing the equipment requirements for the SDI Solo Diver course I think one could...Buy a bunch of them and string them on a belt..over the shoulder like a ammo belt and go take that solo diver course.

 

[angel 13]

Does anybody know which make does the mini tanks(the type that fit directly into your mouth) and about how much they cost?

 

[O-ring]

They are at Spare Air Website ...but I wouldn't recommend using one...you can get more spare gas from your buddy's tanks...

I think they are around $300 or so, but you could probably get one cheaper at leisurepro or diveinn...

 

[MikeS]

Angel,

If I might make a suggestion, think about what your intended use is for the mini tank (spare air), then calculate the duration of the air supply. You might find as I did that the spare air is a waste of money.

Paragraph 7-4.1 of Volume 2 of the U.S. Navy Diving Manual describes the process of calculating the duration of the air supply in great detail. The Reader’s Digest version would go something like this:

The duration of the air supply in minutes is equal to the volume of air divided by the volume of air used per minute.

The volume of air used per minute is calculated based on the surface consumption rate (based on level of activity) adjusted for depth (the deeper you go the more air volume used).

The Oxygen consumption rate chart indicates that on average, with a moderate work load the surface consumption rate is 1.0 cubic feet per minute. But hey, I’m out of air and adrenalin has kicked in, better use 1.5 cubic feet per minute.

So that means that at the surface a 3 cubic foot air tank is good for 2 minutes.
At 15 feet (safety stop), 82.5 seconds
At 33 feet, 60 seconds
At 66 feet, 40 seconds
At 99 feet, 30 seconds

The consumption rate numbers are subjective and some would argue too conservative. Based on these calculations I decided to go with a 30 cubic foot pony. I feel that that gives me enough time to address a minor problem (that caused me to run out of air) and surface safely from 100 fsw including a five-minute safety stop at 15 fsw.

Hope this helps,
Mike

 

[angel 13]

Thanks guys.
Any way I wouldn't of used them as spear bottles for scuba diving, just to be able to stay longer under water, like for watching fish at about 2-3 meters deep

 

[SPEEDSTER]

Have you been certified to use SCUBA? There is a lot more to breathing underwater than a snorkeler might think. Do not, I repeat DO NOT buy and use a spare air without proper SCUBA instruction. People die from exactly what you are talking about.

Mike

 

[SPEEDSTER]

It's been a couple of minutes and you haven't responded even though you are still logged on, I don't want you to think that the previous post doesn't apply to you because you will only be 2-3 meters deep, it takes less than 1 meter of water to cause life-threatening injuries . PLEASE do not use a spare air without proper instruction.

 

[Scubaroo]

Hi angel13,

As you might have gathered from SPEEDSTER's responses, using a SpareAir without scuba instruction can easily be life threatening. This isn't just rhetoric.

The reason for this is that if you take a breath from a SpareAir while underwater (or any other compressed air source such as a scuba tank), the air in your lungs will be at a higher pressure than the air at the surface, due to the ambient pressure of the surrounding water you are immersed in. As you swim back up to the surface, the air in your lungs will EXPAND, trying to match the lower surface air pressure. This can easily result in a "lung overexpansion injury". Your lungs literally stretch like a balloon, and they can only stretch so far in your chest before injury occurs. Such injuries can result in collapsed lungs, or air being forced into the bloodstream, which can result in embolisms. Both are very serious conditions, and more than one (or even one hundred) divers have died from such injuries, which as SPEEDSTER pointed out, can happen in as little as a metre of water.

You can kill yourself in a swimming pool with scuba, and a SpareAir IS a scuba system, and shouldn't be used without scuba instruction, because of the risks outlined. It is unlikely that you would be able to buy or refill a SpareAir without a scuba certification card anyway, but there are always idiots who will loan gear to people without informing them of the very real risks.

Sorry that you got jumped on, but we'd hate to see anyone come to harm.

Ben

 

[IceBergSlim]

just purchased a "spare air".... As one who has run short on gas..I ask why this deivce is concidered a nusance or otherwisse un-worthy.? I did run short on o2 during a dive recently.... a bunch of folks were hogging the ascent line and I had no choice to do no other than hold my breath or try to snorkle with high seas....So I have this spare air thing..I need some advice about how to mount it to my bcd. Any advice would be most welcome...