Hemlon
Contributor
I am considering the purchase of a Spare Air. How are they refilled? Also, do they have to be inspected annually like regular tanks?
Thanks!
Thanks!
Spare Air Questions
- Thread starter Hemlon
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Around scubaboard... Spare Air is a four letter word.
But to answer your questions real quick... the Spare Air is refilled by using a transfill adapter from your main scuba tank. Maintenance is the same as a regular cylinder.. regular yearly inspections, and hydro testing every 5 years.
Now the negative bit... do the math on the spare air and determine if it is a suitable solution for you. Generally speaking, spare air will only provide enough air to get to the surface at depths less than 100 feet in the best case scenario. Worst case, with panic (and higher air consumption as a result) or entanglement issues to worry about, Spare air will not provide enough air to make the surface, and a larger pony bottle would prove a better option.
Others will probably chime in, but a quick search on spare air would probably yield a ton of results / opinion / etc.
-B
But to answer your questions real quick... the Spare Air is refilled by using a transfill adapter from your main scuba tank. Maintenance is the same as a regular cylinder.. regular yearly inspections, and hydro testing every 5 years.
Now the negative bit... do the math on the spare air and determine if it is a suitable solution for you. Generally speaking, spare air will only provide enough air to get to the surface at depths less than 100 feet in the best case scenario. Worst case, with panic (and higher air consumption as a result) or entanglement issues to worry about, Spare air will not provide enough air to make the surface, and a larger pony bottle would prove a better option.
Others will probably chime in, but a quick search on spare air would probably yield a ton of results / opinion / etc.
-B
They are also called Three Breaths To Death for a reason. If you actually need one, it would likely be in a panic situation. You would suck it down before you even got a few feet up. For the same price you can get a 30 cu ft pony bottle and reg, or for free you can watch your spg and dive your plan. 
RICHinNC
Contributor
Get a at least a 19 cuft pony.....stay away from SA.
But on the other hand....Thanks SA for taking on TSA and winning.....I appreciate it.
But on the other hand....Thanks SA for taking on TSA and winning.....I appreciate it.
As you are posting this in the Solo Divers forum it makes me think that you are intending this as a redundant air source? (Forgive me if I'm incorrect). IMO using a spare air like this could be extremely dangerous. As the other posters have already said - a pony costs around the same, and is also the minimum of what you need to solo dive at most depths.
Ick, I didn't even notice what forum it was posted in. Forget it. Bad idea for redundant air source.
MaxBottomtime's characterization of Spare Air as "Three Breaths to Death" isn't an unfair claim when Spare Air is used at an inappropriate depth.
Here's the calculations I mentioned earlier. Notice that Spare Air will NEVER provide you with enough air for a safety stop. Further, in almost all circumstances (Calm @ 50 feet being the exception), maintaining a safe ascent rate becomes a serious problem. It will either barely be possible, or not be possible at all.
Decent Air Consumption rate (.55 SAC):
@ 50 feet = 2:06 minutes (20 fpm ascent)
@ 75 feet = 1:36 minutes (47 fpm ascent)
@100 feet = 1:18 minutes (not enough for safe ascent @ 60fpm)
@120 feet = 1:06 minutes (not enough for safe ascent @ 60fpm)
Panicked Air Consumption rate (1.0 SAC):
@ 50 feet = 1:06 minutes (46 fpm ascent)
@ 75 feet = 0:54 minutes (not enough for safe ascent @ 60fpm)
@ 100 feet = 0:42 minutes (not enough for safe ascent @ 60fpm)
@ 120 feet = 0:36 minutes (not enough for safe ascent @ 60fpm)
A 19cf pony, in comparison, would give you:
Calm @ 120 feet = 7:06 minutes
Panicked @ 120 feet = 3:54 minutes
Kinda gives you an idea about why the common held view is that a 19cf pony is the minimum acceptable size for a redundant air source.
-Brandon.
(some of my math is likely wrong.. but it's close enough for illustration)
MaxBottomtime's characterization of Spare Air as "Three Breaths to Death" isn't an unfair claim when Spare Air is used at an inappropriate depth.
Here's the calculations I mentioned earlier. Notice that Spare Air will NEVER provide you with enough air for a safety stop. Further, in almost all circumstances (Calm @ 50 feet being the exception), maintaining a safe ascent rate becomes a serious problem. It will either barely be possible, or not be possible at all.
Decent Air Consumption rate (.55 SAC):
@ 50 feet = 2:06 minutes (20 fpm ascent)
@ 75 feet = 1:36 minutes (47 fpm ascent)
@100 feet = 1:18 minutes (not enough for safe ascent @ 60fpm)
@120 feet = 1:06 minutes (not enough for safe ascent @ 60fpm)
Panicked Air Consumption rate (1.0 SAC):
@ 50 feet = 1:06 minutes (46 fpm ascent)
@ 75 feet = 0:54 minutes (not enough for safe ascent @ 60fpm)
@ 100 feet = 0:42 minutes (not enough for safe ascent @ 60fpm)
@ 120 feet = 0:36 minutes (not enough for safe ascent @ 60fpm)
A 19cf pony, in comparison, would give you:
Calm @ 120 feet = 7:06 minutes
Panicked @ 120 feet = 3:54 minutes
Kinda gives you an idea about why the common held view is that a 19cf pony is the minimum acceptable size for a redundant air source.
-Brandon.
(some of my math is likely wrong.. but it's close enough for illustration)
OP
Hemlon
Contributor
Great advice...thanks!
Mandy3206
Contributor
I got one, and use it on all my buddied open water dives, it fits me well for any NDL dive and no overhead enviroment.
Make note that this is a bail out reserve, not a redundand air source.
Allways monitor you SPG and in the event of a failure, you have at least some air to work with until you get to your buddy or near the surface.
If you're solo diving, then you would need a pony as redundant air source.
If you're doing deco dives, the SA is useless at any depth.
When I dive solo, I take my new pony with me, just in case SHTF.
Make note that this is a bail out reserve, not a redundand air source.
Allways monitor you SPG and in the event of a failure, you have at least some air to work with until you get to your buddy or near the surface.
If you're solo diving, then you would need a pony as redundant air source.
If you're doing deco dives, the SA is useless at any depth.
When I dive solo, I take my new pony with me, just in case SHTF.
johnmennell
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Just so everybody knows, the spare air was originally manufactured for the U.S. Navy and called the HEEDS Bottle. Helicopter Emergency Escape Device. It was designed ti allow a crewman to remain calm as the aircraft was rolling over and as water was rushing into the cabin. You then safely exited the aircraft without panicking.
not too deep and not to long
not too deep and not to long
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