tank refresher needed

[diverrick]

I have forgotten how to tell the different tanks apart. I hear about LP80's, Hp's, 120's, 80's, Etc.. I have been seeing bigger round tanks, as well as short tanks, long tanks.
How can I tell them all apart when I look at them? Are there clues that give them away to a casual onlooker?
I know that AL tanks have AL stamped on the tank, but can you tell from a distance, by looking at the tank, what volume, pressure, material, Etc.?
We can call it TankID 101.

 

[ScubaJewel]

not many tanks actually have the cu. ft. designation stamped on the tank however some do.

Julie

 

[scubafanatic]

....well, for starters, all steel tanks have 'rounded' bottoms....all aluminum tanks have 'flat' bottoms...however, this detail can be obscured by tank boots. Other than that, I don't know any large scale feature one can use to tell tanks apart from a distance. In the U.S., probably 95 % of the 'flat-bottomed' tanks (Aluminum) will either be 63 or 67 cu. ft tanks.....or 80 cu. ft. tanks. Most of the time, in the U.S. if you see a lady wearing a flat-bottomed tank, it will be the 63/67 cu. ft. AL tank...whereas, in the U.S., if you see a man wearing a flat-bottomed tank, it will be an AL80.
In the U.S., you'll occasionally see the smaller AL50......the biggest AL tank made is the AL100...so if you see a flat-bottomed tank, the maximum capacity it can have is 100 cu. ft.

Steel tanks are more 'complex'...they come in a wider variety of diameters and lengths.....once you've seen enough of them and get familiar with the different sizes/manufacturers you'll get pretty good at estimating from a distance the type of steel tank other divers are using from a distance.

Karl

 

[pescador775]

Sometimes, an aluminum tank can be ID'd by its jazzy blue, green, etc metallic color. Steel tanks, however, are usually grey, zinc, white or black enamal. The steel tank will have an ICC or DOT designation followed by 3AA or E followed by a number. An aluminum will be designated DOT AL or SP. When in doubt, use a magnet.

 

[Web Monkey]

If it's approved for use in the US or Canada, an aluminum tank will be stamped with 3AL, while a steel tank is stamped 3AA.

I don't believe there's any requirement that the actual capacity of the tank is stamped anywhere, but there's usually some indication from the manufacturer.

The service pressure should also be there, in BAR and/or PSI, which will tell you if it's high pressure or low pressure.

There's a pretty good tutorial at: http://diverlink.com/gear/tankmarkings.htm

Terry

I have forgotten how to tell the different tanks apart. I hear about LP80's, Hp's, 120's, 80's, Etc.. I have been seeing bigger round tanks, as well as short tanks, long tanks.
How can I tell them all apart when I look at them? Are there clues that give them away to a casual onlooker?
I know that AL tanks have AL stamped on the tank, but can you tell from a distance, by looking at the tank, what volume, pressure, material, Etc.?
We can call it TankID 101.

 

[Drew Sailbum]

....well, for starters, all steel tanks have 'rounded' bottoms....all aluminum tanks have 'flat' bottoms...

Except for the round bottomed aluminum cylinders specially made for the US Navy by PST (Yup thay made some aluminum ones!) from the 6061 alloy. These are not approved for a DOT stamp and thus are not "legal" for the general public in the US.

 

[cyklon_300]

the LDS guy who just filled my PST cylinder couldn't identify the size.

And it has E8-130 plainly stamped on the neck...

I told him it was a 95...figured he'd probably try to charge me more for 130cf...

 

[scubatoys]

You're probably not far off... If he couldn't tell the size - he probably didn't know the pressure either... and if he filled it to 3000 you only got 115 or so (by the time it cools) and not 130....

 

[cyklon_300]

is 3442 psi...I asked for that and got 3400 (after cooling).

Good enough for government work.

 

[scubatoys]

Great! And rare! Most places will give you any fill you want... as long as you want a hot 3000... and that's wheter it's a 3442 or a 2450!