Fiberglass tank?

^^

That's a very good deal for a tank that has ten years' service life left. Total cost to use and get filled at dive shops is $283.95 if you include shipping and hydro costs. Large 88 cu ft tank, in good shape with tank valve. Why do you say three year hydro?


Fiberglass is 3 yr hydro

newer Carbon Fiber tanks are 5 yr

Fiberglass hydrostatic test valid for 3 years only.
 
@tutuan and @dan_br, the person selling the tank doesn't know what he/she has. Its an SCI tank (Structural Composites Industries) CFFC tank, a.Carbon Fiber filament wound tank just like all the other SCBA tanks we use. They start with an aluminum liner, spin wrap it with carbon fiber filament, then wrap fiberglass sheeting around the carbon fiber for protection, and finally coat it with an epoxy type clear (or color) coat. They're all five year hydro and 15 year service life. See link below for DOT-SP-10945 tanks. 

https://worthingtonindustries.com/getmedia/7d85a43f-e92f-4176-9cb5-c37f031dd646/DOT-SP-10945-REV-27th.pdf


 
The shop I get my tanks filled at had this example.



1536878324_4860182775b9ae6f4a22165.78295553_128.jpg

 
@tutuan and @dan_br, the person selling the tank doesn't know what he/she has. Its an SCI tank (Structural Composites Industries) CFFC tank, a.Carbon Fiber filament wound tank just like all the other SCBA tanks we use. They start with an aluminum liner, spin wrap it with carbon fiber filament, then wrap fiberglass sheeting around the carbon fiber for protection, and finally coat it with an epoxy type clear (or color) coat. They're all five year hydro and 15 year service life. See link below for DOT-SP-10945 tanks. 

https://worthingtonindustries.com/getmedia/7d85a43f-e92f-4176-9cb5-c37f031dd646/DOT-SP-10945-REV-27th.pdf



Wow, hat off to you sir, for the effort to get into details and accuracy. You are always a good solid source of information in this forum. Too bad i cannot give you more pluses, lol.

The DOT-SP-10945 document confirms 5 years hydro for tanks manufactured and tested after 2001.






 
A 9 liter water volume is 99 cubic feet of air at 4500 psi. And yes, you did the math correctly. 9 liters volume is equal to .32 cubic feet. So .32 times 310 bar equals 99 cubic feet of air at that pressure. PS @bigbobbybeef, most guns that have air bottles are .5 liter bottles. So that 9 liter tank won’t fit on your Wildcat. ;)
 
i did the math i think correctly and then went to pyramid and used there tank calculator 9 liters is 0.317832 of a cubic foot so i could not even use it on a wildcat what kind of gun could you use such a small cylindar on if my math is correct?


This is the volume of liquid, which is not compressible.



Scroll to the bottom of the below link from Lloyd Sikes. He has the approximate conversions (for #'s to use in his fill calculator) for popular tanks and their capacity.

http://www.calc.sikes.us/2/index.php