Fiber wrapped tanks

[AGA]

Hello,:martian:

I have heard talk of fiber wrapped bottles working their way into scuba diving. This would be very advantagous for scuba due the the lighter weight in the tanks plus in the fire service they have 1hr bottles. :whoa:

For those on the dark as to what im talking about:

Fiber wrapped bottles are Al tanks wrapped with either carbon fibers or fiberglass fibers. This allows for higher pressures to be used 4500psi.

The only draw back to the these tanks is that they only have a ten year life span and you would have to have higher pressure fills.

If anyone has any info on these tanks being used for scuba lets here it.:brain:

 

[The Chairman]

Fiber reinforced tanks are not suitable for diving for various reasons...

1) they are a high maintenance tank... Hydro every 3, inspection reccomended every 6 months...

2) they are tooooooo light. Talk about your way positive buoyancy!!!

3) they are waaaayyy exspensive... anyone price them yet???

4) they are fragile... JUST DON'T CHIP THE FIBERGLASS!!! These would not be suitable in a boat environment.

I am sure there are others, these are just the ones that came to mind...

 

[herman]

There are a number of reasons these tanks will not see scuba sevice, at least as a main tank. The main one is weight. The weight of scuba tanks is purposely increased over what it needs to be. Metal is added to the tanks so they are close to neutral, otherwise you would have to add a bunch of weight to your belt. As for an hour on a tank, you have to remember that how long you get out of a tank greatly depends on depth. I can easily get over an hour on a AL-80 at average depths of less than 30 ft. I bet I could get 2 hrs or better out of one just milling around on the surface.

 

[Hobbs]

Originally posted by AGA
Hello,:martian:

The only draw back to the these tanks is that they only have a ten year life span and you would have to have higher pressure fills.

If anyone has any info on these tanks being used for scuba lets here it.:brain:

well actually there is another drawback.
since they are so light they are unsuitable for scuba diving.
the amount of lead you will have to put on makes it impractical for using them.
(you realy dont want to put on 35 Kg extra lead)

In sweden the 300 bar bottles are quite normal to use (450 bar at preasure testing) and at least the ones i know of who is composite materials from aga is still just 300 bar and the test preasure is 450 bar.

The higher the preasure the more "wear and tear" it will get.
also the higher the preasure the less liter air per bar at constant temperature you will get.
since the air is not linear under preasure. so actually a 10 liter 300 bar tank only holds around 2700 liters of air.
and the higher the bar count goes the lesser the air / bar.
at 1000 bar its almost just around 600 bar if it would have been linear. according to the figures I have seen.

so more isnt always much more.....

take care and hava a nice dive

 

[FredT]

Fiber wrapped tanks are not resin rich enough to be non-porus. The thin aluminum liner holds the gas in, the fiber wrap holds the pressure and keeps the liner from failing.

Once a fiber wrapped tank has been immersed the water pulled into the tank fiber wall by capillary action STAYS there, eventuallay weakening the resin and pitting through the thin aluminum liner. Hre in the US a fiber wrapped tank can be hydroed ONCE. or TWICE depending on model number, after that they are considered trash. If the tank is wet internally life is even further reduced.

BTW a fiber tank rupture is worse than either a steel or AL tank in potential bodily damage. The fiber tank tends to shatter at rupture throwing schrapnel in all directions, and fiber embedded in flesh is a lot harder to find and remove than either metal.

Leave these tanks on the beach. With their sensitivity to impact and water damage I'd be reluctant to use one even for an emergency O2 bottle on board a small boat.


FT
FT

 

[AGA]

Well the leader of our local dive team stated that he saw somewhere that fiber wrapped tanks were finding their way into scuba.

As for the toughness of these bottles, if they are as weak as some here say, then someone needs to tell the thousands of firefighters around the world that they are strapping time bombs on the backs.:boom: If a fireman cant hurt it NO ONE CAN!!lol

I dont disagree with anyone here, but thats just what I heard form the boss man.

Maybe someone has reinvented the wheel! What do you call it again?

:doctor: "A TIRE"

 

[Mverick]

Fire departments and rescue teams are starting to get away from the fiber reinforced tanks in my area. Because of the problems stated.
You don't want to bang them around and immersion is a no no.


People still pump LP tanks to 3500psi when it's stated only to 2640psi. Mine go to 3300 all the time. Which are no no's also. Basicly you decide what you want.
I don't want that much lead on my belt. I'll stick with steel....

 

[The Chairman]

Firemen rarely have to attach their BC to the fiber wrapped tank on a pitching boat in five foot swells... knowhatImeanVern? The abuse tanks take on a boat is really phenomenal. On a fire truck, they have their own little cubby hole in which they sit. In spite of this, the discard rate with the fire dept is really quite high. Still we are talking safety equipment used to save the lives of others. They have to light for them to be mobile. They don't have a liquid medium to help support them like we do.

 

[scubasam35]

being a fireman and a scubadiver, i see both sides of the story. my department just purchased 25 s.c.b.a's with bottles and 25 additional bottles, for a total of 50 tanks. i do the inspection of all the cylinders and air packs so i had a say in what type of bottles were ordered. naturally we ordered aluminum, from luxfer. we are in the process of giving away, giving away!!!!!, our old bottles and air packs, most of the cylinders are composite and IMO dangerous. most cylinder failures occur while filling, not while being strapped to your back or in storage, though it has happend in storage. the detroit fire department had this happen and it is amazing what a cylinder will do as far as damage. the resulting explosion, ruined the fire apparatus it was in and did substantial damage to the fire hall also. i can't remember which company was saying that their tank was rated for 25ft. immersion, it was either Cairns or Draager and it was a composite bottle but regardless of weather it was a 1 hr. bottle or not i wouldn't even think of using one as a dive cylinder. the technology just isn't quite here yet to be comfortable with. so, dive safe and use a aluminum or steel tank and forget about the carbon composite and fiber wound tanks.

sam

 

[donacheson]

FWIW, I discussed fiber wound tanks in the late '50's with a couple of manufacturers, but only in the context of light shipping weight. At that time we (representing the US Army) discarded the idea since the cost of fiber-wound tanks exceeded the acquisition and lifetime shipping costs of steel tanks.

Of course, as several others have pointed out, the advantage for scuba is offset by the need to carry more lead weights.