Regulations concerning tank fills

jrs_diesel · Sep 27, 2005

Is there a law or regulation concerning tank fills? Namely if the tank HAS to be filled with the tank in a water tub/tank.

One of the LDS here stopped filling tanks in the water. This does not sit well with me. I thought the whole reason for the water tank was to reduce the stress on the tank by keeping it cool.

Diesel298 · Sep 27, 2005

no
the reg on tanks os it has to be hydroed every 5 years amd a visual every year
the filling of tanks in water just keeps the tank a bit cooler during the fill. providing a better fill...
ALOT of shops do not do this..
they just let them sit awhile, and then top them off later in the day.

mike_s · Sep 27, 2005

I think that Luxfer made a recommendation or safety release that it was better not to fill them in the water... I saw/heard/read this somewhere.

Diesel298 · Sep 27, 2005

ever haver a burst disc falure when the tank is being wet filler?

you get wet

Shannon M. · Sep 27, 2005

I have included a link to PSI's website that talks about this very thing. In my opinion, wet filling is an outdate practice. Check out the link and decide for yourself. http://www.psicylinders.com/library/wetfills.htm

CIBDiving · Sep 27, 2005

Diesel298:
.... a visual every year

got a link or reference to the regulation requiring that?

gecko3s · Sep 28, 2005

I was taught the same thing when I started filling tanks- that because compressing air into the tank creates heat, you'll get a 'false' reading on the pressure gauge, i.e. the warm air is expanded showing, say 3000psi, let it cool and it may only be 2900 or less, depending on how fast you fill it.

Keeping the tank in the water helps to dissipate heat faster, therefore causing the air to cool, and it doesn't take as long waiting for the psi to settle before you finish the fill....

This is also useful when doing partial pressure EANx fills for the same reason, the 02 will cool quicker so you can get your reading, and finish the fill, so people don't have to wait all day for their bottle.

nauidiver2004 · Sep 28, 2005

49 CFR various sections. Easily searched thru google.

Ken

CIBDiving · Sep 28, 2005

gecko3s:
I was taught the same thing when I started filling tanks- that because compressing air into the tank creates heat, you'll get a 'false' reading on the pressure gauge, i.e. the warm air is expanded showing, say 3000psi, let it cool and it may only be 2900 or less, depending on how fast you fill it.

Keeping the tank in the water helps to dissipate heat faster, therefore causing the air to cool, and it doesn't take as long waiting for the psi to settle before you finish the fill....

This is also useful when doing partial pressure EANx fills for the same reason, the 02 will cool quicker so you can get your reading, and finish the fill, so people don't have to wait all day for their bottle.

What you say is very true and is the reason tanks were filled wet in days past. I think the excuse of "super chilling" the water for an over fill is BS, no shop is going to spend the money to refigerate a pool of water - most can just barely keep the lights on as it is! Time was when you walked into a shop with a bottle, the guy hooked it up, put it in the water and over filled it a little. You got back a nice fill that was only a little under when cold.

PSI doesn't like any of this - and of course they are the ( self proffessed ) authority.

CIBDiving · Sep 28, 2005

nauidiver2004:
49 CFR various sections. Easily searched thru google.

Ken

It's late and I'm tired so may be I missed some thing but I can't find anything on a scuba shop performing a vis every year. Only the visual inspection that is required for the hydro test. This is done by the hydrostatic tester Before the hydro, not by a scuba shop after the bottle returns from the test.

in fact the section pertaining to luxfers bombs says a vip+ every 5 years!

Regulations concerning tank fills

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