[APD] Re: transporting CO2 tanks?

["Douglas Guynn" <d_guynn at sbcglobal.net>]

My 2 cents worth.

Steven Pituch wrote:

	"Has anyone thought about why the professionals transport gas
bottles vertically?"

I believe this is actually a DOT requirement for sales and delivery
vehicles, although I may be mistaken. There is also a space issue. A
vertical bottle has a smaller footprint than a horizontal one. Plus, if
someone hits the truck, they are less likely to damage the valve if the
cylinder is upright.

Steven Pituch also wrote:

	"Also I was told once that if you have just had a tank refilled you
need to transport it vertically.  Mine forms ice on the outside while I am
putting it into the truck.  I snug it against the rear seat and the front
passenger seat so it stays vertical.  I think the same guy said that if the
cold liquid co2 contacted the seals in the valve that it could cause them to
go brittle or stick."

Well, the cold CO2 contacts the seals during filling, so I'm not sure if
that is really a problem, although I can't refute the statement with surety.
The seals in most CO2 equipment is made from special materials because CO2,
especially the liquid variety, presents very specific handling issues, of
which low temperature service is one. I have seen pump seals in CO2 service
degrade very quickly when the wrong materials were used.

S. Hieber wrote:

	"However, if you leave the thing laying down unsecured, it's more
likely to roll around and bust the valve."

Busted valves are VERY bad. Someone dropped a 300 cu. ft. nitrogen cylinder
(2600 psig pressure, weighed about 70 psig, and was about 5 feet tall) off
of the loading dock one morning. When the cylinder hit the ground, the valve
broke off, and the cylinder was launched into the wild blue yonder. It was
found that evening in the local drive-in movie lot over a half mile away.
There are reports of these high pressure cylinders that have fallen over and
broken the valve that go through cinder block walls. While the cylinders we
use should have considerably less pressure than that, it could still be very
destructive bouncing around in the bed of a truck.

S. Hieber also wrote:

	"Also, if the emergency blow off blows for any reason and the tank
is on its side, you'll get liquid CO2 being pushed out and rapidly
vaporizing, ice forming at and blowing off the hole . . .not a preferred
situation."

A very good point. Liquid CO2 forms dry ice very quickly when allowed to
expand. There are even specific design standards to be used when venting CO2
from a pressurized vessel, one of which is meant to prevent significant
expansion of the fluid until it leaves the vessel or piping. Doing so
prevents the deposition of solid CO2 at the expansion point, potentially
closing the vent. CO2 vent piping is often built with quick opening valves
and a small decrease in pipe diameter at the very end of the pipe to keep
the pressure drop from occurring within the piping.

I transport my 20# cylinder in the back seat floor board. I don't scare
easily, so the noise factor of a rupture disk failure is not a major issue
for me, however I do have a certain affinity for oxygen environments, so I
leave the all of windows rolled down just in case.


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