From: "Tan Khai Seng" <khaiseng**At_Symbol_Here**nus.edu.sg>Date: September 13, 2009 6:26:58 AM
EDT
Subject: RE: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
Hi David
I think this has been
answered by the media. Discovery Channel=92s Mythbusters confirmed that
the snapped-off valve is capable of penetrating concrete block wall. You
may want to check out the clip on youtube.
regards
Khaiseng
===
Date: September 13, 2009 7:26:14 AM
EDT
Subject: Re: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
Hi David,
The Mythbusters folks tested the hypothesis that a lab
gas cylinder could rocket thru a cinder block wall. They found
that it was true. I do not have a copy of the video - someone else
might have this.
Dan Crowl
Michigan
Tech University
===
Date: September 13, 2009 7:39:17 AM
EDT
Subject: Re: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
The young students may be able to relate to the TV
show - Myth Busters. They had a piece on this topic.
===
Date: September 13, 2009 8:34:41 AM
EDT
Subject: Gas Cylinders as
Rockets
David
Finster's question (and worry) is understandable. We don't like to think
of a gas cylinder tipping over on a concrete floor and braking like
a dropped Erlenmayer.
I'm sure that extensive testing has been done on the
safety of compressed gas bottles, as well as the attached valves. CGA
should be able to find the respective documentation. Another source
might be the German TUV (Technischer Ueberwachungsverein). Respective
information can be found through Google.
Of course
one could ask a propulsion engineer to make a calculation. The
controlling factors (size of orifice, internal gas pressure, mass
of cylinder) are well defined. Better still: make the calculation a
teaching project in the physics or engineering
department.
I hope this
helps.
Heinz
Heinz Trebitz, Ph.D.
Consultant, EHS
480 Colby
Road North
Thetford Center, VT
05075
Tel., Fax:
802-785-2129
===
From:
"Carl Zipfel" <czipfel**At_Symbol_Here**comcast.net>Date: September 13, 2009 9:06:48 AM
EDT
Subject: RE: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
YES IT CAN
See it happen
Carl Zipfel ,MS
CSP
===
Date: September 13, 2009
9:09:38 AM EDT
Subject: RE: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
This YouTube clip from Mythbusters did it for
me:
Cheers,
Paul
____________________________________________
Paul
Dover
Resources
Manager
Medicinal Chemistry and Drug
Action
Monash Institute of
Pharmaceutical Sciences
Monash
University (Parkville Campus)
381 Royal
Parade, Parkville
Victoria,
3052. Australia
Phone: +61 3 9903 9551
Fax:
+61 3 9903 9143
===
Date: September 13, 2009 9:46:58 AM
EDT
Subject: Re: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
Good morning David,
While the
CGA and Coyone may believe that the 1-inch plus-or-minus opening may or
may not be "too small for the tank to become a projectile " here are
some examples where Newton's Laws of Motion have been applied to
compressed gas cylinder accidents. Some have been due to
tank failure not at the valve stem, but the general answer to your
question is, "yes, they can fly."
It is
difficult to shear off a tank valve (but it can be done) - more likely
is shearing off a regulator. Regulators are flow-control devices
and the resultant gas velocity out of the hole will depend on where the
failure occurs - first stage or second stage of the
regulator.
It's not
the PRESSURE of the gas alone - it's the pressure drop across the
orifice. The larger the pressure differential across the orifice
the higher the velocity of the material out of the orifice- and higher
the momentum.
H
===
Date: September 13, 2009 10:07:05 AM
EDT
Subject: Re: [DCHAS-L] Gas
cylinders as "rockets in the lab"?
Note also that the *sound* of the air release would be
quite hazardous as well.
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