Date: Sun, 13 Sep 2009 12:28:27 -0400
Reply-To: List Moderator <ecgrants**At_Symbol_Here**UVM.EDU>
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From: List Moderator <ecgrants**At_Symbol_Here**UVM.EDU>
Subject: 8 RE: [DCHAS-L] Gas cylinders as "rockets in the lab"?

From: "Tan Khai Seng" <khaiseng**At_Symbol_Here**>
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. om/watch?v=ejEJGNLTo84





From: Dan Crowl <crowl**At_Symbol_Here**>
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

From: "Walter Garrow" <wgarrow**At_Symbol_Here**>
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.


From: "Heinz Trebitz" <iht63**At_Symbol_Here**>
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 Trebitz, Ph.D.
Consultant, EHS
480 Colby Road North
Thetford Center, VT 05075
Tel., Fax: 802-785-2129
e-mail: iht63**At_Symbol_Here**

From: "Carl Zipfel" <czipfel**At_Symbol_Here**>
Date: September 13, 2009 9:06:48 AM EDT
Subject: RE: [DCHAS-L] Gas cylinders as "rockets in the lab"?

YES IT CAN m/Responsibility/EHS/ProductSafety/ProductSafetyInformation/Safetygrams/sa fetygram14.htm


See it happen inder-rocket/episode/878206/recap.html?tag=episode_recap;recap om/watch?v=ejEJGNLTo84


Carl Zipfel ,MS CSP


From: Paul Dover <Paul.Dover**At_Symbol_Here** .au>
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: om/watch?v=ejEJGNLTo84


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

Email: Paul.Dover**At_Symbol_Here** .au

From: "Harry J. Elston" <helston**At_Symbol_Here**>
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." Safety/Training/


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.  


From: ILPI <info**At_Symbol_Here**>
Date: September 13, 2009 10:07:05 AM EDT
Subject: Re: [DCHAS-L] Gas cylinders as "rockets in the lab"?

Mythbusters did the experiment: om/watch?v=ejEJGNLTo84

Note also that the *sound* of the air release would be quite hazardous as well.

For a comical take on this see om/watch?v=O6CFfxwGP9U

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