To be safe, the carboy would have to be behind a shield strong enough to withstand the breaking force of the expelled glass pieces and sited so as to intercept all potential paths the fragments could take. Not sure if one could possibly a metal trash can for that purpose because it lacks a top and a way to secure it easily to something strong enough. I guess you could make something but an acrylic shield would probably be faster, easier and cheaper. Casting it in Acrylic would, I suspect be much more expensive.
And shielding will protect personnel but it would still be open to criticism if the vendor does not rate the carboy for the maximum possible pressure used.
SO going back to the vendor makes sense to confirm that rating.
Richard Palluzi
BE(ChE), ME(ChE), PE, CSP,FAIChE
Pilot plant and laboratory consulting, safety, design, reviews, and training
www.linkedin.com/in/richardppalluzillc/
Richard P Palluzi LLC
72 Summit Drive
Basking Ridge, NJ 07920
rpalluzi**At_Symbol_Here**verizon.net
908-285-3782
From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> On Behalf Of Benjamin Ruekberg
Sent: Friday, February 25, 2022 10:07 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] Pressurization of 5 gallon glass carboy
I have some questions which may be relevant. (FYI, I seem to recall glass vessels for vacuum that were generously wrapped in electrical tape. Poor man's safety glass, I guess.)
Will the carboys in question conveniently fit in a metal trash can, 5 gallon solvent can, or waste basket? If so, with a suitable cover, would that not make the use of the carboys sufficiently safe? If non-metal versions of these containers are available, with room to fill the space between the carboy and the container wall with water (and means to hold the carboy down), could that be considered safe?
If the cost is not excessive, could the carboys be cast in acrylic to reinforce the glass? Screw eyes could be inserted in the plastic to secure the stopper, possibly with springs to prevent over-pressurization.
In essence, I guess, what I am asking is whether the carboys might be rendered safe?
Another consideration is that if the carboy is filled with water, the pressure at the bottom will be a function of the height of the water. If turning the carboy upside-down mutatis mutandis. Clearly, if that pressure is not exceeded, there should not be a problem.
- We should ALWAYS examine the glassware before we use it before we are about to set up. I have seen where a scratch in a beaker caused it to shatter during an experiment /process.
My thanks to everyone for sharing their thoughts on my question yesterday. I want to point out that the faculty member asked for my help in assessing this risk rather than just ignoring the various warnings etched into the glass by the manufacturer.
The question arose because the member had detected defects in the existing carboys, which are likely to be 40 years old, and had ordered replacements, which included 6 vague warnings, including the reference to the technical information that we couldn't find on their web site. The suggestion to talk to a company rep is the next step.
It is helpful to be reminded of the energy levels involved in pressurized gases, but that was not news to either of us. I do appreciate having the stories people shared with me about bad experiences they've had with similar set ups.
Thanks to everyone for their assistance with this question.
- Ralph
Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859
ralph.stuart**At_Symbol_Here**keene.edu
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