I fail to see how gaseous HF can react with steel to produce an excessive
hydrogen pressure and burst a cylinder:
                                            6HF + 2Fe yields 2FeF3 + 3H2
The product would be FeF3, not FeF2, because fluorine is an excellent
oxidizing agent.  Consequently, if anything, the gas pressure inside the
cylinder would necessarily be reduced as the HF attacks the iron of the
cylinder.

It's obvious that the cause of the explosion was the thinning of the
cylinder wall at one or more locations, NOT the pressure of the hydrogen.

Jay Young

PS: Alas, in these modern times, these young folks just don't know their
descriptive chemistry like us old guys do.  I predict disaster and
catastrophe--as we old guys die off, the world will be left with chemists
who don't know descriptive chemistry.  Alas and Alak! (or whatever)

*************************************************************************
**********************************

On Fri, 8 Jul 2005 15:42:58 -0700 Debbie Decker 
writes:
> Hi gang:
>
>  From our intranet for your information.  If you want copies of the
> photos,
> lemme know.
>
> BTW, I did have a potentially scary situation with HBr in lecture
> bottles -
> quite ancient stuff.  It has a similar nasty habit of
> over-pressurizing
> over time.  It was managed without incident, several $10K later.
>
> Ya'll be safe,
> Debbie
>
>
> >Priority: NORMAL
> >X-Mailer: Execmail for Win32 5.1.1 Build (10)
> >X-Scanned-By: MIMEDefang 2.49 on 169.237.104.156
> >X-Scanned-By: MIMEDefang 2.51 on 128.111.125.200
> >Date:         Fri, 8 Jul 2005 13:55:39 -0700
> >Reply-To: UCIH Program Management Group
> 
> >Sender: UCIH Program Management Group 
> >From: Kevin Kaboli 
> >Subject:      recent lab explosion 
> >To: SBUCIH-L**At_Symbol_Here**LISTSERV.UCSB.EDU
> >
> >Hi Folks,
> >FYI-Here is the report of the explosion by Dave Vandenberg:
> >
> >Best
> >Kevin
> >
> >
> >
> >UC EH&Sers:  Below is a note describing an accident that occurred
> recently
> >on our campus.  You may already be aware of this potential safety
> issue
> >with hydrogen fluroride cylinders.  If not, would recommend that
> you
> >identify and dispose of old cylinders of this material.  We were
> fortunate
> >that no one was injured in this accident.  Feel free to contact me
> with any
> >questions about this incident, but I will be away next week.
> >
> >- Dave Vandenberg, UCSB Laboratory Safety Manager
> >
> >
> >
> >This past Sunday evening (7/3/05) an old gas lecture bottle
> cylinder of
> >anhydrous hydrogen fluoride spontaneously exploded within a gas
> cabinet on
> >the first floor of the Chemistry building.  Thankfully, no one was
> injured
> >because no one was in the room, or adjoining spaces.  However,
> given the
> >extensive damage to the lab, it is likely that anyone present would
> have
> en seriously injured from flying debris and/or HF exposure.  The
> >explosion also resulted in the building being locked down for about
> 12
> >hours by the Fire Department.
> >
> >Attached are pictures showing the remains of the lecture bottle and
> a shelf
> >about 10 feet away where the heavy-duty window from the gas cabinet
> can be
> >seen after it was hurled.
> >
> >Anhydrous hydrogen fluoride in carbon steel cylinders may react
> slowly over
> >years with the iron in the steel to form iron fluoride and
> hydrogen.  The
> >hydrogen pressure can ultimately build to the point where it
> ruptures the
> >cylinder.  This is discussed more fully on the bottom of pg. 5 of
> this MSDS
> >from Air Products:
> >
> >http://www.airproducts.com/MSDS/searchresults.asp
> >
> >Given this potentially serious hazard, WE ASK THAT EACH RESEARCH
> GROUP
> >VERIFY WHETHER THEY HAVE ANY GASEOUS HYDROGEN FLUORIDE IN STOCK.
> If some
> >is  on hand, please do not move it, but inform EH&S at x-4899
> (after Friday
> >call x-3293). Each cylinder will be evaluated individually as to
> it's
> >condition and ultimate fate.
> >
> >Thanks for your cooperation.
> >
> >
> >
> >----------------------
> >David Vandenberg
> >Laboratory Safety Specialist
> >UCSB Env. Health & Safety
> >(805) 893-4899
> >David.Vandenberg**At_Symbol_Here**ehs.ucsb.edu
> >--- End Forwarded Message ---
> >
> >
> >----------------------
> >Kevin Kaboli, MA, MS, CIH
> >Industrial Hygiene Program Manager
> >University of California
> >Santa Barbara, CA 93106
> >Kevin.Kaboli**At_Symbol_Here**ehs.ucsb.edu
> >(805)893-8787
> >(805)893-8659 FAX
> >
> >
> >
>
>

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