RE: H-3 signs behaviour in a fire

["Levin, Robert" <robert.levin@sylvania.com>]

Melting point temperature?  I assume that you mean the softening point.
Depending on the type of borosilicate glass, it would probably fall in the
range of 750-825 degrees C.

Robert E. Levin, Ph.D.
Corporate Scientist
OSRAM SYLVANIA
71 Cherry Hill Drive
Beverly, MA 01915, USA
Phone: (978) 750-1594
Fax:     (978) 750-1794
e-mail: robert.levin@sylvania.com

> -----Original Message-----
> From:	SBD [SMTP:sbd@co.disp.mindef.nl]
> Sent:	Monday, March 27, 2000 1:34 AM
> To:	Multiple recipients of list
> Subject:	Re: H-3 signs behaviour in a fire
> 
> We too had the experience of a (short but hot) fire that completely turned
> some gun sights to ashes. The betalights in the middle however still were
> intact. They glowed in the dark and we did not detect any contamination.
> Borosilicate glass is very high quality glass, being very temperature
> resistant.
> As these glass tubes too are melted at the end after filling them with
> tritium, they too  melt at a certain temperature. However this temperature
> is
> not known to me. Anyone out there who knows the melting point  of
> borosilicate glass? This will be interesting info for fire fighters in
> case
> of a fire involving exit signs.
> 
> Paul Lavely wrote:
> 
> > We had been "assured" by fire fighters that they had not seen a major
> > fire in which these sign were not totally destroyed. I have only seen
> > one post fire sign and it was a lump of solid charred plastic. I
> > guess that some of the tubes could have been intact inside the lump.
> >
> > I plan to use the information you provided to work with local fire
> > responders (who by chance have a HP Tech. now in fire protection) to
> > do some post fire surveys.
> >
> > I agree that the dose from stepping on one of the tubes and releasing
> > the H-3 would be a small dose - especially if they are wearing
> > typical fire-fighting gear.
> >
> > Paul Lavely <lavelyp@uclink4.berkeley.edu>
> 
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