Re: H-3 signs

[Paul Lavely <lavelyp@uclink4.berkeley.edu>]

This is great information.

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.

Thanks again for the information.

Paul Lavely <lavelyp@uclink4.berkeley.edu>



>Paul Lavely considered a scenario in which the glass tubes of a
>tritiated sign melted.
>Several years ago we had a fire at a fossil plant that was being
>renovated.  Six h-3 powered signs were in the fire with three of them
>being severely damaged.  In putting out the fire, the water pressure
>blasted  the loose glass tubes out of the open door and on to the
>turbine hall roof.  I was able to find all but two tubes.  Six were on
>the turbine hall roof, four were on the floor below, and several were
>out in a hallway.  None were broken and all glowed in the dark.  The
>fire was hot enough to twist metal walkways as well as melting the front
>of the signs.  None of the glass tubes showed any signs of damage.
>Therefore, I do not think that a scenario in which the tubes melt is
>likely.  For the two tubes I could not find, I postulated that fireman
>stepped on a tube and broke it being instantly enveloped in a cloud of
>H-3.  The doses were low.
>
>Kjell Johansen
>Wisconsin Electric
>Milwaukee
>
>As, always, my own opinions and not necessarily those of my company.
>
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