>Date: Thu, 09 Mar 2000 09:22:13 +0000
>From: Richard.Pitman@wri-tr.wmids.nhs.uk
>Subject: Liquid Nitrogen - Oxygen depletion
>To: histonet@pathology.swmed.edu
>
>Hi All,
>
>We have stored tissues in liquid nitrogen for many years. We have two 35 
>litre dewars actually in the lab, replenished from a 250 litre store 
>located outside the department. The hospitals Occ Health and Safety dept. 
>have received a mail shot from a company which supplies oxygen depletion 
>monitors. We both agree that we should install one of these gadgets in the 
>lab, even though we've had no problems to date.
>
>(We did once have a vacuum failure in one of the Dewars, and 35 litres of 
>N2 boiled off. Luckily, our lab is well ventilated (draughty).)
>
>Does anyone else have experience of these monitors -  are they a legal 
>requirement in some areas ?
>
>Anyone know how many cubic metres of N2 gas  is evolved from 1 litre of 
>liquid ?
>
>The reasoning is that N2 displaces oxygen, thus entry to a room with a 
>faulty N2 store could have fatal consequences - I have a vague 
>recollection that this happened recently in a lab in Scotland, any info on 
>this ?
>
>Richard.Pitman@wri-tr.wmids.nhs.uk
>
>Richard Pitman FIBMS,
>Head MLSO,
>Dept of Histology, Cytology & Immunology,
>Worcester Royal Infirmary NHS Trust
> 
 >
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