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RE: Standards for the Taking
Chris and Group,
At one time I tried to establish just why or what the basis of 10 year
expiration for sealed standards including but not limited to LSC standards.
I got some responses, but all can be grouped under identifiable things that
did not need a time limit. That is half life was given, but typically LSC
standards are H-3 [12.25 y] and C-14 [5730 y] so by t-1/2 they can go for a
while past 10 years. If statistics are bad for H-3, you can always count
longer. I have noticed recently that newer LSC standards have 5 year
expirations.
That the basis might be an ANSI standard makes sense. But I am still
wondering why the time limit?
I have yet to get an explanation for the rational. I can testify that
standards older than 10 years tend to deteriorate. Glue of for cap on top
of flame sealed vial gets dry and may fail. Such a failure could cause a
jam. But careful inspection should catch that. Labels deteriorate and
such. But I am still interested in the rational or theoretical basis to
retire a sealed standard, SOLELY ON AGE.
Peter G. Vernig,
As always my views are not necessarily those of the Dept. of Veterans
Affairs, the Denver VA Medical Center or the US Government.
Private replies may be directed to peter.vernig@med.va.gov
-----Original Message-----
From: Chris Alston [mailto:alstonc@odrge.odr.georgetown.edu]
Sent: Wednesday, January 05, 2000 2:33 PM
To: Multiple recipients of list
Subject: Re: Standards for the Taking
Isn't the ANSI "useful life" for LSC standards ten (10) years?
cja
alstonc@odrge.odr.georgetown.edu
>1 Reference Background 3/1/83
>
>H-3 quenched standards
># Date DPM
>1 3/1/83 91200
>10 1/1/83 501000
>6 1/5/74 502000
>
>C-14 quenched stds
># Date DPM
>1 3/1/83 30200
>6 12/5/73 208000
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