X-Message-Number: 9513
Date: Fri, 17 Apr 1998 18:12:09 -0700
From: Paul Wakfer <>
Subject: Re: CryoNet #9497 Cheap Storage
References: <>

> Message #9497
> Date: Thu, 16 Apr 1998 12:30:04 -0400
> From: John Bull <>
> Subject: Paul Wakfer & Cheap Storage
> 
> In Cryonet #9491 Paul Wakfer states "the amortized yearly cost of  CI
> storage is at least as high as that of CryoSpan and Alcor." Paul, have
> you factored in the inevitable repair costs to these dewars?

Yes I have, but I believe your use of the word "inevitable" needs some
elucidation. While it is true that some manufactured dewars have
developed leaks and have needed repair and re-evacuation in a 10 year
time frame, there are many that have been in continuous service for
decades. It it not at all clear what the MTBF (mean time between
failures) of a modern, well engineered and constructed dewar will be.
Modern dewars are all welded type 304 stainless steel which has been
found to be best for this purpose. If they are not abused by moving and
tipping, etc. and especially if they are kept in a cool, dry, nitrogen
gas environment, as are the CryoSpan dewars in their underground
reinforced concrete silos, I see no reason why leaks or other failures
should *ever* develop (at least only in geologic time). If they really
needed constant repair and re-evacuation, why would stainless steel
dewar technology have become the standard in many industries which also
do not want loss of contents nor higher long range costs, and
fiberglass/foam technology has been largely abandoned?

> My personal experience goes back to one bought in 1969 by a good friend
> of mine, from Minnesota Valley and Engineering Co. It carried a ten year
> guarantee (not much when you consider what it was to be used for). It
> lasted just about ten years before losing it's vacuum. We had to remove
> the bodies and haul it too a repair shop in the New York City area. The
> "repair" lasted about two years. The second time we didn't get to the
> capsule in time, the bodies thawed out and were later buried.

Alcor's and CryoSpan's dewars are not made by MVE anymore (but, in any
case, MVE now makes far superior dewars than they used to), they are
made by a master dewar repair, evacuation and stainless steel welding
firm in the LA area, CryoTech. Most of the dewars which CryoTech repairs
have been used constantly for delivery during which they take very hard
abuse. CryoTech makes dewars to order with modifications specified by
the customer and with special and extra wrapping of foil and paper to
achieve a low boil off rate. While CryoTech is always busy and *may*
take a long time to effect a repair, they are relatively close by (at
least to CryoSpan) and *could* (and would if pressed) effect any repair
within a two week time frame. When scheduled and organized properly, the
job of unloading the dewar, removing it from the silo and delivering it
to CryoTech would be 1/2 to 1 day depending on how full of patients the
dewar was or if it has already needed to be unloaded because of a fast
leak. This was actually done once when we realized that the second dewar
that had been delivered did not have as low a boil-off rate as it should
have and we took it back. It was an easy job since there were only a few
neuros in the bottom which we were able to put in our A8000 5 neuro
patient dewar while the big one was been checked. We do have a
fiberglass box which we could use for short term LN2 storage of whole
body patients if we needed to.

> CI's oldest fiberglass cryostat is eleven years old, has never been
> repaired, and shows no sign of needing repair.

Since CryoSpan has only had dewars for 4 1/2 years, I cannot given any
comparable information. Perhaps Hugh Hixon are someone else at Alcor
could comment on whatever repairs, if any, have been needed to their
dewars, some of which are older than 11 years. Don't forget also that
the older style dewars which needed repair and were difficult to open
and remove patients from (and possibly damaging to the patient in doing
so), were horizontal sealed units. Today's dewars are vertical and open
topped and the patients are all surrounded by additional aluminum or
stainless steel containers.

> Additionally while CI's
> LN2 cost per patient may be higher than Alcor's and CryoSpan, this cost
> per patient will come down as CI builds bigger cryostats.

There are two things wrong with this reasoning. If Alcor and CryoSpan
stay with -196'C LN2 immersion storage, I expect they both will build
bigger dewars too and achieve even lower boiloff rates. Second, research
progress at 21CM suggest that this will not likely happen now, since
vitrification storage and certainly fully perfected suspended animation
storage will almost certainly require patient maintenance it a "cold
room" at a temperature quite far above LN2. At that time both the dewar
technology of Alcor/CryoSpan *and* the fiberglass/foam technology of CI
will be obsolete for patients cryopreserved by the best current methods.

Thanks for your reply. I don't really wish to get into a long drawn out
debate over this issue. Again I urge those interested to see the more
detailed debate in CryoCare Report.

My point was simply that it is not at all clear or necessarily true that
CI storage technology is cheaper or superior to that of other
organizations. Everyone must weigh the pros and cons of each and make
their choice.

-- Paul --

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