X-Message-Number: 9519 Date: Sun, 19 Apr 1998 02:28:38 -0400 From: Paul Wakfer <> Subject: Re: CryoNet #9497 Cheap Storage Note: I sent this message to cryonet on Friday 10 hours before the CryoNet digest is automatically put together, but it did not appear in Saturday's digest. Please excuse the repetition if both appear in this digest. > 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 -- Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=9519