In August of 2002 thousands of books fell victim of the Prague floods when Vlatava River burst its banks.

UK donates vacuum drying machines to help save books hit by floods 
[19-09-2002] By Ian Willough

An estimated half a million books and documents from archives and libraries were damaged around the Czech Republic during August's floods, and trying to save valuable works is proving to be an absolutely mammoth task. At a ceremony at the National Library on Tuesday, the British Ambassador, Anne Pringle, presented Czech Culture Minister Pavel Dostal with novel vacuum drying machines which will help in that task. Also present was Stuart Welch, the inventor of the ingenious machines; he told Ian Willoughby how they work.

"It's by excluding oxygen within the packages, putting dry material with wet material and in the vacuum the process is speeded up, where the water or moisture from the wet object wants to transfer into the dry material and simply reach equilibrium. It's like putting a wet raincoat in your wardrobe - by the morning you'll find everything's a little bit damper, because the moisture molecules have moved and transferred."

This machine is about as big as a big box; what kind of volume of books or documents can you treat, or at what speed?

"If there's a production line set up of people and a system, then it could take anything from between five minutes and ten minutes overall per items packed. A lot depends on how well the absorbing material is organised, whether it's blotting paper or old newspapers."

The floods were only a month ago and you've come here very quickly - how was it all organized?

"I was on holiday in Italy when I heard about the floods. I knew Jiri Vnoucek from when he was a student in England, so I was particularly concerned that his books were getting damaged. I rang him on my mobile to see if he knew about this system. He then had a meeting with the British Council, and they said they wished to help, so he said ' I know what I want' and they said 'OK'."

Have you been to look at the archives in the libraries here?

"Not in their wet state, no. We'll wait to see the damage but I know that it's not a pretty sight. There's an awful lot of stuff to work's going to be a brave task for those that have to do it. It's not just wet books but they're dirty and smelly. It's not a nice job."

And inventor Stuart Welch referred there to his friend Jiri Vnoucek, the head of conservation at the National Library. Like the rest of his team, Mr Vnoucek was looking forward to using the vacuum drying machines.

"We hope we will use them all the time. They should be heavy duty machines. They hardly will stop, I would say."

How many books and documents, roughly, do you have to treat?

"There are not so many books directly in the National Library, but there are the books of the other libraries. So we are in fact going to help other libraries to dry books."

They haven't wasted any time; the machines began drying books and documents on Wednesday, just a day after arriving in the Czech Republic.

Plastic bags are removed to reveal the frozen books.

“Squelch” Vacuum Pack Drying is a technique developed by Stuart Welch the founder of Conservation By Design after experimenting with vacuum packing a wide variety of materials to find out if they might be suitable for storage in a low oxygen vacuum packed barrier bag. These experiments were carried out from 1992 onwards.

In 1997 he chanced to dry a wet plant which he had packed with a piece of absorbent paper. The paper had taken most of the moisture from the plant which was effectively dry. It occurred to him that if this could be done with a plant it could be done with a book. He then soaked a small paper covered volume with 224 pages and vacuum packed it with several sheets of heavy weight blotting paper on either side of the covers. This was repeated six times until the book was dry. He showed this to his friend Dr Nicholas Hadgraft of the Cambridge Conservation Consortium who saw advantages over freeze drying.

In 1998 Nicholas was asked to advise on the best way to dry rare books following a serious flood in the Founders Library of the Fitzwilliam Museum. He recommended that they try a new technology using vacuum packing. The books were soaking and severely affected by mould. Over a period of three weeks more than seventy wet books were treated using the vacuum packing technique and successfully returned to the library. Following this the technology was used by other conservators in the United Kingdom who with the support of the British Council generously volunteered to teach the method to Czech conservators following the Prague flood of 2002.

So far this has been the largest project for the “Squelch” technique where thousands of rare books have been dried. Stuart’s experiments have also shown that the technique can be used in reverse to humidify objects and has the advantage of humidification without expansion. Much is still to be discovered regarding the uses of vacuum and low oxygen packing and we would welcome hearing about your experiences and experiments if you use this technology.

The book on the left was dried using our vacuum packing method and the one on the right by vacuum freeze drying.

If you are curious and would like to explore further with a member of the CXD team, then please do not hesitate in calling us on +44 (0) 1234 846300. Alternatively feel free to use our contact form.