Looking for ideas to keep moisture out 7

[dicer]

To store books etc.
Also like when using a box or van trailer to store things, how to design to keep out the moisture.

 

[IRstuff]

Hermetic seals to keep moisture out
Dehumidifiers to remove moisture that gets in
Desiccants to remove small amounts of moisture that gets in

this is a very broad question.

TTFN

FAQ731-376

 

[asimpson]

Air vents to allow air circulation is simplest method. Used for electrical enclosures. Depends on outside environment. If the ambient air is dry enough you just need to keep the rain off and prevent condensation. Any moisture trapped inside will cause problems.

Heaters are often added to keep moisture from condensing on surfaces. Fans to boost air flow-through.

Hermetic sealing and using desiccant is good if you can be sure seal is 100% and desiccant is sufficient and not exhausted. Good hermetic sealing is not easy if you want to access contents on a regular basis

 

[arunmrao]

A good sealing along with a desicant which is replenished regularly.

 

[Ron]

Treat the roof like a roof, then treat the walls like a roof. Seal everything.

 

[Warpspeed]

Another different approach to this, is hermetic sealing, plus keeping the internal air pressure slightly above atmospheric.
A dry gas such as nitrogen with a suitable very low pressure regulator can make up for any slight outward leakage over time.

 

[jistre]

Just a warning about the dry gas idea. You don't want to be setting up a low oxygen environment for something like this by inerting the space the same way you would inert petrochemical equipment.

Inert gas asphyxiation is serious and it's lightning fast. It's hard to read one of those books that's being stored when you go to retrieve one and mover from perfectly fine to hypoxic to unconscious in ten seconds. Best part about that is if the environment is low enough on oxygen, you will likely never feel the onset of unconsciousness. It's like someone flips your light switch off. It's gets even harder to read after that because the brain damage starts and then you die.

On the other hand, you'll have plenty of time to read those books when someone unaware enters your low oxygen environment and gets put down, then several other people die trying to help that person. On the other hand, in prison, you kinda have to read what's available to you, not really the books you had stored in that low-oxygen space.

Short story is : DO NOT INERT A ROOM! Even in tightly controlled conditions in plants with people who know the low-oxygen confined spaces exist, who are trained to work around them, and are taught about the effects and how quickly they can hit, people who know better should die.

Outside of that kind of control, an inert space is a killer.

Use dessicants. Use air conditioning. Do not use nitrogen.

 

[dbooker630]

Although it is intended to protect ferrous metals, perhaps you can try VCI paper, which absorbs moisture. We use it for long-distance transportation to protect our goods.

 

[ornerynorsk]

I think another poster mentioned it, the OP is lacking in enough information to give a very focused answer. Is this a permanent installation or meant to be portable, or mobile? What is the climate and variations? What kind of books - million dollar historical stuff or Barnes & Nobles over-runs that are $2 a piece? What is the operational budget for maintaining this storage? How often do the contents need to be accessed? Etc, etc, etc.

 

[dicer]

I pretty much knew all that stuff. As far as using Nitrogen, I was wondering if that would promote degradation of paper? I do now keep books and literature in the big freezer bags, but in the past when I stored in a 40 foot truck van trailer some still got mildew that seeped in some how. I also thought about using something like a barrel and pulling a vaccum on it. I have some literature that some years back did the vaccum pack deal haven't looked in a while I think they are still sealed up. And along with moisture comes the how to protect from fire as well.
Please keep the ideas comming, this is an area of very wet winters. Also since sometimes in the winter time the temps during a 24 hour period cycle drasticly, and will cause any metal container like a van trailer to sweat. Gosh I've seen the engine in vehicles and for that matter the whole underside dripping wet in some weather conditions. Well yeah the engine was not run in over a 24 hour period.

 

[Warpspeed]

I believe degradation of paper from damp mainly has to do with the growth of various mold and bacteria.
Keeping it very dry, and in an inert gas will be fairly detrimental to the long term growth of mold and decay.

I was never suggesting to pressurize a whole room or occupied space with an inert gas !!!

Just perhaps large sealed plastic storage drums or something similar fitted with very small bore tubing to a central low pressure regulator. This would work in a permanently damp humid environment such as an ancient cellar.

 

[IRstuff]

Nitrogen is, by all normal measures, inert for this purpose. A nitrogen purge is often used to ensure that moisture is kept out, but it has to be specially processed to ensure that the trace levels of moisture in the gas are within specifications. If not nitrogen, then argon is sometimes used as the inert gas.

Having containers with a slight positive pressure of nitrogen is sufficient. The only operational requirement is to ensure that sufficient nitrogen is applied so that any leakage paths are flushed with nitrogen at all times. The remainder of the room can be simply dehumidified air, and the low level of nitrogen from the containment vessels will be too low to upset the overall oxygen balance of the air, particularly if there is sufficient airflow in the room.

TTFN

FAQ731-376

 

[unclesyd]

You need to look at this material, Drierite, to be incorporated in your storage system either in part or as whole.
I second the motion to stay away from N2 unless it's used as part of individual packages in a well ventilated room.

http://www.drierite.com/default.cfm?goto_page=page4b.cfm

Addenda:
I personally know of 5 fatalities were N2 was the culprit. As posted above the attempt to rescue one downed man caused the lost of the rescuer. This was in a tank car at a repair shop where the rusting of the freshly sandblasted surface had depleted the O2 level to where the onset of N2 asphyxiation was immediate. They would have lost the third man if our car inspector hadn't understood what was happening.
One of my most memorable moments while working was when I saved a man, while on my way to lunch, from asphyxiation by N2 just in the nick of time.

 

[gerhardl]

Beeing Scandinavian I readily see that condensating moisture in the air is the problem. The air pressure and the temperature will vary, and 'superfluous' moisture will condensate against the cold outer surface. Read your Mollier diagram!

Any good architecht will tell you that for houses you do two things: you isolate against cold, and place and airthight membrane nearest the warmest surface. (To avoid contact for higher temperature air (high humidity) against low temperature metal surfaces (lower dew-point))

You have the highest natural moisture content in the outside air at warmer temperatures (above zero deg C) and well below zero the air will be very dry.

Conclusion: In a tropical climate you will have to keep the near 100% humidity out (books will swell to double or triple size) and you will have to dry the air.

In a temperate climate with cold winters and surging and dropping temperatures autumn and spring, you will have to isolate as described above, and heat the inside somewhat at low temperatures, around 10 deg C should be sufficient, perhaps lower with good insulation.

Think camping trailer instead of exotic N2 solutions, -maybee even a used old camping wagon with a simple air-conditioning/heating unit will be the cheapest available technical solution? Or air conditioning units from camping wagons along with isolation?

 

[Warpspeed]

I doubt very much if 24 hour per day heating and airconditionig is the most economic solution for long term storage of books.

But having lived in the Antarctic for two years myself, on two separate Antarctic expeditions, what you say about insulation, and vapor barriers placed on the "hot" side of an insulating wall is very sound advice.

I still have some rather vivid memories of water trickling out of live 240 volt power outlets during the big summer thaw, when trapped ice in the walls defrosts from 24 hour sunlight.

 

[gerhardl]

Hello Warpspeed, you are of course right! (And just look at the amount of ice you get around and below a normal air to air heating pump (on the outside exchanger) during a normal temperate winter).... But we are presumably not talking about living temperatures, not arctic, and not 365/24, just on/and off periodically parts of the year,in a good, sealed container to keep temperatures some degrees above zero to have a relatively controlled temperature to avoid inside (not outside) condensation.

In a normal, northern Scandinavian climate during winter, you will normally not have problems having books stored in a camping trailer, even if not heated. As stated: it is the condensate on surfaces that is the problem.

 

[dicer]

Just an off the wall question. It is pretty common knowlege 1 that all life forms need O2.
2 that 02 kills some germs.

I don't understand?
How come molds like cool and damp? What will kill them?
What ever the answer is to this question is the best way to store books and paper.

 

[gruntguru]

Plants don't need O2.
However Fungi (including mould) are not plants - or animals.

 

[rmw]

I think that I remember that high concentrations of Ozone will kill mold. Not quite the same as O2, but close.

rmw

 

[zeusfaber]

Dicer,

Oxygen came into the game a long time after life started on the planet, and there are many life forms for which it isn't necessary at all.

There's lots of anaerobic micro-organisms, and it's these that tend to be killed by oxygen. Some of them (e.g botulinium clostridium are nasty little devils.

In terms of your main question, I doubt you'll find a more practical approach than gerhardl's.

However..

If you really do want to play around with gas injection, remember that your original aim was to keep the moisture out, rather than to inert the place. You could do this with dry air rather than N2 - and probably actually with air that's not all that dry, since all you need to do is make sure that the dewpoint stays below the lowest temperature you expect the surfaces in the store to drop to in the time it takes to achieve a change of air.

A.