Moisture condensation

[elpa02]

Hi everyone,

I'm trying to find a way to reduce or even disappear moisture from a vault and i hope someone can help me.

During days with high humidity in the air, and when air temperature is lower than 15 C (observation), water droplets are formed inside the vault just under the doors (manholes), which drop on the floor and corrode the metal fittings. This is most probably caused by humidity in the vault, which is condensed when in contact with cold surfaces (vault ceiling and doors).Keep in mind that the doors open once a week for an hour for inspection reasons.

Is there any tested technical solution to absorb humidity?

[Consider an underground room (vault) with two manholes to enter on the ground level (dimensions 1m x 2m made by cast-iron). The dimensions of the vault is aprox. 7 m debth, 5m width, 5m length. The vault's ceiling,bottom and walls are concrete.]

Thanks in advance,
EP

 

[boo1]

Consider Desiccant-based system dehumidification:
see

http://www.nrel.gov/desiccantcool/intro.html

 

[ChasBean1]

elpa02: Are there temperature requirements for the vault? The easiest way to go would be to place heater(s) inside the vault and maintain the space temperature above the highest anticipated dewpoint. If you maintain the room 75-80°F, it would a) first have to be above 75-80°F (approx. 25°C) outside, and b) dewpoint would have to rise to this value also before condensation would form. In my area (41.3° N. latitude) this dewpoint is rarely reached. This would be a lot simpler and more cost-effective than air conditioning or dehumidification systems.

 

[automatic2]

I agree with raising the temp. Your concrete is likely unsealed, and that cost could be high. Is venting possible. Your exterior air may be drier?. Your moisture is likely moving from subsoils, or, free flowing water (rain) is penetrating the door sills.

 

[bradphillips]

Is corrosion the only problem caused by the moisture? Would it be simpler to paint or coat corroding parts, or change to different materials?

 

[elpa02]

Firstly, thank you very much all of you.

Something that i did not mention is that any device installed in the vault must be ex-proof.
I wonder if the dehumidifiers or the space heaters are ex-proof.
Thanks in advance
elpa02

 

[rsimon]

Look in McMaster-Carr catalog. There is a brush on coating (paint) that you can apply to the metal doors that will stop them from sweating.

 

[rsimon]

Sweat-stop pipe coating 4588K2 McMaster-Carr.

 

[hacksaw]

We use explosion proof lighting fixtures. Incandescent bulbs are fine.

Keeping a light on does wonders.