Libraries
Library: ducts, humidity and book conservation
Paper does not complain. It absorbs moisture in silence for months and one day the stain appears. By the time it shows, the room air has been out of range for a while.
By Limpieza de Ductos Panamá
Yes, it can contribute. A dirty coil and a full pan remove less moisture from the air, and wet insulation adds vapor to the supply. With an annual average humidity of 75.7 % in the city according to ETESA, that is enough for the stacks to cross the threshold beyond which clean paper starts hosting mold. The camera shows the condition of the duct and a humidity log shows the effect on the room.
Paper and humidity: the threshold that matters
The Canadian Conservation Institute, in its sheet on incorrect relative humidity, sets the boundary of a damp environment at 75 % relative humidity and explains that the time until mold appears shortens from about one hundred days at 70 % to barely two days at 90 %. For clean plant-based materials, such as paper without starch or dirt, it indicates that mold usually requires 80 to 85 % to be likely. Dirty paper, paste or leather bindings are more vulnerable and start earlier.
The same sheet describes a minimum control level, which it calls class D, consisting of keeping humidity reliably below 75 %. That is the realistic goal for a library in Panama without a precision controlled stacks room: not to reach the values of a national archive, but never to cross 75 %. In a city whose average outdoor humidity sits right at that value, the air conditioning is the only thing keeping the room on the right side.
How a dirty duct alters the humidity of the room
Air conditioning removes moisture by passing the air over a cold coil, where vapor condenses and drops into a pan. When the coil is covered in dust, the air goes through without cooling enough and condenses less. When the pan does not drain, the standing water evaporates back into the duct. The EPA, in its mold remediation guide, asks for indoor humidity below 60 % and clean pans with free drainage, and notes that hidden mold often appears in condensate pans and in porous duct linings.
When the system allows it, the review of libraries is done by camera through the existing access points, the way the Climatiza technical service performs it.
| System condition | Effect on room humidity |
|---|---|
| Clean coil, pan draining | The unit dehumidifies as designed |
| Coil with dust | Less condensation, the room stays more humid at the same temperature |
| Pan with standing water | Vapor and odor returning to the supply |
| Wet internal insulation | Source of moisture and of an old paper smell at the diffusers |
| Unit off at night with a loaded duct | Room humidity rises until it matches the outdoors |
Collection stacks and reading room
The two rooms are not treated the same. The reading room has people, doors that open and a moisture load that enters with each visitor, so its system works harder and its filter loads sooner. The stacks have few people, stay closed and the unit is often switched off at night to save. That shutdown is the bigger risk, because with the unit stopped the humidity of the stacks rises until it matches the outdoors, and the paper absorbs it.
- Coil and pan of the stacks unit, with a photo, before any duct.
- Duct sections crossing the stacks, looking for exterior condensation and stained insulation.
- Diffusers over the tallest shelving, where cold air drops straight onto the spines.
- Reading room return, with lint and paper dust.
- Actual on and off schedule of each unit, asked of the staff.
Signs: old paper smell and stains
An old paper smell is normal in a library with an old collection, but it changes character when there is humidity: it becomes sweeter and stronger when the air comes on, and concentrates near the diffusers instead of near the shelves. Foxing stains, the brown spots on pages, and warped covers are late signs. By the time they appear, the coil should be looked at and the camera run through the section serving that shelving without waiting for the annual review.
What to record for the person in charge of the collection
The person in charge of the collection needs two records that usually nobody puts together: the room humidity log and the condition of the air system. A digital hygrometer with memory in the stacks, read every week, takes little effort and shows whether 75 % was crossed overnight. Next to that curve, the duct report says what was dirty and what was cleaned, and lets one see whether humidity dropped afterwards.
- Weekly humidity reading. Weekly maximum and minimum in the stacks and the reading room, with the date.
- System condition with photos. Coil, pan, filter and sections checked with the camera, organized by room.
- Action and verification. What was cleaned or repaired, following the criteria of the duct technical guide, and the humidity readings of the following weeks.
With those two records the person in charge can talk to the administration in terms of the collection and not of equipment. Coordination resembles that of a museum where the conservation team decides which rooms are opened, and in university libraries it crosses with the calendar of a campus that almost never closes. For anyone wanting to estimate how much attention each room needs by use and signs, the tools on this site give a starting point.
Scheduling a review starts with a message to Climatiza, and the service page summarizes the process.
Sources
On this site
- Museums and convention centersHow the work is organized in this sector
- Universities and schoolsA neighboring sector
- Camera inspectionThe real condition before deciding
Climatiza and Radar Panamá
Frequently asked questions
What humidity should the stacks of a library in Panama have?
At a minimum, always below 75 %, the damp boundary according to the Canadian Conservation Institute. The EPA recommends under 60 % to avoid mold in buildings. Going lower requires precision control that not every library has.
Does switching the air off at night damage the books?
It raises the risk. With the unit off, the humidity of the stacks tends to match the outdoors, which in the city averages 75.7 % and in the rainy season exceeds 80 %. If something must be switched off, it should be the reading room and not the stacks.
Does cleaning the ducts lower the room humidity?
Only if the problem was in the coil, the pan or wet insulation. If the humidity comes from open doors, leaks or a unit too small for the room, cleaning does not change it. That is why the camera check and the measurement come before the decision.
Can the duct be checked with the collection on the shelves?
Yes, with the shelving covered in plastic under each access panel and without brushing anything until the photos are taken. The inspection releases no dust. If a section over the stacks later needs cleaning, the whole shelving unit is covered and the work is done with vacuum extraction.
Keep reading
Request an inspection
Do you want to know the condition of your system?
A camera inspection lets you see the inside of the ducts before deciding what to do. Message us and we will confirm availability.
- +507 6388-2083
- info@climatizapanama.com
- Calle Gervasio García, 8, Panama City