Solution · Archives & Museums

Preserving cultural heritage,
keeping the climate constant

Cultural heritage has no spare parts. Whether it is a document, painting, historical photograph, or audio tape – once damaged or moldy, the loss is irreparable. DÖLCO keeps the climate in archives and depots precisely regulated, permanently constant, and seamlessly documented. Stationary dehumidification technology Made in Freiburg.

Consultation →Expert consultation: +49 7664 50559-0

The problem

Why collections suffer

Archives and depots rely on a stable climate – which almost never happens by itself. Hygroscopic materials such as paper, parchment, leather, wood, and textiles absorb and release moisture; every fluctuation causes stress within the material.

Too humid: biological infestation
Above approx. 60% RH, mold growth is promoted – foxing, mold, and insect infestation on paper, parchment, leather, and textiles. Affected collections must be laboriously decontaminated or discarded.
Too humid: corrosion
Metal objects, seals, coins, as well as magnetic data carriers and films oxidize and lose their readability – for data carriers, there is a risk of irreversible information loss.
Too dry: embrittlement
If the humidity drops too low, paper, parchment, leather, and wood lose their residual moisture, become brittle, and crack even during normal use.
Fluctuations: mechanical damage
Changing humidity causes materials to swell and shrink – book spines detach, veneers and paint layers crack, wood moves. Damage that worsens with every cycle.

The solution

Regulating to the setpoint – and maintaining it

DÖLCO does not dehumidify "somehow," but rather to the setpoint required for preservation – and maintains it. Stationary systems, demand-based control, and automatic climate documentation work in harmony.

Preserving cultural heritage,
Constant ~50% ± 5%
The system maintains the target corridor of DIN ISO 11799 permanently, instead of just capping peaks. Constancy is the actual protection here.
Material protection for cultural heritage
Mold, corrosion, embrittlement, and swelling/shrinking cycles are prevented at the root – preventive conservation instead of expensive restoration.
ITR – demand-based
The control system only dehumidifies when the measured climate requires it – this protects the collection and the energy budget while avoiding over-drying.
KISS climate documentation
Seamless real-time monitoring with automatic recording provides climate proof – for internal quality assurance, loan traffic, and oversight.

Expertise

DIN ISO 11799 & the importance of constancy

The authoritative standard DIN ISO 11799 recommends a constant climate of around 18 °C and 50% ± 5% relative humidity for mixed archive and library collections. Just as important as the setpoint is stability: daily fluctuations should remain small (a few percentage points RH per 24 hours). A relative humidity permanently below approx. 55% keeps the risk of mold low.

Relative humidity is temperature-dependent – the same absolute amount of water results in completely different values at different temperatures. For hygroscopic material, the individual measurement point is not the deciding factor, but rather that the climate remains calm: every swelling/shrinking cycle creates mechanical stress that accumulates. A constant climate just off the ideal value protects better than a "perfect" average that is constantly fluctuating.

Not every material shares the same setpoint: metal, photos, magnetic tapes, and films sometimes require significantly lower humidity (often 30–40% or below) and are stored in separate climate zones. In unheated or cool depots, where condensation technology reaches its limits, adsorption technology is the method of choice. The design is based on room volume, building physics, air exchange, and target climate – DÖLCO dimensions for the depot, not according to a flat-rate value.

DIN ISO 11799 & the importance of constancy

Products

The right DÖLCO systems

Stationary dehumidification, precisely regulated, with climate proof – combinable into climate zones.

K-Series (stationary)
For heated and temperature-controlled depots, archives, and reading room buffer zones – permanently installed and designed for the constant target climate of ~50% ± 5%.
Adsorption dryers
Maintains low, constant humidity even at low temperatures – ideal for unheated basement depots and moisture-sensitive special collections (metal, photo, film).
ITR dew point control
Demand-based control to the dew point – dehumidifies only according to measured demand, avoids over-drying, and reduces energy consumption.
KISS documentation
Real-time monitoring, alarm in case of setpoint deviation, and automatic climate documentation as verifiable proof.
View stationary systems →

FAQ

Frequently asked questions

What is the correct humidity for an archive?
For mixed collections, a guideline value of around 50% (± 5%) at approx. 18 °C applies according to DIN ISO 11799. It is at least as important that the humidity remains constant – large fluctuations cause more damage than a slightly deviating but stable value.
At what humidity is there a risk of mold in the depot?
Mold growth is promoted above approx. 60% RH. Those who keep the humidity permanently below around 55% significantly reduce the risk of mold, foxing, and insect infestation.
Can a dehumidifier over-dry collections?
With unregulated devices, yes. DÖLCO works with the ITR dew point control in a demand-based manner: it only dehumidifies when the measured climate requires it and stops at the setpoint – thus preventing embrittlement due to over-drying.
How do I document the depot climate?
Via KISS, temperature and humidity are recorded in real-time and automatically logged – a seamless, verifiable climate proof for quality assurance, oversight, and the loaning of objects.
Does dehumidification work in unheated basement depots?
Yes. In cool or unheated rooms where condensation technology reaches its limits, we use adsorption dryers – these achieve low, constant humidity values even at low temperatures.

Consultation

Secure your depot climate?

We design the dehumidification for your archives and depots – incl. separate climate zones and documentation. Free of charge and without obligation.

📞 +49 7664 / 50559-0✉ info@doelco.de