Humidity and indoor air quality in archives
Humidity and temperature are inseparableHumidity and temperature interact. These parameters have an impact on the release and the speed of the chemical reactions that affect documents and works of art. They also contribute to microorganism occurring and insects’ survival.
Thermal shocks, that are strong variations in temperature and relative humidity, are to be avoided.
Hygroscopic materials, paper, canvas, parchment, leather, wood, silk … react to relative humidity; the excess humidity is absorbed, whereas too dry air causes water evaporation from materials and contributes to weaken paper, leather, parchment or canvas.
Ideal humidity and temperature for conservationHumidity and temperature of archives premises are defined in the ISO 11799 standard “Recommendations for storing archive and library documents”:
- ambient temperature ranging between 16°and 24°C,
- relative humidity of between 40 and 60%.
This is to avoid premature aging or alteration of documents in paper, leather or parchment.
In museums –from exhibition rooms to storage-, some material conservation rules are to be met. According to the ICOM’s (International Council of Museums) standards, a constant environment of 50% relative humidity at a temperature of 18°C is required to optimise the conservation of works of arts.
Depending on the environment, defining critical points and logging CO2, humidity and indoor air temperature during a representative period can be a first preventive step in monitoring conservation requirements.
Consultancy and ventilation systems> Services of Domosystem
This moisture meter for building materials allows to measure water content of screed, floor screed, drywall, heavy concrete brick, brick…
Adjustable thanks to it optional sensors:
- Infrared surface temperature probe
- Thermo-humidity probe
- CO2 probe
Four-in-one system: two-pin-contact moisture meter, in depth radiofrequency moisture detector, infrared thermometer, fast responding thermo-hygrometer.
- intuitive user interface with color screen,
- data logging,
- firmware upgradable,
- psychometric calculations,
- non-contact IR temperature probe with laser pointer.
Indoor air acidification
Depending on its manufacturing time and its composition, paper can contribute to make the indoor air more acidic and favour corrosion –that would not be necessarily due to excess moisture then- .
Only indoor air quality diagnosis allows to identify prospective pollutants (chemical, particulate and biological) and to take appropriate corrective actions.