Humidity, temperature and indoor air quality

Measuring humidity, measuring temperature as well as dew point are part of indoor air quality diagnosis in living premises.

Comfort humidity and temperature

According to the OQAI (French Indoor Air Quality Observatory), "the optimum level of air relative humidity in a home should be between 40 and 70%, for a temperature of between 18°and 22°C."

Some specific environments require very special environmental conditions, temperature and humidity content particularly –two key parameters for indoor air quality-:
- Pharmaceutical laboratory or research department cleanrooms or IT rooms,
- Museums or exhibition premises, archives and warehouses.

Humidity and temperature of cleanrooms and IT rooms

Classified into 9 levels in function of their specificity, cleanrooms (also called white rooms) are rooms where any environmental contamination is to be avoided. They are used in many different fields:
- Health and biotechnology industries (pharmacy, cosmetics, fine chemicals, virology, GMO, etc...)
- Hospitals (operating theatres, hospital pharmacies and sterilisation units, etc...)
- Agri-food industry (marine products, dairy products, ready-made meals, pastries, etc...)
- Advanced technologies (aeronautics, nuclear, aerospace, etc...)
- Plastics, automobile, mechanical, optics, etc...

Subject to recommendations and regulations related to their business, controlling air quality in confined spaces mainly depends on:
- the maximum acceptable concentration of particles per m3
- controlling humidity and room temperature.
To insure constant indoor air quality, these environments are subject to 24-hour monitoring.

Measuring humidity and temperature in museums and archives

Museums (exhibition and reserve rooms) have to meet conservation conditions for works of art and archives that are sensitive to humidity and temperature. Otherwise, indoor air quality depends on other factors. For instance, 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- .

Preventive conservation rules for works of art imply mainly:
- Ambient temperature between 18°and 24°C (give or take ±3°C daily),
- Relative humidity between 45% and 55%.

Also, in order to avoid premature aging or fading of paper, leather or parchment-based documents, the atmosphere of the archives must meet the following standards (ISO 11799 “recommendations for storing archive and library documents”):
- Temperature ranging between 16°and 24°C,
- Relative humidity of between 40 and 60%.
Whatever the environment, a thermo-hygrometer allows to measure humidity and room temperature, to figure dew point as well as to monitor these quantities over time.

Indoor air quality: our trainings

- Conciliating energy performance and indoor air quality -October 9, 2012, in Paris-
- Indoor air quality and health in tertiary buildings -October 2, 2012, in Paris-