Relative humidity and temperature sensor FHAD 46 series

digitalair

• Designs and specifications see data sheet A material’s equilibrium moisture contentis that level of relative humidity prevailingin the ambient atmosphere at which thematerial neither gains nor loses moisture.All construction materials may - to agreater or lesser degree - attract watervapor from or emit water vapor to theambient air. They are hygroscopic; i.e.they attempt to establish an equilibrium interms of moisture content with respect tothe ambient air. The construction materialand the ambient air, depending on their respective temperatures, establish aninteractive balance between the adsorptionof and the emission of water vapor from /to one another. Each material thus has,depending on temperature and onatmospheric humidity, a certain moisturecontent level (measured in water as apercentage of overall weight).In the state of equilibrium the relationshipbetween the water content and theequilibrium humidity of a material can bedisplayed graphically as a curve, the so called moisture sorption isotherm. Thesorption isotherm for the material inquestion indicates per atmospherichumidity value the corresponding watercontent value at a given constanttemperature. If the composition or qualityof the material changes then its sorptionbehavior - and thus its sorption isotherm -also changes. Given the great complexityof sorption processes these isothermscannot be determined by calculation; theyhave to be recorded experimentally