Moisture

The term moisture or humidity indicates the measure of the presence of water in or on a substance or in a gas or in a room (eg, in the basement of a building). In physics and materials science one speaks generally of water content.

Gaseous moisture is generally referred to as humidity and in association with liquid water as vapor, mist, or wet steam. The absolute humidity indicates how much water vapor is contained in the unit volume of the gas mixture; Unit of measure: g water · m- third Relative humidity is the ratio of the existing at a certain temperature in the gas volume of water vapor and possible at the same amount of water vapor saturation temperature, multiplied by 100; Unit: % relative humidity.

The moisture of the soil is known as soil moisture, the pores of the rock than water, as the skin as skin moisture and the moisture content of the wood. Moisture in construction see humidity damage and water damage.

The moisture of a substance is linked to many properties. Examples include loss and sources ( dimensional change ) on water absorption and emission, the source strength, electrical conductivity, thermal conductivity, coefficient of friction.

Removal of water from a surface, or of a substance is generally referred to as drying or dewatering.

Analytical determination

For rapid determination of moisture of a substance sample is usually employs infrared moisture meter. These devices are also dryer and scales. The heat source is given to an infrared emitter. The infrared radiation penetrates deeply about 1 cm into the substance to be dried at the same time, the light energy is converted into heat energy. The moisture content is determined from a weighed on the same weighing dish whose weight change (cause: moisture loss ) transferred to a display scale, directly in percent ( %) moisture appears.

A quantitative determination of water content of samples can also be done by titrimetry by the Karl Fischer method.

In industry and leak detections in buildings, the inductive measurement of humidity is common. It caused by the moisture tension changes of an electric field are measured in the comparison values ​​are determined with an electrode in dry and wet places. Measuring the depth varies depending on the material and layer thickness of between 40 and 100 mm, the material being not damaged.