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Humidification Definition of terms

Is a means by which the degree of moisture in the air is increased. This can occur by applying various methods such as steam, (e.g. Electrode steam humidifiers), atomisation or evaporation.

Humidification output

Is the amount of steam that an air humidifier produces in “kilos per hour production time”.


Is water in gas form

Electrode steam humidification

Is a commonly used type of humidification where water is brought to boiling point and is turned into pure sterilized, odourless steam. This kind of humidification can only be used with conductive water, e.g. tap water. An electric field is created through the electrodes that in turn heats up the water. Due to the high water/steam temperature, any risk of contamination is excluded.

Should there be no water present in the steam cylinder, the electrical circuit cannot close ensuring the safety of the system.

Absolute humidity

Is the amount of steam in grams which is present in 1 kg of dry air

Relative air humidity

Is the amount of steam in the air at a certain temperature in comparison to the maximal amount of water, which the air, at the same temperature, is able to absorb i.e. the saturation level. It is the norm to express the relative air humidity in percentage


Is the capability to either absorb or release moisture, i.e. a certain matter absorbs or releases moisture according to the amount of moisture in the surrounding air. Due to this, the quality of the matter can change. For example, wood warps or cracks when the moisture level is too low. Similar problems can occur with textiles, plastics or paper.

h,x-Diagram (Mollier)

is a diagram giving information about the different conditions in the air in relation to the air temperature, absolute and relative humidity, specific Enthalpy, density etc. Among other things, the humidification level can be calculated 

electrical conductivity of the water

Water has certain characteristics, one being its electrical conductivity. In order for this phenomenon to occur, the water must contain a certain number of salts and/or minerals. The conductivity is usually indicated in microSiemens per centimetre (S/cm). To operate Nordmann steam generators the electrical conductivity should be between min. 125 and max. 1250 S/cm.


Can in different areas differentiate in quality being hard, soft, conductive, not conductive, sour etc. It is recommended to use normal drinking water for use with air humidification systems.

Water treatment

is when the water is treated to eliminate the minerals (water hardeners) in order to make the water softer. However, by doing this, the water also becomes quite aggressive.

Water hardness level

By calculating the amount of components (minerals) found in water, the water hardness can be established. The hardness is generally indicated in millimol Calcium and Magnesium Ions per litre (mmol/l) or degrees of German (DH), French (FH), English (EH) or American (AH) hardness levels.  The degree of water hardness can vary from very soft to very hard.








<  7

< 12.53

<   8.75

<   7.35

< 1.3

Medium soft


12.53 - 25.06

8.75 - 17.50

7.35 - 14.70

1.3 - 2.5



25.06 - 37.59

17.50 - 26.25

14.70 - 21.84

2.5 - 3.8

Sehr hart

> 21

> 37.59



> 3.8

1GH (German hardness) equals 1,79FH, 1,25EH, 1,05AH



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