Absolute humidity

Absolute humidity quantifies the actual amount of water vapor contained in a specific volume of air (usually 1 m3). It is usually measured in grams per m3 of air (g/m3). Knowing the temperature, these two values can be used to determine the relative humidity (RH). To calculate the required humidification power, the absolute humidity is always used as a basis. The difference between its actual value and the desired value, plus the

Adiabatic cooling

The atomization of water in high-pressure nozzles converts water from liquid to gas state. This phase transition requires energy, which is extracted from the surrounding air: The air cools down.


Aerosol: The mixture of finely dispersed solid or liquid particles suspended in air in a gas. FINESTFOG high-pressure nozzles atomize water into fine droplets that mix with air outside the nozzle.

Coil membrane

Wound membranes are membranes that achieve a particularly large surface area through tight winding. In reverse osmosis systems by FINESTFOG, high-quality polymeric wound membranes are used. They are semipermeable and separate the water molecule from solids (mainly salts and impurities). Wound membranes can remove 97-99% of salts and other impurities from the water. Reverse osmosis can filter out particles > 0.0001 µm. Wound membranes are considered to be particularly durable.

Damp water

Printing machines require “damp water” on the printing rollers. This water should be of consistent quality. An important aspect is the water hardness, which should be between 8-10 °dH. Reverse osmosis systems initially produce pure water, which is still too aggressive for the printing rollers. Therefore, FINESTFOG adds hardness stabilizers through a dosing mechanism. The result: consistently high water quality without fluctuations.

Dew Point

The dew point (also known as dew point temperature) refers to the temperature at which air with a certain water vapor content cannot absorb any more water. When the dew point temperature is reached or exceeded, condensation occurs (droplet formation). In rooms with high relative humidity, it can especially lead to below-dew point temperature on cold surfaces. Condensation on windows, for example, is a visible consequence.

Dual-fluid nozzle

Nozzles that atomize water using compressed air are called dual-fluid nozzles in air humidification. The performance of dual-fluid nozzles is regulated by water pressure and compressed air supply. Since generating compressed air requires comparatively high energy, single-fluid nozzles are now used significantly more than dual-fluid nozzles. Additionally, the operating noise is much stronger with dual-fluid nozzles. FINESTFOG offers dual-fluid nozzles. Documentation and prices can be requested at any time.

Equilibrium moisture content

Equilibrium moisture content refers to the water content that hygroscopic materials (such as paper, wood, cotton) achieve after prolonged storage in a room with constant relative humidity and temperature. When the moisture content in the material and in the air is balanced, it is referred to as equilibrium moisture content. Problems arise when the air is consistently too dry. In this case, moisture is withdrawn from the material. The air tries to restore equilibrium – this can lead to shrinkage, weight loss, or cracking. Air humidification provides a solution by increasing the humidity in the room. The material will then absorb moisture until equilibrium is restored.

h-x diagram

The Mollier h-x diagram (formerly the i-x diagram) was named after Richard Mollier in 1923. It is used to determine changes in the state of moist air, such as those resulting from humidification, dehumidification, heating, and cooling. A reliable calculation of required humidification performance is always based on the h-x diagram. To do this, at least two variables must be known, such as temperature and desired relative humidity.

FINESTFOG offers the h-x diagram as a PDF upon request.


Hygroscopic materials are those that absorb moisture from the environment (usually in the form of water vapor from humidity). Hygroscopic materials tend to establish an equilibrium between their own moisture content and the surrounding humidity. This property can be used, for example, to remove moisture from containers (such as in medication storage). However, the associated chemical changes make it difficult to process hygroscopic materials in industries such as paper processing, printing, wood, or textiles. Controlled air humidification is of central economic interest for these sectors.


KBE stands for “colony-forming unit” and is a measure for quantifying microorganisms. For the microbiological examination of water, water samples are distributed on suitable culture medium gels. After a certain period of time, the viable cells can be counted in units to derive the number of microorganisms. According to the Drinking Water Regulations, at temperatures of 22 °C and 36 °C, the colony count must not exceed the value of 100/1 ml of water.


Unit of electrical conductance. The quality of pure water is most easily determined by its electrical conductivity: the lower the salt content in the water, the lower the conductance. It is measured in microsiemens (µS). FINESTFOG reverse osmosis systems are equipped with conductivity sensors that provide a pre-alarm or alarm signal as soon as the conductance of the purified water is too high.


Liquid fraction that passes through a filter (permeates). The substances retained by filtration form the retentate/concentrate. In water treatment, the purified water is also called permeate after passing through the membrane. In this context, the term refers to the almost desalinated, pure water.

Purified water

Water purified as a result of water treatment. Water filtered through a FINESTFOG reverse osmosis system is practically free from salt and bacteria (approximately 97-99% of salt is usually removed). Purified water should not be confused with distilled (fully demineralized) water.

Relative humidity

Relative humidity is the most common measure of air humidity. Usually abbreviated as % RH, it indicates the ratio of the current water vapor content to the maximum possible water vapor content at a given temperature (e.g. 20 °C). The maximum possible water vapor content is always 100% relative humidity. This state is also called the dew point. At this point, the air cannot absorb any more water vapor – additional water vapor condenses. In air humidification systems, humidity sensors measure the relative humidity to create the desired air humidity.

Reverse osmosis

Osmosis: the flow of a solvent through a semipermeable membrane to equalize concentration differences spontaneously. Reverse osmosis: a process in which the natural direction of the concentration gradient is reversed using pressure.

FINESTFOG reverse osmosis systems produce up to 98% desalinated purified water by utilizing semipermeable membranes: The medium (water) in which the concentration of a specific substance (salt) is to be reduced is separated from the medium (water) in which the concentration (salt) needs to be increased. This water is subjected to pressure using a pump that is higher than the pressure generated by the osmotic desire for concentration equalization (usually under 2 bar for tap water). As a result, the pure water molecules move (diffuse) through the membrane, while impurities (salt, bacteria, etc.) are retained. The resulting “concentrate” with the impurities is discharged, while the purified water is supplied to the consumer.

Single-fluid nozzle

Type of nozzle through which only one fluid (liquid/gas) flows. In the case of FINESTFOG high-pressure air humidification, the fluid is water. Atomization is achieved solely through the kinetic energy of the water. In contrast, dual-fluid nozzles require a second fluid as an energy source: compressed air.

Soft water

Water quality after the removal of calcium and magnesium ions. FIRENSTFOG softening systems remove the hardening agents magnesium and calcium from the water. In exchange, sodium ions (sodium salt) are added to the water in the same proportion = ion exchange. This makes the water “soft”. Many users confuse soft water with desalinated water. Softening exchanges, but does not reduce the salts. Therefore, soft water is only partially suitable for air humidification.

UV disinfection

The use of ultraviolet radiation with disinfecting effects. Ultraviolet radiation is invisible electromagnetic radiation for humans. Its wavelength is shorter than that of visible light for humans. Ultraviolet radiation is used for treating water, air, and surfaces – microorganisms and bacteria are inactivated (killed) within fractions of a second at a sufficient dose. Mutations caused by UV disinfection are not known. Another advantage is that the addition of chemicals is generally not necessary.

Water softening system

Water softening systems convert “hard” water into “soft” water. Their product should not be confused with distilled water or purified water. In water softening systems by FINESTFOG, tap water flows through a column containing cation exchange resin. Here, calcium ions (Ca2+) and magnesium ions (Mg2+) are exchanged for an equivalent amount of sodium ions (Na+). The softened water now contains more sodium and almost no calcium or magnesium ions. Exhausted ion exchange resin is regenerated using an 8-12% sodium chloride solution (table salt). Thus, a salt container filled with salt tablets is a component of every water softening system.

Water softening systems with two resin columns are called pendulum systems. The advantage of these systems used by FINESTFOG is that they can provide continuous soft water. Systems with only one resin column do not produce soft water during regeneration; they regenerate based on time, often resulting in high consumption of salt and water.

Water softening systems do not reduce the overall salt content of the water, making it generally unsuitable for air humidification. On the other hand, water softening systems are used for pre-treatment of tap water before it enters a reverse osmosis system.

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