The quality of water is crucial for a well-functioning fogging system and determines its durability and maintenance cost. These include health considerations, since the presence of microorganisms in the water fog can cause diseases.
A fog nozzle sprays water under high pressure (60 to 120 bar), and has depending on the model a hole diameter of about 120 microns. This is so small that it can only be seen under the microscope. With a consumption of seven liters of water per hour and a pressure of 60 bars, the flow velocity at the exit point is about 600 kilometers per hour. This speed creates high friction forces acting on the nozzle.
Hard water erodes the fog nozzle faster. The fog nozzle hole increases, eventually leading to higher water consumption and deteriorates the quality of fog. A high calcium content not only damages the fog nozzles, but also the entire pipe system. On lime can also accumulate bacteria. Therefore, I recommend treating water of medium hardness with an ion exchanger, or even with a reverse osmosis.
Other parameters that are relevant for misting systems: pH, total dissolved solids, conductivity, presence of certain substances like iron, suspended solids that affect the turbidity and microorganisms.
The pH value affects the precipitation of certain substances such as lime. This is particularly the case with pH values above 7, in the basic range. This leads to an early erosion of the nozzle hole. In mountainous or hilly regions tap water has very often a higher degree of hardness with a pH between 8 and 9. Therefore, optimal conditions can only be achieved with an additional pH correction. This is not without problems, since for pH correction only products are suitable which are harmless to health, such as citric acid for example.
Therefore, the pH adjustment alone could solve the scale problem. But the addition of substances in a mist system should be done with extreme caution because water is more mineralized, and inhalation of any substances or productions leads them directly into the bloodstream.
In general, the addition of foreign substances such as odor control agents or surfactants is problematic for health reasons. The health examination of these substances is usually only orally or percutaneously, but rarely by inhalation. The associated risks are not always predictable. This is true for all products including those that we spray every day in the household.
An increased iron content of more than 0.5 mg / L may cause rust deposits and encourage the growth of undesirable microorganisms. This is often originated from old drinking water supply pipelines, which also have even increased zinc and lead concentrations.
Turbid water with more than 0.5 NTU contains suspended solids. These lead to bacterial fouling of the filters, which must always be cleaned or replaced, and produce growth of microorganisms, if the suspended solids contain substrates.
It is therefore important for spraying and fogging systems to consider the following:
- A chemical and biological water analysis
- A suitable water treatment
- Beware of the addition of products and substances
- Thorough rinsing of the lines before putting into operation
You are definitely on the safe side with a reverse osmosis or a membrane filtration. Demineralized water can also lead to increased corrosion.
Fog System installations must therefore always consist of stainless steel elements. With the use of plastics, you have to ensure that the surface is not porous, since even here bacterial growth is stimulated.
