How to apply FN® Coatings
- Always apply FN ® functional coatings to a suitable and cohesive substrate . Silicate and acrylic paints are suitable. Completely unsuitable is the base created with the help of clay paint (after application of the sanitation suspension FN ® cracking and peeling). If you are unsure about the suitability of the substrate, it is necessary to test it by performing a FN ® test coat on a small piece, allowing it to dry and checking for scaling or cracking and flaking. In this case, it is necessary to remove the old paint and redecorate it with a suitable paint.
- Silicone paints are also unsuitable . Care should be taken that no wetting of the substrate occurs when applying FN ® coatings . In this case, the organic substances can be washed out of the substrate into a coating formed by the functional coating. This results in rusty stains. However, these spots usually lose themselves after a certain period of time, due to the photocatalytic effect. In the interior, it is always recommended to pre-paint the areas where FN ® will be applied , a quality silicate paint , which separates the substrate which may contain unwanted organic matter from the FN ® layer in which photocatalysis takes place.
- If FN ® coatings are applied to walls that are heavily contaminated with smoke pollution (such as restaurants, bars, smoking rooms, etc.), the substrate must be primed with deep penetration prior to application of FN ® . Otherwise, the impurities inside the plaster and the wall may rise to the surface layer. It then turns yellow and spots can appear on it.
- An ideal base for FN ® 1 functional coating is untreated concrete, and concrete and possibly burnt (without glaze) roof tiles and silicate plaster, stone.
- To create a 10 m 2 active photoactive surface, it is necessary to apply 1 liter (undiluted and perfectly blended !!!) functional coating FN ® to this surface evenly – preferably in two to three layers . This amount is minimal to ensure that the photoactive film is sufficiently strong to be applied by coating. The uniformity of the application of the material and the thickness of the formed layer are a prerequisite for ensuring its proper functioning. In the event of non-compliance with this principle of application and the formation of too weak a layer (for example by improper treatment or dilution with water), the photocatalytic effect may also affect the substrate, resulting in yellowing.
- The individual layers must be applied by applying the second layer after the first layer has been fed. Apply the third layer only after the previous two layers have completely dried.
- In case the aim is to create a surface that allows easy removal of graffiti , it is necessary to apply 6-7 layers of functional coating FN ® second if the substrate concrete is recommended when antigraffiti applications to apply the first layer using a functional coat FN ® 1 and the remaining layers to realize with the FN ® 2 remediation suspension . The optimum procedure is to spray the surface treated with FN ® with a jet of water and then clean the surface with a coarse brush and spray with pressurized water. Graffiti grabbing can also be done with a dry brush, but more effort is required. Five layers of functional coating FN must be applied again to the surface where the graffiti removal was carried out® 2.
- FN ® coatings can be applied by brush, roller or spray.
- Spraying is the most suitable method . It ensures uniform application of the material, fast work progress and lower consumption on the absorbent surface. Spray using a device that produces the finest droplets. Professional or semi-professional HVLP spray guns with nozzles for paint work have proven to be suitable for the interior. For large exterior applications, airless high pressure spray equipment with a suspension mixer can also be used. Mechanical sprayers and sprayers are not recommended for FN ® coatings because they do not form uniform droplets.
- The optimum distance between the spray gun nozzle and the wall is 35 – 40 cm. Spraying should be carried out by rapid oscillating motion of the wrist . In this way, apply the created aerosol “mist” evenly and thinly to the substrate. Be careful not to create wet, shiny spots when spraying on the substrate. They are a sign of over-layer formation. The paint may run on them, the substrate may also be wetted or cracked.
- Proven semi-professional devices: Wagner W550. Use of other types of devices is possible.
- Spraying is also the most appropriate method of application for aesthetic reasons . In particular, FN ® 2 is not fully transparent. It creates milky haziness and lightening on a colored background. If the suspension is not applied by gentle spraying and evenly, “tomcat” is formed. This effect can be alleviated by using FN ® color coatings . However, it cannot be completely removed.
- For roller application are the most suitable in the interior of a low paint rollers. For rough surface applications (eg facade), we recommend higher-tier rollers or a combination of roller and brush (very rough surfaces). Application must be carried out with a non-rolled roller at a brisk pace to prevent wetting and excessive material consumption, especially on more absorbent substrates. The use of a brush is useful when it is not possible to use spraying or roller application.
- Surfaces that are not treated with FN ® functional coating and objects in areas where paint is applied must be covered with a protective film. It is recommended to cover the edges of the film and to attach it with a tape. This measure prevents the uncontrolled deposition of microscopic droplets of the FN ® functional coating on the surfaces of surfaces and objects where this is not desirable and where, for example, dots can form on the painted surface due to the photocatalytic effect.
- In order to ensure the functionality of the photoactive layer created, it is essential that enough daylight is applied to the surfaces treated with the FN ® functional coating , or that the artificial source of ultraviolet (UVA) light is sufficient (sources in the range of 350 – 375 nm, optimal the wavelength for photoactivation is 365 nm). The minimum power of the source in relation to the illuminated area is governed by the UVA lamp according to the 1W electrical power supply rule per 1m 2 illuminated area. The minimum intensity of UV-A radiation to ensure the functionality of the photocatalytic surface is 0.2W / 1m2 .
How to Illuminate with UV lighting
How and when to illuminate with UVA light
In order to ensure the functionality of the photoactive layer formed, it is essential that daylight is impinging on the surfaces treated with the FN ® functional coating , or by providing an artificial source of ultraviolet (UVA) light. For lighting, we recommend using UVA sources and intensity that are totally harmless to human and animal health in the areas where this lighting is used. To give you an idea: in the winter months, when the sky is cloudy, the intensity of UV light in daylight is 10 times higher than the recommended values for lighting our paints in the interior .
Sources are 350 – 375 nm, optimal photoactivation wavelength is 365 nm.
Outside, throughout the year (including winter months) in daylight (even in the shade), the amount of UV radiation that provides the full photocatalytic cleaning performance of the FN ® coating is included .
However, the situation inside the building is different. There is no daylight in a number of spaces, and very little ultraviolet radiation penetrates through their glasses where there are windows. If we want to ensure good photocatalytic paint functionality even in the interior, where there is not enough UV light from daylight, it is necessary that the painted surface is illuminated by ultraviolet light of 355 – 375 nm (UVA).
Even though shorter wavelength ultraviolet light activates the photocatalytic process, it can damage your health. Therefore, the use of UV sources called UVB and UVC is not recommended.
We always install the light source so that the light is directed to the photocatalytic surface created by FN ®coating:
Diagram of possible illumination of room ceiling with UV light:
The minimum power of the source in relation to the illuminated area is governed by the UVA lamp according to the 1W electrical power supply rule per 1m 2 illuminated area. The minimum intensity of UV-A radiation to ensure the functionality of the photocatalytic surface is 0.2W / 1m 2 . The higher the intensity of UV radiation falling on the photocatalytic surface, the better its surface is able to break down the pollutants in the air and dispose of microorganisms. All too bad. This also applies to the use of UVA radiation whose intensity should not be increased above 2W / 1m 2 . It is equally important to follow the light source manufacturer’s instructions and make sure that when using high-power UVA luminaires, the light is directed to FN-painted surfaces and does not shine directly into people’s eyes.
UVA light sources can be purchased in special stores and on the Internet. Most commonly, actinic UVA fluorescent lamps emitting blue-white light or “Black Light” fluorescent lamps emitting UVA radiation in the invisible part of the spectrum are used. In addition to fluorescent lamps, it is also possible to use some types of special lamps and LEDs that produce UVA radiation in the recommended wavelengths from 350 – 368 nm.
For effective lighting, it is important to pay attention to selecting a suitable lamp in which a fluorescent lamp or other UVA light source is placed. The UV light source should not be covered with a glass or plastic cover, which usually (if not a special material) shields a significant portion of the UV light. The luminaire should also include an aluminum reflector, because the reflectors made of iron and other UV materials are poorly reflected or absorbed. This then prepares us for the necessary light output.
Ultraviolet Light Sources (UVA 350 – 370 nm)
Examples of UVA lighting in interiors:
Zdroje ultrafialového světla (UVA 350 – 370 nm)