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Anti-graffiti

The preventive solution

Remmers graffiti protection belongs to the class of semi-permanent anti-graffiti systems. Graffiti and paint smears can be removed from treated surfaces easily thanks to the use of a hot water high pressure water jet equipment (hygrothermal cleaning).

Origin and law

Principles

The word ‘graffiti’ originates from the Greek word ‘graphein’. In Italian-speaking countries it developed from the word sgraffiare (= scratch, scratched) Graffiti and/or Graffiti. Graffiti (singular = graffito) describes words and/or images painted on wall surfaces in public areas, usually without permission. Graffiti protection systems (also called anti-graffiti systems) not only serve to protect against graffiti, but also allow easy and compete removal of this ‘artwork’.

Legal aspects

Graffiti is a criminal offence.

  • Graffiti is an offence of criminal damage and, if prosecuted, the offender could face a fine or even imprisonment.
  • Under 16's are not permitted to buy aerosol paint cans.
  • Local authorities can issue fixed penalty notices for offences of graffiti.
  • Local authorities are responsible for cleaning it up from public buildings and fixtures. They can also clean it from private buildings and can bill the owner for the work.
  • Graffiti should, initially, be reported to the local authority

Customer requirements

There are few product systems in the construction industry where customer demands and reality lie so far apart as for anti-graffiti systems, which is why it is essential to discuss the customers wishes and the performance capability of the available systems before taking any action.

Usually the customer wants the following with respect to an anti-graffiti product:

  • Application of a system that will not lead to optical or technical changes to the original surface. This generally means:
    • No change of colour
    • No change to the level of shine
    • No reduction of the breathability
    • No change to water absorption properties, in particular for partial-surface protection
    • Stability of the products mentioned during the period for which it is intended
  • The graffiti can be 100% removed without leaving any smears or changing the surface after cleaning. This is the same as restoring the appearance of the original state after cleaning.
  • Environmentally-friendly cleaning can be carried out.
  • If necessary, it is assumed that the cleaning work can be carried out by in-house staff, i.e. the system should be suitable for ‘maintenance services'.
  • The system is repeatedly effective.

Classification of the anti-graffiti systems

Depending on their stability when graffiti is removed, anti-graffiti systems are classified into:

This term covers all preventive systems that are removed at the same time when removing graffiti. That is why these are also reffered to as sacrificial layer systems. Products with different bases are available. The most common are:

  • Acrylates
  • Bi-polymers
  • Waxes

In general, these systems have a high level of water vapour diffusion and do not create any or only slight changes of colour on the treated surfaces. The following questions need to be addressed when selecting this kind of product:

  • Is it completely reversible, or do residues of the product remain in or on the surface after cleaning? Repeated application can cause these components to accumulate in the substrate, potentially leading to problems.
  • How good is the weather resistance under the given circumstances of the building. Many of these products are water soluble, which can cause them to leach or be washed away. To maintain effectiveness, the treatment must be repeated after a certain time, even if no cleaning has taken place. The corresponding cycles need to be defined before a measure is carried out.
  • Is there sufficient stability with regard to micro-organisms? Some temporary systems, in particular based on biopolymers, can be a breeding ground for microorganisms.

This term is used to summarise systems that are a combination of at least two protective materials. In general, these systems contain a non-reversible, water repelling and/or oil-repelling component and a reversible component. During cleaning, these, like the temporary systems, are also removed and then need to be replaced. A differentiation is made between single and multi-layer systems for first-time applications. In the case of one-coat paint systems, the combination of active ingredients is produced and applied as a single-component product. The protective substances separate after the application. One example are combinations of special waxes and organosilicon active ingredients. Whilst the wax components remain on the surface of the façade as a reversible part due to their viscosity and particle size, the organosilicon part penetrates the subsurface and generates an irreversible water-repellent layer. In the case of multi-layer systems, the components are applied individually one after another. The following properties need to be observed when opting for this kind of system:

  • None to slight changes of colour are created on the treated surfaces.
  • Semi-permanent systems are generally water vapour permeable.
  • Based on the technical structure of the product, with the first layer penetrating into the substrate, apply these systems only on absorbent, porous surfaces

Permanent anti-graffiti systems generally comprise of several layers that remain permanently on or in the substrate. This suggests that the function of the protection system is also maintained on surfaces that have been soiled several times with graffiti and cleaned again, and does not need to be renewed. However, it does make sense to renew the protection layer after a certain number of cleaning intervals that depends on the respective product. Both water repelling and/or oil-repelling impregnations and also coatings are used as permanent anti-graffiti systems.

  • Impregnations
    • The product base of these systems usually comprises of flourine compounds, generally known as ‘Teflon’ compounds that have an extremely strong ‘pearling’ effect.
    • The optical properties of the substrate treated with this and the vapor permeability do not change.
    • This type of product does not close the pores, but makes the pores on the surface water or oil repellent. The active substance must therefore be able to penetrate into the substrate. However, the substrate may not be too open, because penetration of graffiti particles into the pores of the substrate cannot be prevented.
    • These types of products are particularly suitable for exposed concrete surfaces.

  • Coatings
    • The basis of these systems are usually synthetic resins - often chemically-resistant polyurethanes which is applied in several layers.
    • In addition to transparent paints, opaque paints of different colors and gloss levels are offered.
    • Usually, all surfaces protected in this way are cleaned quickly, easily and completely.
    • These anti-graffiti systems adhere well to almost all substrates, including smooth ones.
    • They close the pores of the building material surface and act as a sealing layer. Current systems are almost vapour-tight which can lead to problems on moist surfaces.

Cleaning technologies

There are various techniques and methods that can be used to remove graffiti depending on the respective anti-graffiti system and possibly the spray paint used.

  • Solvent-based strippers must be applied. Depending on the type of product and the exposure time of the spray paint, the surface is usually cleaned with a high-pressure, hot water or hot steam cleaner.
  • If necessary, other chemical, effective cleaning products or solvents with similar processing techniques can also be used.
  • Blasting, just like high pressure steam, is generally only suitable on well-protected surfaces. While low-pressure wet blasting, micro-mist blasting technology can also be applied to unprotected surfaces.
  • Manual cleaning is possible, in particular, on smooth surfaces by using chemical cleaning agents.
  • To remove graffiti, especially on cultural-historical, valuable substrates, laser technology can possibly be used for cleaning.
Always observe the stipulated personal protective equipment during all cleaning work, which also applies to the legal requirements for the disposal of waste water or waste.

Assessment criteria for selecting anti-graffiti products

Before anti-graffiti measures are taken, the complete effectiveness between substrate, protection system and the way in which it can be cleaned must be assessed. A number of aspects must be taken into account here:

  • It is likely that the protection system will impact on the appearance of the façade and/or should a change of appearance be seen as a restriction because it is possible that only parts of the surface are protected (e.g. only the façade on the ground floor)?
  • Does the owner stipulate the reversibility of the protective measure? This is defined as a basic requirement in some cases, in particular on listed buildings.
  • Which physical changes occur on the façade when a certain protection system is applied? In particular, this aspect affects the moisture balance of the façade construction, or the moisture absorption and discharge behaviour. In this connection, damaging salt loads in the surface need to be looked at critically because the salts, in particular, in breathable systems, retain their damaging potential. Please refer to the chapter on diagnosis, damage assessment and façade hydrophobizing when assessing dangerous salt levels.
  • Is the substrate suitable for the intended cleaning procedure? For mineral building materials such as natural stone and brick masonry, concrete but also stucco, it is generally fairly easy to find a suitable anti-graffiti system, taking into account the preconditions. Special requirements apply to other building materials. In many cases, applying an anti-graffiti product is hassle-free. The surface may be unsuitable for subsequent cleaning. For example, semi-permanent systems, the wax component of which must be dissolved during cleaning, are not suitable for coated facades. The hot water required for cleaning, which is required for cleaning the surface with water temperatures of 80-90º, can also cause the facade paint to dissolve and be removed.
  • How weather-stable are certain products under the given weather conditions? In addition to the general weathering conditions, the micro-climate in the treated area, like the wind and driving rain situation, sunlight and/or shade also need to be considered. Periodic refreshments must be carried out to maintain the efficiency of some products. The corresponding cycles must be defined.
  • How stable are the potential products compared to microbiological infestation? In particular, this aspect plays a role if the façade was already infested before the graffiti was sprayed due to favourable ambient conditions. In this case, the protection product should not form a nutritional basis for renewed, or accelerated infestation.
  • Environmental aspects (ingredients and cleaning technology).
  • Are there any restrictions with respect to the handling ease of certain anti-graffiti systems due to conditions on the building? There is a wide range of potential scenarios here, e.g. limitations to the use of certain cleaning methods based on noise, dust or odour emissions.
  • Is a certain product sufficiently effective in combination with the affected substrate? As already described, there are limits for certain types of anti-graffiti systems with respect to their use of certain surfaces e.g. for pure impregnations and coarse-pore building material surfaces.

It is always recommended using tested and certified products for preventive and cleaning purposes.

  • Quality and test criteria were developed by many agencies in the 1990s to determine the suitability of graffiti removal and graffiti prevention materials. Since 1999, materials based on this quality have been provided with the RAL quality mark Anti-Graffiti.
  • The BASt (Bundesanstalt für Straßenwesen) conducts tested anti-graffiti systems for application on concrete, based on the rules of the Gütegemeinschaft Anti-Graffiti eV

If non-certified products are used, ensure that the following is documented:

  • Possible areas of application or limits of effectiveness (unlimited effectiveness and usability is questionable)
  • Physical effect of the building
  • Processing guidelines/parameters
  • Recommended cleaning technology
  • Consumption
  • Environmental aspects, waste disposal

Testing anti-graffiti systems on sample surface area

Setting up a test surface area is an excellent way to test the interaction of the anti-graffiti products and cleaning method and/or cleaning agents in combination with the surface properties. For a representative test it is necessary to not only apply the protective products and assess the optical effect, but also to apply graffiti to the protected surface and to remove it again using the selected method. This method is the only way to guarantee sustainable assessment of the suitability of a protection system. The sample surface should reflect the important substrate properties and be appropriate to the size of the building. If various substrate types need to be treated, they should be represented in the sample surface or by creating several sample surfaces. A directly adjacent untreated comparative surface is part of the sample surface. This allows optical changes to be assessed. To guarantee this, both the sample surface and also the comparative surface can be processed with similar preparatory steps, e.g. the same preliminary cleaning process.

Maintenance

Façades are treated with anti-graffiti systems to guarantee fast and easy cleaning after graffiti has been sprayed on. Cleaning is part of the system. The anti-graffiti system should of course have to be cleaned by the same company that has also carried out the test surface and the initial treatment.. Only then can the quality and effectiveness of the system and the soundness of the substrate be maintained.

Anti-graffiti

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