Sacrificial Coatings APP 'S' The APP 'S' protection systems are a further development of the original APP 'PSS' product group. APP 'S' is a completely reversible protection system against graffiti for facades and walls. APP 'S' consists of vegetable ingredients and water and have a high viscosity. All the components of APP 'S' carry the E-number used in the food industry and therefore APP 'S' is non toxic to plants, animals and people. APP 'S' is sprayed on to the surface in one or two layers with an airless spraying unit. After drying it forms a very thin, fully breathing layer, invisible to the naked eye. APP 'S' can be used on all kinds of vertical natural and artificial stone facades, clinker, concrete, brick, metallic and aluminium facades. APP-HD (heavy duty) is applied by trained APP specialists using an airless spray process. The specialists control the material application corresponding to the specific characteristics of the surface. The monomolecular layer of APP-HD (heavy duty) molecules is so thin that it does not influence the water vapour diffusion of the sub-surface. One difference from conventional coatings is that APP-HD (heavy duty) is not film-forming so does not change the optical appearance of a natural stone and has no adhesion problems. In addition, the surface protection is not destroyed by abrasion since the molecular layer extends into even the smallest pores and interstices. This is beyond the reach of mechanical forces, unless several tenths of a millimetre of floor are removed. The cleaning of protected surfaces is simple and fast and can, therefore, be carried out at a reduced cost. For the most economic maintenance cleaning, APP recommends the combination of a once-only protective application with APP-HD (heavy duty). Graffiti on facades protected with APP-HD (heavy duty) can be simply removed using water pressure, eventually supported by our graffiti removers which are 100% biologically degradable within 3 days.