The IMP-VP plants are suitable for treatment of items that fall into risk classes three, four and five.

AS has been shown in the previous chapters, the natural conformation of wood makes it unsuitable for use outdoors.
Its composition (20-30% lignin 40-50% cellulose, 20-24% carbohydrates) makes it vulnerable to "degradation agents" which begin their action when humidity is high and the temperature is between 10 and 40 °C.
Fungi, mildew and bacteria are in ideal conditions to develop, whereas the ultraviolet rays present in the sun light photochemically decompose the lignin making it soluble in water.

Degradation of the wood by UV rays

The only way to fight the action of the enemies to wood is to turn to the help modern chemistry provides.

In fact if a good insecticide and fungicide is applied in sufficient quantity so that the internal parts of the wood are involved, the attack from micro organisms and insects can be offset for several years. Both the fungicide and the insecticide lose their effectiveness over the years, therefore the duration of the protection is directly proportional to the quantity applied. An impregnant with a high dry residual level can make the wood waterproof defending it against water as long as it is not applied so as to form a surface film.
The pigments, which are not transparent, form an impermeable surface barrier against ultraviolet rays, thus preventing decomposition of the lignin.

The traditional systems of dipping, brush painting and spraying are not able to guarantee to achieve the three results.
A product with a high dry residue level will form a surface film, limiting the penetration of the insecticide and fungicide solution.
On the contrary, a product with a low dry residue level will have better penetration allowing the insecticide and fungicide solution to be more active, but having very little resistance to the penetration of humidity into the internal parts of the manufactured item.

Only the use of pressure-vacuum technology has enabled pigmentation products with high dry residue levels (12-30%) to be applied resulting in complete protection of the item.