- Present low density (not to overload the weight of the system);
not possess or fix smell;
- be Imputrescibles;
- have low moisture absorption (low permeability);
- provide adequate resistance to diffusion of water vapor;
- not be attacked by insects or rodents;
- exhibit resistance to deformations caused by differences in temperature;
- have high mechanical resistance to shaking;
- not attack or be attacked by the products to be preserved;
- have a low operating cost;
- not flammable; and
- be easy to install.
