Internal coatings of vents and ventilation ducts, both masonry and prefabricated, made from plastic, plastic resins or plastic-based composite materials which, after being drawn into place in a soft form, are inflated and hardened by steam, forming to the path of the duct or the shape of the internal liner of the canals or ducting, being parts of non-metal ducts

Sealant coatings for the interior of masonry and prefabricated vents and ventilation ducts made from plastic, plastic resins or plastic-based composite materials which, after being drawn into place in a soft form, are inflated and hardened by steam, forming to the path of the duct or the shape of the internal liner of the canals or ductings