Corrosive fumes, in large volumes and over long periods, will damage or destroy materials that they come into contact with. Substances containing corrosive bases, such as those found in sulphuric or hydrochloric acids, will erode the surface of fan components if not manufactured in material fit for purpose.
The extraction of corrosive fumes should be done with chemical/corrosion resistant fans. Polypropylene is the standard material which can withstand the nature of the chemical gases that pass through the scroll and the impellers. In this instance, the motor should be kept out of the airstream to ensure long lifespan and also to prevent the overheating of the motorised components. The duct work that is attached to the industrial fan should also carry the same level of protection against corrosion as the fan scroll and impeller itself. In smaller storage units, where the materials are non-corrosive and ventilation is more general, an axial fan can be used for ventilation. This should be certified for use in ATEX applications, where in these instances the motor that is held within the airstream can withstand the nature of the gases, fumes or mists.
It is worth noting that flammable gases are denser than air so they can accumulate at floor level. For this reason, the ventilation system should be set up to ensure that these low level, potentially hazardous, gases can be extracted effectively.
