Disadvantages of Silos with Insulation Jacket / Covers

Grain Silo industry since 1907 is making single walled Steel grain silos and depends upon various techniques to improve the Solar Heat Reflectivity of Steel Silos to decrease the Solar Heat Absorption by Silos. High solar heat absorption by silo increases the average temperature inside the silo and discolor / spoils the grain. The two most commonly used techniques to improve the solar heat reflectivity the following;

1. Improve the quality of alloy coatings so that it maintains its white shiny lustre for longer time.

2. Painting the silo external walls with white paint

Both these techniques are equally accepted and reduce the solar heat absorption by the silos. First one increases the capital cost of silos and second one increases the maintenance cost of the silo.

However, recently some companies had started manufacturing grain Storage Silos with insulation jackets/covers so as to avoid the solar heat penetrating inside the silo. To provide insulation, corrugated steel silos Sidewall sheets are made double layered and insulating material like mineral wool, glass wool or Rockwool is filled in between as shown in the picture.

Grain Silos with Insulation Covers theoretically seems to be a very good choice but in long run it a creates lots of problems which must be understood before actually going in for the same.

1. Due to change in ambient temperatures, condensation happens within insulation layer and moisture droplets slides down the inner wall of insulation, which is actually the external wall of steel silo. This moisture makes the sidewall sheets of silo corrode fast and overall life of silo decreases.

2. Condensation that happens within the insulation area not only corrodes the sidewall sheets but also corrodes the fasteners which results in weakening the whole silo structurally

3. Another disadvantage of insulation covers is that in case there is any leakage past bolted joints of silo, it cannot be seen from outside. This makes preventive maintenance of silo difficult.

4. Sometimes there is ingress of microorganisms inside the insulation area, which makes fumigation ineffective.

5. Condensation inside insulation area gradually results in sagging of insulation material and thus makes it ineffective in long run.