Protective features for bulk storage abound in the marketplace. Here are some of the most common, most advantageous systems today:
Sensors to monitor gas, heat, and moisture come in high on the must-have list. These are affordable and easy to install. Depending on the size of the dome, 10 to 20 sensor arrays are generally sufficient.
Enclosed belt conveyors minimize dust and can easily be serviced by lubricating the bearings from the outside. Enclosed conveyors eliminate expensive high-maintenance headhouses and bin vents on top of the dome.
Air-supported conveyors, though more expensive than conventional belt conveyors, are low friction and do not require rollers and bearings that heat up. Service is minimal.
A floor-aeration system includes troughs or plenums placed in the concrete floor with heavy steel grating and a perforated plate covering the grating, allowing heavy front-end loaders to drive over them. Fans outside the dome are attached to the plenums and provide air to cool the pile. Most handlers agree that an aeration system is an important element to reduce heat in the pile.
Storage fires are most likely introduced from the outside, like rollers freezing, catching the conveyor belt on fire, and potentially conveying the fire into the storage vessel, for instance. This is a function of poor management, maintenance, and housekeeping. A dry water-pipe system at the reclaim conveyor belt attached to the top of the dome shell interior provides fire mitigation. It is activated only when needed and is not expensive.
Nitrogen allows pellets to be pacified for long periods of time if needed. Keeping sufficient nitrogen on hand is not the norm; having a contract with a supplier to provide nitrogen on demand seems more common. Nitrogen can be introduced either through the aeration system in the floor or through a circular piping system attached to the top inner shell or both. If nitrogen is introduced into the dome, precautions must be taken to put a safety perimeter around the dome to keep personnel from being affected.