Ash storage silos are relatively large bins made of concrete, normal or pre-stressed, or carbon steel depending on capacity, to store fly ash and/or bottom ash until it is unloaded for final disposal.

An ash storage silo is typically supplied complete with:

Level probes, vent filter, relief door and ash collection equipment typically mounted on the roof.

Supporting structure complete of stairs, ladders, platforms, walkways and handrails, manholes, air balance valve and rupture disk, maintenance gate valve on discharge.

The loading system can be based either on pneumatic or mechanical conveying systems:
- pneumatic conveying system, either positive pressure type or a combined vacuum /positive type;
- Mechanical handling system typically made of rubber belts, bucket elevators and drag chain conveyors.

The unloading system is typically made of fluid slides installed in the bottom part of the silo to transfer the ash by means of articulated arms to the telescopic spouts for truck loading. The silo is also equipped with an emergency exit provided with a paddle mixer to avoid dusting during discharge on open trucks.