What is Silo Protection?

This addresses the most frequently asked questions about silo protection, including “What is silo protection?”, “What causes silo over-pressurisation?”, “What are the risks of silo pressure?” and “What are the essential components of a comprehensive silo protection system?”

1. What is silo protection?

Storage silos pose numerous issues for site managers, which must be addressed. A silo protection system (SPS) is an integrated safety system for monitoring and controlling both level and (crucially) pressure within a powder or solids silo, typically containing products such as cement, flour or sugar. The system must be able to automatically stop the product inflow if pressure becomes dangerous.


2. What causes silo over-pressurisation?

To understand silo protection you must first understand what creates excess pressure in a silo. Pressure occurs where product is pneumatically transferred from a vessel (for example a road tanker, reclaim system or a bag house) into a silo. If the filtration system allows the pressurised air to escape sufficiently quickly then there should be no problem.

Silo over-pressurisation occurs when the volume of air entering the silo exceeds the volume air escaping or venting from the silo. This happens due to one of two possible reasons: either the airflow out of the silo is restricted (for example by a filter blockage) or the airflow in is excessive (likely an uncontrolled tanker discharge).


3. What are the risks of silo pressure?

There is a common misconception that the biggest risk to silos comes from overfilling. This is simply not the case.  The damage that can be caused by over-pressurising a silo far outstrips the problems of overfilling. Overfilling will not cause a silo to rupture or the filter unit to blow off the top – pressure build-up will! This has the potential to cause fatal injury, as has happened in recent years.


4. What are the essential components of a comprehensive silo protection system?

The Mineral Products Association (MPA) has published guidelines covering essential SPS components. A system must have equipment test functionality, alarms, and be able to automatically stop the product inflow if pressure becomes dangerous.

However Hycontrol assert that comprehensive protection requires more, and so our systems are the only ones to exceed MPA guidance. Please refer to our literature for further information.