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Silo Aeration & Fumigation

Ensure the quality of your stored grain is maintained with the correct aeration and fumigation.

Purpose of aeration:

Is to reduce the grain temperature to below 20 degrees and reducing the humidity within the grain mass. This will reduce potential for mould and insect development while protecting grain quality.

The Silo Construction Company recommends the installation of an aeration controller.

If an aeration controller is not installed use the following guidelines:
  • First cooling action:

Run fans continuously if suitable air is available from when the silo is being loaded and grain is covering the silo floor. This will create a cooling front moving through the grain mass. Period of approx. 5 + days.

The top of the grain mass will be exposed to condensation and the last to be cooled.

The head space above the top of the grain mass will heat and cool on a daily cycle forming condensation while grain is present.

Aeration fans should not operate above 85% relative humidity.

  • Second Cooling action:

For approx. 7 nights run the fans for 9 to 12 hours overnight.

The top of the grain will continue to be exposed to condensation and the last cooled.

  • Maintenance & cooling action:

Run fans for approx. 100 hours per month when suitable atmospheric air is available. E.g. Low humidity and temperature.

As the head space heats and cools on a daily cycle we suggest that fans should run reasonable frequently; E.g. each evening, to remove moisture rich air from the head space reducing condensation.

Aeration Fans

Aeration fans are available from several manufacturers and specified to deliver to your silos main storage task.

Available in single or 3 phase electric motors.

A staggered start feature is highly recommended to manage the power supply to the facility.

Wherever possible fans should have soft start drives incorporated.

Aeration Vents:

The number and type of vents are again matched to your aeration fans and purpose of the silo. We usually install high flow vents that are sealable and ground operated.

Aeration Controllers:

These devices will decide on when and how much air is required for your grain mass. These choices are determined by the cooling or maintenance phase.

It will choose the air when the desired atmospheric air is available.

They will also manage the staggered start process of the fans.

They can also send signals to start & stop a generator, if installed.


TSCC are not an authority on fumigation and we recommend that you consult a specialist supplier/manufacturer of the fumigant.

Insect pests are a significant threat to the Australian grain industry. Some of our insect species are now resistant or tolerant to several of the chemical treatment compounds.

Fortunately, we still have phosphene gas available to us. The preservation of its effectiveness is important and the basis of the sealed silo and proper fumigation process.

The objective is to have the desired concentration delivered to and maintained in you mass of grain. This concentration is to be maintained for minimum of 10 days to achieve the maximum kill of the insect population.

Thermosyphon re entry to aeration transition

How to set up the silo for fumigation:

Close down or seal up your silo and leave until fumigation process is finished.

Install the fan seal plate.

Lock down the sealable vents.

Placing the fumigant.

Lock down the fill hole lid.

After fumigation return the silo to its maintenance function

Sealed silos:

The Cyclone silo is engineered to be sealed to the Australian Standard for fumigation.

The Silo Construction Company will construct the Cyclone Silo to this sealed for fumigation standard.

HiFlow Vent Ground Control

Fumigation devices:

Fumigant products requires knowledge and skill to obtain the best effect and ensure safety.

Special boxes are available that allow you to work at ground level and introduce the fumigant gas via fumigation ports we install for this purpose. Consult with us for a supplier.

Visit GRDC for the Grain Storage Fact Sheet

Thermosyphon Press Relief Valve silo construction
Thermosyphon re entry to aeration transition
Thermosyphon Press Relief Valve

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