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Installation and Maintenance of Grain Dryers (Hardfacts)


Although fire safety in crop dryers has improved over the years the application of heat to a combustible material such as grain presents a significant fire hazard.
This Hardfacts outlines some key action points aimed at the reduction of potential fire hazards for grain dryers in fixed installations or transportable dryers used in a fixed position.

Key Action Points

Dryer Location

Buildings containing drying plant should be

  • constructed of non-combustible materials
  • at least 20 metres from any other building or stack of produce
  • used for no other purpose when drying unless the dryer or, if separate, the hot air furnace is segregated from the remainder of the building by a 2 hour fire resisting wall carried up to the underside of the roof.

The Dryer

All equipment should be installed in accordance with the installation instructions supplied by the manufacturer.

Non combustible materials to be used for the construction of the dryer, hot air ducting and any associated equipment such as platforms, elevators or conveyors

Heating to be indirect preferably using a heat exchanger or otherwise ample baffles need to be provided between the furnace and the drying compartment.

Any furnace flue or engine exhaust should be carried out through and above the roof or through an external wall and be kept at least 1.0 metre clear of combustible material.

Any combustible linings and roofing which are penetrated need to be cut back to at least 100mm from the flue or exhaust and a non combustible, non conductive collar fitted.

Where possible thermostats should be duplicated operating a fail-safe system by shutting down the furnace to prevent overheating and subsequent ignition

In order to prevent combustible matter such as chaff, dust and straw being drawn into the furnace, fresh air needs to be drawn directly from the open to the dryer.

Similar considerations apply when siting a transportable dryer.

Any transportable dryers which polish in addition to drying will produce quantities of dust and need to be sited in open sided or ended buildings to allow a dispersing through-put of air. Consideration should be given to the fitting of dust collectors.

Electrical Equipment

All electrical installation and repair work to be carried out by a competent electrician in accordance with the current edition of the Institute of Electrical Engineers wiring regulations.


Oil fired equipment to have the oil supply pipe fitted with a fire valve close to the burner unit designed to cut off oil supplies in the event of a fire.

Oil tanks to be installed in accordance with the relevant Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations 1991 and should be provided with a non combustible oil tight catch-pit of capacity at least 10% greater than that of the tank. In the case of multiple tanks 110% of the largest tank's capacity or 25 per cent of total capacity - whichever is the greater


Storage and use of LPG cylinders and siting and installation of LPG tanks should in accordance with relevant Liquid Propane Gas Association guidance.

Plant Operation

Manufacturer's instructions to be followed and recommended temperatures laid down for the operation of the plant should not be exceeded.

No operating drying plant should be left unattended, unless of an automatic nature incorporating thermostats which will automatically shut down the equipment in the event of overheating and in such cases hourly checks of the plant should be undertaken.

Plant operatives need to be fully conversant with emergency shut down procedures and a remote isolation switch should be provided.


Before and during use, all surfaces on which dust, grain or other materials can collect should be cleaned out on a daily basis.
The space around the dryer should be kept clear of grain and other combustible material.


The ‘no smoking' regulations to be strictly enforced and appropriate notices displayed.


At the start of each drying season the plant should be serviced by the manufacturers or other competent engineers.

All thermostats and other automatic control gear should be regularly maintained and serviced to help make sure continued correct operation.

Dried Grain

In order to help protect against spontaneous heating dried grain must be allowed to cool to ambient temperature, prior to any further processing or storage.
Cooling must be for a minimum of 20 minutes, but longer if necessary.

Fire Extinguishment

A suitable number of fire extinguishers should be available to fight a fire, appropriate for the type of dryer in use which are approved and certified by an independent, UKAS accredited, third party certification body and inspected and maintained in accordance with BS 5306.

Approved extinguishers having a Class B rating should be provided near burners and oil storage tanks.

For electrical equipment at least one carbon dioxide or dry powder extinguisher should be immediately to hand.

An outbreak of fire involving release of gas from a cylinder should only be controlled and not extinguished until the gas supply can be shut off at the valve.

The fire brigade should be called to all fires involving dryers and gas cylinders

Sources of Further Information

Local Fire Brigade
Liquid Propane Gas Association (LPGA)
Codes of Practice, and also the Safe Use of Gas on Farms - refer
Defra (Department for Environment, Food and Rural Affairs) at

Next Steps:

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Please Note
This document contains general information and guidance and is not and should not be relied on as specific advice. The document may not cover every risk, exposure or hazard that may arise and Aviva recommend that you obtain specific advice relevant to the circumstances. AVIVA accepts no responsibility or liability towards any person who may rely upon this document.

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