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NSW Rural Fire Service

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1. Home
2. For The Community
3. Fire Safety
4. Farm Firewise
5. Hay Shed Fire

Hay Shed Fire

Hayshed Fire Prevention

Over the warmer months the NSW Rural Fire Service is called to extinguish fires in stored hay as a result spontaneous combustion. These fires are usually the result of a combination of storing hay that is too moist and warmer temperatures.  These fires can lead to the loss of valuable feed and stored machinery as well.

Why does hay catch fire?

A number of different factors can contribute to hay fires. When hay is bailed and the plant material is either too green or has excess moisture (a result of rain, dew, flood water, etc) fungi, bacteria or other biological activity increases within the bail. These micro organisms produce heat and along with higher external temperatures and humidity, quickly raise the temperature within the bail to ignition point (200-280’C)

What are some of the signs?

If the hay is stored within a shed you will notice some of the following

• Steam condensation on a steel roof
• Mould growth in and on the bales
• Hot humid air at the top of a stack
• An acrid smell similar to tobacco

Hay stack fires as a result of spontaneous combustion usually occur between two and seven weeks after storage. This period of time may be increased if the stack becomes wet from rain or flooding.

How to prevent fires?

1. To minimise any danger in the first instance hay should be stored when it is relatively dry. The larger the bale the lower the moisture content should be. Moisture content should be approx 18-20% for smaller bales and 14% for large bales.
2. When stacking bales ensure that the bales are properly cured.
3. Bails should be stacked to allow for good airflow as this will help dissipate heat.
4. Try and minimise additional moisture on top of a stack by maintaining roofs.
5. If the stack becomes hot pull the stack apart and allow air to circulate and cool

How do I monitor my hay?

Be extremely careful about walking on top of a stack that is hot. The middle of the stack may already be charred and any additional weight may lead to the stack collapsing. Introducing air may lead to the stack spontaneously combusting which could result in serious injury or even death.

To test the temperature within the stack push a crow bar well into the stack and leave for approximately two hours. If the bar is hot when removed and can only be touched briefly or is to hot to handle, then the bail is ready to ignite. Try not to use a metal pipe as this will introduce oxygen into the stack which may cause a fire.

Always keep adequate water and fire fighting equipment on hand and where possible try not to store hay with farm machinery.

   

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