Spontaneous ignition is the leading cause of haystack fire in Victoria, and just one damp bale is enough to ignite a haystack.
Green or damp hay encourages elements like bacteria and fungi to grow and decompose. A series of complex biological and chemical reactions can then cause a build-up that allows hay to heat. This can produce flammable gasses which may ignite.
Haystack fires are also caused by sparks from machinery and equipment, and embers from burn offs or bushfires
To prevent haystack fires:
- Ensure hay is fully cured before bailing
- Know the history of the hay you purchase
- Keep haystacks to a limited size
- In separate stacks
- In a number of places away from key assets
- Away from possible sources of ignition (roadsides, powerlines workshops and vegetation). Never store vehicles, machinery and equipment in your hayshed - there is increased risk of losing both hay and machinery
- In areas that are not likely to flood and in sheds that are in good repair to minimise the moisture content
- Consider using temporary fencing to allow stock to graze close to hay and silage stores to reduce fuel loads near these assets
- Don't stack hay right to the top of a hay shed. Allow some air to circulate at the top - this helps to carry away moisture
- Protect hay from rain, leaking roofs and spouts
- Monitor hay with a correctly calibrated moisture meter. Moisture content should be no more than 20 per cent (12 - 18 per cent is recommended as a precaution).
If hay gets too hot
- Spread out the stack to allow to cool.
- Don't walk on top of hay that is heating as it may collapse or ignite. Have your local fire brigade in attendance when pulling apart a hot haystack.
- Don't feed to animals. The heating process reduces the nutrient quality of the hay.
Hay cutting and carting
- Your vehicle's exhaust system should have:
- A fire-resistant cover on the load
- A spark shield, OR
- Be located under the body of the vehicle so emissions are away from the hay.
- Be conscious of hot exhaust in contact with long dry grass