Hay fire prevention

Summary

Just one damp hay bale is enough to start a fire.
Ensure hay is fully cured before baling.
Store hay in a dry location away from machinery and equipment.
Monitor temperature of stored hay.
Watch for signs of heating hay.
Create fire breaks around your haystacks.

How to prevent haystack fires

Haystack fires spread quickly and can result in thousands, if not millions, of dollars of damage. You might be in a rush to cut your hay, but it is important to protect your assts by baling and storing hay correctly.

[Preventing Haystack Fires]

[Narrator]
CFA attends around 150 haystack fires every year.

[David Webbware - Livestock Farmer]
The number one cause of haystack fires is when hay containing too much moisture spontaneously combusts, and it can just take one damp bale to ignite a whole stack. But with a few simple steps you can minimise the chance of your investment going up in smoke.

[Narrator]
Hay overheats when there's too much moisture within the hay. If it's green, for example, or if it becomes damp before, during or after baling. The moist environment is favourable to fungi and bacteria whose biological and chemical processes generate heat similar to that in compost. This heats the bale and if left unchecked, will get hotter and hotter. If the hay reaches 70 degrees, it can rapidly increase to the point of spontaneous ignition at around 180 degrees.

Preventing a haystack fire starts with cutting the hay. You shouldn't bale hay until it's fully cured. This varies depending on the crop and the type of bale being used. An easy way to check moisture is to use a correctly calibrated moisture meter as you're baling.

The next step is to protect hay from rain, leaking roofs and spouts. Cover stacks with tarps or hay caps. If storing in a shed don't stack all the way to the roof, leave some space for ventilation.

A useful strategy when it comes to storing hay is to limit the size of haystacks and place them in different locations, so they're not all stored in the one place. This will prevent you from losing all your hay if a fire does happen. It's also a good idea to put a fuel break around each stack.

[David]
You should regularly check your haystack to make sure it's not overheating. If you have one, use a temperature probe to check the temperature inside the haystack. An effective alternative is a crowbar inserted into the haystack. If after two hours the crowbar is too hot to hold, the temperature is over 70degrees and likely to spontaneously combust.

[Narrator]
If the haystack heats to over 60 degrees, you should carefully pull it apart to improve air flow and allow it to cool down. You should be careful when doing this however, as hay may be very hot. If the temperature is over 70 degrees, or if you smell smoke or a caramel smell, do not pull it apart. As you may introduce the oxygen needed to ignite the hay. Call Triple Zero (000) and ask for fire.

Ensure hay is fully cured before baling.
Bale hay at the correct moisture level.
Use a moisture meter to check hay moisture levels throughout the baling process.
Know the history of hay that you purchase, particularly its moisture content.
Use ground moisture barriers under haystacks and hay caps to protect from rain water.
Provide enough airflow around and about the stacks to allow heat and moisture to escape.
Regularly check the temperature of your stored hay.
Don't store vehicles, machinery and equipment in your hayshed.
Don't store hay near fuel, kerosine or other chemicals
Don't weld, grind or use heat or fire near hay
Don't store hay near powerlines.
Don't let hay get wet.

Just one damp bale is enough to ignite a haystack.

What causes haystack fires?

A haystack smouldering in a hay shed which is melting due to fire.

The most common cause of haystack fires is when heat builds up in a haystack and the hay self-ignites (catches fire). This is called spontaneous combustion and is the leading cause of haystack fires in Victoria.

Even hay stored as single bales can start a fire under some conditions.

Hay can combust anytime from two weeks to three or more months after baling.

Haystack fires can also be caused by sparks from machinery and equipment, embers from nearby burn-offs, bushfires or lightning strikes.

Signs of heating hay

It's important to watch for warning signs of hay bales heating up. Increasing heat and moisture can start a fire.
Some common signs your hay is heating:

steam rising from haystacks
condensation or corrosion under hayshed roofing
mould growth in or on bales
unusual odours (burning, musty, a pipe tobacco or caramel smell)
slumping in sections of the haystack.

Learn more about signs of heating hay and preventing haystack fires in our factsheet Preventing haystack fires (PDF 786kB).

How to monitor your hay

It is important to bale and store hay at the right moisture and temperature level. Regular monitoring of these two things is key to preventing hay fires.

Monitoring moisture

Monitor the moisture of your hay with a correctly calibrated moisture meter. Moisture content should be no more than 20 percent (12-18 percent is recommended as a precaution).

When baling, make sure you test plant nodes and heads inside leaf sheaths for hidden moisture.

Monitoring temperature

[New technologies helping farmers prevent haystack fires]

[David Manifold - CFA Buloke West Group Officer]
Well, I suppose on the CFA front, I’m a Jeffcott member. I’m the Buloke West Group Officer and I'm a farmer.

I farm 1,600 hectares of cropping ground by myself and I run another 800 hectares of grazing. And, yeah, we do oat and hay, legume hays. We grow wheat, barley, canola, lentils in a cropping rotation.

Over the last few years, we've worked out new techniques of production, right through from, essentially fungicidal treatments of cropping, right through into new techniques of how we make it during the making process, new technology using different machinery and chemicals.

Not only are we making better hay, we're actually making it in a shorter window than we used to.

So, we're using microwave moisture metres on our balers. We're using the hay probes for monitoring temperature and, new techniques on the machinery side of it to get our window shorter for baling in sub-seven days, which is the key to keep the yeast and moulds lower.

So the main, in our shed storage system, we’re running plastic on the floors to stop any water or moisture coming up from under the stacks. That prevents damage to the hay, but also prevents the risk of water ingression, particularly in a heavy rainfall period during the summer months. The spouts on the shed are well maintained and looked after. The down pipes are a key.

They're all massive factors that that we've learnt in a CFA sense, of why we’re seeing hay shed fires.

So they're a small temperature probe that's got a, I dare say a reader and a sender in it and it goes back to, essentially a base station that we have centrally located in our yard.

So there's 20 probes that I run in two different sheds here.

They're brought into the country by a company called Farmscan Australia. And I'm not sure, these are the only ones I know of. I don't know whether there's other types. But really good way to find out what your temperatures are on any given moment.

So I can look on an app on my phone and it can tell me exactly what my temperatures are. But they'll also alert you to certain parameters you want. And I have these so they alert me at 40 degrees and 50 degrees, if we had that sort of situation. But, at any time of the day or whatever, you can open up the app and see what the actual temperatures are of your haystacks.

So, and we'll generally put these ten per shed, scattered across the shed in different areas, but more than likely in the higher risk areas at the back of the shed where you obviously can't see and the ventilation is low.

So, yeah.

Use a calibrated temperature probe to monitor the temperature of your hay. It can be difficult to measure heat deep inside a hay stack, so you should watch for the warning signs above.

Systems are available that continuously monitor temperature in multiple locations throught haystacks and send alerts to a mobile device.

If you don't have temperature probes, you can use the old crowbar method to assess the temperature based on touch, using the following instructions.

Using a crowbar to gauge hay temperature

a farmer pushing a crowbar into a haystack

Push a crowbar deep into the haystack leaving just the end out. Leave it for two hours.
After two hours, touch the end of the crowbar to feel how hot it is inside the haystack.
Base your next steps on what it feels like to touch:

If you can handle the crowbar without discomfort, the hay is less than 50°C. You should check temperature daily.
If you can only handle crowbar for a short time, the hay is between 50 and 60°C. You should check temperature twice daily.
If you can touch the crowbar only briefly, the hay is between 60 and 70°C. Pull apart and move hay to improve air flow. Check the temperature every two to four hours.
If you can't touch the crowbar because it's is too hot, the temperature is above 70°C and there's potential for fire. Call Triple Zero (000) immediately.
Repeat the first step in a few different sections of large haystacks.

What to do if your hay is heating

If any part of the stack is near or above 70°C or if you see or smell smoke, call Triple Zero (000) immediately.
If your hay is heating up and is between 60 and 70°C, pull the stack apart to improve air flow and let the bales cool down.
Don't pull apart if the internal temperature is 70°C or more. Letting air into the hot haystack can cause the hay to catch fire.
Don't walk across hay that's heating up. Bales inside the stack can suddenly collapse, trapping you.

Protecting your haystacks

A farmer is using a tractor in a hayshed to pull a haystack apart to stop the bales overheating.

Store hay in a number of different locations and limit the size of the stacks. Industry recommendations are that stack sizes should be limited to $50,000 total value, 400 large square bales or 250 tonnes per stack. This reduces the risk of losing all your hay to fire.
Create and maintain fire breaks around haystacks. Ensure stacks are 50m apart and have a 20m graded fire break around each stack.
Keep a firefighting water supply near your hay storage. We recommend a 22,500 litre static supply.
Don't store vehicles, machinery or equipment in the same location as your hay.

Why does hay heat?

If hay is cut too ‘green’ or if hay becomes damp when it is being cut, a complex series of biological and chemical processes may cause the hay to heat up once it's baled.

Green or damp hay encourages bacteria and fungi to grow and decompose. A series of complex biological and chemical reactions can then cause temperature to increase in the hay. The process can produce flammable gasses which then ignite in the high temperature environment within the hay. Even if it doesn't ignite, this process also reduces the nutritional value and quality of the fodder.

If heating remains undetected the temperature within the bales will keep rising. When the temperature reaches 70°C, it may then increase rapidly to the point of spontaneous ignition (at about 180°C).

Haystack fires can happen in any type of bale stored in a haystack.