CREWS from Llandrindod Wells Fire Station carried out haystack testing at a local farm on Saturday evening, July 17.

Some hay bales were recorded at being as warm as 57 degrees and had to be removed to prevent the possibility of a barn fire. If you have any concerns about your bales and would like firefighters to test them please contact the station. This is a free service.

Dyfed Powys Police’s Rural Crime Team said: “With a heat wave in full swing in many parts of Wales, hay can spontaneously combust."

South Wales Fire and Rescue Service have posted an online article on their website warning of the dangers that can be encountered at premises where hay is stored and how the risk of fire can be reduced. Potential for haystack fires are especially prevalent right now with the current heatwave and the fact many farmers are in the middle of the harvest season.

“Oddly enough, wet hay is more likely to lead to a spontaneous combustion fire than dry hay,” it reads.

“If hay is put into a barn or stack when it has more than about 22 per cent moisture, not only does the hay lose forage quality, but it has an increased risk of spontaneous combustion.

“High moisture haystacks can have chemical reactions that build heat. Hay insulates, so the larger the haystack, the less cooling there is to offset the heat.

“When the internal temperature of hay rises above 130 degrees Fahrenheit (55 degrees Celsius), a chemical reaction begins to produce flammable gas that can ignite if the temperature goes high enough.

“Hay fires generally occur within six weeks of baling. Heating occurs in all hay above 15 per cent moisture. Temperature within a stack then declines to safe levels in the next 15 to 60 days, depending on bale and stack density, ambient temperature and humidity, and rainfall absorbed by the hay.

“To avoid hay fires, small, rectangular bales should not exceed 18 to 22 per cent moisture, and large round or rectangular bales should not exceed 16 to 18 per cent moisture for safe storage.

“In addition, you should check your hay regularly. If you detect a slight caramel odour or a distinct musty smell, chances are your hay is heating. At this point, checking the moisture is too late, and you’ll need to keep monitoring the hay’s temperature.

“If you suspect that your hay is heating, a simple probe inserted into the haystack can accurately monitor temperature. You can make a probe from a 10-foot piece of pipe or electrical tubing.

“Sharpen the pipe or screw a pointed dowel to one end, then drill several 1/4-inch diameter holes in the tube just above the dowel. Drive the probe into the haystack and lower a thermometer on a string into the probe. The thermometer should be left for 10 minutes in several areas of the stack to ensure an accurate reading.”

Read more about how to prevent hay fires at http://orlo.uk/KdqKc and, if you live in Powys, contact Mid and West Wales Fire and Rescue Service if you’re concerned.