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SAFE HAY STORAGE (page 2)
Whatever your decision is regarding hay storage, the best fire prevention tool you have is your broom. Keep loose hay and straw swept up, and if you have hay drops, don’t permit loose hay to hang over the edges; like cobwebs, flaming hay can drop through and start other fires. The best prevention for this problem is providing a cover for each hay drop opening. A plywood cover will do, and plywood covered on each side with one-hour rated gypsum board is even better. Here’s a sketch of the hay drop covers I had in my barn:
So, here comes the hay! What can happen in that haystack after all our labor in building it?
Although we usually think of moisture as helping to prevent or extinguish a fire, when it comes to baled hay or straw, excessive moisture is the most common cause of fires.
Ideally, when hay is harvested and baled, its moisture content should be
20% or less. If the moisture is greater than 20%, warm-temperature
bacteria will grow and multiply, releasing more heat until the interior bale
temperature reaches between 130-140°F. At 130°F., most of the bacteria
will die and the interior bale temperature will fall until it is at the ambient
(air) temperature. This is an expected part of the curing process which
normally occurs within six weeks of baling. However, if the interior
bale temperature doesn’t cool after the warm temperature bacteria die, heat-loving
bacteria can multiply and the heat released by their activity can raise the
interior bale temperature to 170°F. before they die. The hay becomes
damaged and can then readily combine with oxygen, resulting in a fire. This
first six weeks after harvesting is the most common time for hay fires, but
hay that has been stored for some time, even if it was baled at the proper
moisture percentage, can become a fire hazard if it becomes wet.
