Timothy
G. Prather
University of Tennessee Extension
Hay
making is in full swing in Tennessee, and in the rush some
farmers will bale hay before it cures properly, ending up
with spoiled hay or, in some instances, fires.
Hay
fires typically result from bacterial heating that takes place
in hay baled at an excessive moisture content. Some heating
will occur in any hay, but usually peaks at about 140°
after a few days. With enough moisture and oxygen, bacteria
flourish and continue heating until hot enough to ignite the
hay.
Round
bales are more susceptible to spoilage and burning than conventional
square bales. Cores of round bales arc insulated by two feet
or more of hay and are not able to cool and dry. However,
fewer barns are lost to round bales because most round bales
are stored outside.
Check
hay moisture content prior to baling to prevent spoilage and
fires. Bale at 15-18 percent moisture for round bales and
20-25 percent moisture for conventional square bales. Round
bales can be formed at 20-25 percent moisture with proper
use of proprionic acid as a preservative.
Check
the moisture content and temperature of bales again before
storage to make sure they are safe.
A hay
moisture and temperature meter is essential, because you can't
accurately judge moisture content by sight and touch. The
meter may seem expensive, but it will help you produce better
hay and protect your investments (production costs and structures).
You
may need to leave round bales in the field up to two weeks
or more before storing to allow the heating process to finish.
Continue monitoring the temperature in the storage area regularly
until you are sure there is no danger of fire.
Take
action immediately if you find temperatures above 160°.
Move the hay to a safe location and allow air circulation
for cooling and drying.
Call
the fire department if the stored hay exceeds 180°, especially
if there is smoke or the smell of burned hay. Do not move
this hay until the fire department is at the scene and has
a charged hose ready to knock down any blazes. As soon as
you move the hay, any smoldering hay could immediately blaze
up. A garden hose will not be sufficient to control the fire.
The
most effective method of controlling a hay fire is to inject
water directly into the hot spot to cool and wet it before
exposing it to the air. This can bc done with a simple probe
that can also be used for checking temperatures to locate
hot spots. Wetting agents are not needed and they contaminate
the hay, making wetted hay unusable.
For
more information on hay fire prevention and control, get a
copy of publication 1306 from your county Extension office.
Your Extension agent can also provide other information on
producing and storing high quality hay for maximum nutritional
value.
Disclaimer
and Reproduction Information: Information in NASD does not represent
NIOSH policy. Information included in NASD appears by permission
of the author and/or copyright holder. More
NASD Review: 04/2002
This
news release was distributed by the University of Tennessee
Agricultural Extension Service, Knoxville, Tennessee 37901.
Publication date: May 1993.
Timothy
G. Prather, Agricultural Safety Specialist, Agricultural Engineering
Department, University of Tennessee Agricultural Extension
Service, Knoxville, Tennessee 37901.
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