Presentation on theme: "Investigating Haystack Fires. Understand the dynamics of spontaneous ignition, i.e. when and how spontaneous ignition occurs in haystacks Understand."— Presentation transcript:
Investigating Haystack Fires
Understand the dynamics of spontaneous ignition, i.e. when and how spontaneous ignition occurs in haystacks Understand hay quality, yield and pricing Determine possible indicators of a spontaneous ignition fire Be able to accurately identify a “clinker” Interview questions
Exothermic—self-heating Exothermic Chemical Causation- Spontaneous Ignition Organic Fuel-coal, hay, vegetable or animal oils, etc. Microbial-relating to microbes
Plant respiration—converts plant sugars to water and carbon dioxide. Microbial respiration—mesophilic bacteria ensure continuity of biodegradation (digestion and decomposition of the organic matter). Mold respiration—converts plant sugars
Exothermic Chemical Causation Exothermic Biological Causation The bursting into flame of a mass of material as a result of chemical reactions within the substance, without the addition of heat from an external source.
Exothermic Chemical Process Theories abound Browne Rathbaum Etc.
The cut hay is not “dead” and respiration of the hay continues to occur when moisture content is between 12%-21% Microbial respiration generates heat Heat builds until microbes die—the thermal death point is reached and heat is generated faster than it can escape
The temperature rises above 160°F. Chemical causation occurs. Chemical reaction begins to occur and may sustain itself. This reaction does not require oxygen, but the flammable gases produced are at a temperature above their ignition point. These gases will ignite when they come in contact with the oxygen.
Hays-Timothy, Sudan, Orchard Grass, etc. Grass, Legume, Mixed (grass and legume) and Cereal Grain Straw (oat hay). Other vegetation residues Bagasse—sugar cane waste Coal Oils-linseed, fish, soy oils, oil stains, etc. Oily rags…
Cut hay must go from approximately 80% moisture to 22% moisture or less in order to be stable in storage as baled hay. The spring season is difficult because of the higher chance of rain and cooler temperatures for drying.
Too much moisture reduces oxygen diffusion into the haystack Too much moisture conducts too much heat out of the stack Too little moisture stops respiration of the hay
If hay is stored at less than 12% moisture content, the respiration often ceases. Large bales less than 12% Small bales less than 18% Ideal fuel moisture content for spontaneous ignition to occur-12% - 21% Round bales –18%-20%
Bale density should be at least 10 pounds per cubic foot to facilitate resistance to weathering. As bale density increases, the rate at which moisture and heat escape decreases. It is critical that dense bales be stored at the proper moisture (18 to 20 percent or less) so that risk of spoilage and heating problems are reduced.
TemperatureActions degrees FThis heat is common. Monitor haystack as usual. Generally, once heat reached 130, it will begin to decrease degrees FMonitor haystack several times each day degrees FDangerous condition. Microorganisms die. It is unlikely that the temperature will decrease on its’ own. Ignition of hay is possible if appropriate actions are not taken. Remove bales, separate and continue to monitor degrees FHot spots and pockets may be expected. Flames will likely develop when heating hay comes in contact with the air degrees FCRITICAL! Temperature rises rapidly above this point. Hay will almost certainly ignite.
Take precautions. Pockets may have already burned out under the hay surface. Do not attempt to walk on the hay mass itself.
TemperatureAction > 115° - 120°No action required. When coupled with high moisture, molds and odors develop and decrease palatability. > 125°Heating reduces digestibility of protein, fiber, and carbohydrate compounds. Forage quality is reduced. Palatability increases. > 130° - 140°Hay is brown and very palatable because of the carmelization of sugars; unfortunately, nutritional value is reduced. > 150°Hay may turn black, forage quality is greatly reduced.
Haystack Temp ActionsForage Quality Actions Common heat. Monitor as usual. > >125 No nutritional value loss Forage quality is reduced. Palatability increases Temperatures can rapidly increase. > Hay is brown and very palatable. Hay loses value Dangerous condition. Microorganisms die. Ignition of hay is possible if appropriate actions are not taken. Remove bales, separate and continue to monitor. >150Hay may turn black. Value greatly decreased
Generally speaking in my area… Because the highest yield of the season is on the first cut, it takes longer for the hay to dry just due to the bulk. 33% to 40% of the total yield for the year is from the first cut. Higher yield equates to lower forage quality-1 st cut Higher forage quality produces lower yield-2 nd cut
PremiumGoodFairUtility 1 st Cut5tpa x 200 $ per ton= $275,000 5tpa x 200 $ per ton= $225,000 5tpa x 200 $ per ton= $200,000 5tpa x 200 $ per ton= $170,000 2 nd Cut2tpa x 200 $ per ton= $110,000 2tpa x 200 $ per ton= $90,000 2tpa x 200 $ per ton= $80,000 2tpa x 200 $ per ton= $68,000
Moisture Meter—Gauges moisture content of the loose or baled hay. Caution! Even properly calibrated and used according to their manufacturer’s instructions, hay moisture meters are accurate to approximately +/- 4. The only accurate method for estimating bale moisture is to dry the forage down.
Heat Probe—Gauges heat in middle areas of the stacks.
Generally found towards the middle of the stack, not at the very edges Grayish, greenish, black, glassy Oftentimes significantly heavier than it looks
The Inorganic Residue of the plant stems Sodium Oxide-used in ceramics and glasses Calcium Oxide-thermal decomposition byproduct Silicon Oxide-principal component in glass Other Trace Elements Almost all natural elements contain calcium, magnesium, sodium, silicon, etc.
Qualitative analysis—gives the properties found within a substance Quantitative analysis—gives the percentage of each item (amount of item in sample as a whole) Fire Debris Analysis—Gas chromatography with mass spectrometric (GC/MS) detection Labs also perform Elemental Analysis for this type of sample
Hands-on examination of specimens Note Colors, Weight, Appearance Not every sample is a clinker!
Moisture content of hay when it is put up Pile size Hay insulates, so the larger the haystack, the less cooling there is to offset the heat. Packing density of the hay Ambient temperature Outside introduction of moisture Length of time the hay has been baled and stacked
days after stacking Haystack fires may occur as soon as 6 days after stacking (under ideal circumstances) May occur months after stacking As long as plant respiration can occur, spontaneous ignition is plausible!
Eyewitness accounts of a sharp/acrid/caramel odor, or burning tobacco smell prior to the fire Spotting or discoloration of the hay Adjoining haystacks with spotting or discoloration Slight vapor or smoke coming from the stacks Temperature readings between degrees prior to the fire
Eyewitness testimony of a fire starting in the “middle” of the stack History of high moisture content in the stacks (greater than 18%) Laboratory report
Where was the fire located in the stack? When was the hay cut? Was this hay from a first cut or 2 nd /3 rd cut? When was the hay baled? Has the stack been moved or manipulated in any way? Were temperature probes conducted on the stack? What temperatures were noted?
Were moisture probes conducted ? Was there above average moisture content in the hay? What size were the bales? Was the hay under a tarp? If so, color of the tarp. Did anyone notice any unusual sweating or browning of the hay?
Was there an unusual odor noted around the stack? Was the hay sold? At what price was the hay sold? What is the current price of hay? To whom was the hay sold? How long has the hay been stacked?
What year was the field seeded? How “old” was the hay field? (1-5 years, more than 5 years, etc.) What are the confirmed crop yields for the past 5 years? Is there a history of crop infestation? Mealybug, Spider Mite, Thrips Have there been previous claims for fire losses? When and under what circumstances?
What type of equipment is routinely used in the operation? Who was running the equipment?
Was the hay treated? With what? Hay treated with preservatives containing ethoxyquin and BHT (butylated hydroxytoluene) produce hydrogen cyanide gas at around 240 degrees (115 degrees C). There are numerous treatments out there
Perimeter examination of haystack Consistent, systematic dig out of scene Any potential evidence located, proceed as with any investigation Haystack fire by-products mimic clinkers— Don’t be fooled!