Silo Fire Prevention and Management

Rescue trucks at silo

Photo source: Penn State University

 

Use the following format to cite this article:
Silo fire prevention and management. (2015) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://articles.extension.org/pages/70637/silo-fire-prevention-and-manag….
 

Because the ingredients needed for a fire to occur are present in silos, agricultural producers who have silos should take steps to minimize the likelihood of silo fires and be prepared to manage silo fires should they occur. Fire prevention steps are similar regardless of what type of silo you have. The approach to managing a fire, however, is based on the type of silo in which the fire is burning.

Ingredients for Fire

Three ingredients are needed for anything to burn: a heat source, air, and fuel.

  • The heat source for a silo fire is bacterial action within the silage. When forage material is cut, bacterial action on the forage begins. This action produces heat until all the oxygen in the pile is consumed. Microorganisms are killed at 250°F–400°F, causing a breakdown in the forage through an oxidation process called pyrolysis. Pyrolysis allows oxygen in the silo to support a smoldering fire that can result in charred cavities in the silage. Once the oxygen is consumed, the fermentation process begins and continues until the forage becomes stable. 
  • The air source for a silo fire includes air that is trapped in chopped forage during harvest and air that blows into the silo. The dryer the material, the more trapped air there is.
  • The fuel source for a silo fire is the silage, although it typically is not a highly effective fuel source because of its moisture content. Even dry silage is too wet to burn quickly.

Causes of Silo Fires

The three main types of upright silos found on farm operations are conventional, oxygen-limiting, and modified oxygen-limiting. Typically, silo fires occur more frequently in conventional silos than in oxygen-limiting silos because oxygen is present in greater amounts in conventional silos. Many silo fires occur in the top layer (approximately the top 10 feet) of dry, loosely packed silage. Such fires can be the result of an overheating unloader motor but more often are caused by spontaneous combustion. Spontaneous combustion can occur when new silage having a too-low moisture content (less than 45%) is placed in the silo, when fresh silage is placed on top of old silage, or when the silo has poorly maintained doors and walls. Putting new silage on top of old silage is especially risky if the old silage is too dry. The dryer the material is, the more air that will be trapped when fresh, wetter material is placed on top of it. That trapped air can allow excessive heating and support a smoldering fire.

A silo fire can start from a source outside the silo as well. The two most common examples of these types of fires are a fire in the chute from a shorted-out electrical wire or a fire from an adjacent barn fire.

Prevention of Silo Fires

Prevention of silo fires involves performing proper maintenance on silos and unloaders and taking appropriate steps when harvesting and storing forages.

Silo and Unloader Maintenance

When a silo is empty, inspect the silo walls (especially the lower 10–15 inches), the silo doors, and the unloader system. Make any necessary repairs. If you have an oxygen-limiting silo, pressure-test it on a regular basis (at least once every other year, preferably when empty). If air is allowed to leak into an oxygen-limiting silo, forage quality can decline, and the chance of a fire developing increases. Many fires have started in oxygen-limiting silos that have been unused for several years but not emptied.

For the unloader system, examine belts, bearings, wiring, and the motor. Lubricate the lift cables, and immediately replace any lift cable showing signs of kinks, cuts, or corrosion. Check for damaged insulation or terminals on the unloader power cable, and repair or replace damaged materials as needed.

Harvesting and Storage Recommendations

Implementing the following steps for harvesting and storing forages will decrease the risk of a silo fire occurring:

  1. Minimize drying time to reduce respiration.
  2. Chop forage at the correct theoretical length cut (TLC). The TLC for hay crop silage is 3/8 inch; the TLC for corn silage is 1/4 inch. Follow the silo manufacturer’s recommendations.
  3. Ensile at 30%–50% dry matter content (i.e., 50%–70% moisture content), based on the silo manufacturer’s recommendations. Using this approach will optimize fermentation.
  4. Leave the silo sealed for at least 14 days to allow complete fermentation to occur.
  5. Unload 2–6 inches per day, and maintain a smooth surface. Using this unloading schedule will help you stay ahead of any spoilage. Spoilage is caused by the bacterial action that can cause heating.
  6. Discard deteriorated silage. Performing this step will help eliminate a fuel source for potential fires and minimize animal health problems.

Management of Silo Fires

Managing silo fires involves monitoring silage to detect a fire early, taking the proper steps when you suspect or discover that a fire is burning, and understanding how fires in different types of silos are extinguished.

Monitoring of Silage

Silage is costly to replace, so one of the main goals of managing a silo fire is to locate the fire and control the area so that only a minimum amount of silage is affected. The first step in managing a silo fire is early detection, so monitor a silo for three weeks postharvest. This length of time is the critical period for fermentation and heating to occur. Because silage burns slowly, detecting a fire early allows you time to evaluate your options and develop a plan for addressing the fire.

Response to the Presence of a Fire

If you suspect or discover a silo fire, contact your local fire department immediately. A silo is a confined space, and firefighters are obligated to follow the US Department of Labor, Occupational Safety and Health Administration (OSHA) Confined Space Standard for entry into a silo. When you contact the fire department, indicate the type of fire so that the fire department can dispatch the correct personnel and equipment (e.g., thermal imaging camera, infrared heat gun, self-contained breathing apparatus).

Wait for the fire service personnel to arrive. Do not enter the silo or climb the chute because unknown factors, such as fire gases or burning embers falling down the chute, may exist. Only rescue personnel with self-contained breathing apparatuses or supplied-air respirators should enter an upright silo because of toxic gases that can be present due to the fermentation process or the fire. The most typical gases in silos include carbon monoxide, carbon dioxide, nitric oxide, nitrogen dioxide, and nitrogen tetroxide. Additional gases can be present due to the burning of substances such as silo liners and epoxy coatings.

While waiting for fire service personnel to arrive on the scene, take the following steps:

  1. Close the bottom of the chute to reduce airflow that may be fanning the fire. Use sheet metal or another noncombustible material to close the chute.
  2. Remove all livestock from any exposed or adjacent buildings.
  3. Spray water to wet down the area around the silo chute to prevent the fire from spreading.
  4. Place noncombustible shields (metal siding, etc.) over any openings in the silo or chute to prevent sparks and embers from flying into or onto other buildings.

Fire Management Approaches for Various Silo Types

It is important to understand how silo fires are managed in various silo types. A fire in a conventional silo will not burn out; instead, it must be extinguished. A fire in oxygen-limiting silo may be managed so that it burns out, or it may have to be extinguished. To extinguish a silo fire, it is necessary to eliminate one of the ingredients needed for fire to occur. Trained fire service personnel are needed to extinguish a fire in any type of silo.

Conventional Silo

Because a conventional silo is not airtight, fire service personnel cannot smother the fire by eliminating the air source. The best approach is to locate the heat source and remove it. If possible, fire service personnel should avoid flooding the silo with water for the following reasons: doing so could ruin good feed; it is difficult to unload wet silage with an unloader; water can damage the silo; and the introduction of water can actually cause additional fires in the silo.

Oxygen-Limiting Silo

With proper management, you may be able to allow a fire in an oxygen-limiting silo to burn out. To reduce any additional air from entering the silo, close the top hatch cover (without latching it) and the bottom unloading door. CAUTION If the silo is heavily smoking or rumbling (vibrating), do not attempt to close the top hatch; rather stay off the silo! The assumption is that after you close the top hatch cover and bottom unloading door, no air will go into the silo, so the fire eventually will use up the residual air in the silo and burn out over time. However, this process can take up to three weeks. If this approach does not work, trained personnel—usually representatives of the silo manufacturer/dealer—can inject carbon dioxide or liquid nitrogen into the silo, causing any oxygen trapped by the silage to be consumed and allowing the fire to burn out.

A concern related to a fire in an oxygen-limiting silo is the potential buildup of confined gases within the silo. Through pyrolysis, a smoldering fire will produce large quantities of carbon monoxide and other products that can result in an explosion when combined with air from outside the silo. Consequently, you should do nothing that will cause air to go into the silo. For example, do not add water or foam or open any portals into the silo.

Modified Oxygen-Limiting Silo

For fire management purposes, you can treat an oxygen-limiting silo that has been modified through the installation of a top unloader the same way as a nonmodified oxygen-limiting silo, at least initially. However, in spite of such modification, these structures are still airtight enough to allow for a dangerous buildup of carbon monoxide in a smoldering fire. In more than one case, an explosion has occurred during firefighting operations involving a modified oxygen-limiting silo.

Additional Recommendations

  • Specialized training in proper techniques for responding to silo fires is available for fire department personnel. If your local firefighters have not had such training, encourage them to locate and participate in a training program.
  • If you no longer use a silo, make sure that it is completely empty. Residual silo material can dry out and pose a fire risk.
  • In the event of a silo fire, do not apply cool or cold water to the outside of a silo because doing so may cause structural damage.
  • After a silo fire, inspect the silo, and make any necessary repairs.

Resources

Click here for a guide to assisting firefighters at the scene of a silo fire. 

 
Use the following format to cite this article:
Silo fire prevention and management. (2015) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://articles.extension.org/pages/70637/silo-fire-prevention-and-manag….
 

Sources

Florida Forage Handbook. (2008). University of Florida Institute of Food and Agricultural Sciences (IFAS). Retrieved from http://edis.ifas.ufl.edu/pdffiles/ag/ag36200.pdf.

Hill, D. (2009) Silo fires—protect your investment. Pennsylvania State University. Retrieved from http://www.farmemergencies.psu.edu/SiloFires-ProtectYourInvestment2.pdf.

Murphy, D., and Arble, W. (2000) Extinguishing fires in silos and hay mows. New York: Natural Resource, Agriculture, and Engineering Service.

 
Article Contributor: 
Davis E. Hill, Pennsylvania State University–deh27@psu.edu
 
Reviewed and Summarized by:
Linda M. Fetzer, Pennsylvania State University-lmf8@psu.edu
Carol Jones, Oklahoma State University–jcarol@okstate.edu
Dennis J. Murphy, Pennsylvania State University–djm13@psu.edu
Aaron M. Yoder, University of Nebraska Medical Center–aaron.yoder@unmc.edu

 

 

Confined Space Safety Video Resources


Grain Bins

Topic Titles Organization Resource Types

Farm S.O.S. (Strategies on Safety) Curriculum Videos: Grain Bin Awareness (2014)

1:26 minutes

Ohio State University Free – Online video via YouTube

Farm S.O.S. (Strategies on Safety) Curriculum Videos: Lock Out/Tag Out (2014)

1:10 minutes

Ohio State University Free – Online video via YouTube

Following Proper Grain Bin Entry Procedures Saves Lives (2013)

3:45 minutes

Grain Handling Safety Coalition Free – Online video via YouTube

Grain Rescue (2009)

2:42 minutes

The Ohio State University Free – Online video via YouTube

Grain Bin Safety: Protecting Yourself and Your Family

13:40 minutes

National Corn Growers Association and National Grain and Feed Foundation Free – Online video

Grain Bin Entrapment | Seconds to Tragedy | Grain Handling Safety Coalition

14:30 minutes

Grain Handling Safety Coalition Free – Online video via YouTube

Manure Storages

Topic Titles Organization Resource Types

Confined Space Safety on the Farm (2011)

3:43 minutes

The Ohio State University Free – Online video via YouTube

Farm S.O.S. (Strategies on Safety) Curriculum Videos: Manure Pit Confined Space (2014)

1:14 minutes

The Ohio State University Free – Online video via YouTube

Manure Pit Safety Introduction (2011)

2:46 minutes

Pennsylvania State University

Free – Online Video via YouTube

Manure Pit Safety: An Interview with Dennis Murphy (2012)

3:53 minutes

Progressive Dairyman

Free – Online Video via YouTube

Slotted Floor Manure Storage Ventilation and Safety (2011)

27:02 minutes

Pennsylvania State University

Free – Online Video via YouTube

Solid Cover Manure Storage Ventilation and Safety (2011)

24:07 minutes

Pennsylvania State University

Free – Online Video via YouTube

 

NCERA 197: Agricultural Safety and Health Research and Extension

Use the following format to cite this article:

NCERA 197: Agricultural safety and health research and extension. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63381/ncera-197:-agricultural-safety-and-….

 

Agriculture, forestry, and fishing continue to have a work-related death rate that is eight times higher than the all-industry average (National Safety Council, 2009). Production agriculture accounted for more than 75% of the work-related deaths within the agriculture, forestry, and fishing category in 2007 (U.S. Department of Labor, Bureau of Labor Statistics, 2009). Injuries and fatalities continue among children, youths, and seniors—age groups that are generally not part of other industries. 

A committee called the North Central Education/Extension Research Activity (NCERA) 197 was founded in 2000 to develop strategies to use the land-grant system’s research and extension capacity and the experience of agricultural producers to reduce work-related injuries, illness, and death. The NCERA 197 committee created the National Land-Grant Research and Extension Agenda for Agricultural Safety and Health: National Agenda for Action, a document that prioritized 12 areas with 115 individual topics relating to agricultural safety and health in which research or extension gaps exist (Committee on Agricultural Safety and Health Research and Extension, 2003). The National Agenda for Action was the first agricultural safety and health agenda by the land-grant system since 1943, and it has been used by the Agriculture, Forestry & Fishing (AgFF) Sector Council of the National Institute of Occupational Safety and Health (NIOSH) as a resource document for its National Occupational Research Agenda (NORA) plans and by the Agricultural Safety and Health Council of America (ASHCA). The Canadian government has also used this document as the foundation for its agricultural safety strategic plan.

The NCERA 197 committee was reappointed in 2005—when it was renamed from NCR 197 to NCERA 197—and again in 2011. After the completion of the national agenda, the committee focused efforts on the development of a white paper concerning agricultural equipment on public roads. This effort was designed to do the following:

1. Identify research, policy, and extension and outreach priorities for these agencies:

  • federal departments of Agriculture and Transportation; 
  • NIOSH; 
  • state departments of agriculture, transportation, and law enforcement; 
  • county governments; and
  • organizations related to production agriculture. 

2. Identify possible design and practice standards, goals, or guidelines for farm equipment manufacturers, standard-setting organizations, and government agencies (Committee on Agricultural Safety and Health Research and Extension, 2009).

Click here to be linked to the NCERA 197 committee’s white paper titled Agricultural Equipment on Public Roads.

Ag Equip on Public Roads Publication Cover

The second priority area for the NCERA 197 committee is agricultural confined spaces. Click here to be linked to the Research and Extension Agenda for Agricultural Confined Spaces.  The NCERA 197 committee will investigate gaps in extension  and research regarding engineering, educational, and legislative controls designed to reduce the frequency and severity of incidents involving confined spaces in agricultural workplaces. The NCERA 197 committee plans to complete the following activities:

  1. Summarize the research literature, engineering needs, and outreach opportunities related to agricultural confined space hazards;
  2. Convene a national conference on this topic;
  3. Encourage additional research and outreach by land-grant universities to reduce hazards of agricultural confined space; and
  4. Encourage increased standards activity by the American Society of Agricultural and Biological Engineers (ASABE) to reduce hazards of agricultural confined spaces.

Ag Confined Space Publication Cover

The NCERA 197 committee will identify additional topics on the basis of the National Land-Grant Research and Extension Agenda for Agricultural Safety and Health: National Agenda for Action document. The committee members will partner with land-grant universities to increase infrastructure support for agricultural safety and health at land-grant universities.

Farm and Ranch eXtension in Safety and Health

The NCERA 197 committee was instrumental in developing the Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice (CoP). FReSH is designed to provide agricultural safety and health information in a user-friendly format to agricultural producers through peer-reviewed article summaries, frequently asked questions, and “ask the expert” opportunities. Click here to be directed to the FReSH CoP.

Resources

Click here to be directed to a summary of the National Land-Grant Research and Extension Agenda for Agricultural Safety and Health: National Agenda for Action.

Click here to open the NCERA197 Impact Summary (2010-2015),

 

 

Use the following format to cite this article:

NCERA 197: Agricultural safety and health research and extension. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63381/ncera-197:-agricultural-safety-and-….

 

 

Sources

Agricultural equipment on public roads. (2009) North Central Education/Extension Research Activity Committee (NCERA) 197, Cooperative State Research, Education, and Extension Service. Retrieved from http://nasdonline.org/static_content/documents/2065/d001906.pdf.

Census of fatal occupational injuries (CFOI) – Current and revised data, 2007 census of fatal occupational injuries (revised data). (2009) U.S. Department of Labor, Bureau of Labor Statistics. Retrieved from http://www.bls.gov/iif/oshcfoi1.htm.

Injury facts. (2009 edition) National Safety Council (NSC). Itasca, IL.

National land grant research and extension agenda for agricultural safety and health. (2014) NCR-197 Committee on Agricultural Safety and Health Research and Extension. Retrieved from http://extension.psu.edu/business/ag-safety/youth-safety/national-safe-t….

 

Reviewed and Summarized by:
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu
Dennis J. Murphy, Pennsylvania State University – djm13@psu.edu
Aaron Yoder, University of Nebraska Medical Center – aaron.yoder@unmc.edu

 

Confined Spaces: Emergencies and Rescue

Use the following format to cite this article:

Confined space: Emergencies and rescue. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63150/confined-spaces:-emergencies-and-re….

 

Entering a confined-space manure storage area can be deadly. Farm and ranch managers, family members, and employees must have a complete understanding of what to do in the event of a confined-space emergency and ways to avoid such an incident.

If you find a victim unresponsive in a manure storage area, immediately call 911. Inform the operator that the incident involves a person in a confined-space manure storage area so that the appropriate emergency response personnel can be dispatched to the scene. Emergency responders trained in confined-space rescue will be equipped with the necessary rescue apparatus and gas detection equipment. Do not enter the manure storage area under any circumstances. 

While waiting for an emergency response team, ventilate the area by blowing fresh air into the space, moving the toxic air away from the victim. Keep a ventilation fan readily available specifically for such emergencies. When using a fan, be aware of the following recommendations:

  • Do not use typical barn or home fans to ventilate manure-storage areas because they may emit sparks from static electricity or an electrical short. If flammable methane gas has collected in the storage area, a spark could cause a fire.
  • Never attempt to get fresh air closer to the victim by lowering a fan into the confined space.
  • Make sure that the ventilation fan does not blow the manure gases back toward you, affecting your breathable air.

Preventing Confined-Space Manure Storage Emergencies

Take the following precautions on your farm or ranch to reduce the risk of a confined-space manure storage emergency:

  • Warning Signs: Post warning signs (example is shown below) about the risks of confined spaces and gas hazards at the openings to manure storage areas. Include warnings against walking or driving on crusted manure surfaces.

    Confined Space Sign

(Source: Pennsylvania State University. Agricultural Safety and Health)

  • Limited Access: Limit access to manure storage areas to authorized personnel. Take these specific steps to keep people away from manure storage areas:

    • Equip exterior ladders with locking mechanisms.
    • Remove temporary-access ladders from areas surrounding aboveground tanks.
    • When manure storage areas are open, place barricades at the openings of storage areas.
    • Install and maintain fencing around uncovered ground-level storage areas such as manure ponds or lagoons.
  • Education: Educate employees, family members, and visitors about the hazards associated with manure storage in confined spaces.
  • Entry Plan: Prepare and document an entry plan for entering confined spaces where manure is stored. Review the entry plan annually with all employees and family members. The entry plan should include specific physical details about the confined space, descriptions of potential hazards, reasons for entry, procedures for entry, and procedures to follow during emergencies. 
  • Two-Person Minimum: Require that two people be present for any confined-space entry and that both individuals be trained in entry and rescue techniques. The person outside the manure storage area should maintain verbal and visual contact with the person inside the confined space at all times. The person outside the storage area should be available to summon help and to implement the rescue and retrieval system if necessary. This person should not enter the manure storage area, even in the event of an emergency.
  • Gas Detection: Use gas detection equipment to monitor oxygen levels and levels of explosive and toxic gases in the confined space.    

Gas Monitor

(Source: Pennsylvania State University. Agricultural Safety and Health)

  • Ventilation: Prior to entry, ventilate the confined-space manure storage area for a minimum of 15 minutes and continue ventilation during entry and occupancy. A positive-pressure ventilation system is recommended because of the reduced risk of fire or explosion.
  • Body Harness: Require that the person entering the manure storage area carry a portable gas monitor and wear an adjustable body harness with a lifeline attached to a rescue and retrieval system. A typical rescue and retrieval system uses a tripod device equipped with a winch to limit a person’s fall and retrieve a person who has been incapacitated. 
  • Power-Source Lockout: To reduce the risk of stray electricity, prior to entry, lock out all power sources in the confined-space manure storage area other than the positive-pressure ventilation system.

Additional Safety Recommendations

  • Remember that youth under the age of 16 are prohibited from working in confined spaces.
  • Provide training about the hazards associated with confined-space manure storage to every person working on, living on, or visiting the farm or ranch.
  • Ventilate manure storage areas appropriately to increase oxygen and decrease explosive and toxic manure gases.
  • Remove personnel and animals from the confinement building during manure storage agitation or pumping. If you are unable to remove the animals, maximize ventilation and begin agitating very slowly while monitoring the animals for abnormal behavior.
  • Prohibit smoking in and around manure storage areas.
  • Operate manure agitators below the surface of liquid manure to reduce the release of manure gases. 
  • Leave 1 to 2 cu. ft. of space above the manure to contain released gases. If you are unable to leave the recommended space, lower the manure level prior to agitation.

 

Use the following format to cite this article:

Confined space: Emergencies and rescue. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63150/confined-spaces:-emergencies-and-re….

 

Sources

 

Hallman, E. & Aldrich, B. (2007) Hydrogen sulfide in manure handling systems: Health and safety issues. Cornell University Manure Management Program. Retrieved from http://www.manuremanagement.cornell.edu/Pages/General_Docs/Fact_Sheets/H2S_Safety_factsheet_2007.pdf.

Hill, D., Murphy, D., Steel, J., & Manbeck, H. (2011) Confined space manure storage emergencies. Penn State Extension. Retrieved from http://www.agsafety.psu.edu/factsheets/E54emergencies.pdf.

Ogejo, J. (2009) Poultry and livestock manure storage: Management and safety. Virginia Cooperative Extension. Retrieved from https://pubs.ext.vt.edu/442/442-308/442-308.html.

 

Reviewed and Summarized by:
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu
LaMar Grafft, East Carolina University – grafftl@ecu.edu
Davis E. Hill, Pennsylvania State University – (has since retired)
Dennis J. Murphy, Pennsylvania State University – (has since retired)
Aaron M. Yoder, University of Nebraska Medical Center – aaron.yoder@unmc.edu
 

Entrapment Risk due to Flowing Grain


Use the following format to cite this article:

Entrapment risk due to flowing grain. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63151/entrapment-risk-due-to-flowing-grain.

Farmers and ranchers use bins to dry and store grain and to feed their livestock. For the most part, augers are used to transfer the grain to and from bins. Some machinery and augers now used in production agriculture have increased in size and power, resulting in less time for farmers and ranchers to react in dangerous situations. It is therefore important to understand fully the hazards and risks associated with flowing grain and to follow safety guidelines to avoid a potentially fatal injury incident. There are four main situations that pose entrapment risks when you work with stored grain: flowing grain, grain bridge collapse, grain wall avalanche, and use of a grain vacuum. Each of these situations and its entrapment risks are described below.

Flowing Grain

Grain Bin with Flowing Corn

(Source: Pennsylvania State University. Agricultural Safety and Health)

An auger is used to move grain from the bottom center to the outer edge of a grain bin, and from there into a vehicle or alternative storage area. As the grain flows, it forms a funnel, with the wide mouth of the funnel at the top and a smaller opening at the bottom, as shown in the diagram above. If you are in the bin when the grain is being unloaded, you can quickly become engulfed in grain. Depending on the size of the auger, you can be trapped in grain up to your waist within 10 seconds and completely submerged within 25 seconds. Once you are submerged in grain, it can take over 1,000 lb. of force to free your body.

Grain Bridge Collapse

Farmer on Moldy Corn Bridge

(Source: Pennsylvania State University. Agricultural Safety and Health)

A grain bridge forms when grain in poor condition exists throughout a bin. Cavities or pockets of loose grain can form under the crusted level when the auger begins to unload grain from the bin. Grain bridges are not stable, and if you are standing on top of a grain bridge when it collapses, you can quickly become entrapped in the grain. Once you fall through the grain bridge and are trapped, it may be difficult to locate you because the grain will flow rapidly into the area around you.

The proper way to break up or remove a grain bridge is to use a long pole inserted through an access hole from outside the grain bin.

Grain Wall Avalanche

Farmer in Bin with Corn

(Source: Pennsylvania State University. Agricultural Safety and Health)

Moldy or frozen grain can cling to the side of a grain bin, as shown in the diagram above. A grain avalanche can occur when you are breaking up crusted grain from within a bin and the grain wall is higher than you. The grain wall can collapse, creating an avalanche that can quickly engulf you, causing injury or death.

If you must enter a bin, use a body harness and a safety line that is securely tied off. Work above the vertical grain wall, staying above its highest point.

Use of a Grain Vacuum

Grain vacuums are being used with higher frequency as a means of moving grain rapidly from older bins with smaller unloading augers, bins in remote locations without augers, and bins that have mechanical problems. Powered by a tractor power take-off, electricity, or an external motor, these vacuums have the capacity to move several thousand bushels of grain an hour. Typically, an operator uses the vacuum inside the bin, moving the nozzle in a sweeping motion. During the last few years, several operators have been killed when using the equipment in this manner. If the operator drops or releases the nozzle, it can quickly become buried in grain. As a result, the operator may try to lift the nozzle while the vacuum is running. This can cause the grain to be sucked out from under the operator, burying him or her in seconds.

Below are two videos that demonstrate the use of a grain vacuum. To view a grain vacuum in use within a bin, click on the video below.

 

To see a grain vacuum transferring grain into a truck, click on the video below.

Suffocation in Grain Bins

Flowing grain is similar to quicksand and can quickly engulf you, resulting in suffocation. When even a small amount of grain has space to move, it quickly fills in that new area. When you are trapped by grain and exhale to breathe, the grain flows into the space created by the movement of your chest, placing pressure on your chest and reducing the space that your lungs have to expand during your next inhalation. Each time you exhale a breath, the space around your chest decreases, eventually causing you to suffocate as you take smaller and smaller breaths (or shallower and shallower). When you are trapped in flowing grain, you can also suffocate from taking grain particles into your lungs, stomach, and throat.  

Entrapment in Grain Transport Vehicles

Entrapment incidents can occur in grain transport vehicles that are used to move grain from one location to another. The most common types of grain transport vehicles are gravity wagons and bulk material semitrailers. Entrapment in these vehicles is similar to entrapment in a grain bin: a quicksand effect can occur during the loading or unloading process. 

Safety Recommendations

  • Lock all access doors to grain storage structures.
  • Secure grain bin ladders and doors to prevent unauthorized entry, especially by children.
  • Never allow children to play or ride in grain wagons. Most grain entrapment incidents in on-farm transport vehicles involve children.
  • Apply entrapment warning decals to all grain bins, wagons, and grain storage areas, as well as commercial transport vehicles.
  • Never work alone! When working with others during grain unloading, know where each person is located and what he or she is doing.
  • Warn workers, family members, and visitors about the dangers of flowing grain and the risk of entrapment.
  • Establish a nonverbal communication system with others when working around flowing grain because of the excessive equipment noise levels.
  • When possible, use inspection holes and grain bin level markers rather than physically entering a grain bin.
  • Before entering the grain bin, lock out and tag out all power controls to unloading augers and conveyors.
  • If you must enter the grain bin, wear a body harness with a lifeline secured to the outside of the bin, and have at least one other person observing your work activity in the bin.
  • When cleaning a grain bin, always work from top to bottom.

 

 

Use the following format to cite this article:

Entrapment risk due to flowing grain. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63151/entrapment-risk-due-to-flowing-grain.

 

 

Sources

LaPrade, J. (2008) Grain bin hazards and safety considerations. Alabama Cooperative Extension System. Retrieved from http://www.aces.edu/pubs/docs/A/ANR-1332/ANR-1332.pdf.

Schwab, C., Hanna, M. & Miller, L. (2004) Handle your grain harvest with care. Iowa State University Extension and Outreach. Retrieved from https://store.extension.iastate.edu/ItemDetail.aspx?ProductID=4614.

Training module: Grain bin entrapment. (2002). Ohio State University Extension Agricultural Tailgate Safety Training. Retrieved from http://nasdonline.org/172/d001693/grain-bin-entrapment.html.

Yoder, A., Murphy, D. & Hilton, J. (2003). Hazards of flowing grain. Pennsylvania State University College of Agricultural Sciences Cooperative Extension. Retrieved from https://extension.psu.edu/hazards-of-flowing-grain.

 

 
Reviewers, Contributors, and Summarized by:
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu
LaMar Grafft, East Carolina University grafftl@ecu.edu
Davis E. Hill, Pennsylvania State University Has since retired
Dennis J. Murphy, Pennsylvania State University – Has since retired
J. Samuel Steel, Pennsylvania State University (Has since retired)
Aaron M. Yoder, University of Nebraska Medical Center – aaron.yoder@unmc.edu

Manure Foaming

Foaming Manure

Foaming Manure – Source: Schimdt, UMN.

 

Use the following format to cite this article:

Manure foaming. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63144/manure-foaming.

 

Foam in manure pits can be a danger both to animals and workers around the pits. Manure foaming occurs primarily in hog facilities, most commonly in the midwestern United States and Canada. The causes of manure foaming remain a mystery. Manure foaming is not predictable, and no known solutions work in every situation. It is therefore important to understand the risks posed by foaming manure and ways to reduce those risks.

Foam is defined as a mass of bubbles of gas on the surface of a liquid. Rather than being crusty or fluffy, foaming manure has a thick, mucous consistency. In manure pits, the bubbles do not burst but rather cling together.

One theory suggests that a specific microbial population causes foaming in manure pits. Another theory suggests that filamentous microorganisms (bacteria, fungi, or algae) are the cause. Neither theory has been confirmed, and research into the causes of manure foaming continues. Possible triggers include a high content of manure solids resulting from water conservation practices; cool weather patterns; reduced antibiotic use; feeding or diet adjustments; changes in DDGS; changes in corn, including genetic modifications; moldy and/or lightweight corn; and changes in the type or quantity of fat fed to the animals. 

Dangers of Foaming Manure

Foam in manure pits may be linked to suffocation of hogs and incidents of fire and explosion. Methane (CH4) and hydrogen sulfide (H2S) are gases produced during the anaerobic breakdown of manure. Methane is a highly flammable gas that can lead to asphyxiation at high levels. The foam in manure pits captures methane, resulting in concentrations of methane in the foam that can be as high as 60% to 70% (600,000 to 700,000 ppm), which is higher than the concentration at which explosions can occur. When the foam bubbles are disturbed or broken, the captured methane is released at an explosive concentration of 5% to 20% (50,000 to 200,000 ppm). If there is an ignition source near an explosive concentration of methane, an explosion or a flash fire could occur. 

Hydrogen sulfide is a colorless gas that smells like rotten eggs at low levels but can overcome a person’s sense of smell at levels of 100 ppm or higher. Hydrogen sulfide is heavier than air and can collect in the floor or lower areas of the pit. Exposure to hydrogen sulfide can cause eye and nose irritation, headache, nausea, and death.

In addition to the danger of explosion or fire, foaming manure poses an asphyxiation risk for both people and hogs when foam rises through the slats in a barn. Anyone working within the building or in the immediate area should be informed about the dangers of foaming manure, including the hazards of methane and hydrogen sulfide. No smoking should be permitted in or near the building.

Methods of Treatment

There are no proven ways to prevent manure foaming; at present, the focus remains on treating the symptoms. Below are some treatments that have yielded mixed results:

  • Water – Spraying water, running sprinklers, or using soaker systems can break the bubbles in foam, releasing the methane in a relatively safe manner. If you are using water to break down foam, remember to follow recommended ventilation practices.
  • Antifoam agents – There are several antifoam agents on the market. Although some have had limited success in reducing foam, none have proven effective on a consistent basis.
  • Microbial enhancements – Microbial enhancements, typically in the form of feed or manure additives, have been effective on an inconsistent basis.
  • Microbial control – Microbial control refers to changes in pH or oxygen levels or the use of antibiotics.

Due to the unpredictable nature of manure foaming, you should complete an audit of manure pits at least once a month. The purpose of the audit is to monitor pits for changes in manure consistency, increases in foam, and other such indicators of a potential problem. Based on information gathered in the audit, you can make necessary management decisions about using a treatment or changing the pumping schedule.

Emergency Action Plans

Develop an emergency action plan and review it annually with employees. It is especially important that anyone on-site during pit pumping receive training about the action plan. The emergency action plan should include a list of clean-up and containment practices in the event of an overflow, breach, leak, fire, or emergency land application. Due to the potential risk of fire or explosion, include in the action plan an evacuation route for employees. In addition, make sure that all employees know the location of fire extinguishers, hose cabinets, fire blankets, and other types of safety equipment. As a farm or ranch manager, make sure that you have necessary safety equipment and that it is in proper working order.

During pit pumping, remember to keep on hand the contact information of first responders, including the fire department, hospital, and police. When calling 911, give your name, location, contact information, and details about the emergency. 

Precautions during Agitation and Pumping

When foaming manure is present, the risk of explosion necessitates additional precautions during pit agitation and pumping. It is strongly recommended that you pump manure pits when the barn is empty. People should remain outside of the building during agitation and pumping. After checking that everyone is out of the facility, add a physical barrier such as yellow caution tape or place warning signs to ensure that no one enters the facility during the process.

Any ignition sources should be turned off and locked out. Possible ignition sources include welders, heaters, motors, and other equipment, such as a feeding system, that uses electricity. (Because of the importance of ventilation, discussed in the next section, ventilation systems that use electricity may operate during agitation and pumping.) 

Do not agitate the manure until the top of the manure surface is at least two feet below the floor slats. Agitate the manure below the surface of the liquid manure and stop the process if you can no longer agitate below the surface level. Agitate intermittently to reduce the risk of sudden gas release.

When possible, cover pump-out ports unless they are needed for agitation or manure load-out, and cover the pump-out around the agitation with a tarp. After pumping is complete, remember to secure manure pit covers.

Ventilation during Agitation and Pumping

Proper ventilation is one of the most important safety measures during agitation and pumping of manure pits. Regularly check your ventilation system to ensure that it is in proper working condition. Use a ventilation rate of 20 to 30 cfm per animal to dilute the methane concentration below 5%. Ventilation inlets, curtains, and pivot doors should be open during the ventilation process. For naturally ventilated barns, make sure that inlets and outlets are open. Circulation fans used in the summer do not provide the necessary air exchange needed during agitation or pumping, so plan these processes for days when wind is present to increase the amount of fresh air circulating through the building.

Ventilation for Curtain-Sided Barns

Ventilation procedures for curtain-sided barns differ slightly depending on weather conditions. When the weather is warm with winds over 5 mph, run exhaust fans while the curtains are open. On a calm day, the sidewall curtains should remain closed with the fans running. If, however, you are running more than half of the fans, the curtains should remain open during the pumping process. During colder weather, keep the curtains closed while running the exhaust fans.

If you are using a stir fan, use a horizontally directed fan rather than a fan directed downward, to reduce pockets of gas concentrations and to ensure that contaminated gas does not blow back onto hogs. Ventilate for approximately one to two hours after pumping and prior to entering the barn.

Ventilation for Tunnel-Ventilated Barns

During warm or hot weather, run all of the pit fans and a minimum of two tunnel fans. The procedure is slightly different for cold or moderate weather, but you should nevertheless run all of the pit fans and the 36 in. fan and open the tunnel curtain approximately 6 to 12 in. to provide air movement through the entire length of the barn. Remember to reduce the static pressure of the inlet velocity at the tunnel curtain from the regular setting of 800 fpm to 1,000 fpm to a lower setting of 300 fpm to 400 fpm. During both cold and hot weather, partially close mechanized/motorized ceiling inlets to allow air to enter from the tunnel curtain. Ventilate for approximately one to two hours after pumping and prior to entering the barn.

 

 

 

Resources

Click here to watch an informative video by Dr. David Schmidt from Iowa State University Extension about foaming manure pits.

 

Use the following format to cite this article:

Manure foaming. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63144/manure-foaming.

 

Sources

Burns, R. & Moody, L. (2009) Literature review – deep pit swine facility flash fires and explosions: Sources, occurrences, factors, and management. Iowa State University Department of Agricultural and Biosystems Engineering. No longer available online.

Foaming manure. (2011) Ontario Ministry of Agriculture, Food, and Rural Affairs. Retrieved from http://www.omafra.gov.on.ca/english/livestock/swine/news/mayjun10a1.htm.

Jacobson, L. (n.d.) Safety measures to prevent barn explosions during pit pumping. University of Minnesota Extension. Retrieved from http://www.agweb.com/article/safety-measures-to-prevent-barn-explosions-….

Rieck-Hinz, A., Shouse, S., & Brenneman, G. (2010) A top ten list: Preparing for fall manure application. Iowa State University, Iowa Manure Management Action Group. Retrieved from http://www.agronext.iastate.edu/immag/info/toptenlist.pdf.

Understanding foam and pump-out safety. (2010) Iowa Pork Producers Association. No longer available online.

 

Reviewers, Contributors and Summarized by:
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu
LaMar Grafft, East Carolina University – grafftl@ecu.edu
Davis E. Hill, Pennsylvania State University (Has since retired)
Dennis J. Murphy, Pennsylvania State University (Has since retired)
Ron Odell, Cactus Feeders, LTD. – ron-odell@cactusfeeders.com
Cheryl Skjolaas, University of Wisconsin – skjolaas@wisc.edu
Aaron M. Yoder, University of Nebraska Medical Center – aaron.yoder@unmc.edu

Confined Spaces: Hazards of Manure Gases


Use the following format to cite this article:

Confined space: Hazards of manure gases. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63141/confined-spaces:-hazards-of-manure-….

The Occupational Safety and Health Administration (OSHA) defines a confined space as a space that:

  • is large enough for a worker to enter and complete a task in,
  • has limited or restricted means of entry or exit, and
  • is not designed for continuous human occupancy.

Confined spaces on a farm or ranch in which manure handling may occur include manure pits, manure transfer pipes and deep gutters, transfer storage areas, and liquid manure spreaders. Farms and ranches continue to expand their operations to include larger manure handling systems. While these new systems are more efficient and reduce manual labor, farmers and ranchers must understand the hazards associated with working in and around confined spaces where manure is stored.  

Gases inside Manure Storage Areas

The breakdown of manure is a biological process, and environmental factors such as temperature, humidity, and air flow can impact the release rate of gases produced during this process. High temperature, lack of air exchange, and humidity can increase the levels of manure gases that are produced and released. The following hazardous gases form naturally in manure storage areas and are difficult to detect because of their properties, impact on a person’s sense of smell, and similarity to other odors on a farm or ranch:

  • Ammonia is found in manure pits or aboveground tanks used for manure storage and has a strong odor that can irritate a person’s eyes or respiratory system.
  • Carbon dioxide is a colorless and odorless gas associated with animal respiration and manure decomposition. Carbon dioxide can replace the oxygen in a confined space. If you breathe in air that contains high levels of carbon dioxide, this gas can replace the oxygen in your bloodstream and may result in headaches, drowsiness, and death (after prolonged exposure). Carbon dioxide is heavier than air, so it can easily accumulate in low-lying areas of confined spaces.
  • Hydrogen sulfide is a colorless gas that smells like rotten eggs at low levels but can overcome a person’s sense of smell at levels of 100 ppm and higher. Exposure to hydrogen sulfide can cause eye and nose irritation, headache, nausea, and death (after prolonged exposure). Hydrogen sulfide is heavier than air, so it can easily accumulate in low-lying areas of confined spaces.
  • Methane is a colorless and odorless gas produced during the decomposition of manure in storage. This gas is flammable and potentially explosive, especially when captured in foam that can form on the surface of stored manure. Methane is lighter than air, so it does not accumulate in low-lying areas of confined spaces.

Handheld gas detection equipment should be used to monitor gas levels prior to entry into and while occupying confined-space manure storage areas. Some equipment used to detect manure gases is configured to measure oxygen level, explosive gases (methane), and toxic gases (hydrogen sulfide).

For each of the hazardous gases mentioned above, OSHA has identified safe exposure levels for humans. Table 1 outlines the acceptable exposure limits in ppm over an eight-hour period. The oxygen level in a given space should be between 19% and 23%.

Table 1: Acceptable Exposure Limits
Hazardous Gas Acceptable Exposure Limits
Ammonia 50 ppm
Carbon dioxide 5,000 ppm
Hydrogen sulfide 10 ppm
Methane 1,000 ppm

One way to reduce levels of hazardous gases is to ventilate the manure storage area using a mechanical ventilation system that forces fresh air into the space, increasing the oxygen level and decreasing the levels of explosive and toxic gases. By using a specially designed positive-pressure mechanical forced-air ventilation system, you can reduce the buildup of dangerous levels of gas. Forcing fresh air through a fan into the storage area reduces the possibility of fire or explosion caused by explosive gas coming into contact with electric fan motors. Fans should be able to move a volume of air equal to one-half the volume of the empty manure storage area every minute. Use the ANSI/ASABE S607 standard, provided by the American National Standard Institute (ANSI) and American Society of Agricultural and Biological Engineers (ASABE), for guidance about ventilation capacity and ventilation time prior to entry and during occupancy. Click HERE for more information from Penn State Extension about the standard. To avoid the failure of a critical ventilation system during a power outage, connect the system to a standby power source that is regularly maintained and tested.

Entering Confined-Space Manure Storage Areas

If possible, avoid entering confined-space manure storage areas. If entry is unavoidable, you should fully understand the risks of entering such a space and have an entry plan that outlines your actions.

Complete the following steps when entering and working in a confined-space manure storage area:

  1. Test the oxygen and explosive and toxic gas levels from outside the manure storage area. 
  2. Prior to entry and during occupancy, use a positive-pressure ventilation system to ventilate the manure-storage area.
  3. Prior to entry, lock out all power sources other than the positive-pressure ventilation system to reduce the risk of stray electricity.
  4. Wear an adjustable body harness with a lifeline attached to a rescue and retrieval system and carry a portable gas monitor.
  5. Assign a second person to remain outside of the manure-storage area in case he or she must implement the rescue and retrieval system or get additional assistance.
  6. Maintain verbal and visual contact with the person outside the manure storage area. The person outside the storage area should not enter the area, even in the event of an emergency.
  7. Retest the air quality continuously during occupancy to monitor gas levels.

Additional Safety Recommendations

  • Remember that youth under the age of 16 are prohibited from working in confined spaces.
  • Post warning signs about the risks of confined spaces and gas hazards on or near all manure storage locations.
  • Instruct family members and employees about the hazards associated with manure storage in confined spaces. Even though most agricultural operations are not covered under OSHA regulations for confined-space entry, confined spaces exist in production agriculture, and it is vital that every person associated with the farm or ranch receive training on the hazards. 
  • Prepare and document an entry plan for confined-space manure storage areas. Inform family members and employees about the plan.
  • Provide annual training for family members and employees about the entry into and emergency procedures associated with confined manure storage spaces.
  • Restrict access to confined spaces to authorized individuals. Remove temporary access ladders, and restrict access to permanent ladders.
  • Be aware that personnel and animals may need to vacate the confinement building during manure storage agitation or pumping.
  • Prohibit smoking in and around manure storage areas.
  • Operate manure agitators below the surface of liquid manure to reduce the release of manure gases.

See the Penn State Extension video below to learn more about safety concerns associated with manure storage in confined spaces.

Use the following format to cite this article:

Confined space: Hazards of manure gases. (2012) Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. Retrieved from http://www.extension.org/pages/63141/confined-spaces:-hazards-of-manure-….

Sources

Confined spaces. (n.d.) United States Department of Labor.  Retrieved from http://www.osha.gov/SLTC/confinedspaces/index.html.

Harshman, W., Yoder, A., Hilton, J., & Murphy, D. (2004) Confined spaces. HOSTA task sheet 3.8. National Safe Tractor and Machinery Operation Program. Retrieved from http://www.extension.org/sites/default/files/NSTMOP%20Task%20Sheets%20Se….

Harshman, W., Yoder, A., Hilton, J., & Murphy, D. (2004) Manure storage. HOSTA task sheet 3.11. National Safe Tractor and Machinery Operation Program. Retrieved from http://www.extension.org/sites/default/files/NSTMOP%20Task%20Sheets%20Se….

Steel, J., Murphy, D., & Manbeck, H. (2011) Confined space manure storage hazards. Penn State Extension. Retrieved from https://extension.psu.edu/confined-space-manure-storage-hazards.

Zhao, L. (2007) How to work safely around manure storage. Ohio State University Extension. No longer available online.

 
Reviewed and Summarized by:
Linda M. Fetzer, Pennsylvania State University – lmf8@psu.edu    
LaMar Grafft, East Carolina University – grafftl@ecu.edu
Davis E. Hill, Pennsylvania State University – deh27@psu.edu
Carol Jones, Oklahoma State University – jcarol@okstate.edu
Dennis J. Murphy, Pennsylvania State University – djm13@psu.edu          

J. Samuel Steel, Pennsylvania State University (Has since retired)