While it doesn't happen often, even a few reports of flash fires and explosions occurring in hog barns should serve as a reminder that safety is critical whenever liquid manure is being agitated and pumped from a holding pit. And as spring pumping begins there are many factors to keep in mind.
The slow decomposition of liquid manure in pits creates several gases including methane and hydrogen sulfide, both of which are flammable. The rate of gas release can be drastically increased when the manure is stirred during pumping. This increase is especially true for hydrogen sulfide, which can have a lethal paralyzing effect in addition to being flammable, notes Shawn Shouse, an Iowa State University (ISU) Extension area agricultural engineer.
The Pork Checkoff's Safe Manure Removal Policies fact sheet offers safety protocols and proper ventilation practices that can minimize the risk of flash fires and explosions when agitating and pumping manure. If you experience any foaming in a manure pit, be sure to contact your local Extension Service as well for additional information and management tips.
According to the University of Minnesota Extension in the past few years, foaming in manure pits has become a serious problem. Extreme caution is needed when agitating, pumping or spraying to reduce foam. Following these tips, offered by the Pork Checkoff and ISU, provides sound manure-handling safety tactics.
Although, some foaming may be a typical sight in manure storage facilities, the type of foam currently causing problems for farmers is a persistent, fast-growing substance that has a mucus-like texture. Here are a few tips to consider during this pumping season:
* Review your emergency action plan with all workers, and have emergency contact numbers available at the site. The Pork Checkoff's Pork Production System, offers tips on developing and implementing an emergency action plan. It also includes sections on hazardous gases and fires.
* Prior to agitation or pumping, turn off electrical power to any non-ventilation equipment, and extinguish any pilot lights or other ignition sources in the building.
* Fully open all ventilation curtains or ventilation pivot-doors, but leave walk-in doors locked to prevent human entry.
* Run ventilation fans at maximum speed.
* Ensure that all people are out of the building and clearly tag all doors, noting that the building is unsafe for entry during agitation and pumping.
* Agitate the manure keeping the jet of pressurized manure below the liquid surface. Don’t let the jet of manure strike walls or columns in the pit.
* Stop agitation when the manure level does not allow agitation below the liquid surface.
* Continue maximum ventilation for thirty minutes after pumping has ended before re-entering the building.
* Never enter a building or manure storage structure when liquid manure is being agitated or pumped.
If a fire does break out at a facility, it's important for individuals to remember the acronym RACE.
- Rescue those in immediate danger, only if one can do so safely.
- Announce to others the immediate need to evacuate the facility.
- Contain the fire by closing doors and windows.
- Evacuate immediately and go straight to a designated meeting spot upon leaving the building.
The West Virginia Extension Service notes in its publication Livestock Safety – Manure Handling and Storage, that many hazards related to manure storage and pumping of pits can be avoided through careful planning during the facility's design and construction.