The manure pumping season is almost at hand for the majority of Midwest production sites. Yesterday while driving to a client’s site I met a semi-tanker manure transport vehicle. Last week I had a conversation with a client who was having storage issues and transferring manure between facilities to ‘get by’ until some application sites opened up.
It’s never too early to think about safety when planning for manure pumping. In addition to the standard warning regarding never enter a facility during agitation and pumping, we also need to think about the risk of explosions and fires. With the advent of aggressive pit foaming we’re now getting reports each year of barns exploding when agitation is begun.
With warm weather, we’ve now got pits are more biologically active. While researchers still can’t pin down the cause, at some sites this activity translates into ‘foaming’. Basically, when pits foam you’ve got hyperactive biological activity at the same time as you’ve got conditions on the surface that make the ‘bubbles’ sticky and less likely to burst. These foam bubbles can contain upwards of 70% methane in the captured gas.
It’s this methane that is the problem. Methane is lighter than air so when agitation breaks the bubbles/foam, the released methane rises rapidly. In the absence of ventilation it accumulates at the ceiling. At concentrations of 5-15% it is explosive. The common ignition source is the furnaces in our production facilities – either pilot lights or spark igniters.
The best advice to reduce the risk of an explosion includes the following:
1) Don’t shut down the ventilation system when the barn is empty – keep removing the released gases as they are generated.
2) Prior to any type of agitation increase the ventilation rate to stage 2 or 3 or even higher – more air is better. If there are pigs in the facility – the rule is fresh air to all pigs at all times!
3) Turn off the gas to the facility. In the case of spark ignition furnaces, turn off the electricity to the furnace so it can’t spark and ignite any released gases.