Slot design problem. Find the width of a single slot inlet to provide ventilation air for the building. A 1-inch slot width provides 50 cfm per foot. If the same slot is used for a winter inlet, it will have to be partially closed to accommodate the lower air requirements. Manure pit ventilation Ventilation systems in buildings with slotted floors and manure storage areas must be modified to prevent build-up of toxic gases.
Toxic gases are either lighter than air or heavier than air.
Gases lighter than air rise up into the animal housing area and are rapidly diluted and removed by the normal ventilation system. You don't need to make special provisions to remove these gases from the housing unit. Gases heavier than air tend to build up in the manure pit and then move up into the housing area where their weight keeps them next to the floor. These gases can be diluted and removed from the building by exhausting the winter minimum ventilation rate through the manure pit. This can be accomplished by either locating the winter minimum fans in the manure pit or by constructing an exhaust air duct from the pit to the minimum level fans.