Brian Andries

The variation in temperature changes starting late fall and progressing into the winter months requires strategies dealing with ventilating pig barns in our cold climate regions. Ventilation deals with brining in fresh air to meet heating and cooling requirements. Cooling during spring and summer months does not require the expenditure of extra energy to heat an entire facility, as in the winter months. There are two main challenges when considering optimum control to ensure proper conditions for both animals and people working in confinement operations. The most important deals with maintaining a healthy environment and the second in conserving energy and keeping costs down to operate the facility. To meet these challenges we need to ensure that we are operating in energy efficient building and effectively controlling a somewhat complex ventilation system to minimize energy loss.

Cold climate ventilation dictates that animals are required to be housed in confinement. Animals housed in close quarters during the winter months produce heat, moisture, and gas. Heat is a result of both the metabolic process resulting in growth of the animal as well as the production of heat from equipment and lights. Moisture results from respiration of animals as well as water spillage from drinkers and evaporation from manure. Gases are emitted from manure storage and dirty pens while dust is a result of dander, dried fecal material and feed. To ensure an adequate environment for both animals and people working in barns, all of these contaminants have to be diluted and removed from this confined space. Ventilation is used to balance temperature, humidity and gas and dust concentration.

When consideration is given to conserving energy in relation to achieving an optimum environment during the winter months we should first consider the concept of heat transfer and loss through the walls ceiling and floor of the facility. We need to ensure that the facility is properly maintained to rectify any chance of heat loss through exterior doors or windows. Seal exterior doors with weather stripping and ensure cracks in walls are also sealed. As well, the insulation values of our building materials need to be monitored to ensure that they have not been compromised by rodent infestation. At least 30% of all heat loss in a facility is through the building envelope.

Part of maintaining a good environment in the barn is to ensure that ventilation controllers are set to ensure proper ventilation rates required to remove moisture, gas and other contaminants from the air space inside the barn. Ventilation rate is also a component of the setpoint temperature and insulation factor of the building itself. A balance needs to be found between the removal of contaminants and moisture, while maintaining a room temperature close to the set point ensuring minimal loss of heat expelled to the outside. Ventilation accounts for close to 70% of the heat loss from a facility over the colder months of the year.

Ensuring proper management and maintenance procedures as well as good husbandry practices to maximize optimum environmental conditions in the barn will assist in decreasing ventilation rates and in doing so conserve energy losses. Repair of all leaking water lines and nipple drinkers will ensure reduced moisture levels in the facility. Reducing humidity levels from the evaporation of urine and fecal material can be accomplished by ensuring proper dunging patterns are maintained by properly monitoring inlets and recirculation ducts as well as regular cleaning of pens. Clean pens will also reduce the level of ammonia in the room. Ammonia is produced by the decomposition of nitrogenous compounds in feces and urine on solid surfaces. At the time of manure removal from the room hydrogen sulfide is released and only at this time should the ventilation rate be increased to reduce hydrogen sulfide levels. Dust levels can be reduced by in a facility by minimizing feed handling and disturbance and by avoiding disturbing the pigs. Proper safety equipment should also be available to staff including dust masks, eye and hearing protection.

Regular maintenance on ventilation equipment is important to ensure proper ventilation rates are maintained during the winter months. All fans need to be cleaned and function properly on a daily basis. As to cold season arrives proper fan covers should be installed on all stages of fans not utilized during the winter months. These covers should be maintained so that they maintain their insulation value and do not allow the back drafting of cold air into the facility. All fan hoods should be mounted to ensure wind protection for exhaust fans so that wind pressure against the fan will not cut off the fan air delivery. Air inlet adjustment is also very important to the ventilation system during the heating season. The opening size should comply with the minimum ventilation rate to ensure more cold air is not entering the room requiring excess heating. Inlet opening controls and actuators should be monitored to ensure proper functioning at all times. Heaters should also be checked and serviced regularly. Corrosion of relay contact points is very common and the pilot of gas heaters should e kept clean.

After a ventilation system is designed it is very important to ensure the proper management of the system. It is recommended to draw up procedures for all seasons to ensure that the ventilation system can be properly monitored on the following basis:
– setpoint temperatures
– minimum ventilation rates during heating seasons
– fan scheduling
– air inlet adjustment
– moisture control
– odour and dust control