With winter upon us, there are many things to keep in mind when it comes to ventilation in the barn. Here are eight things to remember as you brave the cold this season.
1. Set Points
Set points are what you tell the barn to maintain temperature at. Typically, barns will be 1 to 2 degrees cooler most of the time during winter months. If you want the actual temperature to be 70 degrees for example, you may need to run your set point at 71 degrees to average 70 degrees. Every barn is slightly different.
Soffets are important to get air into your attic and then into the room. Soffets commonly get plugged with dust or dirt from harvest and can be further blocked with frost or snow. Take a long-handled broom periodically on a barn walk around to clean soffets off to allow maximum air flow into your attic. Snow doors should be closed on north- or west-facing outer walls to prevent snow drifting in your attic.
3. Heater Off-sets
Heater off-sets – most commonly, you will want your heater to come on at 1.5 to 2 degrees below your set point. The offset is important to check to make sure you are not warming up your barn over the set point. If you are, your fans begin to ramp up to cool the barn down again and you have wasted that heat. It’s simple to check. Watch your controller’s temperature reading when the heater is on. When the heater shuts off, the room will continue to warm. Watch to find the temperature at which it peaks at and then begins to fall. Ideally, the room warms up to just the desired set point and then begins to cool again. Then, no wasted heat is blown out by ramping up fans. If the temperature overruns your set point and fans begin to ramp up, you need to widen your off-set.
4. Back-up Heaters and Alarms
Check your back-up thermostats and alarms to come on at 55 degrees to 60 degrees. To make them work, turn them up and see your heater kick on.
5. Air Speed from Inlets
When you are in minimum ventilation, you still want good air speed for mixing of air from the inlets. Purchase an anemometer for around $50 to give you your exact speed of air from the inlets. Target to get 400 feet per minute. A good rule of thumb if you don’t have an anemometer is to stand 10-12 feet away from the inlet – you should feel air on your forehead if it is working around 400 feet per minute.
Rheostats are notoriously bad in pig barns as they only typically work for about six months. Most farms have a great permanent rheostat – the water lines. Ground water should be around 57 degrees Fahrenheit year-round. If your water lines are dripping in the middle of the room, you are running too high humidity and likely need to increase air exchange (increase minimum ventilation percentage).
7. Pig Comfort
Pigs have three “rooms” in their house: a kitchen, a bedroom and a bathroom. After pigs have established their house, you should only find around 25% of their space serving as the bathroom. If the dunging pattern is greater than this, you may need to adjust your ventilation.
8. Temp Probes
Check each individual temperature probe reading at the controller. They should only vary by one degree. If you find a variance greater than that, you likely need to change one of the probes out.
Farm Journal’s Pork | Dr. Cameron Schmitt, DVM, Pipestone Veterinary Services – PIPESTONE | February 08,
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