Every farm manager knows the importance of proper ventilation to ensure that horses are happy and healthy. But how can you tell if your ventilation is sufficient—and if it isn’t, what can you do to improve your horses’ environment?
The importance of proper ventilation cannot be overstated. Stuffy conditions can lead to coughs and respiratory diseases. Proper ventilation can eliminate these problems.
Ventilation entails more than letting fresh air into your barn. It is “the exchange of internal, moisture-laden air with clean air from outside the barn,” says Judy Cotter, VP of Country Classic Cupolas in Ontario, Canada. “With horses, you have the added problem of ammonia buildup, especially in the winter.”
Cotter notes that many people think ventilation happens at ground level, but in reality, because warm air rises, the stagnant, ammonia- and moisture-laden air rises. Therefore, when considering proper ventilation, include venting up through the roof, Cotter advises.
What are the signs that your building’s ventilation is not sufficient? “You will notice the poor air quality,” says Cotter. “In addition, if your roof is not insulated, you will see condensation and staining on the rafters. On a cold day, check the underside of the rafters. If you see frost, then you need to improve the barn’s ventilation.”
Natural vs. Mechanical
You can achieve proper ventilation through natural means (windows, doors, etc.), mechanical measures (fans, air ducts, etc.) or a mixture of the two. Achieving good air exchange by simply opening a few doors and windows is difficult, particularly with a barn where barriers, such as stall walls, are numerous.
One solution requiring no mechanical intervention, notes Barry Goldsher, president of FarmTek in Dyersville, Iowa, “is the use of curtain sidewalls. These are heavy-duty, industrial fabric curtains that can be installed on any type of building. Once installed, they create a significant amount of air movement. It is easy to retrofit an older building, either a barn or arena, and you can easily control the amount of air circulation by adjusting the curtain.” Keeping in mind that warm air can get trapped by the roof, you’ll still need ridge vents and cupolas in conjunction with the sidewall curtains.
“Depending on the goals of the barn or arena,” says Adam Hatton, agricultural market specialist at Big Ass Fans, “there are several variables to consider that can affect the air movement. Beyond the more obvious, such as the dimensions and height of the space, features such as posts, bleachers and solid stall fronts can create obstructions that may alter the air flow.” This is where mechanical methods may be necessary to get air moving.
Certainly the most common way to increase air flow is through the use of fans. Janet Dahl, president of Northwest Envirofan in Oshkosh, Wisc., explains that what type of fan, and where you place them, will make all the difference. “The large direct drive wall/exhaust fans used in agricultural buildings… move air horizontally across the buildings,��� she says.
However, for horse barns, because of the obstructions, consider using “ceiling fans that re-circulate, mix and homogenize the air, moving large volumes of air vertically over the horses and throughout the entire building,” Dahl says. “The result is a healthier, cooler and more consistent environment all year long.” To this end, she advises “putting ceiling fans on approximate 40-foot centers in large open spaces such as an arena. Most horse barns install one fan over each stall, and then space fans evenly throughout the aisles or walkways.”
Another option, says Goldsher, is to use air inlets (such as powered aluminum shutters) at one end of the barn, and exhaust fans on the other. “When the fan is on, the shutter is open. The shutter lets air in; the exhaust fan takes air out. While this will not distribute fresh air into the stalls, it’s easy to cut holes in partitions and have ducts gently distribute air into each stall. This is a low-cost option with tremendous results.”
It is very important to select fans meant for agricultural purposes. Says Dahl, “Typically, residential or commercial fans are not sealed.” Dahl advises purchasing fans that are rated for agricultural use by Underwriters Laboratories (UL). “To achieve this rating,” she notes, “a fan must pass a series of tests to prove that it will safely hold up in an agricultural environment that usually includes a lot of dust, moisture, condensation and possibly pressure washing.”
Summer vs. Winter
Remember to make adjustments to accommodate seasonal differences in temperature and air flow. Suggests Dahl, “You should adjust the speed of the fan according to the season and desired airflow. Most often, fans are run on medium high or high in the summer for more cooling effect, and medium to medium low in the winter to keep the warm air down off the ceiling and to improve the overall air quality. In cold weather, at lower speeds, the proper fan will mix the air, eliminating the layer of warm air near the cold roof. This greatly reduces or prevents the condensation that forms and ‘hangs’ from the roof, dripping on animals, bedding and surfaces below.”
One winter problem that Cotter encountered was a barn in which the cupola and the ventilation shaft were designed incorrectly. “The shaft created a true chimney effect, with unlimited air flow, and the cupola was a metal structure, with openings at the top of the tower and a roof on top. There was no protection from the weather, and therefore nothing was stopping rain, snow etc. from dropping down the shaft into the stable area below. This was one problem,” she says.
“The other problem, which created frozen water pipes, was caused by the damper in the ventilation shaft. It did not fit tightly and did not control the amount of air escaping out through the cupolas,” she adds. To avoid similar problems, Cotter advises to look for cupolas that are designed so that the ventilation area is protected from the weather.
Regardless of your setup, using automated controls will greatly aid your efforts to properly ventilate your facility. Explains Rick Leone, product specialist at FarmTek, “A two-stage thermostat with a 5- to 6-degree temperature differential between stages is a great product to have in your barn. The first stage of the thermostat activates the first load [in this case, opening a motorized louver or shutter] based upon a predetermined temperature that you set, and if that works to lower the inside temperature, the second stage remains inactive. But if the temperature continues to rise [5 to 6 degrees above the first stage temperature set], the second stage of the thermostat will activate the second load [powering on the exhaust fans].
“Once your system is fully activated, the system draws in fresh air through the louvers/shutters, and the fans exhaust the hotter, staler air, creating a tunnel-like ventilation flow of fresh clean air. The speed of this flow can be controlled by adding variable-speed controllers to increase or decrease the speed of your exhaust fans [example : summer vs. winter ventilation]. The advantage is that you don’t have to manually start and stop ventilation, which requires you to be there and keep checking temperatures; you can be outside working horses and your ventilation system will operate automatically.”
Finally, the higher-end controllers not only help control your fans, shutters, exhaust fans, etc., but can also notify you if there is a problem. That way, if you’re off the property and there is a power outage, poor air quality, high air temperatures, etc., you will be notified immediately.
Maintaining your equipment at peak performance is the simplest way to cut costs, notes Goldsher. Barns are dusty, and that dust can clog fans, shutters, exhaust ducts, etc. While equipment may lose efficiency over time simply by aging (or say, bent blades for a fan), keeping the equipment clean helps extend its functional life and lower energy costs.
Hatton suggests using a variable speed control on fans, which “allows the user to exercise only the power that is needed to optimize airflow and minimize electricity consumption.”
Many facilities turn fans off in the winter. But in colder climates, there can be a 10- to 30-degree difference between the floor and the roof, particularly with larger barns with many horses. Why not use the heat that is generated, instead of letting it dissipate at ceiling level? By running fans at low speed, you can slowly move it back to floor level and cut energy costs at the same time. [See Stable Management, Oct. 2008 for further information.]
Barn ventilation is an important issue that is often given cursory attention. But proper ventilation will make your horses and clients happier and healthier. And that helps you breathe more easily, too.