Ideal Static Pressure Operating Range
If you’re in the agriculture market and are producing indoors with a ventilation system, chances are you are aware of static pressure or the resistance to airflow. We use inches of water column to measure static pressure. Whether through tunnel or cross ventilated applications, the air coming through your intake will create negative pressure inside your barn. An easy way to picture static pressure is to consider a hose when the water is unimpeded (or 0” static pressure). If you put your thumb partially over the end of the hose, it increases the pressure, and the water will come out faster. J&D Manufacturing is a company of ventilation experts. We help sellers and producers design well equipped and optimal performing ventilation systems. Different birds have different needs. We believe the ideal static pressure operating range to be as follows:
Layers– between 0.10” and 0.25”
Broilers – between 0.05” and 0.15”
In tunnel ventilated poultry barns, high static pressure is usually a sign that your fans are having to work harder to pull air through cool cells, light traps, inlets, and tunnel openings. The higher the static pressure, the harder your fans will have to work. If you go from a .05” SP to a .20” SP, you will see a decreased amount of your total air moving capacity from your fans. Your cubic feet per minute (CFM) will decrease by approximately 20-30%. At the same time, the increase in static pressure will also make your power usage increase by 8-16% (Czarick & Fairchild, Measuring Static Pressure in Tunnel-Ventilated Houses, 2010).
The more accessories and equipment you have in your facility, the more resistance the air will meet when traveling through the barn. If for example, a layer barn is operating a cool cell system, and they have implemented a light deprivation system, the air must go through a lot of obstacles which will increase static pressure. A producer could see static pressure around 0.25 if cool cells, light traps, cages, etc. are in the barn. However, running at higher static pressures will result in lowered fan efficiency, excessive strain on the motor, belt slippage (on belt driven fans), possible damage to other ventilation and building components, and uncomfortable conditions for animals and workers.
It’s extremely important to have sufficient air velocity in your house. High static pressure decreases a fan’s ability to provide air volume. There are high performance fans on the market that can perform under higher static pressure, however, we recommend against operating at a high static pressure regardless of if you have a fan that can handle it. Operating below 0.20-0.25” is crucial and vital to animal welfare, not to mention the less wear and tear on your barn equipment. Remember, less efficient cooling from cool cells and decreased air movement are both signs of high static pressure.
But don’t just take our word for it. The University of Georgia Department of Poultry Science (Czarick & Fairchild, 2013) says, “What is the optimal static pressure? The short answer to this important question is between 0.05” and 0.12”.” The optimal static pressure for operating ventilation in a poultry facility depends on a variety of factors including the size and layout of the facility, the type and age of the birds, and the ambient temperature and humidity. In general, a static pressure of between 0.07 in coldest weather and up to 0.15 inches of water column (in WC) in tunnel mode.
As more research is conducted, and technology advances, we’re seeing more barn applications requiring light traps for fans and inlets, while also using evaporative cool cell systems to cool the incoming air. All these things can be properly calculated to help keep your static pressure in your barn at a sufficient level, while also maintaining proper air velocity for cooling your birds during hot summer months. At J&D Manufacturing, that’s where we, the ventilation experts, can help you create the proper working environment for your specific application. We use high performing, energy-efficient, and innovative products to help achieve the best ventilation design possible. At the end of the day, a producer wants equipment that is high-performing and energy-efficient that will last. Calculating ventilation is complicated because there are so many variables. Let J&D Manufacturing help. We will provide a design that keeps your operation running within the ideal conditions.
1. All of the fans listed in this comparison are top performing fans at BESS Lab.
2. The blue and orange J&D Magnum tests were done in an accredited AMCA Air Test Chamber. We added those tests so you could see what this fan performs at at more ideal static pressures. The fan outperformed BESS’s chamber capacity at lower, more ideal static pressures.
3. All of J&D’s tests were done with damper doors.
4. Both DACS’ fans tested above BESS’s chamber capacity, that is why the data starts at 0.10 SP and 0.20 SP.
5. The DACS MagFan 5 test was done with their roller door.
6. AP-Cumberland fan test was done with a roller seal door.
7. The data in this chart goes out to 0.30 SP, however, J&D does not recommend operating above 0.25 SP. See our blog post on why – and what other credible sources also don’t recommend operating at high static pressures.
8. There are many variables to consider when purchasing a fan or ventilation system. CFM, CFM/watt, maintenance, price (and total cost of ownership) should all be considered.