Static Pressure Calculator
What is Static Pressure?
Static pressure is the resistance to airflow within a dust collection or HVAC system. It represents the outward push of air against the walls of the ductwork and the pressure required to overcome the friction of ducts, hoods, and filter media. In simpler terms, if CFM is the volume of air moving, static pressure is the “work” or “muscle” the fan must exert to pull that air through the restrictions of the system.
How to Use This Calculator
⦿ Enter the Current Airflow (CFM): Input the existing volume of air your system moves.
⦿ Enter the Target Airflow (CFM): Input the new or desired volume of air you want the system to move.
⦿ Enter the Current Static Pressure (in. w.g.): Input the known static pressure drop at your current airflow.
⦿ Calculate: Click the calculate button to determine the new static pressure required to achieve the target airflow.
Understanding the Formula
New Static Pressure = Current Static Pressure × (Target CFM ÷ Current CFM)²
Based on the second Fan Law, static pressure varies as the square of the change in airflow. This means if you want to increase the airflow (CFM) in an existing system, the resistance (static pressure) will increase exponentially, not linearly. This formula is vital when planning to speed up a fan or increase system capacity, as it accurately predicts the new resistance the fan must overcome to hit your new target.
Importance of Static Pressure in Baghouse Design
Understanding and accurately calculating static pressure is critical for selecting the correct exhaust fan and motor. It ensures the system has enough suction to pull dust from the source through the ductwork and the filter bags. Underestimating static pressure leads to weak airflow, dust settling in pipes, and inadequate collection, while overestimating can result in oversized equipment, wasted energy, and excessive wear on the filters.
Nota: This calculation is a helpful reference point, but factors like duct layout changes, temperature, elevation, and dust loading also affect performance. Always consult an expert like Baghouse.com for accurate sizing.