To calculate the entire system duct length, multiply the total elbow equivalents by the length of straight duct. Calculate the static pressure for 100 feet of duct by multiplying it by the proportion of 100 feet you have. The static pressure created by the ductwork will be this.
To figure out what the operating total external static pressure should be. Determine the pressures at the points where air enters and exits packaged equipment. To calculate total external static pressure, add the two values together. You may still check for obstruction by measuring the pressure drop of the coil and filter.
The increase in air resistance is proportional to the increase in air flow. Pressure loss is the term for this phenomena. A fan's static pressure creates air velocity in the ventilation system with some resistance. The fan's air flow decreases as the ventilation resistance in the system increases.
The total external static pressure is the sum of the pressures measured at the points where air enters the equipment (suction pressure) and exits the equipment (discharge pressure). The total of the two pressure forces that the fan has to push and pull against is calculated by adding these two pressures together.
The pressure you have when the fluid isn't moving or when you're moving with the fluid is called static pressure. The pressure a fluid exerts as it comes to a complete stop is known as total (or ram) pressure. When you confront the wind and the air collides with your body, whole pressure acts on you.