Once any element of the system changes duct size hood length riser size etc.
Box fan cfm static pressure.
Corsair for example sells quiet edition high static pressure fans.
They apply to a fixed air system.
Static pressure is rated in inches water gauge inwg or the metric equivalent millimeters water gauge mmwg.
A matching of the system occurs when the airflow delivered by the fan at a given static pressure equals the static pressure resistance of the.
If the estimated static pressure resistance is greater than the available static pressure of the fan the airflow cfm delivered by the fan decreases until the system pressures match.
A larger static pressure forces the fan to consume more power to expel the same amount of air.
The fan generates air pressure of 7 63 mmh2o and a healthy airflow of 110 cfm so it provides both high static pressure and high airflow.
This 120mm static pressure fan comes with noctua s sso2 bearing that is known for its reliability low noise and longevity.
The system curve changes.
Static pressure sp static pressure is the resistance to airflow friction caused by the air moving through a pipe duct hose filter hood slots air control dampers or louvers.
An exhaust fan s static pressure also known as its pressure drop describes the resistance the fan must overcome.
1 inwg 25 4 x mmwg.
Set on low these fans runs at 1 450 rpm and push 37 85 cfm while producing just 23 dba.
If you know one cfm s p point of a system you could use fan law 2 to determine the static pressure for other flow rates.
Technicians typically measure static pressure in inches of water gauge.
Whether exhausting air or bringing fresh air into a structure the calculation produced should help to figure out the size of fan s required to accomplish the air exchanges needed.