What is stagnation pressure

What is static pressure?

The static pressure is a technical specification for fans, which gives information about how much pressure they can exert at maximum.

This size quantifies the pressureThe maximum that a fan can build up while the flow rate goes to zero (pipe plug). In order for the ventilation system to function properly, this parameter is already in the initial planning of the air distribution system is critical.

In practice this means that if we have, for example, a 10 m long pipe and place the fan at its beginning, the fan must exert more than enough pressure to set the column of air in motion along its entire length.

What factors affect the pressure itself?

The back pressure (back pressure) is influenced by the diameter of the openings of the entire ventilation system, the length of the pipeline itself and most of the various connections and elbows. Each bend or branch corresponds to approx. the back pressure of half a meter of the pipe. In order to minimize the unnecessary increase in back pressure, all joints must be well sealed with adhesive tape or insulating tape. Based on all parameters, we select a suitably powerful fan that is sufficiently effective under our specific conditions.

The following table helps us to roughly calculate the dynamic pressure:

Pipe length (m)Corresponding pressure (Pa)
2 to 3.530 to 50
3.5 to 5.550 to 65
5.5 to 8.565 to 95
8.5 to 1795 až 140
17 až 28140 to 250
28 to 40250 to 380
40 to 60380 to 600
60 to 80600 to 850