RE: What is static pressure and why is it important?
Static pressure in simple terms is a measure of resistance. Specifically the amount of resistance to the current volume of air flowing through the ducts.
It is typically displayed in inches of water column.
Consider it the blood pressure of a forced air system.
It is useful to tell you the condition of any component associated with air movement in a system, as all of the components add resistance, therefore adding static pressure.
I like to use it as a benchmark tool. To do this the static pressure test points should be set during system commissioning and the values recorded on each fan speed and mode with clean filter(s) and components. The test probe used should also be recorded so that the test can be duplicated each time a maintenance is performed.
I’d the values deviate from recorded values during maintenance the technician will know instantly if something in the system has changed, and with interpretation, where to start looking for issues.