Can some body explane about static pressure,its calculations.
2)can somebody tell me about what are the input and output in hvac.
Waiting for your kind replies.

<I moved this to HVAC where we should get better answers>

Here is something to get you started:

http://www.askthebuilder.com/B12_HVA...Pressure.shtml

Input is probably referring to air before the heating or cooling coils, output is referring to air after the coils.
Input and output are such general terms. I can call energy as input and cooling BTU/hr as output.
I can call people input and their energy production output.