Normal state and Standard state

When dealing with gas flow rates, normal condition, standard condition, and actual condition must be handled carefully. 

Definition of Normal state and Standard state

Normal state is 0℃, 1 atm, and Nm3/hr units are usually used.

Standard state is 15℃ (60℉), 1 atm.

Example of Normal state and Standard state

If the flow rate is 5,000 Nm3/hr at 1 bar and 0 ℃, What is the flow rate at 7 bar and 20 ℃?

Normal condition
Pn = 1 bar (=absolute pressure)
Tn = 0 ℃
Vn = 5000 Nm3/hr

Actual condition
Pa = 7 bar
Ta = 20 ℃
Va = ?

Pn*Vn/Tn = Pa*Va/Ta
Va = Pn/Pa*Ta/Tn*Vn
Va = 1/3*(273+50)/(273+0)*5000 = 1,972 m3/hr