Gas Laws


Pressure or Volume

Constant  Temperature; T

Original pressure x Original Volume=Final pressure x Final Volume

P1V1=P2V2      Isothermic

Pressure or temperature

Constant Volume: V

Original Pressure x Final Temperature=Final Pressure x Original Temperature

P1T2=P2T1      Isochoric

Volume or Temperature

Constant Pressure P

Original Volume x Final temperature=Final Volume x Original temperature

V1T2=V2T1      Isobaric

Pressure or Volume

Temperature Change Due to Heat of Compression

Original Pressure x Original Volume n=Final pressure x Final Volume n


Final temp/Original temp = (Original Volume/Final Volume)n-1

Final temp/Original temp =(Final pressure/Original Pressure)n-1/n


P=psia(absolute)=psig (gauge pressure)+14.7psi



For nitrogen:

n=1.4 For full adiabatic conditions


n=1.3 For rapid cycling.

n=1.1 For normal cycling

n=1.0 Where gas time to return to normal temp before discharge or recharge

Gas Laws: Pressure or Volume, Pressure or Temperature, Volume or Temperature,
Pressure or Volume, Using Nitrogen

Numberfactory: Fluid Power Formulas