# Compressed Gas or Air - Storage Volume

## Calculate the storage volume of compressed gas or air

The storage volume for a compressed gas can be calculated by using Boyle's Law

p_{a}V_{a}= p_{c}V_{c}= constant (1)

where

p_{a}= atmospheric pressure (14.7 psia,101.325 kPa)

V_{a}= volume of the gas atatmosphericpressure (cubic feet,m)^{3}

p_{c}= pressure after compression (psi,kPa)

V_{c}= volume of gas after compression (cubic feet, m^{3})

### Volume of free gas in a Storage Volume

The amount of free gas at atmospheric pressure in a given volume - like a cylinder storage - can be calculated my modifying *(1)*

V_{a}= p_{c}V_{c}/ p_{a}(2)

Gas can be stored in high-pressure cylinders ranging to more than *6000 psig (410 bar)*. Normal-pressure cylinders are in the range *2000 and 2500 psig (140 and 175 bar) *and low-pressure cylinders are in the range *480 psig (34 bar).*

### Example - Volume of Air in a Cylinder Storage

Standard atmospheric volume of air compressed in a *1.76 cubic feet *K-type* *cylinder at *2200 psig (2214.7 psia) *can be calculated

V_{a}= (2214.7 psia) (1.76 cu ft) / (14.7 psia)

= 265 (cu ft)

In other words - if air in a *1.76 cubic feet* container is compressed to *2200 psig * - the same air at atmospheric pressure will occupy *265 cubic feet*.