Scientists, meteorologists and others who work with pressure readings use a number of different units. One such unit is the atmosphere (atm). One atmosphere is the standard sea level atmospheric pressure on Earth. Another unit of pressure is pounds per square inch absolute (psia) which, as the name suggests, describes the pounds of force per square inch produced by air or any other gas. You can convert a pressure reading from psia to atm using a single conversion factor.
Things You'll Need
Enter the numerical value of your pressure reading, in units of psia, into the calculator. For example, if you have a cylinder of compressed gas that is pressurized to 3,000 psia, you would enter 3000.
Divide the value you just entered by 14.696. This is the conversion factor between psia and atm.
Report the result of your calculation as the pressure reading in units of atm. In the example you calculate 3000/14.696 = 204.14 atm.
Tips & Warnings
- A related unit is pounds per square inch gauge (psig) which is equal to psia minus the local atmospheric pressure. Many gauges are calibrated in psig, meaning they will read zero at a pressure of one atmosphere.
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