How is atmospheric pressure expressed at sea level?

Atmospheric pressure at sea level is expressed as 14.7 pounds per square inch absolute (psia). This value is widely recognized as the standard atmospheric pressure and is based on measurements taken at sea level under typical conditions. When discussing pressure in a mechanical or engineering context, absolute pressure is often used because it accounts for the total pressure, including the atmospheric pressure acting on a given surface.

This means that if you were at sea level and you measured the pressure exerted by the atmosphere, you would find that it exerts a force equivalent to 14.7 psi. This figure is critical for various calculations in areas such as fluid dynamics, thermodynamics, and for ensuring the proper operation of many types of machinery and equipment. Understanding this standard value is essential for machinists and engineers as they design and work with systems that operate at or near atmospheric pressure.