A testing apparatus for respirators and a method of using the same. The testing apparatus comprises a piston assembly including a piston movably disposed in a chamber and a motor assembly including a motor operably connected to the piston. The motor configured to move the piston in an exhalation direction producing a simulated exhalation and in an opposite inhalation direction producing a simulated inhalation. An amount of gas in the chamber increases during the simulated inhalation and decreases during the simulated exhalation. The method of using the test apparatus comprises the steps of causing the simulated inhalation and the simulated exhalation to determine whether the respirator meets at least one predefined requirement.