Emerson Process Management’s 4-inch Fisher EZHSO Series spring-to-open, pressure-reducing regulator incorporates a spring cartridge that offers a fail-to-open alternative, ensuring gas delivery in the event of diaphragm failure or lack of supply pressure to the pilot. The failure action is the opposite of the EZH Series spring-to-close, pressure-reducing regulators. Types EZHSO and EZHSO-OSX (slam-shut) regulators are available in 1-, 2-, 3-, and 4-inch sizes. These offerings provide the same features as Emerson’s Fisher Type EZH regulators such as no-bleed design, top-entry maintenance, bubble-tight shutoff, and inlet/outlet rating of 1500 PSIG (103 bar). The Whisper Trim Cage option is available for 2-, 3-, and 4-inch sizes for a broader application range. Noise reduction of 10–20 dB(A) can be achieved, depending on the application. As a “source treatment,” the Whisper Trim technology utilizes multiple orifices of special size, shape and spacing, which reduces noise-producing interactions.??