Valve selection begins with the job the valve must perform: isolation, throttling, non-return, pressure regulation or diversion. A design that works well for one function may be unreliable or unnecessarily expensive for another.
Define the service envelope
Document fluid composition, solids, viscosity, normal and design pressure, full temperature range and expected cycling. Identify hazardous, toxic or fugitive-emission service early because it can change stem sealing, testing and documentation requirements.
Compare body and trim
Body pressure rating alone is not enough. Seats, seals, stem, closure element and fasteners must tolerate the same service. Check corrosion allowance, erosion velocity, galvanic combinations and whether soft seats retain strength at maximum temperature.
Plan actuation and maintenance
Calculate torque or thrust at the worst differential pressure. Decide the fail position, operating speed, position feedback and manual override. Confirm that the installed orientation and surrounding structure leave space to remove the actuator, bonnet or internal cartridge.
